]> git.proxmox.com Git - mirror_qemu.git/blobdiff - hw/vfio/common.c
vfio: Support for RamDiscardManager in the vIOMMU case
[mirror_qemu.git] / hw / vfio / common.c
index 33357140b8de8ad857f38ef538dd4c9a36ebdad6..8a9bbf27918d8249e0d470c2cc03f059a5967867 100644 (file)
 #include "hw/vfio/vfio.h"
 #include "exec/address-spaces.h"
 #include "exec/memory.h"
+#include "exec/ram_addr.h"
 #include "hw/hw.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qemu/range.h"
 #include "sysemu/kvm.h"
 #include "sysemu/reset.h"
+#include "sysemu/runstate.h"
 #include "trace.h"
 #include "qapi/error.h"
+#include "migration/migration.h"
 
 VFIOGroupList vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -203,7 +206,7 @@ void vfio_region_write(void *opaque, hwaddr addr,
         buf.qword = cpu_to_le64(data);
         break;
     default:
-        hw_error("vfio: unsupported write size, %d bytes", size);
+        hw_error("vfio: unsupported write size, %u bytes", size);
         break;
     }
 
@@ -260,7 +263,7 @@ uint64_t vfio_region_read(void *opaque,
         data = le64_to_cpu(buf.qword);
         break;
     default:
-        hw_error("vfio: unsupported read size, %d bytes", size);
+        hw_error("vfio: unsupported read size, %u bytes", size);
         break;
     }
 
@@ -286,11 +289,145 @@ const MemoryRegionOps vfio_region_ops = {
     },
 };
 
+/*
+ * Device state interfaces
+ */
+
+bool vfio_mig_active(void)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev;
+
+    if (QLIST_EMPTY(&vfio_group_list)) {
+        return false;
+    }
+
+    QLIST_FOREACH(group, &vfio_group_list, next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            if (vbasedev->migration_blocker) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+static bool vfio_devices_all_dirty_tracking(VFIOContainer *container)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev;
+    MigrationState *ms = migrate_get_current();
+
+    if (!migration_is_setup_or_active(ms->state)) {
+        return false;
+    }
+
+    QLIST_FOREACH(group, &container->group_list, container_next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            VFIOMigration *migration = vbasedev->migration;
+
+            if (!migration) {
+                return false;
+            }
+
+            if ((vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF)
+                && (migration->device_state & VFIO_DEVICE_STATE_RUNNING)) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+static bool vfio_devices_all_running_and_saving(VFIOContainer *container)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev;
+    MigrationState *ms = migrate_get_current();
+
+    if (!migration_is_setup_or_active(ms->state)) {
+        return false;
+    }
+
+    QLIST_FOREACH(group, &container->group_list, container_next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            VFIOMigration *migration = vbasedev->migration;
+
+            if (!migration) {
+                return false;
+            }
+
+            if ((migration->device_state & VFIO_DEVICE_STATE_SAVING) &&
+                (migration->device_state & VFIO_DEVICE_STATE_RUNNING)) {
+                continue;
+            } else {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+static int vfio_dma_unmap_bitmap(VFIOContainer *container,
+                                 hwaddr iova, ram_addr_t size,
+                                 IOMMUTLBEntry *iotlb)
+{
+    struct vfio_iommu_type1_dma_unmap *unmap;
+    struct vfio_bitmap *bitmap;
+    uint64_t pages = REAL_HOST_PAGE_ALIGN(size) / qemu_real_host_page_size;
+    int ret;
+
+    unmap = g_malloc0(sizeof(*unmap) + sizeof(*bitmap));
+
+    unmap->argsz = sizeof(*unmap) + sizeof(*bitmap);
+    unmap->iova = iova;
+    unmap->size = size;
+    unmap->flags |= VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP;
+    bitmap = (struct vfio_bitmap *)&unmap->data;
+
+    /*
+     * cpu_physical_memory_set_dirty_lebitmap() supports pages in bitmap of
+     * qemu_real_host_page_size to mark those dirty. Hence set bitmap_pgsize
+     * to qemu_real_host_page_size.
+     */
+
+    bitmap->pgsize = qemu_real_host_page_size;
+    bitmap->size = ROUND_UP(pages, sizeof(__u64) * BITS_PER_BYTE) /
+                   BITS_PER_BYTE;
+
+    if (bitmap->size > container->max_dirty_bitmap_size) {
+        error_report("UNMAP: Size of bitmap too big 0x%"PRIx64,
+                     (uint64_t)bitmap->size);
+        ret = -E2BIG;
+        goto unmap_exit;
+    }
+
+    bitmap->data = g_try_malloc0(bitmap->size);
+    if (!bitmap->data) {
+        ret = -ENOMEM;
+        goto unmap_exit;
+    }
+
+    ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
+    if (!ret) {
+        cpu_physical_memory_set_dirty_lebitmap((unsigned long *)bitmap->data,
+                iotlb->translated_addr, pages);
+    } else {
+        error_report("VFIO_UNMAP_DMA with DIRTY_BITMAP : %m");
+    }
+
+    g_free(bitmap->data);
+unmap_exit:
+    g_free(unmap);
+    return ret;
+}
+
 /*
  * DMA - Mapping and unmapping for the "type1" IOMMU interface used on x86
  */
 static int vfio_dma_unmap(VFIOContainer *container,
-                          hwaddr iova, ram_addr_t size)
+                          hwaddr iova, ram_addr_t size,
+                          IOMMUTLBEntry *iotlb)
 {
     struct vfio_iommu_type1_dma_unmap unmap = {
         .argsz = sizeof(unmap),
@@ -299,6 +436,11 @@ static int vfio_dma_unmap(VFIOContainer *container,
         .size = size,
     };
 
