hw/i386/intel_iommu.c - qemu - Git at Google

 /*
  * QEMU emulation of an Intel IOMMU (VT-d)
  *   (DMA Remapping device)
  *
  * Copyright (C) 2013 Knut Omang, Oracle <knut.omang@oracle.com>
  * Copyright (C) 2014 Le Tan, <tamlokveer@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.

  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.

  * You should have received a copy of the GNU General Public License along
  * with this program; if not, see <http://www.gnu.org/licenses/>.
  */

 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qapi/error.h"
 #include "hw/sysbus.h"
 #include "intel_iommu_internal.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/qdev-properties.h"
 #include "hw/i386/pc.h"
 #include "hw/i386/apic-msidef.h"
 #include "hw/i386/x86-iommu.h"
 #include "hw/pci-host/q35.h"
 #include "sysemu/kvm.h"
 #include "sysemu/dma.h"
 #include "sysemu/sysemu.h"
 #include "hw/i386/apic_internal.h"
 #include "kvm/kvm_i386.h"
 #include "migration/vmstate.h"
 #include "trace.h"

 /* context entry operations */
 #define VTD_CE_GET_RID2PASID(ce) \
     ((ce)->val[1] & VTD_SM_CONTEXT_ENTRY_RID2PASID_MASK)
 #define VTD_CE_GET_PASID_DIR_TABLE(ce) \
     ((ce)->val[0] & VTD_PASID_DIR_BASE_ADDR_MASK)

 /* pe operations */
 #define VTD_PE_GET_TYPE(pe) ((pe)->val[0] & VTD_SM_PASID_ENTRY_PGTT)
 #define VTD_PE_GET_LEVEL(pe) (2 + (((pe)->val[0] >> 2) & VTD_SM_PASID_ENTRY_AW))

 /*
  * PCI bus number (or SID) is not reliable since the device is usaully
  * initialized before guest can configure the PCI bridge
  * (SECONDARY_BUS_NUMBER).
  */
 struct vtd_as_key {
     PCIBus *bus;
     uint8_t devfn;
     uint32_t pasid;
 };

 /* bus/devfn is PCI device's real BDF not the aliased one */
 struct vtd_hiod_key {
     PCIBus *bus;
     uint8_t devfn;
 };

 struct vtd_iotlb_key {
     uint64_t gfn;
     uint32_t pasid;
     uint16_t sid;
     uint8_t level;
 };

 static void vtd_address_space_refresh_all(IntelIOMMUState *s);
 static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);

 static void vtd_panic_require_caching_mode(void)
 {
     error_report("We need to set caching-mode=on for intel-iommu to enable "
                  "device assignment with IOMMU protection.");
     exit(1);
 }

 static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
                             uint64_t wmask, uint64_t w1cmask)
 {
     stq_le_p(&s->csr[addr], val);
     stq_le_p(&s->wmask[addr], wmask);
     stq_le_p(&s->w1cmask[addr], w1cmask);
 }

 static void vtd_define_quad_wo(IntelIOMMUState *s, hwaddr addr, uint64_t mask)
 {
     stq_le_p(&s->womask[addr], mask);
 }

 static void vtd_define_long(IntelIOMMUState *s, hwaddr addr, uint32_t val,
                             uint32_t wmask, uint32_t w1cmask)
 {
     stl_le_p(&s->csr[addr], val);
     stl_le_p(&s->wmask[addr], wmask);
     stl_le_p(&s->w1cmask[addr], w1cmask);
 }

 static void vtd_define_long_wo(IntelIOMMUState *s, hwaddr addr, uint32_t mask)
 {
     stl_le_p(&s->womask[addr], mask);
 }

 /* "External" get/set operations */
 static void vtd_set_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val)
 {
     uint64_t oldval = ldq_le_p(&s->csr[addr]);
     uint64_t wmask = ldq_le_p(&s->wmask[addr]);
     uint64_t w1cmask = ldq_le_p(&s->w1cmask[addr]);
     stq_le_p(&s->csr[addr],
              ((oldval & ~wmask) | (val & wmask)) & ~(w1cmask & val));
 }

 static void vtd_set_long(IntelIOMMUState *s, hwaddr addr, uint32_t val)
 {
     uint32_t oldval = ldl_le_p(&s->csr[addr]);
     uint32_t wmask = ldl_le_p(&s->wmask[addr]);
     uint32_t w1cmask = ldl_le_p(&s->w1cmask[addr]);
     stl_le_p(&s->csr[addr],
              ((oldval & ~wmask) | (val & wmask)) & ~(w1cmask & val));
 }

 static uint64_t vtd_get_quad(IntelIOMMUState *s, hwaddr addr)
 {
     uint64_t val = ldq_le_p(&s->csr[addr]);
     uint64_t womask = ldq_le_p(&s->womask[addr]);
     return val & ~womask;
 }

 static uint32_t vtd_get_long(IntelIOMMUState *s, hwaddr addr)
 {
     uint32_t val = ldl_le_p(&s->csr[addr]);
     uint32_t womask = ldl_le_p(&s->womask[addr]);
     return val & ~womask;
 }

 /* "Internal" get/set operations */
 static uint64_t vtd_get_quad_raw(IntelIOMMUState *s, hwaddr addr)
 {
     return ldq_le_p(&s->csr[addr]);
 }

 static uint32_t vtd_get_long_raw(IntelIOMMUState *s, hwaddr addr)
 {
     return ldl_le_p(&s->csr[addr]);
 }

 static void vtd_set_quad_raw(IntelIOMMUState *s, hwaddr addr, uint64_t val)
 {
     stq_le_p(&s->csr[addr], val);
 }

 static uint32_t vtd_set_clear_mask_long(IntelIOMMUState *s, hwaddr addr,
                                         uint32_t clear, uint32_t mask)
 {
     uint32_t new_val = (ldl_le_p(&s->csr[addr]) & ~clear) | mask;
     stl_le_p(&s->csr[addr], new_val);
     return new_val;
 }

 static uint64_t vtd_set_clear_mask_quad(IntelIOMMUState *s, hwaddr addr,
                                         uint64_t clear, uint64_t mask)
 {
     uint64_t new_val = (ldq_le_p(&s->csr[addr]) & ~clear) | mask;
     stq_le_p(&s->csr[addr], new_val);
     return new_val;
 }

 static inline void vtd_iommu_lock(IntelIOMMUState *s)
 {
     qemu_mutex_lock(&s->iommu_lock);
 }

 static inline void vtd_iommu_unlock(IntelIOMMUState *s)
 {
     qemu_mutex_unlock(&s->iommu_lock);
 }

 static void vtd_update_scalable_state(IntelIOMMUState *s)
 {
     uint64_t val = vtd_get_quad_raw(s, DMAR_RTADDR_REG);

     if (s->scalable_mode) {
         s->root_scalable = val & VTD_RTADDR_SMT;
     }
 }

 static void vtd_update_iq_dw(IntelIOMMUState *s)
 {
     uint64_t val = vtd_get_quad_raw(s, DMAR_IQA_REG);

     if (s->ecap & VTD_ECAP_SMTS &&
         val & VTD_IQA_DW_MASK) {
         s->iq_dw = true;
     } else {
         s->iq_dw = false;
     }
 }

 /* Whether the address space needs to notify new mappings */
 static inline gboolean vtd_as_has_map_notifier(VTDAddressSpace *as)
 {
     return as->notifier_flags & IOMMU_NOTIFIER_MAP;
 }

 /* GHashTable functions */
 static gboolean vtd_iotlb_equal(gconstpointer v1, gconstpointer v2)
 {
     const struct vtd_iotlb_key *key1 = v1;
     const struct vtd_iotlb_key *key2 = v2;

     return key1->sid == key2->sid &&
            key1->pasid == key2->pasid &&
            key1->level == key2->level &&
            key1->gfn == key2->gfn;
 }

 static guint vtd_iotlb_hash(gconstpointer v)
 {
     const struct vtd_iotlb_key *key = v;
     uint64_t hash64 = key->gfn | ((uint64_t)(key->sid) << VTD_IOTLB_SID_SHIFT) |
         (uint64_t)(key->level - 1) << VTD_IOTLB_LVL_SHIFT |
         (uint64_t)(key->pasid) << VTD_IOTLB_PASID_SHIFT;

     return (guint)((hash64 >> 32) ^ (hash64 & 0xffffffffU));
 }

 static gboolean vtd_as_equal(gconstpointer v1, gconstpointer v2)
 {
     const struct vtd_as_key *key1 = v1;
     const struct vtd_as_key *key2 = v2;

     return (key1->bus == key2->bus) && (key1->devfn == key2->devfn) &&
            (key1->pasid == key2->pasid);
 }

 /*
  * Note that we use pointer to PCIBus as the key, so hashing/shifting
  * based on the pointer value is intended. Note that we deal with
  * collisions through vtd_as_equal().
  */
 static guint vtd_as_hash(gconstpointer v)
 {
     const struct vtd_as_key *key = v;
     guint value = (guint)(uintptr_t)key->bus;

     return (guint)(value << 8 | key->devfn);
 }

 /* Same implementation as vtd_as_hash() */
 static guint vtd_hiod_hash(gconstpointer v)
 {
     return vtd_as_hash(v);
 }

 static gboolean vtd_hiod_equal(gconstpointer v1, gconstpointer v2)
 {
     const struct vtd_hiod_key *key1 = v1;
     const struct vtd_hiod_key *key2 = v2;

     return (key1->bus == key2->bus) && (key1->devfn == key2->devfn);
 }

 static void vtd_hiod_destroy(gpointer v)
 {
     object_unref(v);
 }

 static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
                                           gpointer user_data)
 {
     VTDIOTLBEntry *entry = (VTDIOTLBEntry *)value;
     uint16_t domain_id = *(uint16_t *)user_data;
     return entry->domain_id == domain_id;
 }

 /* The shift of an addr for a certain level of paging structure */
 static inline uint32_t vtd_slpt_level_shift(uint32_t level)
 {
     assert(level != 0);
     return VTD_PAGE_SHIFT_4K + (level - 1) * VTD_SL_LEVEL_BITS;
 }

 static inline uint64_t vtd_slpt_level_page_mask(uint32_t level)
 {
     return ~((1ULL << vtd_slpt_level_shift(level)) - 1);
 }

 static gboolean vtd_hash_remove_by_page(gpointer key, gpointer value,
                                         gpointer user_data)
 {
     VTDIOTLBEntry *entry = (VTDIOTLBEntry *)value;
     VTDIOTLBPageInvInfo *info = (VTDIOTLBPageInvInfo *)user_data;
     uint64_t gfn = (info->addr >> VTD_PAGE_SHIFT_4K) & info->mask;
     uint64_t gfn_tlb = (info->addr & entry->mask) >> VTD_PAGE_SHIFT_4K;
     return (entry->domain_id == info->domain_id) &&
             (((entry->gfn & info->mask) == gfn) ||
              (entry->gfn == gfn_tlb));
 }

 /* Reset all the gen of VTDAddressSpace to zero and set the gen of
  * IntelIOMMUState to 1.  Must be called with IOMMU lock held.
  */
 static void vtd_reset_context_cache_locked(IntelIOMMUState *s)
 {
     VTDAddressSpace *vtd_as;
     GHashTableIter as_it;

     trace_vtd_context_cache_reset();

     g_hash_table_iter_init(&as_it, s->vtd_address_spaces);

     while (g_hash_table_iter_next(&as_it, NULL, (void **)&vtd_as)) {
         vtd_as->context_cache_entry.context_cache_gen = 0;
     }
     s->context_cache_gen = 1;
 }

 /* Must be called with IOMMU lock held. */
 static void vtd_reset_iotlb_locked(IntelIOMMUState *s)
 {
     assert(s->iotlb);
     g_hash_table_remove_all(s->iotlb);
 }

 static void vtd_reset_iotlb(IntelIOMMUState *s)
 {
     vtd_iommu_lock(s);
     vtd_reset_iotlb_locked(s);
     vtd_iommu_unlock(s);
 }

 static void vtd_reset_caches(IntelIOMMUState *s)
 {
     vtd_iommu_lock(s);
     vtd_reset_iotlb_locked(s);
     vtd_reset_context_cache_locked(s);
     vtd_iommu_unlock(s);
 }

 static uint64_t vtd_get_iotlb_gfn(hwaddr addr, uint32_t level)
 {
     return (addr & vtd_slpt_level_page_mask(level)) >> VTD_PAGE_SHIFT_4K;
 }

 /* Must be called with IOMMU lock held */
 static VTDIOTLBEntry *vtd_lookup_iotlb(IntelIOMMUState *s, uint16_t source_id,
                                        uint32_t pasid, hwaddr addr)
 {
     struct vtd_iotlb_key key;
     VTDIOTLBEntry *entry;
     unsigned level;

     for (level = VTD_SL_PT_LEVEL; level < VTD_SL_PML4_LEVEL; level++) {
         key.gfn = vtd_get_iotlb_gfn(addr, level);
         key.level = level;
         key.sid = source_id;
         key.pasid = pasid;
         entry = g_hash_table_lookup(s->iotlb, &key);
         if (entry) {
             goto out;
         }
     }

 out:
     return entry;
 }

 /* Must be with IOMMU lock held */
 static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
                              uint16_t domain_id, hwaddr addr, uint64_t slpte,
                              uint8_t access_flags, uint32_t level,
                              uint32_t pasid)
 {
     VTDIOTLBEntry *entry = g_malloc(sizeof(*entry));
     struct vtd_iotlb_key *key = g_malloc(sizeof(*key));
     uint64_t gfn = vtd_get_iotlb_gfn(addr, level);

     trace_vtd_iotlb_page_update(source_id, addr, slpte, domain_id);
     if (g_hash_table_size(s->iotlb) >= VTD_IOTLB_MAX_SIZE) {
         trace_vtd_iotlb_reset("iotlb exceeds size limit");
         vtd_reset_iotlb_locked(s);
     }

     entry->gfn = gfn;
     entry->domain_id = domain_id;
     entry->slpte = slpte;
     entry->access_flags = access_flags;
     entry->mask = vtd_slpt_level_page_mask(level);
     entry->pasid = pasid;

     key->gfn = gfn;
     key->sid = source_id;
     key->level = level;
     key->pasid = pasid;

     g_hash_table_replace(s->iotlb, key, entry);
 }

 /* Given the reg addr of both the message data and address, generate an
  * interrupt via MSI.
  */
 static void vtd_generate_interrupt(IntelIOMMUState *s, hwaddr mesg_addr_reg,
                                    hwaddr mesg_data_reg)
 {
     MSIMessage msi;

     assert(mesg_data_reg < DMAR_REG_SIZE);
     assert(mesg_addr_reg < DMAR_REG_SIZE);

     msi.address = vtd_get_long_raw(s, mesg_addr_reg);
     msi.data = vtd_get_long_raw(s, mesg_data_reg);

     trace_vtd_irq_generate(msi.address, msi.data);

     apic_get_class(NULL)->send_msi(&msi);
 }

 /* Generate a fault event to software via MSI if conditions are met.
  * Notice that the value of FSTS_REG being passed to it should be the one
  * before any update.
  */
 static void vtd_generate_fault_event(IntelIOMMUState *s, uint32_t pre_fsts)
 {
     if (pre_fsts & VTD_FSTS_PPF || pre_fsts & VTD_FSTS_PFO ||
         pre_fsts & VTD_FSTS_IQE) {
         error_report_once("There are previous interrupt conditions "
                           "to be serviced by software, fault event "
                           "is not generated");
         return;
     }
     vtd_set_clear_mask_long(s, DMAR_FECTL_REG, 0, VTD_FECTL_IP);
     if (vtd_get_long_raw(s, DMAR_FECTL_REG) & VTD_FECTL_IM) {
         error_report_once("Interrupt Mask set, irq is not generated");
     } else {
         vtd_generate_interrupt(s, DMAR_FEADDR_REG, DMAR_FEDATA_REG);
         vtd_set_clear_mask_long(s, DMAR_FECTL_REG, VTD_FECTL_IP, 0);
     }
 }

 /* Check if the Fault (F) field of the Fault Recording Register referenced by
  * @index is Set.
  */
 static bool vtd_is_frcd_set(IntelIOMMUState *s, uint16_t index)
 {
     /* Each reg is 128-bit */
     hwaddr addr = DMAR_FRCD_REG_OFFSET + (((uint64_t)index) << 4);
     addr += 8; /* Access the high 64-bit half */

     assert(index < DMAR_FRCD_REG_NR);

     return vtd_get_quad_raw(s, addr) & VTD_FRCD_F;
 }

 /* Update the PPF field of Fault Status Register.
  * Should be called whenever change the F field of any fault recording
  * registers.
  */
 static void vtd_update_fsts_ppf(IntelIOMMUState *s)
 {
     uint32_t i;
     uint32_t ppf_mask = 0;

     for (i = 0; i < DMAR_FRCD_REG_NR; i++) {
         if (vtd_is_frcd_set(s, i)) {
             ppf_mask = VTD_FSTS_PPF;
             break;
         }
     }
     vtd_set_clear_mask_long(s, DMAR_FSTS_REG, VTD_FSTS_PPF, ppf_mask);
     trace_vtd_fsts_ppf(!!ppf_mask);
 }

 static void vtd_set_frcd_and_update_ppf(IntelIOMMUState *s, uint16_t index)
 {
     /* Each reg is 128-bit */
     hwaddr addr = DMAR_FRCD_REG_OFFSET + (((uint64_t)index) << 4);
     addr += 8; /* Access the high 64-bit half */

     assert(index < DMAR_FRCD_REG_NR);

     vtd_set_clear_mask_quad(s, addr, 0, VTD_FRCD_F);
     vtd_update_fsts_ppf(s);
 }

 /* Must not update F field now, should be done later */
 static void vtd_record_frcd(IntelIOMMUState *s, uint16_t index,
                             uint64_t hi, uint64_t lo)
 {
     hwaddr frcd_reg_addr = DMAR_FRCD_REG_OFFSET + (((uint64_t)index) << 4);

     assert(index < DMAR_FRCD_REG_NR);

     vtd_set_quad_raw(s, frcd_reg_addr, lo);
     vtd_set_quad_raw(s, frcd_reg_addr + 8, hi);

     trace_vtd_frr_new(index, hi, lo);
 }

 /* Try to collapse multiple pending faults from the same requester */
 static bool vtd_try_collapse_fault(IntelIOMMUState *s, uint16_t source_id)
 {
     uint32_t i;
     uint64_t frcd_reg;
     hwaddr addr = DMAR_FRCD_REG_OFFSET + 8; /* The high 64-bit half */

     for (i = 0; i < DMAR_FRCD_REG_NR; i++) {
         frcd_reg = vtd_get_quad_raw(s, addr);
         if ((frcd_reg & VTD_FRCD_F) &&
             ((frcd_reg & VTD_FRCD_SID_MASK) == source_id)) {
             return true;
         }
         addr += 16; /* 128-bit for each */
     }
     return false;
 }

