Merge remote-tracking branch 'remotes/awilliam/tags/vfio-pci-for-qemu-20140602.0' into staging

VFIO patches: realtek NIC quirk + SPAPR IOMMU AddressSpace support

# gpg: Signature made Mon 02 Jun 2014 22:44:42 BST using RSA key ID 3BB08B22
# gpg: Can't check signature: public key not found

* remotes/awilliam/tags/vfio-pci-for-qemu-20140602.0:
  vfio: Add guest side IOMMU support
  vfio: Create VFIOAddressSpace objects as needed
  vfio: Introduce VFIO address spaces
  vfio: Rework to have error paths
  vfio: Fix 128 bit handling
  int128: Add int128_exts64()
  memory: Sanity check that no listeners remain on a destroyed AddressSpace
  vfio-pci: Quirk RTL8168 NIC

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 9cf5b84..7437c2e 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -133,6 +133,15 @@
     VFIO_INT_MSIX = 3,
 };
 
+typedef struct VFIOAddressSpace {
+    AddressSpace *as;
+    QLIST_HEAD(, VFIOContainer) containers;
+    QLIST_ENTRY(VFIOAddressSpace) list;
+} VFIOAddressSpace;
+
+static QLIST_HEAD(, VFIOAddressSpace) vfio_address_spaces =
+    QLIST_HEAD_INITIALIZER(vfio_address_spaces);
+
 struct VFIOGroup;
 
 typedef struct VFIOType1 {
@@ -142,6 +151,7 @@
 } VFIOType1;
 
 typedef struct VFIOContainer {
+    VFIOAddressSpace *space;
     int fd; /* /dev/vfio/vfio, empowered by the attached groups */
     struct {
         /* enable abstraction to support various iommu backends */
@@ -150,10 +160,18 @@
         };
         void (*release)(struct VFIOContainer *);
     } iommu_data;
+    QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
     QLIST_HEAD(, VFIOGroup) group_list;
     QLIST_ENTRY(VFIOContainer) next;
 } VFIOContainer;
 
+typedef struct VFIOGuestIOMMU {
+    VFIOContainer *container;
+    MemoryRegion *iommu;
+    Notifier n;
+    QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
+} VFIOGuestIOMMU;
+
 /* Cache of MSI-X setup plus extra mmap and memory region for split BAR map */
 typedef struct VFIOMSIXInfo {
     uint8_t table_bar;
@@ -234,9 +252,6 @@
 
 #define MSIX_CAP_LENGTH 12
 
-static QLIST_HEAD(, VFIOContainer)
-    container_list = QLIST_HEAD_INITIALIZER(container_list);
-
 static QLIST_HEAD(, VFIOGroup)
     group_list = QLIST_HEAD_INITIALIZER(group_list);
 