+    if (iotlb && container->dirty_pages_supported &&
+        vfio_devices_all_running_and_saving(container)) {
+        return vfio_dma_unmap_bitmap(container, iova, size, iotlb);
+    }
+
     while (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
         /*
          * The type1 backend has an off-by-one bug in the kernel (71a7d3d78e3c
@@ -346,7 +488,7 @@ static int vfio_dma_map(VFIOContainer *container, hwaddr iova,
      * the VGA ROM space.
      */
     if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0 ||
-        (errno == EBUSY && vfio_dma_unmap(container, iova, size) == 0 &&
+        (errno == EBUSY && vfio_dma_unmap(container, iova, size, NULL) == 0 &&
          ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0)) {
         return 0;
     }
@@ -407,8 +549,8 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
 }
 
 /* Called with rcu_read_lock held.  */
-static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
-                           bool *read_only)
+static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
+                               ram_addr_t *ram_addr, bool *read_only)
 {
     MemoryRegion *mr;
     hwaddr xlat;
@@ -428,6 +570,44 @@ static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
         error_report("iommu map to non memory area %"HWADDR_PRIx"",
                      xlat);
         return false;
+    } else if (memory_region_has_ram_discard_manager(mr)) {
+        RamDiscardManager *rdm = memory_region_get_ram_discard_manager(mr);
+        MemoryRegionSection tmp = {
+            .mr = mr,
+            .offset_within_region = xlat,
+            .size = int128_make64(len),
+        };
+
+        /*
+         * Malicious VMs can map memory into the IOMMU, which is expected
+         * to remain discarded. vfio will pin all pages, populating memory.
+         * Disallow that. vmstate priorities make sure any RamDiscardManager
+         * were already restored before IOMMUs are restored.
+         */
+        if (!ram_discard_manager_is_populated(rdm, &tmp)) {
+            error_report("iommu map to discarded memory (e.g., unplugged via"
+                         " virtio-mem): %"HWADDR_PRIx"",
+                         iotlb->translated_addr);
+            return false;
+        }
+
+        /*
+         * Malicious VMs might trigger discarding of IOMMU-mapped memory. The
+         * pages will remain pinned inside vfio until unmapped, resulting in a
+         * higher memory consumption than expected. If memory would get
+         * populated again later, there would be an inconsistency between pages
+         * pinned by vfio and pages seen by QEMU. This is the case until
+         * unmapped from the IOMMU (e.g., during device reset).
+         *
+         * With malicious guests, we really only care about pinning more memory
+         * than expected. RLIMIT_MEMLOCK set for the user/process can never be
+         * exceeded and can be used to mitigate this problem.
+         */
+        warn_report_once("Using vfio with vIOMMUs and coordinated discarding of"
+                         " RAM (e.g., virtio-mem) works, however, malicious"
+                         " guests can trigger pinning of more memory than"
+                         " intended via an IOMMU. It's possible to mitigate "
+                         " by setting/adjusting RLIMIT_MEMLOCK.");
     }
 
     /*
@@ -439,8 +619,17 @@ static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
         return false;
     }
 
-    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
-    *read_only = !writable || mr->readonly;
+    if (vaddr) {
+        *vaddr = memory_region_get_ram_ptr(mr) + xlat;
+    }
+
+    if (ram_addr) {
+        *ram_addr = memory_region_get_ram_addr(mr) + xlat;
+    }
+
+    if (read_only) {
+        *read_only = !writable || mr->readonly;
+    }
 
     return true;
 }
@@ -450,7 +639,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
     VFIOContainer *container = giommu->container;
     hwaddr iova = iotlb->iova + giommu->iommu_offset;
-    bool read_only;
     void *vaddr;
     int ret;
 
@@ -466,7 +654,9 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     rcu_read_lock();
 
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
-        if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
+        bool read_only;
+
+        if (!vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only)) {
             goto out;
         }
         /*
@@ -486,7 +676,7 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
                          iotlb->addr_mask + 1, vaddr, ret);
         }
     } else {
-        ret = vfio_dma_unmap(container, iova, iotlb->addr_mask + 1);
+        ret = vfio_dma_unmap(container, iova, iotlb->addr_mask + 1, iotlb);
         if (ret) {
             error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%m)",
@@ -498,6 +688,153 @@ out:
     rcu_read_unlock();
 }
 