 /* Log and report an DMAR (address translation) fault to software */
 static void vtd_report_frcd_fault(IntelIOMMUState *s, uint64_t source_id,
                                   uint64_t hi, uint64_t lo)
 {
     uint32_t fsts_reg = vtd_get_long_raw(s, DMAR_FSTS_REG);

     if (fsts_reg & VTD_FSTS_PFO) {
         error_report_once("New fault is not recorded due to "
                           "Primary Fault Overflow");
         return;
     }

     if (vtd_try_collapse_fault(s, source_id)) {
         error_report_once("New fault is not recorded due to "
                           "compression of faults");
         return;
     }

     if (vtd_is_frcd_set(s, s->next_frcd_reg)) {
         error_report_once("Next Fault Recording Reg is used, "
                           "new fault is not recorded, set PFO field");
         vtd_set_clear_mask_long(s, DMAR_FSTS_REG, 0, VTD_FSTS_PFO);
         return;
     }

     vtd_record_frcd(s, s->next_frcd_reg, hi, lo);

     if (fsts_reg & VTD_FSTS_PPF) {
         error_report_once("There are pending faults already, "
                           "fault event is not generated");
         vtd_set_frcd_and_update_ppf(s, s->next_frcd_reg);
         s->next_frcd_reg++;
         if (s->next_frcd_reg == DMAR_FRCD_REG_NR) {
             s->next_frcd_reg = 0;
         }
     } else {
         vtd_set_clear_mask_long(s, DMAR_FSTS_REG, VTD_FSTS_FRI_MASK,
                                 VTD_FSTS_FRI(s->next_frcd_reg));
         vtd_set_frcd_and_update_ppf(s, s->next_frcd_reg); /* Will set PPF */
         s->next_frcd_reg++;
         if (s->next_frcd_reg == DMAR_FRCD_REG_NR) {
             s->next_frcd_reg = 0;
         }
         /* This case actually cause the PPF to be Set.
          * So generate fault event (interrupt).
          */
          vtd_generate_fault_event(s, fsts_reg);
     }
 }

 /* Log and report an DMAR (address translation) fault to software */
 static void vtd_report_dmar_fault(IntelIOMMUState *s, uint16_t source_id,
                                   hwaddr addr, VTDFaultReason fault,
                                   bool is_write, bool is_pasid,
                                   uint32_t pasid)
 {
     uint64_t hi, lo;

     assert(fault < VTD_FR_MAX);

     trace_vtd_dmar_fault(source_id, fault, addr, is_write);

     lo = VTD_FRCD_FI(addr);
     hi = VTD_FRCD_SID(source_id) | VTD_FRCD_FR(fault) |
          VTD_FRCD_PV(pasid) | VTD_FRCD_PP(is_pasid);
     if (!is_write) {
         hi |= VTD_FRCD_T;
     }

     vtd_report_frcd_fault(s, source_id, hi, lo);
 }


 static void vtd_report_ir_fault(IntelIOMMUState *s, uint64_t source_id,
                                 VTDFaultReason fault, uint16_t index)
 {
     uint64_t hi, lo;

     lo = VTD_FRCD_IR_IDX(index);
     hi = VTD_FRCD_SID(source_id) | VTD_FRCD_FR(fault);

     vtd_report_frcd_fault(s, source_id, hi, lo);
 }

 /* Handle Invalidation Queue Errors of queued invalidation interface error
  * conditions.
  */
 static void vtd_handle_inv_queue_error(IntelIOMMUState *s)
 {
     uint32_t fsts_reg = vtd_get_long_raw(s, DMAR_FSTS_REG);

     vtd_set_clear_mask_long(s, DMAR_FSTS_REG, 0, VTD_FSTS_IQE);
     vtd_generate_fault_event(s, fsts_reg);
 }

 /* Set the IWC field and try to generate an invalidation completion interrupt */
 static void vtd_generate_completion_event(IntelIOMMUState *s)
 {
     if (vtd_get_long_raw(s, DMAR_ICS_REG) & VTD_ICS_IWC) {
         trace_vtd_inv_desc_wait_irq("One pending, skip current");
         return;
     }
     vtd_set_clear_mask_long(s, DMAR_ICS_REG, 0, VTD_ICS_IWC);
     vtd_set_clear_mask_long(s, DMAR_IECTL_REG, 0, VTD_IECTL_IP);
     if (vtd_get_long_raw(s, DMAR_IECTL_REG) & VTD_IECTL_IM) {
         trace_vtd_inv_desc_wait_irq("IM in IECTL_REG is set, "
                                     "new event not generated");
         return;
     } else {
         /* Generate the interrupt event */
         trace_vtd_inv_desc_wait_irq("Generating complete event");
         vtd_generate_interrupt(s, DMAR_IEADDR_REG, DMAR_IEDATA_REG);
         vtd_set_clear_mask_long(s, DMAR_IECTL_REG, VTD_IECTL_IP, 0);
     }
 }

 static inline bool vtd_root_entry_present(IntelIOMMUState *s,
                                           VTDRootEntry *re,
                                           uint8_t devfn)
 {
     if (s->root_scalable && devfn > UINT8_MAX / 2) {
         return re->hi & VTD_ROOT_ENTRY_P;
     }

     return re->lo & VTD_ROOT_ENTRY_P;
 }

 static int vtd_get_root_entry(IntelIOMMUState *s, uint8_t index,
                               VTDRootEntry *re)
 {
     dma_addr_t addr;

     addr = s->root + index * sizeof(*re);
     if (dma_memory_read(&address_space_memory, addr,
                         re, sizeof(*re), MEMTXATTRS_UNSPECIFIED)) {
         re->lo = 0;
         return -VTD_FR_ROOT_TABLE_INV;
     }
     re->lo = le64_to_cpu(re->lo);
     re->hi = le64_to_cpu(re->hi);
     return 0;
 }

 static inline bool vtd_ce_present(VTDContextEntry *context)
 {
     return context->lo & VTD_CONTEXT_ENTRY_P;
 }

 static int vtd_get_context_entry_from_root(IntelIOMMUState *s,
                                            VTDRootEntry *re,
                                            uint8_t index,
                                            VTDContextEntry *ce)
 {
     dma_addr_t addr, ce_size;

     /* we have checked that root entry is present */
     ce_size = s->root_scalable ? VTD_CTX_ENTRY_SCALABLE_SIZE :
               VTD_CTX_ENTRY_LEGACY_SIZE;

     if (s->root_scalable && index > UINT8_MAX / 2) {
         index = index & (~VTD_DEVFN_CHECK_MASK);
         addr = re->hi & VTD_ROOT_ENTRY_CTP;
     } else {
         addr = re->lo & VTD_ROOT_ENTRY_CTP;
     }

     addr = addr + index * ce_size;
     if (dma_memory_read(&address_space_memory, addr,
                         ce, ce_size, MEMTXATTRS_UNSPECIFIED)) {
         return -VTD_FR_CONTEXT_TABLE_INV;
     }

     ce->lo = le64_to_cpu(ce->lo);
     ce->hi = le64_to_cpu(ce->hi);
     if (ce_size == VTD_CTX_ENTRY_SCALABLE_SIZE) {
         ce->val[2] = le64_to_cpu(ce->val[2]);
         ce->val[3] = le64_to_cpu(ce->val[3]);
     }
     return 0;
 }

 static inline dma_addr_t vtd_ce_get_slpt_base(VTDContextEntry *ce)
 {
     return ce->lo & VTD_CONTEXT_ENTRY_SLPTPTR;
 }

 static inline uint64_t vtd_get_slpte_addr(uint64_t slpte, uint8_t aw)
 {
     return slpte & VTD_SL_PT_BASE_ADDR_MASK(aw);
 }

 /* Whether the pte indicates the address of the page frame */
 static inline bool vtd_is_last_slpte(uint64_t slpte, uint32_t level)
 {
     return level == VTD_SL_PT_LEVEL || (slpte & VTD_SL_PT_PAGE_SIZE_MASK);
 }

 /* Get the content of a spte located in @base_addr[@index] */
 static uint64_t vtd_get_slpte(dma_addr_t base_addr, uint32_t index)
 {
     uint64_t slpte;

     assert(index < VTD_SL_PT_ENTRY_NR);

     if (dma_memory_read(&address_space_memory,
                         base_addr + index * sizeof(slpte),
                         &slpte, sizeof(slpte), MEMTXATTRS_UNSPECIFIED)) {
         slpte = (uint64_t)-1;
         return slpte;
     }
     slpte = le64_to_cpu(slpte);
     return slpte;
 }

 /* Given an iova and the level of paging structure, return the offset
  * of current level.
  */
 static inline uint32_t vtd_iova_level_offset(uint64_t iova, uint32_t level)
 {
     return (iova >> vtd_slpt_level_shift(level)) &
             ((1ULL << VTD_SL_LEVEL_BITS) - 1);
 }

 /* Check Capability Register to see if the @level of page-table is supported */
 static inline bool vtd_is_level_supported(IntelIOMMUState *s, uint32_t level)
 {
     return VTD_CAP_SAGAW_MASK & s->cap &
            (1ULL << (level - 2 + VTD_CAP_SAGAW_SHIFT));
 }

 /* Return true if check passed, otherwise false */
 static inline bool vtd_pe_type_check(X86IOMMUState *x86_iommu,
                                      VTDPASIDEntry *pe)
 {
     switch (VTD_PE_GET_TYPE(pe)) {
     case VTD_SM_PASID_ENTRY_FLT:
     case VTD_SM_PASID_ENTRY_SLT:
     case VTD_SM_PASID_ENTRY_NESTED:
         break;
     case VTD_SM_PASID_ENTRY_PT:
         if (!x86_iommu->pt_supported) {
             return false;
         }
         break;
     default:
         /* Unknown type */
         return false;
     }
     return true;
 }

 static inline bool vtd_pdire_present(VTDPASIDDirEntry *pdire)
 {
     return pdire->val & 1;
 }

 /**
  * Caller of this function should check present bit if wants
  * to use pdir entry for further usage except for fpd bit check.
  */
 static int vtd_get_pdire_from_pdir_table(dma_addr_t pasid_dir_base,
                                          uint32_t pasid,
                                          VTDPASIDDirEntry *pdire)
 {
     uint32_t index;
     dma_addr_t addr, entry_size;

     index = VTD_PASID_DIR_INDEX(pasid);
     entry_size = VTD_PASID_DIR_ENTRY_SIZE;
     addr = pasid_dir_base + index * entry_size;
     if (dma_memory_read(&address_space_memory, addr,
                         pdire, entry_size, MEMTXATTRS_UNSPECIFIED)) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     pdire->val = le64_to_cpu(pdire->val);

     return 0;
 }

 static inline bool vtd_pe_present(VTDPASIDEntry *pe)
 {
     return pe->val[0] & VTD_PASID_ENTRY_P;
 }

 static int vtd_get_pe_in_pasid_leaf_table(IntelIOMMUState *s,
                                           uint32_t pasid,
                                           dma_addr_t addr,
                                           VTDPASIDEntry *pe)
 {
     uint32_t index;
     dma_addr_t entry_size;
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     index = VTD_PASID_TABLE_INDEX(pasid);
     entry_size = VTD_PASID_ENTRY_SIZE;
     addr = addr + index * entry_size;
     if (dma_memory_read(&address_space_memory, addr,
                         pe, entry_size, MEMTXATTRS_UNSPECIFIED)) {
         return -VTD_FR_PASID_TABLE_INV;
     }
     for (size_t i = 0; i < ARRAY_SIZE(pe->val); i++) {
         pe->val[i] = le64_to_cpu(pe->val[i]);
     }

     /* Do translation type check */
     if (!vtd_pe_type_check(x86_iommu, pe)) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     if (!vtd_is_level_supported(s, VTD_PE_GET_LEVEL(pe))) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     return 0;
 }

 /**
  * Caller of this function should check present bit if wants
  * to use pasid entry for further usage except for fpd bit check.
  */
 static int vtd_get_pe_from_pdire(IntelIOMMUState *s,
                                  uint32_t pasid,
                                  VTDPASIDDirEntry *pdire,
                                  VTDPASIDEntry *pe)
 {
     dma_addr_t addr = pdire->val & VTD_PASID_TABLE_BASE_ADDR_MASK;

     return vtd_get_pe_in_pasid_leaf_table(s, pasid, addr, pe);
 }

 /**
  * This function gets a pasid entry from a specified pasid
  * table (includes dir and leaf table) with a specified pasid.
  * Sanity check should be done to ensure return a present
  * pasid entry to caller.
  */
 static int vtd_get_pe_from_pasid_table(IntelIOMMUState *s,
                                        dma_addr_t pasid_dir_base,
                                        uint32_t pasid,
                                        VTDPASIDEntry *pe)
 {
     int ret;
     VTDPASIDDirEntry pdire;

     ret = vtd_get_pdire_from_pdir_table(pasid_dir_base,
                                         pasid, &pdire);
     if (ret) {
         return ret;
     }

     if (!vtd_pdire_present(&pdire)) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     ret = vtd_get_pe_from_pdire(s, pasid, &pdire, pe);
     if (ret) {
         return ret;
     }

     if (!vtd_pe_present(pe)) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     return 0;
 }

 static int vtd_ce_get_rid2pasid_entry(IntelIOMMUState *s,
                                       VTDContextEntry *ce,
                                       VTDPASIDEntry *pe,
                                       uint32_t pasid)
 {
     dma_addr_t pasid_dir_base;
     int ret = 0;

     if (pasid == PCI_NO_PASID) {
         pasid = VTD_CE_GET_RID2PASID(ce);
     }
     pasid_dir_base = VTD_CE_GET_PASID_DIR_TABLE(ce);
     ret = vtd_get_pe_from_pasid_table(s, pasid_dir_base, pasid, pe);

     return ret;
 }

 static int vtd_ce_get_pasid_fpd(IntelIOMMUState *s,
                                 VTDContextEntry *ce,
                                 bool *pe_fpd_set,
                                 uint32_t pasid)
 {
     int ret;
     dma_addr_t pasid_dir_base;
     VTDPASIDDirEntry pdire;
     VTDPASIDEntry pe;

     if (pasid == PCI_NO_PASID) {
         pasid = VTD_CE_GET_RID2PASID(ce);
     }
     pasid_dir_base = VTD_CE_GET_PASID_DIR_TABLE(ce);

     /*
      * No present bit check since fpd is meaningful even
      * if the present bit is clear.
      */
     ret = vtd_get_pdire_from_pdir_table(pasid_dir_base, pasid, &pdire);
     if (ret) {
         return ret;
     }

     if (pdire.val & VTD_PASID_DIR_FPD) {
         *pe_fpd_set = true;
         return 0;
     }

     if (!vtd_pdire_present(&pdire)) {
         return -VTD_FR_PASID_TABLE_INV;
     }

     /*
      * No present bit check since fpd is meaningful even
      * if the present bit is clear.
      */
     ret = vtd_get_pe_from_pdire(s, pasid, &pdire, &pe);
     if (ret) {
         return ret;
     }

     if (pe.val[0] & VTD_PASID_ENTRY_FPD) {
         *pe_fpd_set = true;
     }

     return 0;
 }

 /* Get the page-table level that hardware should use for the second-level
  * page-table walk from the Address Width field of context-entry.
  */
 static inline uint32_t vtd_ce_get_level(VTDContextEntry *ce)
 {
     return 2 + (ce->hi & VTD_CONTEXT_ENTRY_AW);
 }

 static uint32_t vtd_get_iova_level(IntelIOMMUState *s,
                                    VTDContextEntry *ce,
                                    uint32_t pasid)
 {
     VTDPASIDEntry pe;

     if (s->root_scalable) {
         vtd_ce_get_rid2pasid_entry(s, ce, &pe, pasid);
         return VTD_PE_GET_LEVEL(&pe);
     }

     return vtd_ce_get_level(ce);
 }

 static inline uint32_t vtd_ce_get_agaw(VTDContextEntry *ce)
 {
     return 30 + (ce->hi & VTD_CONTEXT_ENTRY_AW) * 9;
 }

 static uint32_t vtd_get_iova_agaw(IntelIOMMUState *s,
                                   VTDContextEntry *ce,
                                   uint32_t pasid)
 {
     VTDPASIDEntry pe;

     if (s->root_scalable) {
         vtd_ce_get_rid2pasid_entry(s, ce, &pe, pasid);
         return 30 + ((pe.val[0] >> 2) & VTD_SM_PASID_ENTRY_AW) * 9;
     }

     return vtd_ce_get_agaw(ce);
 }

 static inline uint32_t vtd_ce_get_type(VTDContextEntry *ce)
 {
     return ce->lo & VTD_CONTEXT_ENTRY_TT;
 }

 /* Only for Legacy Mode. Return true if check passed, otherwise false */
 static inline bool vtd_ce_type_check(X86IOMMUState *x86_iommu,
                                      VTDContextEntry *ce)
 {
     switch (vtd_ce_get_type(ce)) {
     case VTD_CONTEXT_TT_MULTI_LEVEL:
         /* Always supported */
         break;
     case VTD_CONTEXT_TT_DEV_IOTLB:
         if (!x86_iommu->dt_supported) {
             error_report_once("%s: DT specified but not supported", __func__);
             return false;
         }
         break;
     case VTD_CONTEXT_TT_PASS_THROUGH:
         if (!x86_iommu->pt_supported) {
             error_report_once("%s: PT specified but not supported", __func__);
             return false;
         }
         break;
     default:
         /* Unknown type */
         error_report_once("%s: unknown ce type: %"PRIu32, __func__,
                           vtd_ce_get_type(ce));
         return false;
     }
     return true;
 }

 static inline uint64_t vtd_iova_limit(IntelIOMMUState *s,
                                       VTDContextEntry *ce, uint8_t aw,
                                       uint32_t pasid)
 {
     uint32_t ce_agaw = vtd_get_iova_agaw(s, ce, pasid);
     return 1ULL << MIN(ce_agaw, aw);
 }

 /* Return true if IOVA passes range check, otherwise false. */
 static inline bool vtd_iova_range_check(IntelIOMMUState *s,
                                         uint64_t iova, VTDContextEntry *ce,
                                         uint8_t aw, uint32_t pasid)
 {
     /*
      * Check if @iova is above 2^X-1, where X is the minimum of MGAW
      * in CAP_REG and AW in context-entry.
      */
     return !(iova & ~(vtd_iova_limit(s, ce, aw, pasid) - 1));
 }

 static dma_addr_t vtd_get_iova_pgtbl_base(IntelIOMMUState *s,
                                           VTDContextEntry *ce,
                                           uint32_t pasid)
 {
     VTDPASIDEntry pe;

     if (s->root_scalable) {
         vtd_ce_get_rid2pasid_entry(s, ce, &pe, pasid);
         return pe.val[0] & VTD_SM_PASID_ENTRY_SLPTPTR;
     }

     return vtd_ce_get_slpt_base(ce);
 }

 /*
  * Rsvd field masks for spte:
  *     vtd_spte_rsvd 4k pages
  *     vtd_spte_rsvd_large large pages
  *
  * We support only 3-level and 4-level page tables (see vtd_init() which
  * sets only VTD_CAP_SAGAW_39bit and maybe VTD_CAP_SAGAW_48bit bits in s->cap).
  */
 #define VTD_SPTE_RSVD_LEN 5
 static uint64_t vtd_spte_rsvd[VTD_SPTE_RSVD_LEN];
 static uint64_t vtd_spte_rsvd_large[VTD_SPTE_RSVD_LEN];

 static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, uint32_t level)
 {
     uint64_t rsvd_mask;

