hw/vfio/spapr.c - qemu - Git at Google

 /*
  * DMA memory preregistration
  *
  * Authors:
  *  Alexey Kardashevskiy <aik@ozlabs.ru>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
  */

 #include "qemu/osdep.h"
 #include <sys/ioctl.h>
 #include <linux/vfio.h>

 #include "hw/vfio/vfio-common.h"
 #include "hw/hw.h"
 #include "exec/ram_addr.h"
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "trace.h"

 static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section)
 {
     if (memory_region_is_iommu(section->mr)) {
         hw_error("Cannot possibly preregister IOMMU memory");
     }

     return !memory_region_is_ram(section->mr) ||
             memory_region_is_ram_device(section->mr);
 }

 static void *vfio_prereg_gpa_to_vaddr(MemoryRegionSection *section, hwaddr gpa)
 {
     return memory_region_get_ram_ptr(section->mr) +
         section->offset_within_region +
         (gpa - section->offset_within_address_space);
 }

 static void vfio_prereg_listener_region_add(MemoryListener *listener,
                                             MemoryRegionSection *section)
 {
     VFIOContainer *container = container_of(listener, VFIOContainer,
                                             prereg_listener);
     const hwaddr gpa = section->offset_within_address_space;
     hwaddr end;
     int ret;
     hwaddr page_mask = qemu_real_host_page_mask();
     struct vfio_iommu_spapr_register_memory reg = {
         .argsz = sizeof(reg),
         .flags = 0,
     };

     if (vfio_prereg_listener_skipped_section(section)) {
         trace_vfio_prereg_listener_region_add_skip(
                 section->offset_within_address_space,
                 section->offset_within_address_space +
                 int128_get64(int128_sub(section->size, int128_one())));
         return;
     }

     if (unlikely((section->offset_within_address_space & ~page_mask) ||
                  (section->offset_within_region & ~page_mask) ||
                  (int128_get64(section->size) & ~page_mask))) {
         error_report("%s received unaligned region", __func__);
         return;
     }

     end = section->offset_within_address_space + int128_get64(section->size);
     if (gpa >= end) {
         return;
     }

     memory_region_ref(section->mr);

     reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
     reg.size = end - gpa;

     ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, &reg);
     trace_vfio_prereg_register(reg.vaddr, reg.size, ret ? -errno : 0);
     if (ret) {
         /*
          * On the initfn path, store the first error in the container so we
          * can gracefully fail.  Runtime, there's not much we can do other
          * than throw a hardware error.
          */
         if (!container->initialized) {
             if (!container->error) {
                 error_setg_errno(&container->error, -ret,
                                  "Memory registering failed");
             }
         } else {
             hw_error("vfio: Memory registering failed, unable to continue");
         }
     }
 }

 static void vfio_prereg_listener_region_del(MemoryListener *listener,
                                             MemoryRegionSection *section)
 {
     VFIOContainer *container = container_of(listener, VFIOContainer,
                                             prereg_listener);
     const hwaddr gpa = section->offset_within_address_space;
     hwaddr end;
     int ret;
     hwaddr page_mask = qemu_real_host_page_mask();
     struct vfio_iommu_spapr_register_memory reg = {
         .argsz = sizeof(reg),
         .flags = 0,
     };

     if (vfio_prereg_listener_skipped_section(section)) {
         trace_vfio_prereg_listener_region_del_skip(
                 section->offset_within_address_space,
                 section->offset_within_address_space +
                 int128_get64(int128_sub(section->size, int128_one())));
         return;
     }

     if (unlikely((section->offset_within_address_space & ~page_mask) ||
                  (section->offset_within_region & ~page_mask) ||
                  (int128_get64(section->size) & ~page_mask))) {
         error_report("%s received unaligned region", __func__);
         return;
     }

     end = section->offset_within_address_space + int128_get64(section->size);
     if (gpa >= end) {
         return;
     }

     reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
     reg.size = end - gpa;

     ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, &reg);
     trace_vfio_prereg_unregister(reg.vaddr, reg.size, ret ? -errno : 0);
 }

 const MemoryListener vfio_prereg_listener = {
     .name = "vfio-pre-reg",
     .region_add = vfio_prereg_listener_region_add,
     .region_del = vfio_prereg_listener_region_del,
 };

 int vfio_spapr_create_window(VFIOContainer *container,
                              MemoryRegionSection *section,
                              hwaddr *pgsize)
 {
     int ret = 0;
     IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
     uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask;
     unsigned entries, bits_total, bits_per_level, max_levels;
     struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
     long rampagesize = qemu_minrampagesize();

     /*
      * The host might not support the guest supported IOMMU page size,
      * so we will use smaller physical IOMMU pages to back them.
      */
     if (pagesize > rampagesize) {
         pagesize = rampagesize;
     }
     pgmask = container->pgsizes & (pagesize | (pagesize - 1));
     pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0;
     if (!pagesize) {
         error_report("Host doesn't support page size 0x%"PRIx64
                      ", the supported mask is 0x%lx",
                      memory_region_iommu_get_min_page_size(iommu_mr),
                      container->pgsizes);
         return -EINVAL;
     }

     /*
      * FIXME: For VFIO iommu types which have KVM acceleration to
      * avoid bouncing all map/unmaps through qemu this way, this
      * would be the right place to wire that up (tell the KVM
      * device emulation the VFIO iommu handles to use).
      */
     create.window_size = int128_get64(section->size);
     create.page_shift = ctz64(pagesize);
     /*
      * SPAPR host supports multilevel TCE tables. We try to guess optimal
      * levels number and if this fails (for example due to the host memory
      * fragmentation), we increase levels. The DMA address structure is:
      * rrrrrrrr rxxxxxxx xxxxxxxx xxxxxxxx  xxxxxxxx xxxxxxxx xxxxxxxx iiiiiiii
      * where:
      *   r = reserved (bits >= 55 are reserved in the existing hardware)
      *   i = IOMMU page offset (64K in this example)
      *   x = bits to index a TCE which can be split to equal chunks to index
      *      within the level.
      * The aim is to split "x" to smaller possible number of levels.
      */
     entries = create.window_size >> create.page_shift;
     /* bits_total is number of "x" needed */
     bits_total = ctz64(entries * sizeof(uint64_t));
     /*
      * bits_per_level is a safe guess of how much we can allocate per level:
      * 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER
      * is usually bigger than that.
      * Below we look at qemu_real_host_page_size as TCEs are allocated from
      * system pages.
      */
     bits_per_level = ctz64(qemu_real_host_page_size()) + 8;
     create.levels = bits_total / bits_per_level;
     if (bits_total % bits_per_level) {
         ++create.levels;
     }
     max_levels = (64 - create.page_shift) / ctz64(qemu_real_host_page_size());
     for ( ; create.levels <= max_levels; ++create.levels) {
         ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
         if (!ret) {
             break;
         }
     }
     if (ret) {
         error_report("Failed to create a window, ret = %d (%m)", ret);
         return -errno;
     }

     if (create.start_addr != section->offset_within_address_space) {
         vfio_spapr_remove_window(container, create.start_addr);

         error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
                      section->offset_within_address_space,
                      (uint64_t)create.start_addr);
         return -EINVAL;
     }
     trace_vfio_spapr_create_window(create.page_shift,
                                    create.levels,
                                    create.window_size,
                                    create.start_addr);
     *pgsize = pagesize;

     return 0;
 }

 int vfio_spapr_remove_window(VFIOContainer *container,
                              hwaddr offset_within_address_space)
 {
     struct vfio_iommu_spapr_tce_remove remove = {
         .argsz = sizeof(remove),
         .start_addr = offset_within_address_space,
     };
     int ret;

     ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
     if (ret) {
         error_report("Failed to remove window at %"PRIx64,
                      (uint64_t)remove.start_addr);
         return -errno;
     }

     trace_vfio_spapr_remove_window(offset_within_address_space);

     return 0;
 }
	/*
	* DMA memory preregistration
	*
	* Authors:
	* Alexey Kardashevskiy <aik@ozlabs.ru>
	*
	* This work is licensed under the terms of the GNU GPL, version 2. See
	* the COPYING file in the top-level directory.
	*/

	#include "qemu/osdep.h"
	#include <sys/ioctl.h>
	#include <linux/vfio.h>

	#include "hw/vfio/vfio-common.h"
	#include "hw/hw.h"
	#include "exec/ram_addr.h"
	#include "qemu/error-report.h"
	#include "qapi/error.h"
	#include "trace.h"

	static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section)
	{
	if (memory_region_is_iommu(section->mr)) {
	hw_error("Cannot possibly preregister IOMMU memory");
	}

	return !memory_region_is_ram(section->mr) \|\|
	memory_region_is_ram_device(section->mr);
	}

	static void vfio_prereg_gpa_to_vaddr(MemoryRegionSection section, hwaddr gpa)
	{
	return memory_region_get_ram_ptr(section->mr) +
	section->offset_within_region +
	(gpa - section->offset_within_address_space);
	}

	static void vfio_prereg_listener_region_add(MemoryListener *listener,
	MemoryRegionSection *section)
	{
	VFIOContainer *container = container_of(listener, VFIOContainer,
	prereg_listener);
	const hwaddr gpa = section->offset_within_address_space;
	hwaddr end;
	int ret;
	hwaddr page_mask = qemu_real_host_page_mask();
	struct vfio_iommu_spapr_register_memory reg = {
	.argsz = sizeof(reg),
	.flags = 0,
	};

	if (vfio_prereg_listener_skipped_section(section)) {
	trace_vfio_prereg_listener_region_add_skip(
	section->offset_within_address_space,
	section->offset_within_address_space +
	int128_get64(int128_sub(section->size, int128_one())));
	return;
	}

	if (unlikely((section->offset_within_address_space & ~page_mask) \|\|
	(section->offset_within_region & ~page_mask) \|\|
	(int128_get64(section->size) & ~page_mask))) {
	error_report("%s received unaligned region", __func__);
	return;
	}

	end = section->offset_within_address_space + int128_get64(section->size);
	if (gpa >= end) {
	return;
	}

	memory_region_ref(section->mr);

	reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
	reg.size = end - gpa;

	ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, &reg);
	trace_vfio_prereg_register(reg.vaddr, reg.size, ret ? -errno : 0);
	if (ret) {
	/*
	* On the initfn path, store the first error in the container so we
	* can gracefully fail. Runtime, there's not much we can do other
	* than throw a hardware error.
	*/
	if (!container->initialized) {
	if (!container->error) {
	error_setg_errno(&container->error, -ret,
	"Memory registering failed");
	}
	} else {
	hw_error("vfio: Memory registering failed, unable to continue");
	}
	}
	}

	static void vfio_prereg_listener_region_del(MemoryListener *listener,
	MemoryRegionSection *section)
	{
	VFIOContainer *container = container_of(listener, VFIOContainer,
	prereg_listener);
	const hwaddr gpa = section->offset_within_address_space;
	hwaddr end;
	int ret;
	hwaddr page_mask = qemu_real_host_page_mask();
	struct vfio_iommu_spapr_register_memory reg = {
	.argsz = sizeof(reg),
	.flags = 0,
	};

	if (vfio_prereg_listener_skipped_section(section)) {
	trace_vfio_prereg_listener_region_del_skip(
	section->offset_within_address_space,
	section->offset_within_address_space +
	int128_get64(int128_sub(section->size, int128_one())));
	return;
	}

	if (unlikely((section->offset_within_address_space & ~page_mask) \|\|
	(section->offset_within_region & ~page_mask) \|\|
	(int128_get64(section->size) & ~page_mask))) {
	error_report("%s received unaligned region", __func__);
	return;
	}

	end = section->offset_within_address_space + int128_get64(section->size);
	if (gpa >= end) {
	return;
	}

	reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
	reg.size = end - gpa;

	ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, &reg);
	trace_vfio_prereg_unregister(reg.vaddr, reg.size, ret ? -errno : 0);
	}

	const MemoryListener vfio_prereg_listener = {
	.name = "vfio-pre-reg",
	.region_add = vfio_prereg_listener_region_add,
	.region_del = vfio_prereg_listener_region_del,
	};

	int vfio_spapr_create_window(VFIOContainer *container,
	MemoryRegionSection *section,
	hwaddr *pgsize)
	{
	int ret = 0;
	IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
	uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask;
	unsigned entries, bits_total, bits_per_level, max_levels;
	struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
	long rampagesize = qemu_minrampagesize();

	/*
	* The host might not support the guest supported IOMMU page size,
	* so we will use smaller physical IOMMU pages to back them.
	*/
	if (pagesize > rampagesize) {
	pagesize = rampagesize;
	}
	pgmask = container->pgsizes & (pagesize \| (pagesize - 1));
	pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0;
	if (!pagesize) {
	error_report("Host doesn't support page size 0x%"PRIx64
	", the supported mask is 0x%lx",
	memory_region_iommu_get_min_page_size(iommu_mr),
	container->pgsizes);
	return -EINVAL;
	}

	/*
	* FIXME: For VFIO iommu types which have KVM acceleration to
	* avoid bouncing all map/unmaps through qemu this way, this
	* would be the right place to wire that up (tell the KVM
	* device emulation the VFIO iommu handles to use).
	*/
	create.window_size = int128_get64(section->size);
	create.page_shift = ctz64(pagesize);
	/*
	* SPAPR host supports multilevel TCE tables. We try to guess optimal
	* levels number and if this fails (for example due to the host memory
	* fragmentation), we increase levels. The DMA address structure is:
	* rrrrrrrr rxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx iiiiiiii
	* where:
	* r = reserved (bits >= 55 are reserved in the existing hardware)
	* i = IOMMU page offset (64K in this example)
	* x = bits to index a TCE which can be split to equal chunks to index
	* within the level.
	* The aim is to split "x" to smaller possible number of levels.
	*/
	entries = create.window_size >> create.page_shift;
	/* bits_total is number of "x" needed */
	bits_total = ctz64(entries * sizeof(uint64_t));
	/*
	* bits_per_level is a safe guess of how much we can allocate per level:
	* 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER
	* is usually bigger than that.
	* Below we look at qemu_real_host_page_size as TCEs are allocated from
	* system pages.
	*/
	bits_per_level = ctz64(qemu_real_host_page_size()) + 8;
	create.levels = bits_total / bits_per_level;
	if (bits_total % bits_per_level) {
	++create.levels;
	}
	max_levels = (64 - create.page_shift) / ctz64(qemu_real_host_page_size());
	for ( ; create.levels <= max_levels; ++create.levels) {
	ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
	if (!ret) {
	break;
	}
	}
	if (ret) {
	error_report("Failed to create a window, ret = %d (%m)", ret);
	return -errno;
	}

	if (create.start_addr != section->offset_within_address_space) {
	vfio_spapr_remove_window(container, create.start_addr);

	error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
	section->offset_within_address_space,
	(uint64_t)create.start_addr);
	return -EINVAL;
	}
	trace_vfio_spapr_create_window(create.page_shift,
	create.levels,
	create.window_size,
	create.start_addr);
	*pgsize = pagesize;

	return 0;
	}

	int vfio_spapr_remove_window(VFIOContainer *container,
	hwaddr offset_within_address_space)
	{
	struct vfio_iommu_spapr_tce_remove remove = {
	.argsz = sizeof(remove),
	.start_addr = offset_within_address_space,
	};
	int ret;

	ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
	if (ret) {
	error_report("Failed to remove window at %"PRIx64,
	(uint64_t)remove.start_addr);
	return -errno;
	}

	trace_vfio_spapr_remove_window(offset_within_address_space);

	return 0;
	}