+static void vfio_ram_discard_notify_discard(RamDiscardListener *rdl,
+                                            MemoryRegionSection *section)
+{
+    VFIORamDiscardListener *vrdl = container_of(rdl, VFIORamDiscardListener,
+                                                listener);
+    const hwaddr size = int128_get64(section->size);
+    const hwaddr iova = section->offset_within_address_space;
+    int ret;
+
+    /* Unmap with a single call. */
+    ret = vfio_dma_unmap(vrdl->container, iova, size , NULL);
+    if (ret) {
+        error_report("%s: vfio_dma_unmap() failed: %s", __func__,
+                     strerror(-ret));
+    }
+}
+
+static int vfio_ram_discard_notify_populate(RamDiscardListener *rdl,
+                                            MemoryRegionSection *section)
+{
+    VFIORamDiscardListener *vrdl = container_of(rdl, VFIORamDiscardListener,
+                                                listener);
+    const hwaddr end = section->offset_within_region +
+                       int128_get64(section->size);
+    hwaddr start, next, iova;
+    void *vaddr;
+    int ret;
+
+    /*
+     * Map in (aligned within memory region) minimum granularity, so we can
+     * unmap in minimum granularity later.
+     */
+    for (start = section->offset_within_region; start < end; start = next) {
+        next = ROUND_UP(start + 1, vrdl->granularity);
+        next = MIN(next, end);
+
+        iova = start - section->offset_within_region +
+               section->offset_within_address_space;
+        vaddr = memory_region_get_ram_ptr(section->mr) + start;
+
+        ret = vfio_dma_map(vrdl->container, iova, next - start,
+                           vaddr, section->readonly);
+        if (ret) {
+            /* Rollback */
+            vfio_ram_discard_notify_discard(rdl, section);
+            return ret;
+        }
+    }
+    return 0;
+}
+
+static void vfio_register_ram_discard_listener(VFIOContainer *container,
+                                               MemoryRegionSection *section)
+{
+    RamDiscardManager *rdm = memory_region_get_ram_discard_manager(section->mr);
+    VFIORamDiscardListener *vrdl;
+
+    /* Ignore some corner cases not relevant in practice. */
+    g_assert(QEMU_IS_ALIGNED(section->offset_within_region, TARGET_PAGE_SIZE));
+    g_assert(QEMU_IS_ALIGNED(section->offset_within_address_space,
+                             TARGET_PAGE_SIZE));
+    g_assert(QEMU_IS_ALIGNED(int128_get64(section->size), TARGET_PAGE_SIZE));
+
+    vrdl = g_new0(VFIORamDiscardListener, 1);
+    vrdl->container = container;
+    vrdl->mr = section->mr;
+    vrdl->offset_within_address_space = section->offset_within_address_space;
+    vrdl->size = int128_get64(section->size);
+    vrdl->granularity = ram_discard_manager_get_min_granularity(rdm,
+                                                                section->mr);
+
+    g_assert(vrdl->granularity && is_power_of_2(vrdl->granularity));
+    g_assert(vrdl->granularity >= 1 << ctz64(container->pgsizes));
+
+    ram_discard_listener_init(&vrdl->listener,
+                              vfio_ram_discard_notify_populate,
+                              vfio_ram_discard_notify_discard, true);
+    ram_discard_manager_register_listener(rdm, &vrdl->listener, section);
+    QLIST_INSERT_HEAD(&container->vrdl_list, vrdl, next);
+
+    /*
+     * Sanity-check if we have a theoretically problematic setup where we could
+     * exceed the maximum number of possible DMA mappings over time. We assume
+     * that each mapped section in the same address space as a RamDiscardManager
+     * section consumes exactly one DMA mapping, with the exception of
+     * RamDiscardManager sections; i.e., we don't expect to have gIOMMU sections
+     * in the same address space as RamDiscardManager sections.
+     *
+     * We assume that each section in the address space consumes one memslot.
+     * We take the number of KVM memory slots as a best guess for the maximum
+     * number of sections in the address space we could have over time,
+     * also consuming DMA mappings.
+     */
+    if (container->dma_max_mappings) {
+        unsigned int vrdl_count = 0, vrdl_mappings = 0, max_memslots = 512;
+
+#ifdef CONFIG_KVM
+        if (kvm_enabled()) {
+            max_memslots = kvm_get_max_memslots();
+        }
+#endif
+
+        QLIST_FOREACH(vrdl, &container->vrdl_list, next) {
+            hwaddr start, end;
+
+            start = QEMU_ALIGN_DOWN(vrdl->offset_within_address_space,
+                                    vrdl->granularity);
+            end = ROUND_UP(vrdl->offset_within_address_space + vrdl->size,
+                           vrdl->granularity);
+            vrdl_mappings += (end - start) / vrdl->granularity;
+            vrdl_count++;
+        }
+
+        if (vrdl_mappings + max_memslots - vrdl_count >
+            container->dma_max_mappings) {
+            warn_report("%s: possibly running out of DMA mappings. E.g., try"
+                        " increasing the 'block-size' of virtio-mem devies."
+                        " Maximum possible DMA mappings: %d, Maximum possible"
+                        " memslots: %d", __func__, container->dma_max_mappings,
+                        max_memslots);
+        }
+    }
+}
+
+static void vfio_unregister_ram_discard_listener(VFIOContainer *container,
+                                                 MemoryRegionSection *section)
+{
+    RamDiscardManager *rdm = memory_region_get_ram_discard_manager(section->mr);
+    VFIORamDiscardListener *vrdl = NULL;
+
+    QLIST_FOREACH(vrdl, &container->vrdl_list, next) {
+        if (vrdl->mr == section->mr &&
+            vrdl->offset_within_address_space ==
+            section->offset_within_address_space) {
+            break;
+        }
+    }
+
+    if (!vrdl) {
+        hw_error("vfio: Trying to unregister missing RAM discard listener");
+    }
+
+    ram_discard_manager_unregister_listener(rdm, &vrdl->listener);
+    QLIST_REMOVE(vrdl, next);
+    g_free(vrdl);
+}
+
 static void vfio_listener_region_add(MemoryListener *listener,
                                      MemoryRegionSection *section)
 {
@@ -518,16 +855,17 @@ static void vfio_listener_region_add(MemoryListener *listener,
         return;
     }
 