     /*
      * We should have caught a guest-mis-programmed level earlier,
      * via vtd_is_level_supported.
      */
     assert(level < VTD_SPTE_RSVD_LEN);
     /*
      * Zero level doesn't exist. The smallest level is VTD_SL_PT_LEVEL=1 and
      * checked by vtd_is_last_slpte().
      */
     assert(level);

     if ((level == VTD_SL_PD_LEVEL || level == VTD_SL_PDP_LEVEL) &&
         (slpte & VTD_SL_PT_PAGE_SIZE_MASK)) {
         /* large page */
         rsvd_mask = vtd_spte_rsvd_large[level];
     } else {
         rsvd_mask = vtd_spte_rsvd[level];
     }

     return slpte & rsvd_mask;
 }

 /* Given the @iova, get relevant @slptep. @slpte_level will be the last level
  * of the translation, can be used for deciding the size of large page.
  */
 static int vtd_iova_to_slpte(IntelIOMMUState *s, VTDContextEntry *ce,
                              uint64_t iova, bool is_write,
                              uint64_t *slptep, uint32_t *slpte_level,
                              bool *reads, bool *writes, uint8_t aw_bits,
                              uint32_t pasid)
 {
     dma_addr_t addr = vtd_get_iova_pgtbl_base(s, ce, pasid);
     uint32_t level = vtd_get_iova_level(s, ce, pasid);
     uint32_t offset;
     uint64_t slpte;
     uint64_t access_right_check;
     uint64_t xlat, size;

     if (!vtd_iova_range_check(s, iova, ce, aw_bits, pasid)) {
         error_report_once("%s: detected IOVA overflow (iova=0x%" PRIx64 ","
                           "pasid=0x%" PRIx32 ")", __func__, iova, pasid);
         return -VTD_FR_ADDR_BEYOND_MGAW;
     }

     /* FIXME: what is the Atomics request here? */
     access_right_check = is_write ? VTD_SL_W : VTD_SL_R;

     while (true) {
         offset = vtd_iova_level_offset(iova, level);
         slpte = vtd_get_slpte(addr, offset);

         if (slpte == (uint64_t)-1) {
             error_report_once("%s: detected read error on DMAR slpte "
                               "(iova=0x%" PRIx64 ", pasid=0x%" PRIx32 ")",
                               __func__, iova, pasid);
             if (level == vtd_get_iova_level(s, ce, pasid)) {
                 /* Invalid programming of context-entry */
                 return -VTD_FR_CONTEXT_ENTRY_INV;
             } else {
                 return -VTD_FR_PAGING_ENTRY_INV;
             }
         }
         *reads = (*reads) && (slpte & VTD_SL_R);
         *writes = (*writes) && (slpte & VTD_SL_W);
         if (!(slpte & access_right_check)) {
             error_report_once("%s: detected slpte permission error "
                               "(iova=0x%" PRIx64 ", level=0x%" PRIx32 ", "
                               "slpte=0x%" PRIx64 ", write=%d, pasid=0x%"
                               PRIx32 ")", __func__, iova, level,
                               slpte, is_write, pasid);
             return is_write ? -VTD_FR_WRITE : -VTD_FR_READ;
         }
         if (vtd_slpte_nonzero_rsvd(slpte, level)) {
             error_report_once("%s: detected splte reserve non-zero "
                               "iova=0x%" PRIx64 ", level=0x%" PRIx32
                               "slpte=0x%" PRIx64 ", pasid=0x%" PRIX32 ")",
                               __func__, iova, level, slpte, pasid);
             return -VTD_FR_PAGING_ENTRY_RSVD;
         }

         if (vtd_is_last_slpte(slpte, level)) {
             *slptep = slpte;
             *slpte_level = level;
             break;
         }
         addr = vtd_get_slpte_addr(slpte, aw_bits);
         level--;
     }

     xlat = vtd_get_slpte_addr(*slptep, aw_bits);
     size = ~vtd_slpt_level_page_mask(level) + 1;

     /*
      * From VT-d spec 3.14: Untranslated requests and translation
      * requests that result in an address in the interrupt range will be
      * blocked with condition code LGN.4 or SGN.8.
      */
     if ((xlat > VTD_INTERRUPT_ADDR_LAST ||
          xlat + size - 1 < VTD_INTERRUPT_ADDR_FIRST)) {
         return 0;
     } else {
         error_report_once("%s: xlat address is in interrupt range "
                           "(iova=0x%" PRIx64 ", level=0x%" PRIx32 ", "
                           "slpte=0x%" PRIx64 ", write=%d, "
                           "xlat=0x%" PRIx64 ", size=0x%" PRIx64 ", "
                           "pasid=0x%" PRIx32 ")",
                           __func__, iova, level, slpte, is_write,
                           xlat, size, pasid);
         return s->scalable_mode ? -VTD_FR_SM_INTERRUPT_ADDR :
                                   -VTD_FR_INTERRUPT_ADDR;
     }
 }

 typedef int (*vtd_page_walk_hook)(const IOMMUTLBEvent *event, void *private);

 /**
  * Constant information used during page walking
  *
  * @hook_fn: hook func to be called when detected page
  * @private: private data to be passed into hook func
  * @notify_unmap: whether we should notify invalid entries
  * @as: VT-d address space of the device
  * @aw: maximum address width
  * @domain: domain ID of the page walk
  */
 typedef struct {
     VTDAddressSpace *as;
     vtd_page_walk_hook hook_fn;
     void *private;
     bool notify_unmap;
     uint8_t aw;
     uint16_t domain_id;
 } vtd_page_walk_info;

 static int vtd_page_walk_one(IOMMUTLBEvent *event, vtd_page_walk_info *info)
 {
     VTDAddressSpace *as = info->as;
     vtd_page_walk_hook hook_fn = info->hook_fn;
     void *private = info->private;
     IOMMUTLBEntry *entry = &event->entry;
     DMAMap target = {
         .iova = entry->iova,
         .size = entry->addr_mask,
         .translated_addr = entry->translated_addr,
         .perm = entry->perm,
     };
     const DMAMap *mapped = iova_tree_find(as->iova_tree, &target);

     if (event->type == IOMMU_NOTIFIER_UNMAP && !info->notify_unmap) {
         trace_vtd_page_walk_one_skip_unmap(entry->iova, entry->addr_mask);
         return 0;
     }

     assert(hook_fn);

     /* Update local IOVA mapped ranges */
     if (event->type == IOMMU_NOTIFIER_MAP) {
         if (mapped) {
             /* If it's exactly the same translation, skip */
             if (!memcmp(mapped, &target, sizeof(target))) {
                 trace_vtd_page_walk_one_skip_map(entry->iova, entry->addr_mask,
                                                  entry->translated_addr);
                 return 0;
             } else {
                 /*
                  * Translation changed.  Normally this should not
                  * happen, but it can happen when with buggy guest
                  * OSes.  Note that there will be a small window that
                  * we don't have map at all.  But that's the best
                  * effort we can do.  The ideal way to emulate this is
                  * atomically modify the PTE to follow what has
                  * changed, but we can't.  One example is that vfio
                  * driver only has VFIO_IOMMU_[UN]MAP_DMA but no
                  * interface to modify a mapping (meanwhile it seems
                  * meaningless to even provide one).  Anyway, let's
                  * mark this as a TODO in case one day we'll have
                  * a better solution.
                  */
                 IOMMUAccessFlags cache_perm = entry->perm;
                 int ret;

                 /* Emulate an UNMAP */
                 event->type = IOMMU_NOTIFIER_UNMAP;
                 entry->perm = IOMMU_NONE;
                 trace_vtd_page_walk_one(info->domain_id,
                                         entry->iova,
                                         entry->translated_addr,
                                         entry->addr_mask,
                                         entry->perm);
                 ret = hook_fn(event, private);
                 if (ret) {
                     return ret;
                 }
                 /* Drop any existing mapping */
                 iova_tree_remove(as->iova_tree, target);
                 /* Recover the correct type */
                 event->type = IOMMU_NOTIFIER_MAP;
                 entry->perm = cache_perm;
             }
         }
         iova_tree_insert(as->iova_tree, &target);
     } else {
         if (!mapped) {
             /* Skip since we didn't map this range at all */
             trace_vtd_page_walk_one_skip_unmap(entry->iova, entry->addr_mask);
             return 0;
         }
         iova_tree_remove(as->iova_tree, target);
     }

     trace_vtd_page_walk_one(info->domain_id, entry->iova,
                             entry->translated_addr, entry->addr_mask,
                             entry->perm);
     return hook_fn(event, private);
 }

 /**
  * vtd_page_walk_level - walk over specific level for IOVA range
  *
  * @addr: base GPA addr to start the walk
  * @start: IOVA range start address
  * @end: IOVA range end address (start <= addr < end)
  * @read: whether parent level has read permission
  * @write: whether parent level has write permission
  * @info: constant information for the page walk
  */
 static int vtd_page_walk_level(dma_addr_t addr, uint64_t start,
                                uint64_t end, uint32_t level, bool read,
                                bool write, vtd_page_walk_info *info)
 {
     bool read_cur, write_cur, entry_valid;
     uint32_t offset;
     uint64_t slpte;
     uint64_t subpage_size, subpage_mask;
     IOMMUTLBEvent event;
     uint64_t iova = start;
     uint64_t iova_next;
     int ret = 0;

     trace_vtd_page_walk_level(addr, level, start, end);

     subpage_size = 1ULL << vtd_slpt_level_shift(level);
     subpage_mask = vtd_slpt_level_page_mask(level);

     while (iova < end) {
         iova_next = (iova & subpage_mask) + subpage_size;

         offset = vtd_iova_level_offset(iova, level);
         slpte = vtd_get_slpte(addr, offset);

         if (slpte == (uint64_t)-1) {
             trace_vtd_page_walk_skip_read(iova, iova_next);
             goto next;
         }

         if (vtd_slpte_nonzero_rsvd(slpte, level)) {
             trace_vtd_page_walk_skip_reserve(iova, iova_next);
             goto next;
         }

         /* Permissions are stacked with parents' */
         read_cur = read && (slpte & VTD_SL_R);
         write_cur = write && (slpte & VTD_SL_W);

         /*
          * As long as we have either read/write permission, this is a
          * valid entry. The rule works for both page entries and page
          * table entries.
          */
         entry_valid = read_cur | write_cur;

         if (!vtd_is_last_slpte(slpte, level) && entry_valid) {
             /*
              * This is a valid PDE (or even bigger than PDE).  We need
              * to walk one further level.
              */
             ret = vtd_page_walk_level(vtd_get_slpte_addr(slpte, info->aw),
                                       iova, MIN(iova_next, end), level - 1,
                                       read_cur, write_cur, info);
         } else {
             /*
              * This means we are either:
              *
              * (1) the real page entry (either 4K page, or huge page)
              * (2) the whole range is invalid
              *
              * In either case, we send an IOTLB notification down.
              */
             event.entry.target_as = &address_space_memory;
             event.entry.iova = iova & subpage_mask;
             event.entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur);
             event.entry.addr_mask = ~subpage_mask;
             /* NOTE: this is only meaningful if entry_valid == true */
             event.entry.translated_addr = vtd_get_slpte_addr(slpte, info->aw);
             event.type = event.entry.perm ? IOMMU_NOTIFIER_MAP :
                                             IOMMU_NOTIFIER_UNMAP;
             ret = vtd_page_walk_one(&event, info);
         }

         if (ret < 0) {
             return ret;
         }

 next:
         iova = iova_next;
     }

     return 0;
 }

 /**
  * vtd_page_walk - walk specific IOVA range, and call the hook
  *
  * @s: intel iommu state
  * @ce: context entry to walk upon
  * @start: IOVA address to start the walk
  * @end: IOVA range end address (start <= addr < end)
  * @info: page walking information struct
  */
 static int vtd_page_walk(IntelIOMMUState *s, VTDContextEntry *ce,
                          uint64_t start, uint64_t end,
                          vtd_page_walk_info *info,
                          uint32_t pasid)
 {
     dma_addr_t addr = vtd_get_iova_pgtbl_base(s, ce, pasid);
     uint32_t level = vtd_get_iova_level(s, ce, pasid);

     if (!vtd_iova_range_check(s, start, ce, info->aw, pasid)) {
         return -VTD_FR_ADDR_BEYOND_MGAW;
     }

     if (!vtd_iova_range_check(s, end, ce, info->aw, pasid)) {
         /* Fix end so that it reaches the maximum */
         end = vtd_iova_limit(s, ce, info->aw, pasid);
     }

     return vtd_page_walk_level(addr, start, end, level, true, true, info);
 }

 static int vtd_root_entry_rsvd_bits_check(IntelIOMMUState *s,
                                           VTDRootEntry *re)
 {
     /* Legacy Mode reserved bits check */
     if (!s->root_scalable &&
         (re->hi || (re->lo & VTD_ROOT_ENTRY_RSVD(s->aw_bits))))
         goto rsvd_err;

     /* Scalable Mode reserved bits check */
     if (s->root_scalable &&
         ((re->lo & VTD_ROOT_ENTRY_RSVD(s->aw_bits)) ||
          (re->hi & VTD_ROOT_ENTRY_RSVD(s->aw_bits))))
         goto rsvd_err;

     return 0;

 rsvd_err:
     error_report_once("%s: invalid root entry: hi=0x%"PRIx64
                       ", lo=0x%"PRIx64,
                       __func__, re->hi, re->lo);
     return -VTD_FR_ROOT_ENTRY_RSVD;
 }

 static inline int vtd_context_entry_rsvd_bits_check(IntelIOMMUState *s,
                                                     VTDContextEntry *ce)
 {
     if (!s->root_scalable &&
         (ce->hi & VTD_CONTEXT_ENTRY_RSVD_HI ||
          ce->lo & VTD_CONTEXT_ENTRY_RSVD_LO(s->aw_bits))) {
         error_report_once("%s: invalid context entry: hi=%"PRIx64
                           ", lo=%"PRIx64" (reserved nonzero)",
                           __func__, ce->hi, ce->lo);
         return -VTD_FR_CONTEXT_ENTRY_RSVD;
     }

     if (s->root_scalable &&
         (ce->val[0] & VTD_SM_CONTEXT_ENTRY_RSVD_VAL0(s->aw_bits) ||
          ce->val[1] & VTD_SM_CONTEXT_ENTRY_RSVD_VAL1 ||
          ce->val[2] ||
          ce->val[3])) {
         error_report_once("%s: invalid context entry: val[3]=%"PRIx64
                           ", val[2]=%"PRIx64
                           ", val[1]=%"PRIx64
                           ", val[0]=%"PRIx64" (reserved nonzero)",
                           __func__, ce->val[3], ce->val[2],
                           ce->val[1], ce->val[0]);
         return -VTD_FR_CONTEXT_ENTRY_RSVD;
     }

     return 0;
 }

 static int vtd_ce_rid2pasid_check(IntelIOMMUState *s,
                                   VTDContextEntry *ce)
 {
     VTDPASIDEntry pe;

     /*
      * Make sure in Scalable Mode, a present context entry
      * has valid rid2pasid setting, which includes valid
      * rid2pasid field and corresponding pasid entry setting
      */
     return vtd_ce_get_rid2pasid_entry(s, ce, &pe, PCI_NO_PASID);
 }

 /* Map a device to its corresponding domain (context-entry) */
 static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num,
                                     uint8_t devfn, VTDContextEntry *ce)
 {
     VTDRootEntry re;
     int ret_fr;
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     ret_fr = vtd_get_root_entry(s, bus_num, &re);
     if (ret_fr) {
         return ret_fr;
     }

     if (!vtd_root_entry_present(s, &re, devfn)) {
         /* Not error - it's okay we don't have root entry. */
         trace_vtd_re_not_present(bus_num);
         return -VTD_FR_ROOT_ENTRY_P;
     }

     ret_fr = vtd_root_entry_rsvd_bits_check(s, &re);
     if (ret_fr) {
         return ret_fr;
     }

     ret_fr = vtd_get_context_entry_from_root(s, &re, devfn, ce);
     if (ret_fr) {
         return ret_fr;
     }

     if (!vtd_ce_present(ce)) {
         /* Not error - it's okay we don't have context entry. */
         trace_vtd_ce_not_present(bus_num, devfn);
         return -VTD_FR_CONTEXT_ENTRY_P;
     }

     ret_fr = vtd_context_entry_rsvd_bits_check(s, ce);
     if (ret_fr) {
         return ret_fr;
     }

     /* Check if the programming of context-entry is valid */
     if (!s->root_scalable &&
         !vtd_is_level_supported(s, vtd_ce_get_level(ce))) {
         error_report_once("%s: invalid context entry: hi=%"PRIx64
                           ", lo=%"PRIx64" (level %d not supported)",
                           __func__, ce->hi, ce->lo,
                           vtd_ce_get_level(ce));
         return -VTD_FR_CONTEXT_ENTRY_INV;
     }

     if (!s->root_scalable) {
         /* Do translation type check */
         if (!vtd_ce_type_check(x86_iommu, ce)) {
             /* Errors dumped in vtd_ce_type_check() */
             return -VTD_FR_CONTEXT_ENTRY_INV;
         }
     } else {
         /*
          * Check if the programming of context-entry.rid2pasid
          * and corresponding pasid setting is valid, and thus
          * avoids to check pasid entry fetching result in future
          * helper function calling.
          */
         ret_fr = vtd_ce_rid2pasid_check(s, ce);
         if (ret_fr) {
             return ret_fr;
         }
     }

     return 0;
 }

 static int vtd_sync_shadow_page_hook(const IOMMUTLBEvent *event,
                                      void *private)
 {
     memory_region_notify_iommu(private, 0, *event);
     return 0;
 }

 static uint16_t vtd_get_domain_id(IntelIOMMUState *s,
                                   VTDContextEntry *ce,
                                   uint32_t pasid)
 {
     VTDPASIDEntry pe;

     if (s->root_scalable) {
         vtd_ce_get_rid2pasid_entry(s, ce, &pe, pasid);
         return VTD_SM_PASID_ENTRY_DID(pe.val[1]);
     }

     return VTD_CONTEXT_ENTRY_DID(ce->hi);
 }

 static int vtd_sync_shadow_page_table_range(VTDAddressSpace *vtd_as,
                                             VTDContextEntry *ce,
                                             hwaddr addr, hwaddr size)
 {
     IntelIOMMUState *s = vtd_as->iommu_state;
     vtd_page_walk_info info = {
         .hook_fn = vtd_sync_shadow_page_hook,
         .private = (void *)&vtd_as->iommu,
         .notify_unmap = true,
         .aw = s->aw_bits,
         .as = vtd_as,
         .domain_id = vtd_get_domain_id(s, ce, vtd_as->pasid),
     };

     return vtd_page_walk(s, ce, addr, addr + size, &info, vtd_as->pasid);
 }

 static int vtd_address_space_sync(VTDAddressSpace *vtd_as)
 {
     int ret;
     VTDContextEntry ce;
     IOMMUNotifier *n;