@@ -1668,6 +1683,149 @@
             vdev->host.function);
 }
 
+#define PCI_VENDOR_ID_REALTEK 0x10ec
+
+/*
+ * RTL8168 devices have a backdoor that can access the MSI-X table.  At BAR2
+ * offset 0x70 there is a dword data register, offset 0x74 is a dword address
+ * register.  According to the Linux r8169 driver, the MSI-X table is addressed
+ * when the "type" portion of the address register is set to 0x1.  This appears
+ * to be bits 16:30.  Bit 31 is both a write indicator and some sort of
+ * "address latched" indicator.  Bits 12:15 are a mask field, which we can
+ * ignore because the MSI-X table should always be accessed as a dword (full
+ * mask).  Bits 0:11 is offset within the type.
+ *
+ * Example trace:
+ *
+ * Read from MSI-X table offset 0
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x74, 0x1f000, 4) // store read addr
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x74, 4) = 0x8001f000 // latch
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x70, 4) = 0xfee00398 // read data
+ *
+ * Write 0xfee00000 to MSI-X table offset 0
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x70, 0xfee00000, 4) // write data
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x74, 0x8001f000, 4) // do write
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x74, 4) = 0x1f000 // complete
+ */
+
+static uint64_t vfio_rtl8168_window_quirk_read(void *opaque,
+                                               hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIODevice *vdev = quirk->vdev;
+
+    switch (addr) {
+    case 4: /* address */
+        if (quirk->data.flags) {
+            DPRINTF("%s fake read(%04x:%02x:%02x.%d)\n",
+                    memory_region_name(&quirk->mem), vdev->host.domain,
+                    vdev->host.bus, vdev->host.slot, vdev->host.function);
+
+            return quirk->data.address_match ^ 0x10000000U;
+        }
+        break;
+    case 0: /* data */
+        if (quirk->data.flags) {
+            uint64_t val;
+
+            DPRINTF("%s MSI-X table read(%04x:%02x:%02x.%d)\n",
+                    memory_region_name(&quirk->mem), vdev->host.domain,
+                    vdev->host.bus, vdev->host.slot, vdev->host.function);
+
+            if (!(vdev->pdev.cap_present & QEMU_PCI_CAP_MSIX)) {
+                return 0;
+            }
+
+            io_mem_read(&vdev->pdev.msix_table_mmio,
+                        (hwaddr)(quirk->data.address_match & 0xfff),
+                        &val, size);
+            return val;
+        }
+    }
+
+    DPRINTF("%s direct read(%04x:%02x:%02x.%d)\n",
+            memory_region_name(&quirk->mem), vdev->host.domain,
+            vdev->host.bus, vdev->host.slot, vdev->host.function);
+
+    return vfio_bar_read(&vdev->bars[quirk->data.bar], addr + 0x70, size);
+}
+
+static void vfio_rtl8168_window_quirk_write(void *opaque, hwaddr addr,
+                                            uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIODevice *vdev = quirk->vdev;
+
+    switch (addr) {
+    case 4: /* address */
+        if ((data & 0x7fff0000) == 0x10000) {
+            if (data & 0x10000000U &&
+                vdev->pdev.cap_present & QEMU_PCI_CAP_MSIX) {
+
+                DPRINTF("%s MSI-X table write(%04x:%02x:%02x.%d)\n",
+                        memory_region_name(&quirk->mem), vdev->host.domain,
+                        vdev->host.bus, vdev->host.slot, vdev->host.function);
+
+                io_mem_write(&vdev->pdev.msix_table_mmio,
+                             (hwaddr)(quirk->data.address_match & 0xfff),
+                             data, size);
+            }
+
+            quirk->data.flags = 1;
+            quirk->data.address_match = data;
+
+            return;
+        }
+        quirk->data.flags = 0;
+        break;
+    case 0: /* data */
+        quirk->data.address_mask = data;
+        break;
+    }
+
+    DPRINTF("%s direct write(%04x:%02x:%02x.%d)\n",
+            memory_region_name(&quirk->mem), vdev->host.domain,
+            vdev->host.bus, vdev->host.slot, vdev->host.function);
+
+    vfio_bar_write(&vdev->bars[quirk->data.bar], addr + 0x70, data, size);
+}
+
+static const MemoryRegionOps vfio_rtl8168_window_quirk = {
+    .read = vfio_rtl8168_window_quirk_read,
+    .write = vfio_rtl8168_window_quirk_write,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void vfio_probe_rtl8168_bar2_window_quirk(VFIODevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_REALTEK ||
+        pci_get_word(pdev->config + PCI_DEVICE_ID) != 0x8168 || nr != 2) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_rtl8168_window_quirk,
+                          quirk, "vfio-rtl8168-window-quirk", 8);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].mem,
+                                        0x70, &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    DPRINTF("Enabled RTL8168 BAR2 window quirk for device %04x:%02x:%02x.%x\n",
+            vdev->host.domain, vdev->host.bus, vdev->host.slot,
+            vdev->host.function);
+}
 /*
  * Trap the BAR2 MMIO window to config space as well.
  */
@@ -2071,6 +2229,7 @@
     vfio_probe_nvidia_bar5_window_quirk(vdev, nr);
     vfio_probe_nvidia_bar0_88000_quirk(vdev, nr);
     vfio_probe_nvidia_bar0_1800_quirk(vdev, nr);
+    vfio_probe_rtl8168_bar2_window_quirk(vdev, nr);
 }
 
 static void vfio_bar_quirk_teardown(VFIODevice *vdev, int nr)
@@ -2232,7 +2391,8 @@
 
 static bool vfio_listener_skipped_section(MemoryRegionSection *section)
 {
-    return !memory_region_is_ram(section->mr) ||
+    return (!memory_region_is_ram(section->mr) &&
+            !memory_region_is_iommu(section->mr)) ||
            /*
             * Sizing an enabled 64-bit BAR can cause spurious mappings to
             * addresses in the upper part of the 64-bit address space.  These
@@ -2242,17 +2402,75 @@
            section->offset_within_address_space & (1ULL << 63);
 }
 