-    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
-                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
+    if (unlikely((section->offset_within_address_space &
+                  ~qemu_real_host_page_mask) !=
+                 (section->offset_within_region & ~qemu_real_host_page_mask))) {
         error_report("%s received unaligned region", __func__);
         return;
     }
 
-    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
+    iova = REAL_HOST_PAGE_ALIGN(section->offset_within_address_space);
     llend = int128_make64(section->offset_within_address_space);
     llend = int128_add(llend, section->size);
-    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
+    llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
 
     if (int128_ge(int128_make64(iova), llend)) {
         return;
@@ -631,11 +969,19 @@ static void vfio_listener_region_add(MemoryListener *listener,
         iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
                                                        MEMTXATTRS_UNSPECIFIED);
         iommu_notifier_init(&giommu->n, vfio_iommu_map_notify,
-                            IOMMU_NOTIFIER_ALL,
+                            IOMMU_NOTIFIER_IOTLB_EVENTS,
                             section->offset_within_region,
                             int128_get64(llend),
                             iommu_idx);
 
+        ret = memory_region_iommu_set_page_size_mask(giommu->iommu,
+                                                     container->pgsizes,
+                                                     &err);
+        if (ret) {
+            g_free(giommu);
+            goto fail;
+        }
+
         ret = memory_region_register_iommu_notifier(section->mr, &giommu->n,
                                                     &err);
         if (ret) {
@@ -650,6 +996,16 @@ static void vfio_listener_region_add(MemoryListener *listener,
 
     /* Here we assume that memory_region_is_ram(section->mr)==true */
 
+    /*
+     * For RAM memory regions with a RamDiscardManager, we only want to map the
+     * actually populated parts - and update the mapping whenever we're notified
+     * about changes.
+     */
+    if (memory_region_has_ram_discard_manager(section->mr)) {
+        vfio_register_ram_discard_listener(container, section);
+        return;
+    }
+
     vaddr = memory_region_get_ram_ptr(section->mr) +
             section->offset_within_region +
             (iova - section->offset_within_address_space);
@@ -728,8 +1084,9 @@ static void vfio_listener_region_del(MemoryListener *listener,
         return;
     }
 
-    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
-                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
+    if (unlikely((section->offset_within_address_space &
+                  ~qemu_real_host_page_mask) !=
+                 (section->offset_within_region & ~qemu_real_host_page_mask))) {
         error_report("%s received unaligned region", __func__);
         return;
     }
@@ -757,10 +1114,10 @@ static void vfio_listener_region_del(MemoryListener *listener,
          */
     }
 