     /* If no MAP notifier registered, we simply invalidate all the cache */
     if (!vtd_as_has_map_notifier(vtd_as)) {
         IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) {
             memory_region_unmap_iommu_notifier_range(n);
         }
         return 0;
     }

     ret = vtd_dev_to_context_entry(vtd_as->iommu_state,
                                    pci_bus_num(vtd_as->bus),
                                    vtd_as->devfn, &ce);
     if (ret) {
         if (ret == -VTD_FR_CONTEXT_ENTRY_P) {
             /*
              * It's a valid scenario to have a context entry that is
              * not present.  For example, when a device is removed
              * from an existing domain then the context entry will be
              * zeroed by the guest before it was put into another
              * domain.  When this happens, instead of synchronizing
              * the shadow pages we should invalidate all existing
              * mappings and notify the backends.
              */
             IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) {
                 vtd_address_space_unmap(vtd_as, n);
             }
             ret = 0;
         }
         return ret;
     }

     return vtd_sync_shadow_page_table_range(vtd_as, &ce, 0, UINT64_MAX);
 }

 /*
  * Check if specific device is configured to bypass address
  * translation for DMA requests. In Scalable Mode, bypass
  * 1st-level translation or 2nd-level translation, it depends
  * on PGTT setting.
  */
 static bool vtd_dev_pt_enabled(IntelIOMMUState *s, VTDContextEntry *ce,
                                uint32_t pasid)
 {
     VTDPASIDEntry pe;
     int ret;

     if (s->root_scalable) {
         ret = vtd_ce_get_rid2pasid_entry(s, ce, &pe, pasid);
         if (ret) {
             /*
              * This error is guest triggerable. We should assumt PT
              * not enabled for safety.
              */
             return false;
         }
         return (VTD_PE_GET_TYPE(&pe) == VTD_SM_PASID_ENTRY_PT);
     }

     return (vtd_ce_get_type(ce) == VTD_CONTEXT_TT_PASS_THROUGH);

 }

 static bool vtd_as_pt_enabled(VTDAddressSpace *as)
 {
     IntelIOMMUState *s;
     VTDContextEntry ce;

     assert(as);

     s = as->iommu_state;
     if (vtd_dev_to_context_entry(s, pci_bus_num(as->bus), as->devfn,
                                  &ce)) {
         /*
          * Possibly failed to parse the context entry for some reason
          * (e.g., during init, or any guest configuration errors on
          * context entries). We should assume PT not enabled for
          * safety.
          */
         return false;
     }

     return vtd_dev_pt_enabled(s, &ce, as->pasid);
 }

 /* Return whether the device is using IOMMU translation. */
 static bool vtd_switch_address_space(VTDAddressSpace *as)
 {
     bool use_iommu, pt;
     /* Whether we need to take the BQL on our own */
     bool take_bql = !bql_locked();

     assert(as);

     use_iommu = as->iommu_state->dmar_enabled && !vtd_as_pt_enabled(as);
     pt = as->iommu_state->dmar_enabled && vtd_as_pt_enabled(as);

     trace_vtd_switch_address_space(pci_bus_num(as->bus),
                                    VTD_PCI_SLOT(as->devfn),
                                    VTD_PCI_FUNC(as->devfn),
                                    use_iommu);

     /*
      * It's possible that we reach here without BQL, e.g., when called
      * from vtd_pt_enable_fast_path(). However the memory APIs need
      * it. We'd better make sure we have had it already, or, take it.
      */
     if (take_bql) {
         bql_lock();
     }

     /* Turn off first then on the other */
     if (use_iommu) {
         memory_region_set_enabled(&as->nodmar, false);
         memory_region_set_enabled(MEMORY_REGION(&as->iommu), true);
         /*
          * vt-d spec v3.4 3.14:
          *
          * """
          * Requests-with-PASID with input address in range 0xFEEx_xxxx
          * are translated normally like any other request-with-PASID
          * through DMA-remapping hardware.
          * """
          *
          * Need to disable ir for as with PASID.
          */
         if (as->pasid != PCI_NO_PASID) {
             memory_region_set_enabled(&as->iommu_ir, false);
         } else {
             memory_region_set_enabled(&as->iommu_ir, true);
         }
     } else {
         memory_region_set_enabled(MEMORY_REGION(&as->iommu), false);
         memory_region_set_enabled(&as->nodmar, true);
     }

     /*
      * vtd-spec v3.4 3.14:
      *
      * """
      * Requests-with-PASID with input address in range 0xFEEx_xxxx are
      * translated normally like any other request-with-PASID through
      * DMA-remapping hardware. However, if such a request is processed
      * using pass-through translation, it will be blocked as described
      * in the paragraph below.
      *
      * Software must not program paging-structure entries to remap any
      * address to the interrupt address range. Untranslated requests
      * and translation requests that result in an address in the
      * interrupt range will be blocked with condition code LGN.4 or
      * SGN.8.
      * """
      *
      * We enable per as memory region (iommu_ir_fault) for catching
      * the translation for interrupt range through PASID + PT.
      */
     if (pt && as->pasid != PCI_NO_PASID) {
         memory_region_set_enabled(&as->iommu_ir_fault, true);
     } else {
         memory_region_set_enabled(&as->iommu_ir_fault, false);
     }

     if (take_bql) {
         bql_unlock();
     }

     return use_iommu;
 }

 static void vtd_switch_address_space_all(IntelIOMMUState *s)
 {
     VTDAddressSpace *vtd_as;
     GHashTableIter iter;

     g_hash_table_iter_init(&iter, s->vtd_address_spaces);
     while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_as)) {
         vtd_switch_address_space(vtd_as);
     }
 }

 static const bool vtd_qualified_faults[] = {
     [VTD_FR_RESERVED] = false,
     [VTD_FR_ROOT_ENTRY_P] = false,
     [VTD_FR_CONTEXT_ENTRY_P] = true,
     [VTD_FR_CONTEXT_ENTRY_INV] = true,
     [VTD_FR_ADDR_BEYOND_MGAW] = true,
     [VTD_FR_WRITE] = true,
     [VTD_FR_READ] = true,
     [VTD_FR_PAGING_ENTRY_INV] = true,
     [VTD_FR_ROOT_TABLE_INV] = false,
     [VTD_FR_CONTEXT_TABLE_INV] = false,
     [VTD_FR_INTERRUPT_ADDR] = true,
     [VTD_FR_ROOT_ENTRY_RSVD] = false,
     [VTD_FR_PAGING_ENTRY_RSVD] = true,
     [VTD_FR_CONTEXT_ENTRY_TT] = true,
     [VTD_FR_PASID_TABLE_INV] = false,
     [VTD_FR_SM_INTERRUPT_ADDR] = true,
     [VTD_FR_MAX] = false,
 };

 /* To see if a fault condition is "qualified", which is reported to software
  * only if the FPD field in the context-entry used to process the faulting
  * request is 0.
  */
 static inline bool vtd_is_qualified_fault(VTDFaultReason fault)
 {
     return vtd_qualified_faults[fault];
 }

 static inline bool vtd_is_interrupt_addr(hwaddr addr)
 {
     return VTD_INTERRUPT_ADDR_FIRST <= addr && addr <= VTD_INTERRUPT_ADDR_LAST;
 }

 static gboolean vtd_find_as_by_sid(gpointer key, gpointer value,
                                    gpointer user_data)
 {
     struct vtd_as_key *as_key = (struct vtd_as_key *)key;
     uint16_t target_sid = *(uint16_t *)user_data;
     uint16_t sid = PCI_BUILD_BDF(pci_bus_num(as_key->bus), as_key->devfn);
     return sid == target_sid;
 }

 static VTDAddressSpace *vtd_get_as_by_sid(IntelIOMMUState *s, uint16_t sid)
 {
     uint8_t bus_num = PCI_BUS_NUM(sid);
     VTDAddressSpace *vtd_as = s->vtd_as_cache[bus_num];

     if (vtd_as &&
         (sid == PCI_BUILD_BDF(pci_bus_num(vtd_as->bus), vtd_as->devfn))) {
         return vtd_as;
     }

     vtd_as = g_hash_table_find(s->vtd_address_spaces, vtd_find_as_by_sid, &sid);
     s->vtd_as_cache[bus_num] = vtd_as;

     return vtd_as;
 }

 static void vtd_pt_enable_fast_path(IntelIOMMUState *s, uint16_t source_id)
 {
     VTDAddressSpace *vtd_as;
     bool success = false;

     vtd_as = vtd_get_as_by_sid(s, source_id);
     if (!vtd_as) {
         goto out;
     }

     if (vtd_switch_address_space(vtd_as) == false) {
         /* We switched off IOMMU region successfully. */
         success = true;
     }

 out:
     trace_vtd_pt_enable_fast_path(source_id, success);
 }

 static void vtd_report_fault(IntelIOMMUState *s,
                              int err, bool is_fpd_set,
                              uint16_t source_id,
                              hwaddr addr,
                              bool is_write,
                              bool is_pasid,
                              uint32_t pasid)
 {
     if (is_fpd_set && vtd_is_qualified_fault(err)) {
         trace_vtd_fault_disabled();
     } else {
         vtd_report_dmar_fault(s, source_id, addr, err, is_write,
                               is_pasid, pasid);
     }
 }

 /* Map dev to context-entry then do a paging-structures walk to do a iommu
  * translation.
  *
  * Called from RCU critical section.
  *
  * @bus_num: The bus number
  * @devfn: The devfn, which is the  combined of device and function number
  * @is_write: The access is a write operation
  * @entry: IOMMUTLBEntry that contain the addr to be translated and result
  *
  * Returns true if translation is successful, otherwise false.
  */
 static bool vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
                                    uint8_t devfn, hwaddr addr, bool is_write,
                                    IOMMUTLBEntry *entry)
 {
     IntelIOMMUState *s = vtd_as->iommu_state;
     VTDContextEntry ce;
     uint8_t bus_num = pci_bus_num(bus);
     VTDContextCacheEntry *cc_entry;
     uint64_t slpte, page_mask;
     uint32_t level, pasid = vtd_as->pasid;
     uint16_t source_id = PCI_BUILD_BDF(bus_num, devfn);
     int ret_fr;
     bool is_fpd_set = false;
     bool reads = true;
     bool writes = true;
     uint8_t access_flags;
     bool rid2pasid = (pasid == PCI_NO_PASID) && s->root_scalable;
     VTDIOTLBEntry *iotlb_entry;

     /*
      * We have standalone memory region for interrupt addresses, we
      * should never receive translation requests in this region.
      */
     assert(!vtd_is_interrupt_addr(addr));

     vtd_iommu_lock(s);

     cc_entry = &vtd_as->context_cache_entry;

     /* Try to fetch slpte form IOTLB, we don't need RID2PASID logic */
     if (!rid2pasid) {
         iotlb_entry = vtd_lookup_iotlb(s, source_id, pasid, addr);
         if (iotlb_entry) {
             trace_vtd_iotlb_page_hit(source_id, addr, iotlb_entry->slpte,
                                      iotlb_entry->domain_id);
             slpte = iotlb_entry->slpte;
             access_flags = iotlb_entry->access_flags;
             page_mask = iotlb_entry->mask;
             goto out;
         }
     }

     /* Try to fetch context-entry from cache first */
     if (cc_entry->context_cache_gen == s->context_cache_gen) {
         trace_vtd_iotlb_cc_hit(bus_num, devfn, cc_entry->context_entry.hi,
                                cc_entry->context_entry.lo,
                                cc_entry->context_cache_gen);
         ce = cc_entry->context_entry;
         is_fpd_set = ce.lo & VTD_CONTEXT_ENTRY_FPD;
         if (!is_fpd_set && s->root_scalable) {
             ret_fr = vtd_ce_get_pasid_fpd(s, &ce, &is_fpd_set, pasid);
             if (ret_fr) {
                 vtd_report_fault(s, -ret_fr, is_fpd_set,
                                  source_id, addr, is_write,
                                  false, 0);
                 goto error;
             }
         }
     } else {
         ret_fr = vtd_dev_to_context_entry(s, bus_num, devfn, &ce);
         is_fpd_set = ce.lo & VTD_CONTEXT_ENTRY_FPD;
         if (!ret_fr && !is_fpd_set && s->root_scalable) {
             ret_fr = vtd_ce_get_pasid_fpd(s, &ce, &is_fpd_set, pasid);
         }
         if (ret_fr) {
             vtd_report_fault(s, -ret_fr, is_fpd_set,
                              source_id, addr, is_write,
                              false, 0);
             goto error;
         }
         /* Update context-cache */
         trace_vtd_iotlb_cc_update(bus_num, devfn, ce.hi, ce.lo,
                                   cc_entry->context_cache_gen,
                                   s->context_cache_gen);
         cc_entry->context_entry = ce;
         cc_entry->context_cache_gen = s->context_cache_gen;
     }

     if (rid2pasid) {
         pasid = VTD_CE_GET_RID2PASID(&ce);
     }

     /*
      * We don't need to translate for pass-through context entries.
      * Also, let's ignore IOTLB caching as well for PT devices.
      */
     if (vtd_dev_pt_enabled(s, &ce, pasid)) {
         entry->iova = addr & VTD_PAGE_MASK_4K;
         entry->translated_addr = entry->iova;
         entry->addr_mask = ~VTD_PAGE_MASK_4K;
         entry->perm = IOMMU_RW;
         trace_vtd_translate_pt(source_id, entry->iova);

         /*
          * When this happens, it means firstly caching-mode is not
          * enabled, and this is the first passthrough translation for
          * the device. Let's enable the fast path for passthrough.
          *
          * When passthrough is disabled again for the device, we can
          * capture it via the context entry invalidation, then the
          * IOMMU region can be swapped back.
          */
         vtd_pt_enable_fast_path(s, source_id);
         vtd_iommu_unlock(s);
         return true;
     }

     /* Try to fetch slpte form IOTLB for RID2PASID slow path */
     if (rid2pasid) {
         iotlb_entry = vtd_lookup_iotlb(s, source_id, pasid, addr);
         if (iotlb_entry) {
             trace_vtd_iotlb_page_hit(source_id, addr, iotlb_entry->slpte,
                                      iotlb_entry->domain_id);
             slpte = iotlb_entry->slpte;
             access_flags = iotlb_entry->access_flags;
             page_mask = iotlb_entry->mask;
             goto out;
         }
     }

     ret_fr = vtd_iova_to_slpte(s, &ce, addr, is_write, &slpte, &level,
                                &reads, &writes, s->aw_bits, pasid);
     if (ret_fr) {
         vtd_report_fault(s, -ret_fr, is_fpd_set, source_id,
                          addr, is_write, pasid != PCI_NO_PASID, pasid);
         goto error;
     }

     page_mask = vtd_slpt_level_page_mask(level);
     access_flags = IOMMU_ACCESS_FLAG(reads, writes);
     vtd_update_iotlb(s, source_id, vtd_get_domain_id(s, &ce, pasid),
                      addr, slpte, access_flags, level, pasid);
 out:
     vtd_iommu_unlock(s);
     entry->iova = addr & page_mask;
     entry->translated_addr = vtd_get_slpte_addr(slpte, s->aw_bits) & page_mask;
     entry->addr_mask = ~page_mask;
     entry->perm = access_flags;
     return true;

 error:
     vtd_iommu_unlock(s);
     entry->iova = 0;
     entry->translated_addr = 0;
     entry->addr_mask = 0;
     entry->perm = IOMMU_NONE;
     return false;
 }

 static void vtd_root_table_setup(IntelIOMMUState *s)
 {
     s->root = vtd_get_quad_raw(s, DMAR_RTADDR_REG);
     s->root &= VTD_RTADDR_ADDR_MASK(s->aw_bits);

     vtd_update_scalable_state(s);

     trace_vtd_reg_dmar_root(s->root, s->root_scalable);
 }

 static void vtd_iec_notify_all(IntelIOMMUState *s, bool global,
                                uint32_t index, uint32_t mask)
 {
     x86_iommu_iec_notify_all(X86_IOMMU_DEVICE(s), global, index, mask);
 }

 static void vtd_interrupt_remap_table_setup(IntelIOMMUState *s)
 {
     uint64_t value = 0;
     value = vtd_get_quad_raw(s, DMAR_IRTA_REG);
     s->intr_size = 1UL << ((value & VTD_IRTA_SIZE_MASK) + 1);
     s->intr_root = value & VTD_IRTA_ADDR_MASK(s->aw_bits);
     s->intr_eime = value & VTD_IRTA_EIME;

     /* Notify global invalidation */
     vtd_iec_notify_all(s, true, 0, 0);

     trace_vtd_reg_ir_root(s->intr_root, s->intr_size);
 }

 static void vtd_iommu_replay_all(IntelIOMMUState *s)
 {
     VTDAddressSpace *vtd_as;

     QLIST_FOREACH(vtd_as, &s->vtd_as_with_notifiers, next) {
         vtd_address_space_sync(vtd_as);
     }
 }

 static void vtd_context_global_invalidate(IntelIOMMUState *s)
 {
     trace_vtd_inv_desc_cc_global();
     /* Protects context cache */
     vtd_iommu_lock(s);
     s->context_cache_gen++;
     if (s->context_cache_gen == VTD_CONTEXT_CACHE_GEN_MAX) {
         vtd_reset_context_cache_locked(s);
     }
     vtd_iommu_unlock(s);
     vtd_address_space_refresh_all(s);
     /*
      * From VT-d spec 6.5.2.1, a global context entry invalidation
      * should be followed by a IOTLB global invalidation, so we should
      * be safe even without this. Hoewever, let's replay the region as
      * well to be safer, and go back here when we need finer tunes for
      * VT-d emulation codes.
      */
     vtd_iommu_replay_all(s);
 }

 /* Do a context-cache device-selective invalidation.
  * @func_mask: FM field after shifting
  */
 static void vtd_context_device_invalidate(IntelIOMMUState *s,
                                           uint16_t source_id,
                                           uint16_t func_mask)
 {
     GHashTableIter as_it;
     uint16_t mask;
     VTDAddressSpace *vtd_as;
     uint8_t bus_n, devfn;

     trace_vtd_inv_desc_cc_devices(source_id, func_mask);

     switch (func_mask & 3) {
     case 0:
         mask = 0;   /* No bits in the SID field masked */
         break;
     case 1:
         mask = 4;   /* Mask bit 2 in the SID field */
         break;
     case 2:
         mask = 6;   /* Mask bit 2:1 in the SID field */
         break;
     case 3:
         mask = 7;   /* Mask bit 2:0 in the SID field */
         break;
     default:
         g_assert_not_reached();
     }
     mask = ~mask;

     bus_n = VTD_SID_TO_BUS(source_id);
     devfn = VTD_SID_TO_DEVFN(source_id);

     g_hash_table_iter_init(&as_it, s->vtd_address_spaces);
     while (g_hash_table_iter_next(&as_it, NULL, (void **)&vtd_as)) {
         if ((pci_bus_num(vtd_as->bus) == bus_n) &&
             (vtd_as->devfn & mask) == (devfn & mask)) {
             trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(vtd_as->devfn),
                                          VTD_PCI_FUNC(vtd_as->devfn));
             vtd_iommu_lock(s);
             vtd_as->context_cache_entry.context_cache_gen = 0;
             vtd_iommu_unlock(s);
             /*
              * Do switch address space when needed, in case if the
              * device passthrough bit is switched.
              */
             vtd_switch_address_space(vtd_as);
             /*
              * So a device is moving out of (or moving into) a
              * domain, resync the shadow page table.
              * This won't bring bad even if we have no such
              * notifier registered - the IOMMU notification
              * framework will skip MAP notifications if that
              * happened.
              */
             vtd_address_space_sync(vtd_as);
         }
     }
 }