+static void vfio_iommu_map_notify(Notifier *n, void *data)
+{
+    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
+    VFIOContainer *container = giommu->container;
+    IOMMUTLBEntry *iotlb = data;
+    MemoryRegion *mr;
+    hwaddr xlat;
+    hwaddr len = iotlb->addr_mask + 1;
+    void *vaddr;
+    int ret;
+
+    DPRINTF("iommu map @ %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
+            iotlb->iova, iotlb->iova + iotlb->addr_mask);
+
+    /*
+     * The IOMMU TLB entry we have just covers translation through
+     * this IOMMU to its immediate target.  We need to translate
+     * it the rest of the way through to memory.
+     */
+    mr = address_space_translate(&address_space_memory,
+                                 iotlb->translated_addr,
+                                 &xlat, &len, iotlb->perm & IOMMU_WO);
+    if (!memory_region_is_ram(mr)) {
+        DPRINTF("iommu map to non memory area %"HWADDR_PRIx"\n",
+                xlat);
+        return;
+    }
+    /*
+     * Translation truncates length to the IOMMU page size,
+     * check that it did not truncate too much.
+     */
+    if (len & iotlb->addr_mask) {
+        DPRINTF("iommu has granularity incompatible with target AS\n");
+        return;
+    }
+
+    if (iotlb->perm != IOMMU_NONE) {
+        vaddr = memory_region_get_ram_ptr(mr) + xlat;
+
+        ret = vfio_dma_map(container, iotlb->iova,
+                           iotlb->addr_mask + 1, vaddr,
+                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
+        if (ret) {
+            error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
+                         "0x%"HWADDR_PRIx", %p) = %d (%m)",
+                         container, iotlb->iova,
+                         iotlb->addr_mask + 1, vaddr, ret);
+        }
+    } else {
+        ret = vfio_dma_unmap(container, iotlb->iova, iotlb->addr_mask + 1);
+        if (ret) {
+            error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
+                         "0x%"HWADDR_PRIx") = %d (%m)",
+                         container, iotlb->iova,
+                         iotlb->addr_mask + 1, ret);
+        }
+    }
+}
+
 static void vfio_listener_region_add(MemoryListener *listener,
                                      MemoryRegionSection *section)
 {
     VFIOContainer *container = container_of(listener, VFIOContainer,
                                             iommu_data.type1.listener);
     hwaddr iova, end;
+    Int128 llend;
     void *vaddr;
     int ret;
 
-    assert(!memory_region_is_iommu(section->mr));
-
     if (vfio_listener_skipped_section(section)) {
         DPRINTF("SKIPPING region_add %"HWADDR_PRIx" - %"PRIx64"\n",
                 section->offset_within_address_space,
@@ -2268,21 +2486,65 @@
     }
 
     iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
-    end = (section->offset_within_address_space + int128_get64(section->size)) &
-          TARGET_PAGE_MASK;
+    llend = int128_make64(section->offset_within_address_space);
+    llend = int128_add(llend, section->size);
+    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
 
-    if (iova >= end) {
+    if (int128_ge(int128_make64(iova), llend)) {
         return;
     }
 
+    memory_region_ref(section->mr);
+
+    if (memory_region_is_iommu(section->mr)) {
+        VFIOGuestIOMMU *giommu;
+
+        DPRINTF("region_add [iommu] %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
+                iova, int128_get64(int128_sub(llend, int128_one())));
+        /*
+         * FIXME: We should do some checking to see if the
+         * capabilities of the host VFIO IOMMU are adequate to model
+         * the guest IOMMU
+         *
+         * 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).
+         */
+        /*
+         * This assumes that the guest IOMMU is empty of
+         * mappings at this point.
+         *
+         * One way of doing this is:
+         * 1. Avoid sharing IOMMUs between emulated devices or different
+         * IOMMU groups.
+         * 2. Implement VFIO_IOMMU_ENABLE in the host kernel to fail if
+         * there are some mappings in IOMMU.
+         *
+         * VFIO on SPAPR does that. Other IOMMU models may do that different,
+         * they must make sure there are no existing mappings or
+         * loop through existing mappings to map them into VFIO.
+         */
+        giommu = g_malloc0(sizeof(*giommu));
+        giommu->iommu = section->mr;
+        giommu->container = container;
+        giommu->n.notify = vfio_iommu_map_notify;
+        QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
+        memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
+
+        return;
+    }
+
+    /* Here we assume that memory_region_is_ram(section->mr)==true */
+
+    end = int128_get64(llend);
     vaddr = memory_region_get_ram_ptr(section->mr) +
             section->offset_within_region +
             (iova - section->offset_within_address_space);
 
-    DPRINTF("region_add %"HWADDR_PRIx" - %"HWADDR_PRIx" [%p]\n",
+    DPRINTF("region_add [ram] %"HWADDR_PRIx" - %"HWADDR_PRIx" [%p]\n",
             iova, end - 1, vaddr);
 