-    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
+    iova = REAL_HOST_PAGE_ALIGN(section->offset_within_address_space);
     llend = int128_make64(section->offset_within_address_space);
     llend = int128_add(llend, section->size);
-    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
+    llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
 
     if (int128_ge(int128_make64(iova), llend)) {
         return;
@@ -786,10 +1143,25 @@ static void vfio_listener_region_del(MemoryListener *listener,
 
         pgmask = (1ULL << ctz64(hostwin->iova_pgsizes)) - 1;
         try_unmap = !((iova & pgmask) || (int128_get64(llsize) & pgmask));
+    } else if (memory_region_has_ram_discard_manager(section->mr)) {
+        vfio_unregister_ram_discard_listener(container, section);
+        /* Unregistering will trigger an unmap. */
+        try_unmap = false;
     }
 
     if (try_unmap) {
-        ret = vfio_dma_unmap(container, iova, int128_get64(llsize));
+        if (int128_eq(llsize, int128_2_64())) {
+            /* The unmap ioctl doesn't accept a full 64-bit span. */
+            llsize = int128_rshift(llsize, 1);
+            ret = vfio_dma_unmap(container, iova, int128_get64(llsize), NULL);
+            if (ret) {
+                error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
+                             "0x%"HWADDR_PRIx") = %d (%m)",
+                             container, iova, int128_get64(llsize), ret);
+            }
+            iova += int128_get64(llsize);
+        }
+        ret = vfio_dma_unmap(container, iova, int128_get64(llsize), NULL);
         if (ret) {
             error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%m)",
@@ -812,9 +1184,237 @@ static void vfio_listener_region_del(MemoryListener *listener,
     }
 }
 