 /* Context-cache invalidation
  * Returns the Context Actual Invalidation Granularity.
  * @val: the content of the CCMD_REG
  */
 static uint64_t vtd_context_cache_invalidate(IntelIOMMUState *s, uint64_t val)
 {
     uint64_t caig;
     uint64_t type = val & VTD_CCMD_CIRG_MASK;

     switch (type) {
     case VTD_CCMD_DOMAIN_INVL:
         /* Fall through */
     case VTD_CCMD_GLOBAL_INVL:
         caig = VTD_CCMD_GLOBAL_INVL_A;
         vtd_context_global_invalidate(s);
         break;

     case VTD_CCMD_DEVICE_INVL:
         caig = VTD_CCMD_DEVICE_INVL_A;
         vtd_context_device_invalidate(s, VTD_CCMD_SID(val), VTD_CCMD_FM(val));
         break;

     default:
         error_report_once("%s: invalid context: 0x%" PRIx64,
                           __func__, val);
         caig = 0;
     }
     return caig;
 }

 static void vtd_iotlb_global_invalidate(IntelIOMMUState *s)
 {
     trace_vtd_inv_desc_iotlb_global();
     vtd_reset_iotlb(s);
     vtd_iommu_replay_all(s);
 }

 static void vtd_iotlb_domain_invalidate(IntelIOMMUState *s, uint16_t domain_id)
 {
     VTDContextEntry ce;
     VTDAddressSpace *vtd_as;

     trace_vtd_inv_desc_iotlb_domain(domain_id);

     vtd_iommu_lock(s);
     g_hash_table_foreach_remove(s->iotlb, vtd_hash_remove_by_domain,
                                 &domain_id);
     vtd_iommu_unlock(s);

     QLIST_FOREACH(vtd_as, &s->vtd_as_with_notifiers, next) {
         if (!vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
                                       vtd_as->devfn, &ce) &&
             domain_id == vtd_get_domain_id(s, &ce, vtd_as->pasid)) {
             vtd_address_space_sync(vtd_as);
         }
     }
 }

 static void vtd_iotlb_page_invalidate_notify(IntelIOMMUState *s,
                                            uint16_t domain_id, hwaddr addr,
                                              uint8_t am, uint32_t pasid)
 {
     VTDAddressSpace *vtd_as;
     VTDContextEntry ce;
     int ret;
     hwaddr size = (1 << am) * VTD_PAGE_SIZE;

     QLIST_FOREACH(vtd_as, &(s->vtd_as_with_notifiers), next) {
         if (pasid != PCI_NO_PASID && pasid != vtd_as->pasid) {
             continue;
         }
         ret = vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
                                        vtd_as->devfn, &ce);
         if (!ret && domain_id == vtd_get_domain_id(s, &ce, vtd_as->pasid)) {
             if (vtd_as_has_map_notifier(vtd_as)) {
                 /*
                  * As long as we have MAP notifications registered in
                  * any of our IOMMU notifiers, we need to sync the
                  * shadow page table.
                  */
                 vtd_sync_shadow_page_table_range(vtd_as, &ce, addr, size);
             } else {
                 /*
                  * For UNMAP-only notifiers, we don't need to walk the
                  * page tables.  We just deliver the PSI down to
                  * invalidate caches.
                  */
                 const IOMMUTLBEvent event = {
                     .type = IOMMU_NOTIFIER_UNMAP,
                     .entry = {
                         .target_as = &address_space_memory,
                         .iova = addr,
                         .translated_addr = 0,
                         .addr_mask = size - 1,
                         .perm = IOMMU_NONE,
                     },
                 };
                 memory_region_notify_iommu(&vtd_as->iommu, 0, event);
             }
         }
     }
 }

 static void vtd_iotlb_page_invalidate(IntelIOMMUState *s, uint16_t domain_id,
                                       hwaddr addr, uint8_t am)
 {
     VTDIOTLBPageInvInfo info;

     trace_vtd_inv_desc_iotlb_pages(domain_id, addr, am);

     assert(am <= VTD_MAMV);
     info.domain_id = domain_id;
     info.addr = addr;
     info.mask = ~((1 << am) - 1);
     vtd_iommu_lock(s);
     g_hash_table_foreach_remove(s->iotlb, vtd_hash_remove_by_page, &info);
     vtd_iommu_unlock(s);
     vtd_iotlb_page_invalidate_notify(s, domain_id, addr, am, PCI_NO_PASID);
 }

 /* Flush IOTLB
  * Returns the IOTLB Actual Invalidation Granularity.
  * @val: the content of the IOTLB_REG
  */
 static uint64_t vtd_iotlb_flush(IntelIOMMUState *s, uint64_t val)
 {
     uint64_t iaig;
     uint64_t type = val & VTD_TLB_FLUSH_GRANU_MASK;
     uint16_t domain_id;
     hwaddr addr;
     uint8_t am;

     switch (type) {
     case VTD_TLB_GLOBAL_FLUSH:
         iaig = VTD_TLB_GLOBAL_FLUSH_A;
         vtd_iotlb_global_invalidate(s);
         break;

     case VTD_TLB_DSI_FLUSH:
         domain_id = VTD_TLB_DID(val);
         iaig = VTD_TLB_DSI_FLUSH_A;
         vtd_iotlb_domain_invalidate(s, domain_id);
         break;

     case VTD_TLB_PSI_FLUSH:
         domain_id = VTD_TLB_DID(val);
         addr = vtd_get_quad_raw(s, DMAR_IVA_REG);
         am = VTD_IVA_AM(addr);
         addr = VTD_IVA_ADDR(addr);
         if (am > VTD_MAMV) {
             error_report_once("%s: address mask overflow: 0x%" PRIx64,
                               __func__, vtd_get_quad_raw(s, DMAR_IVA_REG));
             iaig = 0;
             break;
         }
         iaig = VTD_TLB_PSI_FLUSH_A;
         vtd_iotlb_page_invalidate(s, domain_id, addr, am);
         break;

     default:
         error_report_once("%s: invalid granularity: 0x%" PRIx64,
                           __func__, val);
         iaig = 0;
     }
     return iaig;
 }

 static void vtd_fetch_inv_desc(IntelIOMMUState *s);

 static inline bool vtd_queued_inv_disable_check(IntelIOMMUState *s)
 {
     return s->qi_enabled && (s->iq_tail == s->iq_head) &&
            (s->iq_last_desc_type == VTD_INV_DESC_WAIT);
 }

 static void vtd_handle_gcmd_qie(IntelIOMMUState *s, bool en)
 {
     uint64_t iqa_val = vtd_get_quad_raw(s, DMAR_IQA_REG);

     trace_vtd_inv_qi_enable(en);

     if (en) {
         s->iq = iqa_val & VTD_IQA_IQA_MASK(s->aw_bits);
         /* 2^(x+8) entries */
         s->iq_size = 1UL << ((iqa_val & VTD_IQA_QS) + 8 - (s->iq_dw ? 1 : 0));
         s->qi_enabled = true;
         trace_vtd_inv_qi_setup(s->iq, s->iq_size);
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_QIES);

         if (s->iq_tail != 0) {
             /*
              * This is a spec violation but Windows guests are known to set up
              * Queued Invalidation this way so we allow the write and process
              * Invalidation Descriptors right away.
              */
             trace_vtd_warn_invalid_qi_tail(s->iq_tail);
             if (!(vtd_get_long_raw(s, DMAR_FSTS_REG) & VTD_FSTS_IQE)) {
                 vtd_fetch_inv_desc(s);
             }
         }
     } else {
         if (vtd_queued_inv_disable_check(s)) {
             /* disable Queued Invalidation */
             vtd_set_quad_raw(s, DMAR_IQH_REG, 0);
             s->iq_head = 0;
             s->qi_enabled = false;
             /* Ok - report back to driver */
             vtd_set_clear_mask_long(s, DMAR_GSTS_REG, VTD_GSTS_QIES, 0);
         } else {
             error_report_once("%s: detected improper state when disable QI "
                               "(head=0x%x, tail=0x%x, last_type=%d)",
                               __func__,
                               s->iq_head, s->iq_tail, s->iq_last_desc_type);
         }
     }
 }

 /* Set Root Table Pointer */
 static void vtd_handle_gcmd_srtp(IntelIOMMUState *s)
 {
     vtd_root_table_setup(s);
     /* Ok - report back to driver */
     vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_RTPS);
     vtd_reset_caches(s);
     vtd_address_space_refresh_all(s);
 }

 /* Set Interrupt Remap Table Pointer */
 static void vtd_handle_gcmd_sirtp(IntelIOMMUState *s)
 {
     vtd_interrupt_remap_table_setup(s);
     /* Ok - report back to driver */
     vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_IRTPS);
 }

 /* Handle Translation Enable/Disable */
 static void vtd_handle_gcmd_te(IntelIOMMUState *s, bool en)
 {
     if (s->dmar_enabled == en) {
         return;
     }

     trace_vtd_dmar_enable(en);

     if (en) {
         s->dmar_enabled = true;
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_TES);
     } else {
         s->dmar_enabled = false;

         /* Clear the index of Fault Recording Register */
         s->next_frcd_reg = 0;
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, VTD_GSTS_TES, 0);
     }

     vtd_reset_caches(s);
     vtd_address_space_refresh_all(s);
 }

 /* Handle Interrupt Remap Enable/Disable */
 static void vtd_handle_gcmd_ire(IntelIOMMUState *s, bool en)
 {
     trace_vtd_ir_enable(en);

     if (en) {
         s->intr_enabled = true;
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_IRES);
     } else {
         s->intr_enabled = false;
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, VTD_GSTS_IRES, 0);
     }
 }

 /* Handle write to Global Command Register */
 static void vtd_handle_gcmd_write(IntelIOMMUState *s)
 {
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
     uint32_t status = vtd_get_long_raw(s, DMAR_GSTS_REG);
     uint32_t val = vtd_get_long_raw(s, DMAR_GCMD_REG);
     uint32_t changed = status ^ val;

     trace_vtd_reg_write_gcmd(status, val);
     if ((changed & VTD_GCMD_TE) && s->dma_translation) {
         /* Translation enable/disable */
         vtd_handle_gcmd_te(s, val & VTD_GCMD_TE);
     }
     if (val & VTD_GCMD_SRTP) {
         /* Set/update the root-table pointer */
         vtd_handle_gcmd_srtp(s);
     }
     if (changed & VTD_GCMD_QIE) {
         /* Queued Invalidation Enable */
         vtd_handle_gcmd_qie(s, val & VTD_GCMD_QIE);
     }
     if (val & VTD_GCMD_SIRTP) {
         /* Set/update the interrupt remapping root-table pointer */
         vtd_handle_gcmd_sirtp(s);
     }
     if ((changed & VTD_GCMD_IRE) &&
         x86_iommu_ir_supported(x86_iommu)) {
         /* Interrupt remap enable/disable */
         vtd_handle_gcmd_ire(s, val & VTD_GCMD_IRE);
     }
 }

 /* Handle write to Context Command Register */
 static void vtd_handle_ccmd_write(IntelIOMMUState *s)
 {
     uint64_t ret;
     uint64_t val = vtd_get_quad_raw(s, DMAR_CCMD_REG);

     /* Context-cache invalidation request */
     if (val & VTD_CCMD_ICC) {
         if (s->qi_enabled) {
             error_report_once("Queued Invalidation enabled, "
                               "should not use register-based invalidation");
             return;
         }
         ret = vtd_context_cache_invalidate(s, val);
         /* Invalidation completed. Change something to show */
         vtd_set_clear_mask_quad(s, DMAR_CCMD_REG, VTD_CCMD_ICC, 0ULL);
         ret = vtd_set_clear_mask_quad(s, DMAR_CCMD_REG, VTD_CCMD_CAIG_MASK,
                                       ret);
     }
 }

 /* Handle write to IOTLB Invalidation Register */
 static void vtd_handle_iotlb_write(IntelIOMMUState *s)
 {
     uint64_t ret;
     uint64_t val = vtd_get_quad_raw(s, DMAR_IOTLB_REG);

     /* IOTLB invalidation request */
     if (val & VTD_TLB_IVT) {
         if (s->qi_enabled) {
             error_report_once("Queued Invalidation enabled, "
                               "should not use register-based invalidation");
             return;
         }
         ret = vtd_iotlb_flush(s, val);
         /* Invalidation completed. Change something to show */
         vtd_set_clear_mask_quad(s, DMAR_IOTLB_REG, VTD_TLB_IVT, 0ULL);
         ret = vtd_set_clear_mask_quad(s, DMAR_IOTLB_REG,
                                       VTD_TLB_FLUSH_GRANU_MASK_A, ret);
     }
 }

 /* Fetch an Invalidation Descriptor from the Invalidation Queue */
 static bool vtd_get_inv_desc(IntelIOMMUState *s,
                              VTDInvDesc *inv_desc)
 {
     dma_addr_t base_addr = s->iq;
     uint32_t offset = s->iq_head;
     uint32_t dw = s->iq_dw ? 32 : 16;
     dma_addr_t addr = base_addr + offset * dw;

     if (dma_memory_read(&address_space_memory, addr,
                         inv_desc, dw, MEMTXATTRS_UNSPECIFIED)) {
         error_report_once("Read INV DESC failed.");
         return false;
     }
     inv_desc->lo = le64_to_cpu(inv_desc->lo);
     inv_desc->hi = le64_to_cpu(inv_desc->hi);
     if (dw == 32) {
         inv_desc->val[2] = le64_to_cpu(inv_desc->val[2]);
         inv_desc->val[3] = le64_to_cpu(inv_desc->val[3]);
     }
     return true;
 }

 static bool vtd_process_wait_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 {
     if ((inv_desc->hi & VTD_INV_DESC_WAIT_RSVD_HI) ||
         (inv_desc->lo & VTD_INV_DESC_WAIT_RSVD_LO)) {
         error_report_once("%s: invalid wait desc: hi=%"PRIx64", lo=%"PRIx64
                           " (reserved nonzero)", __func__, inv_desc->hi,
                           inv_desc->lo);
         return false;
     }
     if (inv_desc->lo & VTD_INV_DESC_WAIT_SW) {
         /* Status Write */
         uint32_t status_data = (uint32_t)(inv_desc->lo >>
                                VTD_INV_DESC_WAIT_DATA_SHIFT);

         assert(!(inv_desc->lo & VTD_INV_DESC_WAIT_IF));

         /* FIXME: need to be masked with HAW? */
         dma_addr_t status_addr = inv_desc->hi;
         trace_vtd_inv_desc_wait_sw(status_addr, status_data);
         status_data = cpu_to_le32(status_data);
         if (dma_memory_write(&address_space_memory, status_addr,
                              &status_data, sizeof(status_data),
                              MEMTXATTRS_UNSPECIFIED)) {
             trace_vtd_inv_desc_wait_write_fail(inv_desc->hi, inv_desc->lo);
             return false;
         }
     } else if (inv_desc->lo & VTD_INV_DESC_WAIT_IF) {
         /* Interrupt flag */
         vtd_generate_completion_event(s);
     } else {
         error_report_once("%s: invalid wait desc: hi=%"PRIx64", lo=%"PRIx64
                           " (unknown type)", __func__, inv_desc->hi,
                           inv_desc->lo);
         return false;
     }
     return true;
 }

 static bool vtd_process_context_cache_desc(IntelIOMMUState *s,
                                            VTDInvDesc *inv_desc)
 {
     uint16_t sid, fmask;

     if ((inv_desc->lo & VTD_INV_DESC_CC_RSVD) || inv_desc->hi) {
         error_report_once("%s: invalid cc inv desc: hi=%"PRIx64", lo=%"PRIx64
                           " (reserved nonzero)", __func__, inv_desc->hi,
                           inv_desc->lo);
         return false;
     }
     switch (inv_desc->lo & VTD_INV_DESC_CC_G) {
     case VTD_INV_DESC_CC_DOMAIN:
         trace_vtd_inv_desc_cc_domain(
             (uint16_t)VTD_INV_DESC_CC_DID(inv_desc->lo));
         /* Fall through */
     case VTD_INV_DESC_CC_GLOBAL:
         vtd_context_global_invalidate(s);
         break;

     case VTD_INV_DESC_CC_DEVICE:
         sid = VTD_INV_DESC_CC_SID(inv_desc->lo);
         fmask = VTD_INV_DESC_CC_FM(inv_desc->lo);
         vtd_context_device_invalidate(s, sid, fmask);
         break;

     default:
         error_report_once("%s: invalid cc inv desc: hi=%"PRIx64", lo=%"PRIx64
                           " (invalid type)", __func__, inv_desc->hi,
                           inv_desc->lo);
         return false;
     }
     return true;
 }

 static bool vtd_process_iotlb_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 {
     uint16_t domain_id;
     uint8_t am;
     hwaddr addr;

     if ((inv_desc->lo & VTD_INV_DESC_IOTLB_RSVD_LO) ||
         (inv_desc->hi & VTD_INV_DESC_IOTLB_RSVD_HI)) {
         error_report_once("%s: invalid iotlb inv desc: hi=0x%"PRIx64
                           ", lo=0x%"PRIx64" (reserved bits unzero)",
                           __func__, inv_desc->hi, inv_desc->lo);
         return false;
     }

     switch (inv_desc->lo & VTD_INV_DESC_IOTLB_G) {
     case VTD_INV_DESC_IOTLB_GLOBAL:
         vtd_iotlb_global_invalidate(s);
         break;

     case VTD_INV_DESC_IOTLB_DOMAIN:
         domain_id = VTD_INV_DESC_IOTLB_DID(inv_desc->lo);
         vtd_iotlb_domain_invalidate(s, domain_id);
         break;

     case VTD_INV_DESC_IOTLB_PAGE:
         domain_id = VTD_INV_DESC_IOTLB_DID(inv_desc->lo);
         addr = VTD_INV_DESC_IOTLB_ADDR(inv_desc->hi);
         am = VTD_INV_DESC_IOTLB_AM(inv_desc->hi);
         if (am > VTD_MAMV) {
             error_report_once("%s: invalid iotlb inv desc: hi=0x%"PRIx64
                               ", lo=0x%"PRIx64" (am=%u > VTD_MAMV=%u)",
                               __func__, inv_desc->hi, inv_desc->lo,
                               am, (unsigned)VTD_MAMV);
             return false;
         }
         vtd_iotlb_page_invalidate(s, domain_id, addr, am);
         break;

     default:
         error_report_once("%s: invalid iotlb inv desc: hi=0x%"PRIx64
                           ", lo=0x%"PRIx64" (type mismatch: 0x%llx)",
                           __func__, inv_desc->hi, inv_desc->lo,
                           inv_desc->lo & VTD_INV_DESC_IOTLB_G);
         return false;
     }
     return true;
 }

 static bool vtd_process_inv_iec_desc(IntelIOMMUState *s,
                                      VTDInvDesc *inv_desc)
 {
     trace_vtd_inv_desc_iec(inv_desc->iec.granularity,
                            inv_desc->iec.index,
                            inv_desc->iec.index_mask);

     vtd_iec_notify_all(s, !inv_desc->iec.granularity,
                        inv_desc->iec.index,
                        inv_desc->iec.index_mask);
     return true;
 }

 static void do_invalidate_device_tlb(VTDAddressSpace *vtd_dev_as,
                                      bool size, hwaddr addr)
 {
     /*
      * According to ATS spec table 2.4:
      * S = 0, bits 15:12 = xxxx     range size: 4K
      * S = 1, bits 15:12 = xxx0     range size: 8K
      * S = 1, bits 15:12 = xx01     range size: 16K
      * S = 1, bits 15:12 = x011     range size: 32K
      * S = 1, bits 15:12 = 0111     range size: 64K
      * ...
      */