-    memory_region_ref(section->mr);
     ret = vfio_dma_map(container, iova, end - iova, vaddr, section->readonly);
     if (ret) {
         error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
@@ -2326,6 +2588,27 @@
         return;
     }
 
+    if (memory_region_is_iommu(section->mr)) {
+        VFIOGuestIOMMU *giommu;
+
+        QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
+            if (giommu->iommu == section->mr) {
+                memory_region_unregister_iommu_notifier(&giommu->n);
+                QLIST_REMOVE(giommu, giommu_next);
+                g_free(giommu);
+                break;
+            }
+        }
+
+        /*
+         * FIXME: We assume the one big unmap below is adequate to
+         * remove any individual page mappings in the IOMMU which
+         * might have been copied into VFIO. This works for a page table
+         * based IOMMU where a big unmap flattens a large range of IO-PTEs.
+         * That may not be true for all IOMMU types.
+         */
+    }
+
     iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
     end = (section->offset_within_address_space + int128_get64(section->size)) &
           TARGET_PAGE_MASK;
@@ -3274,16 +3557,43 @@
 #endif
 }
 
-static int vfio_connect_container(VFIOGroup *group)
+static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
+{
+    VFIOAddressSpace *space;
+
+    QLIST_FOREACH(space, &vfio_address_spaces, list) {
+        if (space->as == as) {
+            return space;
+        }
+    }
+
+    /* No suitable VFIOAddressSpace, create a new one */
+    space = g_malloc0(sizeof(*space));
+    space->as = as;
+    QLIST_INIT(&space->containers);
+
+    QLIST_INSERT_HEAD(&vfio_address_spaces, space, list);
+
+    return space;
+}
+
+static void vfio_put_address_space(VFIOAddressSpace *space)
+{
+    if (QLIST_EMPTY(&space->containers)) {
+        QLIST_REMOVE(space, list);
+        g_free(space);
+    }
+}
+
+static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
 {
     VFIOContainer *container;
     int ret, fd;
+    VFIOAddressSpace *space;
 
-    if (group->container) {
-        return 0;
-    }
+    space = vfio_get_address_space(as);
 
-    QLIST_FOREACH(container, &container_list, next) {
+    QLIST_FOREACH(container, &space->containers, next) {
         if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
             group->container = container;
             QLIST_INSERT_HEAD(&container->group_list, group, container_next);
@@ -3294,35 +3604,35 @@
     fd = qemu_open("/dev/vfio/vfio", O_RDWR);
     if (fd < 0) {
         error_report("vfio: failed to open /dev/vfio/vfio: %m");
-        return -errno;
+        ret = -errno;
+        goto put_space_exit;
     }
 
     ret = ioctl(fd, VFIO_GET_API_VERSION);
     if (ret != VFIO_API_VERSION) {
         error_report("vfio: supported vfio version: %d, "
                      "reported version: %d", VFIO_API_VERSION, ret);
-        close(fd);
-        return -EINVAL;
+        ret = -EINVAL;
+        goto close_fd_exit;
     }
 
     container = g_malloc0(sizeof(*container));
+    container->space = space;
     container->fd = fd;
 
     if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
         ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
         if (ret) {
             error_report("vfio: failed to set group container: %m");
-            g_free(container);
-            close(fd);
-            return -errno;
+            ret = -errno;
+            goto free_container_exit;
         }
 
         ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU);
         if (ret) {
             error_report("vfio: failed to set iommu for container: %m");
-            g_free(container);
-            close(fd);
-            return -errno;
+            ret = -errno;
+            goto free_container_exit;
         }
 
         container->iommu_data.type1.listener = vfio_memory_listener;
@@ -3333,29 +3643,39 @@
 
         if (container->iommu_data.type1.error) {
             ret = container->iommu_data.type1.error;
-            vfio_listener_release(container);
-            g_free(container);
-            close(fd);
             error_report("vfio: memory listener initialization failed for container");
-            return ret;
+            goto listener_release_exit;
         }
 
         container->iommu_data.type1.initialized = true;
 
     } else {
         error_report("vfio: No available IOMMU models");
-        g_free(container);
-        close(fd);
-        return -EINVAL;
+        ret = -EINVAL;
+        goto free_container_exit;
     }
 