+static void vfio_set_dirty_page_tracking(VFIOContainer *container, bool start)
+{
+    int ret;
+    struct vfio_iommu_type1_dirty_bitmap dirty = {
+        .argsz = sizeof(dirty),
+    };
+
+    if (start) {
+        dirty.flags = VFIO_IOMMU_DIRTY_PAGES_FLAG_START;
+    } else {
+        dirty.flags = VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP;
+    }
+
+    ret = ioctl(container->fd, VFIO_IOMMU_DIRTY_PAGES, &dirty);
+    if (ret) {
+        error_report("Failed to set dirty tracking flag 0x%x errno: %d",
+                     dirty.flags, errno);
+    }
+}
+
+static void vfio_listener_log_global_start(MemoryListener *listener)
+{
+    VFIOContainer *container = container_of(listener, VFIOContainer, listener);
+
+    vfio_set_dirty_page_tracking(container, true);
+}
+
+static void vfio_listener_log_global_stop(MemoryListener *listener)
+{
+    VFIOContainer *container = container_of(listener, VFIOContainer, listener);
+
+    vfio_set_dirty_page_tracking(container, false);
+}
+
+static int vfio_get_dirty_bitmap(VFIOContainer *container, uint64_t iova,
+                                 uint64_t size, ram_addr_t ram_addr)
+{
+    struct vfio_iommu_type1_dirty_bitmap *dbitmap;
+    struct vfio_iommu_type1_dirty_bitmap_get *range;
+    uint64_t pages;
+    int ret;
+
+    dbitmap = g_malloc0(sizeof(*dbitmap) + sizeof(*range));
+
+    dbitmap->argsz = sizeof(*dbitmap) + sizeof(*range);
+    dbitmap->flags = VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
+    range = (struct vfio_iommu_type1_dirty_bitmap_get *)&dbitmap->data;
+    range->iova = iova;
+    range->size = size;
+
+    /*
+     * cpu_physical_memory_set_dirty_lebitmap() supports pages in bitmap of
+     * qemu_real_host_page_size to mark those dirty. Hence set bitmap's pgsize
+     * to qemu_real_host_page_size.
+     */
+    range->bitmap.pgsize = qemu_real_host_page_size;
+
+    pages = REAL_HOST_PAGE_ALIGN(range->size) / qemu_real_host_page_size;
+    range->bitmap.size = ROUND_UP(pages, sizeof(__u64) * BITS_PER_BYTE) /
+                                         BITS_PER_BYTE;
+    range->bitmap.data = g_try_malloc0(range->bitmap.size);
+    if (!range->bitmap.data) {
+        ret = -ENOMEM;
+        goto err_out;
+    }
+
+    ret = ioctl(container->fd, VFIO_IOMMU_DIRTY_PAGES, dbitmap);
+    if (ret) {
+        error_report("Failed to get dirty bitmap for iova: 0x%"PRIx64
+                " size: 0x%"PRIx64" err: %d", (uint64_t)range->iova,
+                (uint64_t)range->size, errno);
+        goto err_out;
+    }
+
+    cpu_physical_memory_set_dirty_lebitmap((unsigned long *)range->bitmap.data,
+                                            ram_addr, pages);
+
+    trace_vfio_get_dirty_bitmap(container->fd, range->iova, range->size,
+                                range->bitmap.size, ram_addr);
+err_out:
+    g_free(range->bitmap.data);
+    g_free(dbitmap);
+
+    return ret;
+}
+
+typedef struct {
+    IOMMUNotifier n;
+    VFIOGuestIOMMU *giommu;
+} vfio_giommu_dirty_notifier;
+
+static void vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
+{
+    vfio_giommu_dirty_notifier *gdn = container_of(n,
+                                                vfio_giommu_dirty_notifier, n);
+    VFIOGuestIOMMU *giommu = gdn->giommu;
+    VFIOContainer *container = giommu->container;
+    hwaddr iova = iotlb->iova + giommu->iommu_offset;
+    ram_addr_t translated_addr;
+
+    trace_vfio_iommu_map_dirty_notify(iova, iova + iotlb->addr_mask);
+
+    if (iotlb->target_as != &address_space_memory) {
+        error_report("Wrong target AS \"%s\", only system memory is allowed",
+                     iotlb->target_as->name ? iotlb->target_as->name : "none");
+        return;
+    }
+
+    rcu_read_lock();
+    if (vfio_get_xlat_addr(iotlb, NULL, &translated_addr, NULL)) {
+        int ret;
+
+        ret = vfio_get_dirty_bitmap(container, iova, iotlb->addr_mask + 1,
+                                    translated_addr);
+        if (ret) {
+            error_report("vfio_iommu_map_dirty_notify(%p, 0x%"HWADDR_PRIx", "
+                         "0x%"HWADDR_PRIx") = %d (%m)",
+                         container, iova,
+                         iotlb->addr_mask + 1, ret);
+        }
+    }
+    rcu_read_unlock();
+}
+
+static int vfio_ram_discard_get_dirty_bitmap(MemoryRegionSection *section,
+                                             void *opaque)
+{
+    const hwaddr size = int128_get64(section->size);
+    const hwaddr iova = section->offset_within_address_space;
+    const ram_addr_t ram_addr = memory_region_get_ram_addr(section->mr) +
+                                section->offset_within_region;
+    VFIORamDiscardListener *vrdl = opaque;
+
+    /*
+     * Sync the whole mapped region (spanning multiple individual mappings)
+     * in one go.
+     */
+    return vfio_get_dirty_bitmap(vrdl->container, iova, size, ram_addr);
+}
+
+static int vfio_sync_ram_discard_listener_dirty_bitmap(VFIOContainer *container,
+                                                   MemoryRegionSection *section)
+{
+    RamDiscardManager *rdm = memory_region_get_ram_discard_manager(section->mr);
+    VFIORamDiscardListener *vrdl = NULL;
+
+    QLIST_FOREACH(vrdl, &container->vrdl_list, next) {
+        if (vrdl->mr == section->mr &&
+            vrdl->offset_within_address_space ==
+            section->offset_within_address_space) {
+            break;
+        }
+    }
+
+    if (!vrdl) {
+        hw_error("vfio: Trying to sync missing RAM discard listener");
+    }
+
+    /*
+     * We only want/can synchronize the bitmap for actually mapped parts -
+     * which correspond to populated parts. Replay all populated parts.
+     */
+    return ram_discard_manager_replay_populated(rdm, section,
+                                              vfio_ram_discard_get_dirty_bitmap,
+                                                &vrdl);
+}
+
+static int vfio_sync_dirty_bitmap(VFIOContainer *container,
+                                  MemoryRegionSection *section)
+{
+    ram_addr_t ram_addr;
+
+    if (memory_region_is_iommu(section->mr)) {
+        VFIOGuestIOMMU *giommu;
+
+        QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
+            if (MEMORY_REGION(giommu->iommu) == section->mr &&
+                giommu->n.start == section->offset_within_region) {
+                Int128 llend;
+                vfio_giommu_dirty_notifier gdn = { .giommu = giommu };
+                int idx = memory_region_iommu_attrs_to_index(giommu->iommu,
+                                                       MEMTXATTRS_UNSPECIFIED);
+
+                llend = int128_add(int128_make64(section->offset_within_region),
+                                   section->size);
+                llend = int128_sub(llend, int128_one());
+
+                iommu_notifier_init(&gdn.n,
+                                    vfio_iommu_map_dirty_notify,
+                                    IOMMU_NOTIFIER_MAP,
+                                    section->offset_within_region,
+                                    int128_get64(llend),
+                                    idx);
+                memory_region_iommu_replay(giommu->iommu, &gdn.n);
+                break;
+            }
+        }
+        return 0;
+    } else if (memory_region_has_ram_discard_manager(section->mr)) {
+        return vfio_sync_ram_discard_listener_dirty_bitmap(container, section);
+    }
+
+    ram_addr = memory_region_get_ram_addr(section->mr) +
+               section->offset_within_region;
+
+    return vfio_get_dirty_bitmap(container,
+                   REAL_HOST_PAGE_ALIGN(section->offset_within_address_space),
+                   int128_get64(section->size), ram_addr);
+}
+
+static void vfio_listener_log_sync(MemoryListener *listener,
+        MemoryRegionSection *section)
+{
+    VFIOContainer *container = container_of(listener, VFIOContainer, listener);
+
+    if (vfio_listener_skipped_section(section) ||
+        !container->dirty_pages_supported) {
+        return;
+    }
+
+    if (vfio_devices_all_dirty_tracking(container)) {
+        vfio_sync_dirty_bitmap(container, section);
+    }
+}
+
 static const MemoryListener vfio_memory_listener = {
     .region_add = vfio_listener_region_add,
     .region_del = vfio_listener_region_del,
+    .log_global_start = vfio_listener_log_global_start,
+    .log_global_stop = vfio_listener_log_global_stop,
+    .log_sync = vfio_listener_log_sync,
 };
 
 static void vfio_listener_release(VFIOContainer *container)
@@ -825,17 +1425,12 @@ static void vfio_listener_release(VFIOContainer *container)
     }
 }
 