     IOMMUTLBEvent event;
     uint64_t sz;

     if (size) {
         sz = (VTD_PAGE_SIZE * 2) << cto64(addr >> VTD_PAGE_SHIFT);
         addr &= ~(sz - 1);
     } else {
         sz = VTD_PAGE_SIZE;
     }

     event.type = IOMMU_NOTIFIER_DEVIOTLB_UNMAP;
     event.entry.target_as = &vtd_dev_as->as;
     event.entry.addr_mask = sz - 1;
     event.entry.iova = addr;
     event.entry.perm = IOMMU_NONE;
     event.entry.translated_addr = 0;
     memory_region_notify_iommu(&vtd_dev_as->iommu, 0, event);
 }

 static bool vtd_process_device_iotlb_desc(IntelIOMMUState *s,
                                           VTDInvDesc *inv_desc)
 {
     VTDAddressSpace *vtd_dev_as;
     hwaddr addr;
     uint16_t sid;
     bool size;

     addr = VTD_INV_DESC_DEVICE_IOTLB_ADDR(inv_desc->hi);
     sid = VTD_INV_DESC_DEVICE_IOTLB_SID(inv_desc->lo);
     size = VTD_INV_DESC_DEVICE_IOTLB_SIZE(inv_desc->hi);

     if ((inv_desc->lo & VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO) ||
         (inv_desc->hi & VTD_INV_DESC_DEVICE_IOTLB_RSVD_HI)) {
         error_report_once("%s: invalid dev-iotlb inv desc: hi=%"PRIx64
                           ", lo=%"PRIx64" (reserved nonzero)", __func__,
                           inv_desc->hi, inv_desc->lo);
         return false;
     }

     /*
      * Using sid is OK since the guest should have finished the
      * initialization of both the bus and device.
      */
     vtd_dev_as = vtd_get_as_by_sid(s, sid);
     if (!vtd_dev_as) {
         goto done;
     }

     do_invalidate_device_tlb(vtd_dev_as, size, addr);

 done:
     return true;
 }

 static bool vtd_process_inv_desc(IntelIOMMUState *s)
 {
     VTDInvDesc inv_desc;
     uint8_t desc_type;

     trace_vtd_inv_qi_head(s->iq_head);
     if (!vtd_get_inv_desc(s, &inv_desc)) {
         s->iq_last_desc_type = VTD_INV_DESC_NONE;
         return false;
     }

     desc_type = inv_desc.lo & VTD_INV_DESC_TYPE;
     /* FIXME: should update at first or at last? */
     s->iq_last_desc_type = desc_type;

     switch (desc_type) {
     case VTD_INV_DESC_CC:
         trace_vtd_inv_desc("context-cache", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_context_cache_desc(s, &inv_desc)) {
             return false;
         }
         break;

     case VTD_INV_DESC_IOTLB:
         trace_vtd_inv_desc("iotlb", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_iotlb_desc(s, &inv_desc)) {
             return false;
         }
         break;

     /*
      * TODO: the entity of below two cases will be implemented in future series.
      * To make guest (which integrates scalable mode support patch set in
      * iommu driver) work, just return true is enough so far.
      */
     case VTD_INV_DESC_PC:
         break;

     case VTD_INV_DESC_PIOTLB:
         break;

     case VTD_INV_DESC_WAIT:
         trace_vtd_inv_desc("wait", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_wait_desc(s, &inv_desc)) {
             return false;
         }
         break;

     case VTD_INV_DESC_IEC:
         trace_vtd_inv_desc("iec", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_inv_iec_desc(s, &inv_desc)) {
             return false;
         }
         break;

     case VTD_INV_DESC_DEVICE:
         trace_vtd_inv_desc("device", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_device_iotlb_desc(s, &inv_desc)) {
             return false;
         }
         break;

     default:
         error_report_once("%s: invalid inv desc: hi=%"PRIx64", lo=%"PRIx64
                           " (unknown type)", __func__, inv_desc.hi,
                           inv_desc.lo);
         return false;
     }
     s->iq_head++;
     if (s->iq_head == s->iq_size) {
         s->iq_head = 0;
     }
     return true;
 }

 /* Try to fetch and process more Invalidation Descriptors */
 static void vtd_fetch_inv_desc(IntelIOMMUState *s)
 {
     int qi_shift;

     /* Refer to 10.4.23 of VT-d spec 3.0 */
     qi_shift = s->iq_dw ? VTD_IQH_QH_SHIFT_5 : VTD_IQH_QH_SHIFT_4;

     trace_vtd_inv_qi_fetch();

     if (s->iq_tail >= s->iq_size) {
         /* Detects an invalid Tail pointer */
         error_report_once("%s: detected invalid QI tail "
                           "(tail=0x%x, size=0x%x)",
                           __func__, s->iq_tail, s->iq_size);
         vtd_handle_inv_queue_error(s);
         return;
     }
     while (s->iq_head != s->iq_tail) {
         if (!vtd_process_inv_desc(s)) {
             /* Invalidation Queue Errors */
             vtd_handle_inv_queue_error(s);
             break;
         }
         /* Must update the IQH_REG in time */
         vtd_set_quad_raw(s, DMAR_IQH_REG,
                          (((uint64_t)(s->iq_head)) << qi_shift) &
                          VTD_IQH_QH_MASK);
     }
 }

 /* Handle write to Invalidation Queue Tail Register */
 static void vtd_handle_iqt_write(IntelIOMMUState *s)
 {
     uint64_t val = vtd_get_quad_raw(s, DMAR_IQT_REG);

     if (s->iq_dw && (val & VTD_IQT_QT_256_RSV_BIT)) {
         error_report_once("%s: RSV bit is set: val=0x%"PRIx64,
                           __func__, val);
         return;
     }
     s->iq_tail = VTD_IQT_QT(s->iq_dw, val);
     trace_vtd_inv_qi_tail(s->iq_tail);

     if (s->qi_enabled && !(vtd_get_long_raw(s, DMAR_FSTS_REG) & VTD_FSTS_IQE)) {
         /* Process Invalidation Queue here */
         vtd_fetch_inv_desc(s);
     }
 }

 static void vtd_handle_fsts_write(IntelIOMMUState *s)
 {
     uint32_t fsts_reg = vtd_get_long_raw(s, DMAR_FSTS_REG);
     uint32_t fectl_reg = vtd_get_long_raw(s, DMAR_FECTL_REG);
     uint32_t status_fields = VTD_FSTS_PFO | VTD_FSTS_PPF | VTD_FSTS_IQE;

     if ((fectl_reg & VTD_FECTL_IP) && !(fsts_reg & status_fields)) {
         vtd_set_clear_mask_long(s, DMAR_FECTL_REG, VTD_FECTL_IP, 0);
         trace_vtd_fsts_clear_ip();
     }
     /* FIXME: when IQE is Clear, should we try to fetch some Invalidation
      * Descriptors if there are any when Queued Invalidation is enabled?
      */
 }

 static void vtd_handle_fectl_write(IntelIOMMUState *s)
 {
     uint32_t fectl_reg;
     /* FIXME: when software clears the IM field, check the IP field. But do we
      * need to compare the old value and the new value to conclude that
      * software clears the IM field? Or just check if the IM field is zero?
      */
     fectl_reg = vtd_get_long_raw(s, DMAR_FECTL_REG);

     trace_vtd_reg_write_fectl(fectl_reg);

     if ((fectl_reg & VTD_FECTL_IP) && !(fectl_reg & VTD_FECTL_IM)) {
         vtd_generate_interrupt(s, DMAR_FEADDR_REG, DMAR_FEDATA_REG);
         vtd_set_clear_mask_long(s, DMAR_FECTL_REG, VTD_FECTL_IP, 0);
     }
 }

 static void vtd_handle_ics_write(IntelIOMMUState *s)
 {
     uint32_t ics_reg = vtd_get_long_raw(s, DMAR_ICS_REG);
     uint32_t iectl_reg = vtd_get_long_raw(s, DMAR_IECTL_REG);

     if ((iectl_reg & VTD_IECTL_IP) && !(ics_reg & VTD_ICS_IWC)) {
         trace_vtd_reg_ics_clear_ip();
         vtd_set_clear_mask_long(s, DMAR_IECTL_REG, VTD_IECTL_IP, 0);
     }
 }

 static void vtd_handle_iectl_write(IntelIOMMUState *s)
 {
     uint32_t iectl_reg;
     /* FIXME: when software clears the IM field, check the IP field. But do we
      * need to compare the old value and the new value to conclude that
      * software clears the IM field? Or just check if the IM field is zero?
      */
     iectl_reg = vtd_get_long_raw(s, DMAR_IECTL_REG);

     trace_vtd_reg_write_iectl(iectl_reg);

     if ((iectl_reg & VTD_IECTL_IP) && !(iectl_reg & VTD_IECTL_IM)) {
         vtd_generate_interrupt(s, DMAR_IEADDR_REG, DMAR_IEDATA_REG);
         vtd_set_clear_mask_long(s, DMAR_IECTL_REG, VTD_IECTL_IP, 0);
     }
 }

 static uint64_t vtd_mem_read(void *opaque, hwaddr addr, unsigned size)
 {
     IntelIOMMUState *s = opaque;
     uint64_t val;

     trace_vtd_reg_read(addr, size);

     if (addr + size > DMAR_REG_SIZE) {
         error_report_once("%s: MMIO over range: addr=0x%" PRIx64
                           " size=0x%x", __func__, addr, size);
         return (uint64_t)-1;
     }

     switch (addr) {
     /* Root Table Address Register, 64-bit */
     case DMAR_RTADDR_REG:
         val = vtd_get_quad_raw(s, DMAR_RTADDR_REG);
         if (size == 4) {
             val = val & ((1ULL << 32) - 1);
         }
         break;

     case DMAR_RTADDR_REG_HI:
         assert(size == 4);
         val = vtd_get_quad_raw(s, DMAR_RTADDR_REG) >> 32;
         break;

     /* Invalidation Queue Address Register, 64-bit */
     case DMAR_IQA_REG:
         val = s->iq |
               (vtd_get_quad(s, DMAR_IQA_REG) &
               (VTD_IQA_QS | VTD_IQA_DW_MASK));
         if (size == 4) {
             val = val & ((1ULL << 32) - 1);
         }
         break;

     case DMAR_IQA_REG_HI:
         assert(size == 4);
         val = s->iq >> 32;
         break;

     default:
         if (size == 4) {
             val = vtd_get_long(s, addr);
         } else {
             val = vtd_get_quad(s, addr);
         }
     }

     return val;
 }

 static void vtd_mem_write(void *opaque, hwaddr addr,
                           uint64_t val, unsigned size)
 {
     IntelIOMMUState *s = opaque;

     trace_vtd_reg_write(addr, size, val);

     if (addr + size > DMAR_REG_SIZE) {
         error_report_once("%s: MMIO over range: addr=0x%" PRIx64
                           " size=0x%x", __func__, addr, size);
         return;
     }

     switch (addr) {
     /* Global Command Register, 32-bit */
     case DMAR_GCMD_REG:
         vtd_set_long(s, addr, val);
         vtd_handle_gcmd_write(s);
         break;

     /* Context Command Register, 64-bit */
     case DMAR_CCMD_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
             vtd_handle_ccmd_write(s);
         }
         break;

     case DMAR_CCMD_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_ccmd_write(s);
         break;

     /* IOTLB Invalidation Register, 64-bit */
     case DMAR_IOTLB_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
             vtd_handle_iotlb_write(s);
         }
         break;

     case DMAR_IOTLB_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_iotlb_write(s);
         break;

     /* Invalidate Address Register, 64-bit */
     case DMAR_IVA_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         break;

     case DMAR_IVA_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Fault Status Register, 32-bit */
     case DMAR_FSTS_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_fsts_write(s);
         break;

     /* Fault Event Control Register, 32-bit */
     case DMAR_FECTL_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_fectl_write(s);
         break;

     /* Fault Event Data Register, 32-bit */
     case DMAR_FEDATA_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Fault Event Address Register, 32-bit */
     case DMAR_FEADDR_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             /*
              * While the register is 32-bit only, some guests (Xen...) write to
              * it with 64-bit.
              */
             vtd_set_quad(s, addr, val);
         }
         break;

     /* Fault Event Upper Address Register, 32-bit */
     case DMAR_FEUADDR_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Protected Memory Enable Register, 32-bit */
     case DMAR_PMEN_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Root Table Address Register, 64-bit */
     case DMAR_RTADDR_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         break;

     case DMAR_RTADDR_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Invalidation Queue Tail Register, 64-bit */
     case DMAR_IQT_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         vtd_handle_iqt_write(s);
         break;

     case DMAR_IQT_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         /* 19:63 of IQT_REG is RsvdZ, do nothing here */
         break;

     /* Invalidation Queue Address Register, 64-bit */
     case DMAR_IQA_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         vtd_update_iq_dw(s);
         break;

     case DMAR_IQA_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Invalidation Completion Status Register, 32-bit */
     case DMAR_ICS_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_ics_write(s);
         break;

     /* Invalidation Event Control Register, 32-bit */
     case DMAR_IECTL_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         vtd_handle_iectl_write(s);
         break;

     /* Invalidation Event Data Register, 32-bit */
     case DMAR_IEDATA_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Invalidation Event Address Register, 32-bit */
     case DMAR_IEADDR_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Invalidation Event Upper Address Register, 32-bit */
     case DMAR_IEUADDR_REG:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     /* Fault Recording Registers, 128-bit */
     case DMAR_FRCD_REG_0_0:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         break;

     case DMAR_FRCD_REG_0_1:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     case DMAR_FRCD_REG_0_2:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
             /* May clear bit 127 (Fault), update PPF */
             vtd_update_fsts_ppf(s);
         }
         break;

     case DMAR_FRCD_REG_0_3:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         /* May clear bit 127 (Fault), update PPF */
         vtd_update_fsts_ppf(s);
         break;

     case DMAR_IRTA_REG:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
         break;

     case DMAR_IRTA_REG_HI:
         assert(size == 4);
         vtd_set_long(s, addr, val);
         break;

     default:
         if (size == 4) {
             vtd_set_long(s, addr, val);
         } else {
             vtd_set_quad(s, addr, val);
         }
     }
 }

 static IOMMUTLBEntry vtd_iommu_translate(IOMMUMemoryRegion *iommu, hwaddr addr,
                                          IOMMUAccessFlags flag, int iommu_idx)
 {
     VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
     IntelIOMMUState *s = vtd_as->iommu_state;
     IOMMUTLBEntry iotlb = {
         /* We'll fill in the rest later. */
         .target_as = &address_space_memory,
     };
     bool success;

     if (likely(s->dmar_enabled)) {
         success = vtd_do_iommu_translate(vtd_as, vtd_as->bus, vtd_as->devfn,
                                          addr, flag & IOMMU_WO, &iotlb);
     } else {
         /* DMAR disabled, passthrough, use 4k-page*/
         iotlb.iova = addr & VTD_PAGE_MASK_4K;
         iotlb.translated_addr = addr & VTD_PAGE_MASK_4K;
         iotlb.addr_mask = ~VTD_PAGE_MASK_4K;
         iotlb.perm = IOMMU_RW;
         success = true;
     }

     if (likely(success)) {
         trace_vtd_dmar_translate(pci_bus_num(vtd_as->bus),
                                  VTD_PCI_SLOT(vtd_as->devfn),
                                  VTD_PCI_FUNC(vtd_as->devfn),
                                  iotlb.iova, iotlb.translated_addr,
                                  iotlb.addr_mask);
     } else {
         error_report_once("%s: detected translation failure "
                           "(dev=%02x:%02x:%02x, iova=0x%" PRIx64 ")",
                           __func__, pci_bus_num(vtd_as->bus),
                           VTD_PCI_SLOT(vtd_as->devfn),
                           VTD_PCI_FUNC(vtd_as->devfn),
                           addr);
     }

     return iotlb;
 }

 static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
                                          IOMMUNotifierFlag old,
                                          IOMMUNotifierFlag new,
                                          Error **errp)
 {
     VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
     IntelIOMMUState *s = vtd_as->iommu_state;
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     /* TODO: add support for VFIO and vhost users */
     if (s->snoop_control) {
         error_setg_errno(errp, ENOTSUP,
                          "Snoop Control with vhost or VFIO is not supported");
         return -ENOTSUP;
     }
     if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) {
         error_setg_errno(errp, ENOTSUP,
                          "device %02x.%02x.%x requires caching mode",
                          pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
                          PCI_FUNC(vtd_as->devfn));
         return -ENOTSUP;
     }
     if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
         error_setg_errno(errp, ENOTSUP,
                          "device %02x.%02x.%x requires device IOTLB mode",
                          pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
                          PCI_FUNC(vtd_as->devfn));
         return -ENOTSUP;
     }

     /* Update per-address-space notifier flags */
     vtd_as->notifier_flags = new;

     if (old == IOMMU_NOTIFIER_NONE) {
         QLIST_INSERT_HEAD(&s->vtd_as_with_notifiers, vtd_as, next);
     } else if (new == IOMMU_NOTIFIER_NONE) {
         QLIST_REMOVE(vtd_as, next);
     }
     return 0;
 }

 static int vtd_post_load(void *opaque, int version_id)
 {
     IntelIOMMUState *iommu = opaque;

     /*
      * We don't need to migrate the root_scalable because we can
      * simply do the calculation after the loading is complete.  We
      * can actually do similar things with root, dmar_enabled, etc.
      * however since we've had them already so we'd better keep them
      * for compatibility of migration.
      */
     vtd_update_scalable_state(iommu);

     vtd_update_iq_dw(iommu);

     /*
      * Memory regions are dynamically turned on/off depending on
      * context entry configurations from the guest. After migration,
      * we need to make sure the memory regions are still correct.
      */
     vtd_switch_address_space_all(iommu);

     return 0;
 }

 static const VMStateDescription vtd_vmstate = {
     .name = "iommu-intel",
     .version_id = 1,
     .minimum_version_id = 1,
     .priority = MIG_PRI_IOMMU,
     .post_load = vtd_post_load,
     .fields = (const VMStateField[]) {
         VMSTATE_UINT64(root, IntelIOMMUState),
         VMSTATE_UINT64(intr_root, IntelIOMMUState),
         VMSTATE_UINT64(iq, IntelIOMMUState),
         VMSTATE_UINT32(intr_size, IntelIOMMUState),
         VMSTATE_UINT16(iq_head, IntelIOMMUState),
         VMSTATE_UINT16(iq_tail, IntelIOMMUState),
         VMSTATE_UINT16(iq_size, IntelIOMMUState),
         VMSTATE_UINT16(next_frcd_reg, IntelIOMMUState),
         VMSTATE_UINT8_ARRAY(csr, IntelIOMMUState, DMAR_REG_SIZE),
         VMSTATE_UINT8(iq_last_desc_type, IntelIOMMUState),
         VMSTATE_UNUSED(1),      /* bool root_extended is obsolete by VT-d */
         VMSTATE_BOOL(dmar_enabled, IntelIOMMUState),
         VMSTATE_BOOL(qi_enabled, IntelIOMMUState),
         VMSTATE_BOOL(intr_enabled, IntelIOMMUState),
         VMSTATE_BOOL(intr_eime, IntelIOMMUState),
         VMSTATE_END_OF_LIST()
     }
 };

 static const MemoryRegionOps vtd_mem_ops = {
     .read = vtd_mem_read,
     .write = vtd_mem_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .impl = {
         .min_access_size = 4,
         .max_access_size = 8,
     },
     .valid = {
         .min_access_size = 4,
         .max_access_size = 8,
     },
 };

 static Property vtd_properties[] = {
     DEFINE_PROP_UINT32("version", IntelIOMMUState, version, 0),
     DEFINE_PROP_ON_OFF_AUTO("eim", IntelIOMMUState, intr_eim,
                             ON_OFF_AUTO_AUTO),
     DEFINE_PROP_BOOL("x-buggy-eim", IntelIOMMUState, buggy_eim, false),
     DEFINE_PROP_UINT8("aw-bits", IntelIOMMUState, aw_bits,
                       VTD_HOST_ADDRESS_WIDTH),
     DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode, FALSE),
     DEFINE_PROP_BOOL("x-scalable-mode", IntelIOMMUState, scalable_mode, FALSE),
     DEFINE_PROP_BOOL("snoop-control", IntelIOMMUState, snoop_control, false),
     DEFINE_PROP_BOOL("x-pasid-mode", IntelIOMMUState, pasid, false),
     DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true),
     DEFINE_PROP_BOOL("dma-translation", IntelIOMMUState, dma_translation, true),
     DEFINE_PROP_END_OF_LIST(),
 };