     QLIST_INIT(&container->group_list);
-    QLIST_INSERT_HEAD(&container_list, container, next);
+    QLIST_INSERT_HEAD(&space->containers, container, next);
 
     group->container = container;
     QLIST_INSERT_HEAD(&container->group_list, group, container_next);
 
     return 0;
+
+listener_release_exit:
+    vfio_listener_release(container);
+
+free_container_exit:
+    g_free(container);
+
+close_fd_exit:
+    close(fd);
+
+put_space_exit:
+    vfio_put_address_space(space);
+
+    return ret;
 }
 
 static void vfio_disconnect_container(VFIOGroup *group)
@@ -3371,6 +3691,8 @@
     group->container = NULL;
 
     if (QLIST_EMPTY(&container->group_list)) {
+        VFIOAddressSpace *space = container->space;
+
         if (container->iommu_data.release) {
             container->iommu_data.release(container);
         }
@@ -3378,10 +3700,12 @@
         DPRINTF("vfio_disconnect_container: close container->fd\n");
         close(container->fd);
         g_free(container);
+
+        vfio_put_address_space(space);
     }
 }
 
-static VFIOGroup *vfio_get_group(int groupid)
+static VFIOGroup *vfio_get_group(int groupid, AddressSpace *as)
 {
     VFIOGroup *group;
     char path[32];
@@ -3389,7 +3713,14 @@
 
     QLIST_FOREACH(group, &group_list, next) {
         if (group->groupid == groupid) {
-            return group;
+            /* Found it.  Now is it already in the right context? */
+            if (group->container->space->as == as) {
+                return group;
+            } else {
+                error_report("vfio: group %d used in multiple address spaces",
+                             group->groupid);
+                return NULL;
+            }
         }
     }
 
@@ -3399,34 +3730,27 @@
     group->fd = qemu_open(path, O_RDWR);
     if (group->fd < 0) {
         error_report("vfio: error opening %s: %m", path);
-        g_free(group);
-        return NULL;
+        goto free_group_exit;
     }
 
     if (ioctl(group->fd, VFIO_GROUP_GET_STATUS, &status)) {
         error_report("vfio: error getting group status: %m");
-        close(group->fd);
-        g_free(group);
-        return NULL;
+        goto close_fd_exit;
     }
 
     if (!(status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
         error_report("vfio: error, group %d is not viable, please ensure "
                      "all devices within the iommu_group are bound to their "
                      "vfio bus driver.", groupid);
-        close(group->fd);
-        g_free(group);
-        return NULL;
+        goto close_fd_exit;
     }
 
     group->groupid = groupid;
     QLIST_INIT(&group->device_list);
 
-    if (vfio_connect_container(group)) {
+    if (vfio_connect_container(group, as)) {
         error_report("vfio: failed to setup container for group %d", groupid);
-        close(group->fd);
-        g_free(group);
-        return NULL;
+        goto close_fd_exit;
     }
 
     if (QLIST_EMPTY(&group_list)) {
@@ -3438,6 +3762,14 @@
     vfio_kvm_device_add_group(group);
 
     return group;
+
+close_fd_exit:
+    close(group->fd);
+
+free_group_exit:
+    g_free(group);
+
+    return NULL;
 }
 
 static void vfio_put_group(VFIOGroup *group)
@@ -3768,7 +4100,7 @@
     DPRINTF("%s(%04x:%02x:%02x.%x) group %d\n", __func__, vdev->host.domain,
             vdev->host.bus, vdev->host.slot, vdev->host.function, groupid);
 
-    group = vfio_get_group(groupid);
+    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev));
     if (!group) {
         error_report("vfio: failed to get group %d", groupid);
         return -ENOENT;
diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index f597031..fb782aa 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -38,6 +38,11 @@
     return (Int128) { 0, 1 };
 }
 
+static inline Int128 int128_exts64(int64_t a)
+{
+    return (Int128) { .lo = a, .hi = (a < 0) ? -1 : 0 };
+}
+
 static inline Int128 int128_and(Int128 a, Int128 b)
 {
     return (Int128) { a.lo & b.lo, a.hi & b.hi };
diff --git a/memory.c b/memory.c
index 3f1df23..678661e 100644
--- a/memory.c
+++ b/memory.c
@@ -1722,12 +1722,19 @@
 
 void address_space_destroy(AddressSpace *as)
 {
+    MemoryListener *listener;
+
     /* Flush out anything from MemoryListeners listening in on this */
     memory_region_transaction_begin();
     as->root = NULL;
     memory_region_transaction_commit();
     QTAILQ_REMOVE(&address_spaces, as, address_spaces_link);
     address_space_destroy_dispatch(as);
+
+    QTAILQ_FOREACH(listener, &memory_listeners, link) {
+        assert(listener->address_space_filter != as);
+    }
+
     flatview_unref(as->current_map);
     g_free(as->name);
     g_free(as->ioeventfds);