-struct vfio_info_cap_header *
-vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id)
+static struct vfio_info_cap_header *
+vfio_get_cap(void *ptr, uint32_t cap_offset, uint16_t id)
 {
     struct vfio_info_cap_header *hdr;
-    void *ptr = info;
 
-    if (!(info->flags & VFIO_REGION_INFO_FLAG_CAPS)) {
-        return NULL;
-    }
-
-    for (hdr = ptr + info->cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
+    for (hdr = ptr + cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
         if (hdr->id == id) {
             return hdr;
         }
@@ -844,6 +1439,57 @@ vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id)
     return NULL;
 }
 
+struct vfio_info_cap_header *
+vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id)
+{
+    if (!(info->flags & VFIO_REGION_INFO_FLAG_CAPS)) {
+        return NULL;
+    }
+
+    return vfio_get_cap((void *)info, info->cap_offset, id);
+}
+
+static struct vfio_info_cap_header *
+vfio_get_iommu_type1_info_cap(struct vfio_iommu_type1_info *info, uint16_t id)
+{
+    if (!(info->flags & VFIO_IOMMU_INFO_CAPS)) {
+        return NULL;
+    }
+
+    return vfio_get_cap((void *)info, info->cap_offset, id);
+}
+
+struct vfio_info_cap_header *
+vfio_get_device_info_cap(struct vfio_device_info *info, uint16_t id)
+{
+    if (!(info->flags & VFIO_DEVICE_FLAGS_CAPS)) {
+        return NULL;
+    }
+
+    return vfio_get_cap((void *)info, info->cap_offset, id);
+}
+
+bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info *info,
+                             unsigned int *avail)
+{
+    struct vfio_info_cap_header *hdr;
+    struct vfio_iommu_type1_info_dma_avail *cap;
+
+    /* If the capability cannot be found, assume no DMA limiting */
+    hdr = vfio_get_iommu_type1_info_cap(info,
+                                        VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL);
+    if (hdr == NULL) {
+        return false;
+    }
+
+    if (avail != NULL) {
+        cap = (void *) hdr;
+        *avail = cap->avail;
+    }
+
+    return true;
+}
+
 static int vfio_setup_region_sparse_mmaps(VFIORegion *region,
                                           struct vfio_region_info *info)
 {
@@ -924,6 +1570,18 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
     return 0;
 }
 
+static void vfio_subregion_unmap(VFIORegion *region, int index)
+{
+    trace_vfio_region_unmap(memory_region_name(&region->mmaps[index].mem),
+                            region->mmaps[index].offset,
+                            region->mmaps[index].offset +
+                            region->mmaps[index].size - 1);
+    memory_region_del_subregion(region->mem, &region->mmaps[index].mem);
+    munmap(region->mmaps[index].mmap, region->mmaps[index].size);
+    object_unparent(OBJECT(&region->mmaps[index].mem));
+    region->mmaps[index].mmap = NULL;
+}
+
 int vfio_region_mmap(VFIORegion *region)
 {
     int i, prot = 0;
@@ -954,10 +1612,7 @@ int vfio_region_mmap(VFIORegion *region)
             region->mmaps[i].mmap = NULL;
 
             for (i--; i >= 0; i--) {
-                memory_region_del_subregion(region->mem, &region->mmaps[i].mem);
-                munmap(region->mmaps[i].mmap, region->mmaps[i].size);
-                object_unparent(OBJECT(&region->mmaps[i].mem));
-                region->mmaps[i].mmap = NULL;
+                vfio_subregion_unmap(region, i);
             }
 
             return ret;
@@ -982,6 +1637,21 @@ int vfio_region_mmap(VFIORegion *region)
     return 0;
 }
 
+void vfio_region_unmap(VFIORegion *region)
+{
+    int i;
+
+    if (!region->mem) {
+        return;
+    }
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        if (region->mmaps[i].mmap) {
+            vfio_subregion_unmap(region, i);
+        }
+    }
+}
+
 void vfio_region_exit(VFIORegion *region)
 {
     int i;
@@ -1204,6 +1874,75 @@ static int vfio_init_container(VFIOContainer *container, int group_fd,
     return 0;
 }
 