 /* Read IRTE entry with specific index */
 static bool vtd_irte_get(IntelIOMMUState *iommu, uint16_t index,
                          VTD_IR_TableEntry *entry, uint16_t sid,
                          bool do_fault)
 {
     static const uint16_t vtd_svt_mask[VTD_SQ_MAX] = \
         {0xffff, 0xfffb, 0xfff9, 0xfff8};
     dma_addr_t addr = 0x00;
     uint16_t mask, source_id;
     uint8_t bus, bus_max, bus_min;

     if (index >= iommu->intr_size) {
         error_report_once("%s: index too large: ind=0x%x",
                           __func__, index);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_INDEX_OVER, index);
         }
         return false;
     }

     addr = iommu->intr_root + index * sizeof(*entry);
     if (dma_memory_read(&address_space_memory, addr,
                         entry, sizeof(*entry), MEMTXATTRS_UNSPECIFIED)) {
         error_report_once("%s: read failed: ind=0x%x addr=0x%" PRIx64,
                           __func__, index, addr);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_ROOT_INVAL, index);
         }
         return false;
     }

     entry->data[0] = le64_to_cpu(entry->data[0]);
     entry->data[1] = le64_to_cpu(entry->data[1]);

     trace_vtd_ir_irte_get(index, entry->data[1], entry->data[0]);

     /*
      * The remaining potential fault conditions are "qualified" by the
      * Fault Processing Disable bit in the IRTE. Even "not present".
      * So just clear the do_fault flag if PFD is set, which will
      * prevent faults being raised.
      */
     if (entry->irte.fault_disable) {
         do_fault = false;
     }

     if (!entry->irte.present) {
         error_report_once("%s: detected non-present IRTE "
                           "(index=%u, high=0x%" PRIx64 ", low=0x%" PRIx64 ")",
                           __func__, index, entry->data[1], entry->data[0]);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_ENTRY_P, index);
         }
         return false;
     }

     if (entry->irte.__reserved_0 || entry->irte.__reserved_1 ||
         entry->irte.__reserved_2) {
         error_report_once("%s: detected non-zero reserved IRTE "
                           "(index=%u, high=0x%" PRIx64 ", low=0x%" PRIx64 ")",
                           __func__, index, entry->data[1], entry->data[0]);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_IRTE_RSVD, index);
         }
         return false;
     }

     if (sid != X86_IOMMU_SID_INVALID) {
         /* Validate IRTE SID */
         source_id = entry->irte.source_id;
         switch (entry->irte.sid_vtype) {
         case VTD_SVT_NONE:
             break;

         case VTD_SVT_ALL:
             mask = vtd_svt_mask[entry->irte.sid_q];
             if ((source_id & mask) != (sid & mask)) {
                 error_report_once("%s: invalid IRTE SID "
                                   "(index=%u, sid=%u, source_id=%u)",
                                   __func__, index, sid, source_id);
                 if (do_fault) {
                     vtd_report_ir_fault(iommu, sid, VTD_FR_IR_SID_ERR, index);
                 }
                 return false;
             }
             break;

         case VTD_SVT_BUS:
             bus_max = source_id >> 8;
             bus_min = source_id & 0xff;
             bus = sid >> 8;
             if (bus > bus_max || bus < bus_min) {
                 error_report_once("%s: invalid SVT_BUS "
                                   "(index=%u, bus=%u, min=%u, max=%u)",
                                   __func__, index, bus, bus_min, bus_max);
                 if (do_fault) {
                     vtd_report_ir_fault(iommu, sid, VTD_FR_IR_SID_ERR, index);
                 }
                 return false;
             }
             break;

         default:
             error_report_once("%s: detected invalid IRTE SVT "
                               "(index=%u, type=%d)", __func__,
                               index, entry->irte.sid_vtype);
             /* Take this as verification failure. */
             if (do_fault) {
                 vtd_report_ir_fault(iommu, sid, VTD_FR_IR_SID_ERR, index);
             }
             return false;
         }
     }

     return true;
 }

 /* Fetch IRQ information of specific IR index */
 static bool vtd_remap_irq_get(IntelIOMMUState *iommu, uint16_t index,
                               X86IOMMUIrq *irq, uint16_t sid, bool do_fault)
 {
     VTD_IR_TableEntry irte = {};

     if (!vtd_irte_get(iommu, index, &irte, sid, do_fault)) {
         return false;
     }

     irq->trigger_mode = irte.irte.trigger_mode;
     irq->vector = irte.irte.vector;
     irq->delivery_mode = irte.irte.delivery_mode;
     irq->dest = irte.irte.dest_id;
     if (!iommu->intr_eime) {
 #define  VTD_IR_APIC_DEST_MASK         (0xff00ULL)
 #define  VTD_IR_APIC_DEST_SHIFT        (8)
         irq->dest = (irq->dest & VTD_IR_APIC_DEST_MASK) >>
             VTD_IR_APIC_DEST_SHIFT;
     }
     irq->dest_mode = irte.irte.dest_mode;
     irq->redir_hint = irte.irte.redir_hint;

     trace_vtd_ir_remap(index, irq->trigger_mode, irq->vector,
                        irq->delivery_mode, irq->dest, irq->dest_mode);

     return true;
 }

 /* Interrupt remapping for MSI/MSI-X entry */
 static int vtd_interrupt_remap_msi(IntelIOMMUState *iommu,
                                    MSIMessage *origin,
                                    MSIMessage *translated,
                                    uint16_t sid, bool do_fault)
 {
     VTD_IR_MSIAddress addr;
     uint16_t index;
     X86IOMMUIrq irq = {};

     assert(origin && translated);

     trace_vtd_ir_remap_msi_req(origin->address, origin->data);

     if (!iommu || !iommu->intr_enabled) {
         memcpy(translated, origin, sizeof(*origin));
         goto out;
     }

     if (origin->address & VTD_MSI_ADDR_HI_MASK) {
         error_report_once("%s: MSI address high 32 bits non-zero detected: "
                           "address=0x%" PRIx64, __func__, origin->address);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_REQ_RSVD, 0);
         }
         return -EINVAL;
     }

     addr.data = origin->address & VTD_MSI_ADDR_LO_MASK;
     if (addr.addr.__head != 0xfee) {
         error_report_once("%s: MSI address low 32 bit invalid: 0x%" PRIx32,
                           __func__, addr.data);
         if (do_fault) {
             vtd_report_ir_fault(iommu, sid, VTD_FR_IR_REQ_RSVD, 0);
         }
         return -EINVAL;
     }

     /* This is compatible mode. */
     if (addr.addr.int_mode != VTD_IR_INT_FORMAT_REMAP) {
         memcpy(translated, origin, sizeof(*origin));
         goto out;
     }

     index = addr.addr.index_h << 15 | addr.addr.index_l;

 #define  VTD_IR_MSI_DATA_SUBHANDLE       (0x0000ffff)
 #define  VTD_IR_MSI_DATA_RESERVED        (0xffff0000)

     if (addr.addr.sub_valid) {
         /* See VT-d spec 5.1.2.2 and 5.1.3 on subhandle */
         index += origin->data & VTD_IR_MSI_DATA_SUBHANDLE;
     }

     if (!vtd_remap_irq_get(iommu, index, &irq, sid, do_fault)) {
         return -EINVAL;
     }

     if (addr.addr.sub_valid) {
         trace_vtd_ir_remap_type("MSI");
         if (origin->data & VTD_IR_MSI_DATA_RESERVED) {
             error_report_once("%s: invalid IR MSI "
                               "(sid=%u, address=0x%" PRIx64
                               ", data=0x%" PRIx32 ")",
                               __func__, sid, origin->address, origin->data);
             if (do_fault) {
                 vtd_report_ir_fault(iommu, sid, VTD_FR_IR_REQ_RSVD, 0);
             }
             return -EINVAL;
         }
     } else {
         uint8_t vector = origin->data & 0xff;
         uint8_t trigger_mode = (origin->data >> MSI_DATA_TRIGGER_SHIFT) & 0x1;

         trace_vtd_ir_remap_type("IOAPIC");
         /* IOAPIC entry vector should be aligned with IRTE vector
          * (see vt-d spec 5.1.5.1). */
         if (vector != irq.vector) {
             trace_vtd_warn_ir_vector(sid, index, vector, irq.vector);
         }

         /* The Trigger Mode field must match the Trigger Mode in the IRTE.
          * (see vt-d spec 5.1.5.1). */
         if (trigger_mode != irq.trigger_mode) {
             trace_vtd_warn_ir_trigger(sid, index, trigger_mode,
                                       irq.trigger_mode);
         }
     }

     /*
      * We'd better keep the last two bits, assuming that guest OS
      * might modify it. Keep it does not hurt after all.
      */
     irq.msi_addr_last_bits = addr.addr.__not_care;

     /* Translate X86IOMMUIrq to MSI message */
     x86_iommu_irq_to_msi_message(&irq, translated);

 out:
     trace_vtd_ir_remap_msi(origin->address, origin->data,
                            translated->address, translated->data);
     return 0;
 }

 static int vtd_int_remap(X86IOMMUState *iommu, MSIMessage *src,
                          MSIMessage *dst, uint16_t sid)
 {
     return vtd_interrupt_remap_msi(INTEL_IOMMU_DEVICE(iommu),
                                    src, dst, sid, false);
 }

 static MemTxResult vtd_mem_ir_read(void *opaque, hwaddr addr,
                                    uint64_t *data, unsigned size,
                                    MemTxAttrs attrs)
 {
     return MEMTX_OK;
 }

 static MemTxResult vtd_mem_ir_write(void *opaque, hwaddr addr,
                                     uint64_t value, unsigned size,
                                     MemTxAttrs attrs)
 {
     int ret = 0;
     MSIMessage from = {}, to = {};
     uint16_t sid = X86_IOMMU_SID_INVALID;

     from.address = (uint64_t) addr + VTD_INTERRUPT_ADDR_FIRST;
     from.data = (uint32_t) value;

     if (!attrs.unspecified) {
         /* We have explicit Source ID */
         sid = attrs.requester_id;
     }

     ret = vtd_interrupt_remap_msi(opaque, &from, &to, sid, true);
     if (ret) {
         /* Drop this interrupt */
         return MEMTX_ERROR;
     }

     apic_get_class(NULL)->send_msi(&to);

     return MEMTX_OK;
 }

 static const MemoryRegionOps vtd_mem_ir_ops = {
     .read_with_attrs = vtd_mem_ir_read,
     .write_with_attrs = vtd_mem_ir_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .impl = {
         .min_access_size = 4,
         .max_access_size = 4,
     },
     .valid = {
         .min_access_size = 4,
         .max_access_size = 4,
     },
 };

 static void vtd_report_ir_illegal_access(VTDAddressSpace *vtd_as,
                                          hwaddr addr, bool is_write)
 {
     IntelIOMMUState *s = vtd_as->iommu_state;
     uint8_t bus_n = pci_bus_num(vtd_as->bus);
     uint16_t sid = PCI_BUILD_BDF(bus_n, vtd_as->devfn);
     bool is_fpd_set = false;
     VTDContextEntry ce;

     assert(vtd_as->pasid != PCI_NO_PASID);

     /* Try out best to fetch FPD, we can't do anything more */
     if (vtd_dev_to_context_entry(s, bus_n, vtd_as->devfn, &ce) == 0) {
         is_fpd_set = ce.lo & VTD_CONTEXT_ENTRY_FPD;
         if (!is_fpd_set && s->root_scalable) {
             vtd_ce_get_pasid_fpd(s, &ce, &is_fpd_set, vtd_as->pasid);
         }
     }

     vtd_report_fault(s, VTD_FR_SM_INTERRUPT_ADDR,
                      is_fpd_set, sid, addr, is_write,
                      true, vtd_as->pasid);
 }

 static MemTxResult vtd_mem_ir_fault_read(void *opaque, hwaddr addr,
                                          uint64_t *data, unsigned size,
                                          MemTxAttrs attrs)
 {
     vtd_report_ir_illegal_access(opaque, addr, false);

     return MEMTX_ERROR;
 }

 static MemTxResult vtd_mem_ir_fault_write(void *opaque, hwaddr addr,
                                           uint64_t value, unsigned size,
                                           MemTxAttrs attrs)
 {
     vtd_report_ir_illegal_access(opaque, addr, true);

     return MEMTX_ERROR;
 }

 static const MemoryRegionOps vtd_mem_ir_fault_ops = {
     .read_with_attrs = vtd_mem_ir_fault_read,
     .write_with_attrs = vtd_mem_ir_fault_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .impl = {
         .min_access_size = 1,
         .max_access_size = 8,
     },
     .valid = {
         .min_access_size = 1,
         .max_access_size = 8,
     },
 };

 VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
                                  int devfn, unsigned int pasid)
 {
     /*
      * We can't simply use sid here since the bus number might not be
      * initialized by the guest.
      */
     struct vtd_as_key key = {
         .bus = bus,
         .devfn = devfn,
         .pasid = pasid,
     };
     VTDAddressSpace *vtd_dev_as;
     char name[128];

     vtd_dev_as = g_hash_table_lookup(s->vtd_address_spaces, &key);
     if (!vtd_dev_as) {
         struct vtd_as_key *new_key = g_malloc(sizeof(*new_key));

         new_key->bus = bus;
         new_key->devfn = devfn;
         new_key->pasid = pasid;

         if (pasid == PCI_NO_PASID) {
             snprintf(name, sizeof(name), "vtd-%02x.%x", PCI_SLOT(devfn),
                      PCI_FUNC(devfn));
         } else {
             snprintf(name, sizeof(name), "vtd-%02x.%x-pasid-%x", PCI_SLOT(devfn),
                      PCI_FUNC(devfn), pasid);
         }

         vtd_dev_as = g_new0(VTDAddressSpace, 1);

         vtd_dev_as->bus = bus;
         vtd_dev_as->devfn = (uint8_t)devfn;
         vtd_dev_as->pasid = pasid;
         vtd_dev_as->iommu_state = s;
         vtd_dev_as->context_cache_entry.context_cache_gen = 0;
         vtd_dev_as->iova_tree = iova_tree_new();

         memory_region_init(&vtd_dev_as->root, OBJECT(s), name, UINT64_MAX);
         address_space_init(&vtd_dev_as->as, &vtd_dev_as->root, "vtd-root");

         /*
          * Build the DMAR-disabled container with aliases to the
          * shared MRs.  Note that aliasing to a shared memory region
          * could help the memory API to detect same FlatViews so we
          * can have devices to share the same FlatView when DMAR is
          * disabled (either by not providing "intel_iommu=on" or with
          * "iommu=pt").  It will greatly reduce the total number of
          * FlatViews of the system hence VM runs faster.
          */
         memory_region_init_alias(&vtd_dev_as->nodmar, OBJECT(s),
                                  "vtd-nodmar", &s->mr_nodmar, 0,
                                  memory_region_size(&s->mr_nodmar));

         /*
          * Build the per-device DMAR-enabled container.
          *
          * TODO: currently we have per-device IOMMU memory region only
          * because we have per-device IOMMU notifiers for devices.  If
          * one day we can abstract the IOMMU notifiers out of the
          * memory regions then we can also share the same memory
          * region here just like what we've done above with the nodmar
          * region.
          */
         strcat(name, "-dmar");
         memory_region_init_iommu(&vtd_dev_as->iommu, sizeof(vtd_dev_as->iommu),
                                  TYPE_INTEL_IOMMU_MEMORY_REGION, OBJECT(s),
                                  name, UINT64_MAX);
         memory_region_init_alias(&vtd_dev_as->iommu_ir, OBJECT(s), "vtd-ir",
                                  &s->mr_ir, 0, memory_region_size(&s->mr_ir));
         memory_region_add_subregion_overlap(MEMORY_REGION(&vtd_dev_as->iommu),
                                             VTD_INTERRUPT_ADDR_FIRST,
                                             &vtd_dev_as->iommu_ir, 1);

         /*
          * This region is used for catching fault to access interrupt
          * range via passthrough + PASID. See also
          * vtd_switch_address_space(). We can't use alias since we
          * need to know the sid which is valid for MSI who uses
          * bus_master_as (see msi_send_message()).
          */
         memory_region_init_io(&vtd_dev_as->iommu_ir_fault, OBJECT(s),
                               &vtd_mem_ir_fault_ops, vtd_dev_as, "vtd-no-ir",
                               VTD_INTERRUPT_ADDR_SIZE);
         /*
          * Hook to root since when PT is enabled vtd_dev_as->iommu
          * will be disabled.
          */
         memory_region_add_subregion_overlap(MEMORY_REGION(&vtd_dev_as->root),
                                             VTD_INTERRUPT_ADDR_FIRST,
                                             &vtd_dev_as->iommu_ir_fault, 2);

         /*
          * Hook both the containers under the root container, we
          * switch between DMAR & noDMAR by enable/disable
          * corresponding sub-containers
          */
         memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
                                             MEMORY_REGION(&vtd_dev_as->iommu),
                                             0);
         memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
                                             &vtd_dev_as->nodmar, 0);

         vtd_switch_address_space(vtd_dev_as);

         g_hash_table_insert(s->vtd_address_spaces, new_key, vtd_dev_as);
     }
     return vtd_dev_as;
 }

 static bool vtd_check_hiod(IntelIOMMUState *s, HostIOMMUDevice *hiod,
                            Error **errp)
 {
     HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
     int ret;

     if (!hiodc->get_cap) {
         error_setg(errp, ".get_cap() not implemented");
         return false;
     }

     /* Common checks */
     ret = hiodc->get_cap(hiod, HOST_IOMMU_DEVICE_CAP_AW_BITS, errp);
     if (ret < 0) {
         return false;
     }
     if (s->aw_bits > ret) {
         error_setg(errp, "aw-bits %d > host aw-bits %d", s->aw_bits, ret);
         return false;
     }

     return true;
 }

 static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
                                      HostIOMMUDevice *hiod, Error **errp)
 {
     IntelIOMMUState *s = opaque;
     struct vtd_as_key key = {
         .bus = bus,
         .devfn = devfn,
     };
     struct vtd_as_key *new_key;

     assert(hiod);

     vtd_iommu_lock(s);

     if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
         error_setg(errp, "Host IOMMU device already exist");
         vtd_iommu_unlock(s);
         return false;
     }

     if (!vtd_check_hiod(s, hiod, errp)) {
         vtd_iommu_unlock(s);
         return false;
     }

     new_key = g_malloc(sizeof(*new_key));
     new_key->bus = bus;
     new_key->devfn = devfn;

     object_ref(hiod);
     g_hash_table_insert(s->vtd_host_iommu_dev, new_key, hiod);

     vtd_iommu_unlock(s);

     return true;
 }

 static void vtd_dev_unset_iommu_device(PCIBus *bus, void *opaque, int devfn)
 {
     IntelIOMMUState *s = opaque;
     struct vtd_as_key key = {
         .bus = bus,
         .devfn = devfn,
     };

     vtd_iommu_lock(s);

     if (!g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
         vtd_iommu_unlock(s);
         return;
     }

     g_hash_table_remove(s->vtd_host_iommu_dev, &key);

     vtd_iommu_unlock(s);
 }

 /* Unmap the whole range in the notifier's scope. */
 static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
 {
     hwaddr total, remain;
     hwaddr start = n->start;
     hwaddr end = n->end;
     IntelIOMMUState *s = as->iommu_state;
     DMAMap map;