+static int vfio_get_iommu_info(VFIOContainer *container,
+                               struct vfio_iommu_type1_info **info)
+{
+
+    size_t argsz = sizeof(struct vfio_iommu_type1_info);
+
+    *info = g_new0(struct vfio_iommu_type1_info, 1);
+again:
+    (*info)->argsz = argsz;
+
+    if (ioctl(container->fd, VFIO_IOMMU_GET_INFO, *info)) {
+        g_free(*info);
+        *info = NULL;
+        return -errno;
+    }
+
+    if (((*info)->argsz > argsz)) {
+        argsz = (*info)->argsz;
+        *info = g_realloc(*info, argsz);
+        goto again;
+    }
+
+    return 0;
+}
+
+static struct vfio_info_cap_header *
+vfio_get_iommu_info_cap(struct vfio_iommu_type1_info *info, uint16_t id)
+{
+    struct vfio_info_cap_header *hdr;
+    void *ptr = info;
+
+    if (!(info->flags & VFIO_IOMMU_INFO_CAPS)) {
+        return NULL;
+    }
+
+    for (hdr = ptr + info->cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
+        if (hdr->id == id) {
+            return hdr;
+        }
+    }
+
+    return NULL;
+}
+
+static void vfio_get_iommu_info_migration(VFIOContainer *container,
+                                         struct vfio_iommu_type1_info *info)
+{
+    struct vfio_info_cap_header *hdr;
+    struct vfio_iommu_type1_info_cap_migration *cap_mig;
+
+    hdr = vfio_get_iommu_info_cap(info, VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION);
+    if (!hdr) {
+        return;
+    }
+
+    cap_mig = container_of(hdr, struct vfio_iommu_type1_info_cap_migration,
+                            header);
+
+    /*
+     * cpu_physical_memory_set_dirty_lebitmap() supports pages in bitmap of
+     * qemu_real_host_page_size to mark those dirty.
+     */
+    if (cap_mig->pgsize_bitmap & qemu_real_host_page_size) {
+        container->dirty_pages_supported = true;
+        container->max_dirty_bitmap_size = cap_mig->max_dirty_bitmap_size;
+        container->dirty_pgsizes = cap_mig->pgsize_bitmap;
+    }
+}
+
 static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
                                   Error **errp)
 {
@@ -1254,7 +1993,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
         }
     }
 
-    fd = qemu_open("/dev/vfio/vfio", O_RDWR);
+    fd = qemu_open_old("/dev/vfio/vfio", O_RDWR);
     if (fd < 0) {
         error_setg_errno(errp, errno, "failed to open /dev/vfio/vfio");
         ret = -errno;
@@ -1273,8 +2012,11 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
     container->space = space;
     container->fd = fd;
     container->error = NULL;
+    container->dirty_pages_supported = false;
+    container->dma_max_mappings = 0;
     QLIST_INIT(&container->giommu_list);
     QLIST_INIT(&container->hostwin_list);
+    QLIST_INIT(&container->vrdl_list);
 
     ret = vfio_init_container(container, group->fd, errp);
     if (ret) {
@@ -1285,7 +2027,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
     case VFIO_TYPE1v2_IOMMU:
     case VFIO_TYPE1_IOMMU:
     {
-        struct vfio_iommu_type1_info info;
+        struct vfio_iommu_type1_info *info;
 
         /*
          * FIXME: This assumes that a Type1 IOMMU can map any 64-bit
@@ -1294,15 +2036,22 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
          * existing Type1 IOMMUs generally support any IOVA we're
          * going to actually try in practice.
          */
-        info.argsz = sizeof(info);
-        ret = ioctl(fd, VFIO_IOMMU_GET_INFO, &info);
-        /* Ignore errors */
-        if (ret || !(info.flags & VFIO_IOMMU_INFO_PGSIZES)) {
+        ret = vfio_get_iommu_info(container, &info);
+
+        if (ret || !(info->flags & VFIO_IOMMU_INFO_PGSIZES)) {
             /* Assume 4k IOVA page size */
-            info.iova_pgsizes = 4096;
+            info->iova_pgsizes = 4096;
         }
-        vfio_host_win_add(container, 0, (hwaddr)-1, info.iova_pgsizes);
-        container->pgsizes = info.iova_pgsizes;
+        vfio_host_win_add(container, 0, (hwaddr)-1, info->iova_pgsizes);
+        container->pgsizes = info->iova_pgsizes;
+
+        /* The default in the kernel ("dma_entry_limit") is 65535. */
+        container->dma_max_mappings = 65535;
+        if (!ret) {
+            vfio_get_info_dma_avail(info, &container->dma_max_mappings);
+            vfio_get_iommu_info_migration(container, info);
+        }
+        g_free(info);
         break;
     }
     case VFIO_SPAPR_TCE_v2_IOMMU:
@@ -1479,7 +2228,7 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp)
     group = g_malloc0(sizeof(*group));
 
     snprintf(path, sizeof(path), "/dev/vfio/%d", groupid);
-    group->fd = qemu_open(path, O_RDWR);
+    group->fd = qemu_open_old(path, O_RDWR);
     if (group->fd < 0) {
         error_setg_errno(errp, errno, "failed to open %s", path);
         goto free_group_exit;