     /*
      * Note: all the codes in this function has a assumption that IOVA
      * bits are no more than VTD_MGAW bits (which is restricted by
      * VT-d spec), otherwise we need to consider overflow of 64 bits.
      */

     if (end > VTD_ADDRESS_SIZE(s->aw_bits) - 1) {
         /*
          * Don't need to unmap regions that is bigger than the whole
          * VT-d supported address space size
          */
         end = VTD_ADDRESS_SIZE(s->aw_bits) - 1;
     }

     assert(start <= end);
     total = remain = end - start + 1;

     while (remain >= VTD_PAGE_SIZE) {
         IOMMUTLBEvent event;
         uint64_t mask = dma_aligned_pow2_mask(start, end, s->aw_bits);
         uint64_t size = mask + 1;

         assert(size);

         event.type = IOMMU_NOTIFIER_UNMAP;
         event.entry.iova = start;
         event.entry.addr_mask = mask;
         event.entry.target_as = &address_space_memory;
         event.entry.perm = IOMMU_NONE;
         /* This field is meaningless for unmap */
         event.entry.translated_addr = 0;

         memory_region_notify_iommu_one(n, &event);

         start += size;
         remain -= size;
     }

     assert(!remain);

     trace_vtd_as_unmap_whole(pci_bus_num(as->bus),
                              VTD_PCI_SLOT(as->devfn),
                              VTD_PCI_FUNC(as->devfn),
                              n->start, total);

     map.iova = n->start;
     map.size = total - 1; /* Inclusive */
     iova_tree_remove(as->iova_tree, map);
 }

 static void vtd_address_space_unmap_all(IntelIOMMUState *s)
 {
     VTDAddressSpace *vtd_as;
     IOMMUNotifier *n;

     QLIST_FOREACH(vtd_as, &s->vtd_as_with_notifiers, next) {
         IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) {
             vtd_address_space_unmap(vtd_as, n);
         }
     }
 }

 static void vtd_address_space_refresh_all(IntelIOMMUState *s)
 {
     vtd_address_space_unmap_all(s);
     vtd_switch_address_space_all(s);
 }

 static int vtd_replay_hook(const IOMMUTLBEvent *event, void *private)
 {
     memory_region_notify_iommu_one(private, event);
     return 0;
 }

 static void vtd_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n)
 {
     VTDAddressSpace *vtd_as = container_of(iommu_mr, VTDAddressSpace, iommu);
     IntelIOMMUState *s = vtd_as->iommu_state;
     uint8_t bus_n = pci_bus_num(vtd_as->bus);
     VTDContextEntry ce;
     DMAMap map = { .iova = 0, .size = HWADDR_MAX };

     /* replay is protected by BQL, page walk will re-setup it safely */
     iova_tree_remove(vtd_as->iova_tree, map);

     if (vtd_dev_to_context_entry(s, bus_n, vtd_as->devfn, &ce) == 0) {
         trace_vtd_replay_ce_valid(s->root_scalable ? "scalable mode" :
                                   "legacy mode",
                                   bus_n, PCI_SLOT(vtd_as->devfn),
                                   PCI_FUNC(vtd_as->devfn),
                                   vtd_get_domain_id(s, &ce, vtd_as->pasid),
                                   ce.hi, ce.lo);
         if (n->notifier_flags & IOMMU_NOTIFIER_MAP) {
             /* This is required only for MAP typed notifiers */
             vtd_page_walk_info info = {
                 .hook_fn = vtd_replay_hook,
                 .private = (void *)n,
                 .notify_unmap = false,
                 .aw = s->aw_bits,
                 .as = vtd_as,
                 .domain_id = vtd_get_domain_id(s, &ce, vtd_as->pasid),
             };

             vtd_page_walk(s, &ce, 0, ~0ULL, &info, vtd_as->pasid);
         }
     } else {
         trace_vtd_replay_ce_invalid(bus_n, PCI_SLOT(vtd_as->devfn),
                                     PCI_FUNC(vtd_as->devfn));
     }

     return;
 }

 static void vtd_cap_init(IntelIOMMUState *s)
 {
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     s->cap = VTD_CAP_FRO | VTD_CAP_NFR | VTD_CAP_ND |
              VTD_CAP_MAMV | VTD_CAP_PSI | VTD_CAP_SLLPS |
              VTD_CAP_MGAW(s->aw_bits);
     if (s->dma_drain) {
         s->cap |= VTD_CAP_DRAIN;
     }
     if (s->dma_translation) {
             if (s->aw_bits >= VTD_HOST_AW_39BIT) {
                     s->cap |= VTD_CAP_SAGAW_39bit;
             }
             if (s->aw_bits >= VTD_HOST_AW_48BIT) {
                     s->cap |= VTD_CAP_SAGAW_48bit;
             }
     }
     s->ecap = VTD_ECAP_QI | VTD_ECAP_IRO;

     if (x86_iommu_ir_supported(x86_iommu)) {
         s->ecap |= VTD_ECAP_IR | VTD_ECAP_MHMV;
         if (s->intr_eim == ON_OFF_AUTO_ON) {
             s->ecap |= VTD_ECAP_EIM;
         }
         assert(s->intr_eim != ON_OFF_AUTO_AUTO);
     }

     if (x86_iommu->dt_supported) {
         s->ecap |= VTD_ECAP_DT;
     }

     if (x86_iommu->pt_supported) {
         s->ecap |= VTD_ECAP_PT;
     }

     if (s->caching_mode) {
         s->cap |= VTD_CAP_CM;
     }

     /* TODO: read cap/ecap from host to decide which cap to be exposed. */
     if (s->scalable_mode) {
         s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
     }

     if (s->snoop_control) {
         s->ecap |= VTD_ECAP_SC;
     }

     if (s->pasid) {
         s->ecap |= VTD_ECAP_PASID;
     }
 }

 /*
  * Do the initialization. It will also be called when reset, so pay
  * attention when adding new initialization stuff.
  */
 static void vtd_init(IntelIOMMUState *s)
 {
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     memset(s->csr, 0, DMAR_REG_SIZE);
     memset(s->wmask, 0, DMAR_REG_SIZE);
     memset(s->w1cmask, 0, DMAR_REG_SIZE);
     memset(s->womask, 0, DMAR_REG_SIZE);

     s->root = 0;
     s->root_scalable = false;
     s->dmar_enabled = false;
     s->intr_enabled = false;
     s->iq_head = 0;
     s->iq_tail = 0;
     s->iq = 0;
     s->iq_size = 0;
     s->qi_enabled = false;
     s->iq_last_desc_type = VTD_INV_DESC_NONE;
     s->iq_dw = false;
     s->next_frcd_reg = 0;

     vtd_cap_init(s);

     /*
      * Rsvd field masks for spte
      */
     vtd_spte_rsvd[0] = ~0ULL;
     vtd_spte_rsvd[1] = VTD_SPTE_PAGE_L1_RSVD_MASK(s->aw_bits,
                                                   x86_iommu->dt_supported);
     vtd_spte_rsvd[2] = VTD_SPTE_PAGE_L2_RSVD_MASK(s->aw_bits);
     vtd_spte_rsvd[3] = VTD_SPTE_PAGE_L3_RSVD_MASK(s->aw_bits);
     vtd_spte_rsvd[4] = VTD_SPTE_PAGE_L4_RSVD_MASK(s->aw_bits);

     vtd_spte_rsvd_large[2] = VTD_SPTE_LPAGE_L2_RSVD_MASK(s->aw_bits,
                                                     x86_iommu->dt_supported);
     vtd_spte_rsvd_large[3] = VTD_SPTE_LPAGE_L3_RSVD_MASK(s->aw_bits,
                                                     x86_iommu->dt_supported);

     if (s->scalable_mode || s->snoop_control) {
         vtd_spte_rsvd[1] &= ~VTD_SPTE_SNP;
         vtd_spte_rsvd_large[2] &= ~VTD_SPTE_SNP;
         vtd_spte_rsvd_large[3] &= ~VTD_SPTE_SNP;
     }

     vtd_reset_caches(s);

     /* Define registers with default values and bit semantics */
     vtd_define_long(s, DMAR_VER_REG, 0x10UL, 0, 0);
     vtd_define_quad(s, DMAR_CAP_REG, s->cap, 0, 0);
     vtd_define_quad(s, DMAR_ECAP_REG, s->ecap, 0, 0);
     vtd_define_long(s, DMAR_GCMD_REG, 0, 0xff800000UL, 0);
     vtd_define_long_wo(s, DMAR_GCMD_REG, 0xff800000UL);
     vtd_define_long(s, DMAR_GSTS_REG, 0, 0, 0);
     vtd_define_quad(s, DMAR_RTADDR_REG, 0, 0xfffffffffffffc00ULL, 0);
     vtd_define_quad(s, DMAR_CCMD_REG, 0, 0xe0000003ffffffffULL, 0);
     vtd_define_quad_wo(s, DMAR_CCMD_REG, 0x3ffff0000ULL);

     /* Advanced Fault Logging not supported */
     vtd_define_long(s, DMAR_FSTS_REG, 0, 0, 0x11UL);
     vtd_define_long(s, DMAR_FECTL_REG, 0x80000000UL, 0x80000000UL, 0);
     vtd_define_long(s, DMAR_FEDATA_REG, 0, 0x0000ffffUL, 0);
     vtd_define_long(s, DMAR_FEADDR_REG, 0, 0xfffffffcUL, 0);

     /* Treated as RsvdZ when EIM in ECAP_REG is not supported
      * vtd_define_long(s, DMAR_FEUADDR_REG, 0, 0xffffffffUL, 0);
      */
     vtd_define_long(s, DMAR_FEUADDR_REG, 0, 0, 0);

     /* Treated as RO for implementations that PLMR and PHMR fields reported
      * as Clear in the CAP_REG.
      * vtd_define_long(s, DMAR_PMEN_REG, 0, 0x80000000UL, 0);
      */
     vtd_define_long(s, DMAR_PMEN_REG, 0, 0, 0);

     vtd_define_quad(s, DMAR_IQH_REG, 0, 0, 0);
     vtd_define_quad(s, DMAR_IQT_REG, 0, 0x7fff0ULL, 0);
     vtd_define_quad(s, DMAR_IQA_REG, 0, 0xfffffffffffff807ULL, 0);
     vtd_define_long(s, DMAR_ICS_REG, 0, 0, 0x1UL);
     vtd_define_long(s, DMAR_IECTL_REG, 0x80000000UL, 0x80000000UL, 0);
     vtd_define_long(s, DMAR_IEDATA_REG, 0, 0xffffffffUL, 0);
     vtd_define_long(s, DMAR_IEADDR_REG, 0, 0xfffffffcUL, 0);
     /* Treadted as RsvdZ when EIM in ECAP_REG is not supported */
     vtd_define_long(s, DMAR_IEUADDR_REG, 0, 0, 0);

     /* IOTLB registers */
     vtd_define_quad(s, DMAR_IOTLB_REG, 0, 0Xb003ffff00000000ULL, 0);
     vtd_define_quad(s, DMAR_IVA_REG, 0, 0xfffffffffffff07fULL, 0);
     vtd_define_quad_wo(s, DMAR_IVA_REG, 0xfffffffffffff07fULL);

     /* Fault Recording Registers, 128-bit */
     vtd_define_quad(s, DMAR_FRCD_REG_0_0, 0, 0, 0);
     vtd_define_quad(s, DMAR_FRCD_REG_0_2, 0, 0, 0x8000000000000000ULL);

     /*
      * Interrupt remapping registers.
      */
     vtd_define_quad(s, DMAR_IRTA_REG, 0, 0xfffffffffffff80fULL, 0);
 }

 /* Should not reset address_spaces when reset because devices will still use
  * the address space they got at first (won't ask the bus again).
  */
 static void vtd_reset(DeviceState *dev)
 {
     IntelIOMMUState *s = INTEL_IOMMU_DEVICE(dev);

     vtd_init(s);
     vtd_address_space_refresh_all(s);
 }

 static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
 {
     IntelIOMMUState *s = opaque;
     VTDAddressSpace *vtd_as;

     assert(0 <= devfn && devfn < PCI_DEVFN_MAX);

     vtd_as = vtd_find_add_as(s, bus, devfn, PCI_NO_PASID);
     return &vtd_as->as;
 }

 static PCIIOMMUOps vtd_iommu_ops = {
     .get_address_space = vtd_host_dma_iommu,
     .set_iommu_device = vtd_dev_set_iommu_device,
     .unset_iommu_device = vtd_dev_unset_iommu_device,
 };

 static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
 {
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     if (s->intr_eim == ON_OFF_AUTO_ON && !x86_iommu_ir_supported(x86_iommu)) {
         error_setg(errp, "eim=on cannot be selected without intremap=on");
         return false;
     }

     if (s->intr_eim == ON_OFF_AUTO_AUTO) {
         s->intr_eim = (kvm_irqchip_in_kernel() || s->buggy_eim)
                       && x86_iommu_ir_supported(x86_iommu) ?
                                               ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
     }
     if (s->intr_eim == ON_OFF_AUTO_ON && !s->buggy_eim) {
         if (kvm_irqchip_is_split() && !kvm_enable_x2apic()) {
             error_setg(errp, "eim=on requires support on the KVM side"
                              "(X2APIC_API, first shipped in v4.7)");
             return false;
         }
     }

     /* Currently only address widths supported are 39 and 48 bits */
     if ((s->aw_bits != VTD_HOST_AW_39BIT) &&
         (s->aw_bits != VTD_HOST_AW_48BIT)) {
         error_setg(errp, "Supported values for aw-bits are: %d, %d",
                    VTD_HOST_AW_39BIT, VTD_HOST_AW_48BIT);
         return false;
     }

     if (s->scalable_mode && !s->dma_drain) {
         error_setg(errp, "Need to set dma_drain for scalable mode");
         return false;
     }

     if (s->pasid && !s->scalable_mode) {
         error_setg(errp, "Need to set scalable mode for PASID");
         return false;
     }

     return true;
 }

 static int vtd_machine_done_notify_one(Object *child, void *unused)
 {
     IntelIOMMUState *iommu = INTEL_IOMMU_DEVICE(x86_iommu_get_default());

     /*
      * We hard-coded here because vfio-pci is the only special case
      * here.  Let's be more elegant in the future when we can, but so
      * far there seems to be no better way.
      */
     if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) {
         vtd_panic_require_caching_mode();
     }

     return 0;
 }

 static void vtd_machine_done_hook(Notifier *notifier, void *unused)
 {
     object_child_foreach_recursive(object_get_root(),
                                    vtd_machine_done_notify_one, NULL);
 }

 static Notifier vtd_machine_done_notify = {
     .notify = vtd_machine_done_hook,
 };

 static void vtd_realize(DeviceState *dev, Error **errp)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
     PCMachineState *pcms = PC_MACHINE(ms);
     X86MachineState *x86ms = X86_MACHINE(ms);
     PCIBus *bus = pcms->pcibus;
     IntelIOMMUState *s = INTEL_IOMMU_DEVICE(dev);
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);

     if (s->pasid && x86_iommu->dt_supported) {
         /*
          * PASID-based-Device-TLB Invalidate Descriptor is not
          * implemented and it requires support from vhost layer which
          * needs to be implemented in the future.
          */
         error_setg(errp, "PASID based device IOTLB is not supported");
         return;
     }

     if (!vtd_decide_config(s, errp)) {
         return;
     }

     QLIST_INIT(&s->vtd_as_with_notifiers);
     qemu_mutex_init(&s->iommu_lock);
     memory_region_init_io(&s->csrmem, OBJECT(s), &vtd_mem_ops, s,
                           "intel_iommu", DMAR_REG_SIZE);
     memory_region_add_subregion(get_system_memory(),
                                 Q35_HOST_BRIDGE_IOMMU_ADDR, &s->csrmem);

     /* Create the shared memory regions by all devices */
     memory_region_init(&s->mr_nodmar, OBJECT(s), "vtd-nodmar",
                        UINT64_MAX);
     memory_region_init_io(&s->mr_ir, OBJECT(s), &vtd_mem_ir_ops,
                           s, "vtd-ir", VTD_INTERRUPT_ADDR_SIZE);
     memory_region_init_alias(&s->mr_sys_alias, OBJECT(s),
                              "vtd-sys-alias", get_system_memory(), 0,
                              memory_region_size(get_system_memory()));
     memory_region_add_subregion_overlap(&s->mr_nodmar, 0,
                                         &s->mr_sys_alias, 0);
     memory_region_add_subregion_overlap(&s->mr_nodmar,
                                         VTD_INTERRUPT_ADDR_FIRST,
                                         &s->mr_ir, 1);
     /* No corresponding destroy */
     s->iotlb = g_hash_table_new_full(vtd_iotlb_hash, vtd_iotlb_equal,
                                      g_free, g_free);
     s->vtd_address_spaces = g_hash_table_new_full(vtd_as_hash, vtd_as_equal,
                                       g_free, g_free);
     s->vtd_host_iommu_dev = g_hash_table_new_full(vtd_hiod_hash, vtd_hiod_equal,
                                                   g_free, vtd_hiod_destroy);
     vtd_init(s);
     pci_setup_iommu(bus, &vtd_iommu_ops, dev);
     /* Pseudo address space under root PCI bus. */
     x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
     qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);
 }

 static void vtd_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     X86IOMMUClass *x86_class = X86_IOMMU_DEVICE_CLASS(klass);

     dc->reset = vtd_reset;
     dc->vmsd = &vtd_vmstate;
     device_class_set_props(dc, vtd_properties);
     dc->hotpluggable = false;
     x86_class->realize = vtd_realize;
     x86_class->int_remap = vtd_int_remap;
     /* Supported by the pc-q35-* machine types */
     dc->user_creatable = true;
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
     dc->desc = "Intel IOMMU (VT-d) DMA Remapping device";
 }

 static const TypeInfo vtd_info = {
     .name          = TYPE_INTEL_IOMMU_DEVICE,
     .parent        = TYPE_X86_IOMMU_DEVICE,
     .instance_size = sizeof(IntelIOMMUState),
     .class_init    = vtd_class_init,
 };

 static void vtd_iommu_memory_region_class_init(ObjectClass *klass,
                                                      void *data)
 {
     IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);

     imrc->translate = vtd_iommu_translate;
     imrc->notify_flag_changed = vtd_iommu_notify_flag_changed;
     imrc->replay = vtd_iommu_replay;
 }

 static const TypeInfo vtd_iommu_memory_region_info = {
     .parent = TYPE_IOMMU_MEMORY_REGION,
     .name = TYPE_INTEL_IOMMU_MEMORY_REGION,
     .class_init = vtd_iommu_memory_region_class_init,
 };

 static void vtd_register_types(void)
 {
     type_register_static(&vtd_info);
     type_register_static(&vtd_iommu_memory_region_info);
 }

 type_init(vtd_register_types)