Re: [PATCH] vfio/container: pass MemoryRegion to DMA operations

[Cédric Le Goater]

On 5/21/25 23:55, John Levon wrote:

Pass through the MemoryRegion to DMA operation handlers of vfio
containers. The vfio-user container will need this later, to translate
the vaddr into an offset for the dma map vfio-user message; CPR will
also will need this.

Originally-by: John Johnson <john.g.john...@oracle.com>
Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com>
Signed-off-by: John Levon <john.le...@nutanix.com>
---
  include/hw/vfio/vfio-container-base.h | 9 +++++----
  hw/vfio/container-base.c              | 4 ++--
  hw/vfio/container.c                   | 3 ++-
  hw/vfio/iommufd.c                     | 3 ++-
  hw/vfio/listener.c                    | 6 +++---
  5 files changed, 14 insertions(+), 11 deletions(-)

Steven,

Can you base the live update series on this patch ?

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

diff --git a/include/hw/vfio/vfio-container-base.h 
b/include/hw/vfio/vfio-container-base.h
index f9e561cb08..3feb773e5f 100644
--- a/include/hw/vfio/vfio-container-base.h
+++ b/include/hw/vfio/vfio-container-base.h
@@ -78,7 +78,7 @@ void vfio_address_space_insert(VFIOAddressSpace *space,

int vfio_container_dma_map(VFIOContainerBase *bcontainer,

                             hwaddr iova, ram_addr_t size,
-                           void *vaddr, bool readonly);
+                           void *vaddr, bool readonly, MemoryRegion *mr);
  int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,
                               hwaddr iova, ram_addr_t size,
                               IOMMUTLBEntry *iotlb, bool unmap_all);
@@ -151,20 +151,21 @@ struct VFIOIOMMUClass {
      /**
       * @dma_map
       *
-     * Map an address range into the container.
+     * Map an address range into the container. Note that the memory region is
+     * referenced within an RCU read lock region across this call.
       *
       * @bcontainer: #VFIOContainerBase to use
       * @iova: start address to map
       * @size: size of the range to map
       * @vaddr: process virtual address of mapping
       * @readonly: true if mapping should be readonly
+     * @mr: the memory region for this mapping
       *
       * Returns 0 to indicate success and -errno otherwise.
       */
      int (*dma_map)(const VFIOContainerBase *bcontainer,
                     hwaddr iova, ram_addr_t size,
-                   void *vaddr, bool readonly);
-
+                   void *vaddr, bool readonly, MemoryRegion *mr);
      /**
       * @dma_unmap
       *
diff --git a/hw/vfio/container-base.c b/hw/vfio/container-base.c
index 1c6ca94b60..d834bd4822 100644
--- a/hw/vfio/container-base.c
+++ b/hw/vfio/container-base.c
@@ -75,12 +75,12 @@ void vfio_address_space_insert(VFIOAddressSpace *space,

int vfio_container_dma_map(VFIOContainerBase *bcontainer,

                             hwaddr iova, ram_addr_t size,
-                           void *vaddr, bool readonly)
+                           void *vaddr, bool readonly, MemoryRegion *mr)
  {
      VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);

g_assert(vioc->dma_map);

-    return vioc->dma_map(bcontainer, iova, size, vaddr, readonly);
+    return vioc->dma_map(bcontainer, iova, size, vaddr, readonly, mr);
  }

int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index a9f0dbaec4..a8c76eb481 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -207,7 +207,8 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase 
*bcontainer,
  }

static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,

-                               ram_addr_t size, void *vaddr, bool readonly)
+                               ram_addr_t size, void *vaddr, bool readonly,
+                               MemoryRegion *mr)
  {
      const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
                                                    bcontainer);
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 6b2696793f..46a3b36301 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -34,7 +34,8 @@
              TYPE_HOST_IOMMU_DEVICE_IOMMUFD "-vfio"

static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,

-                            ram_addr_t size, void *vaddr, bool readonly)
+                            ram_addr_t size, void *vaddr, bool readonly,
+                            MemoryRegion *mr)
  {
      const VFIOIOMMUFDContainer *container =
          container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index 38e3dc82cf..7495866123 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -170,7 +170,7 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, 
IOMMUTLBEntry *iotlb)
           */
          ret = vfio_container_dma_map(bcontainer, iova,
                                       iotlb->addr_mask + 1, vaddr,
-                                     read_only);
+                                     read_only, mr);
          if (ret) {
              error_report("vfio_container_dma_map(%p, 0x%"HWADDR_PRIx", "
                           "0x%"HWADDR_PRIx", %p) = %d (%s)",
@@ -240,7 +240,7 @@ static int 
vfio_ram_discard_notify_populate(RamDiscardListener *rdl,
          vaddr = memory_region_get_ram_ptr(section->mr) + start;

ret = vfio_container_dma_map(bcontainer, iova, next - start,

-                                     vaddr, section->readonly);
+                                     vaddr, section->readonly, section->mr);
          if (ret) {
              /* Rollback */
              vfio_ram_discard_notify_discard(rdl, section);
@@ -564,7 +564,7 @@ static void vfio_listener_region_add(MemoryListener 
*listener,
      }

ret = vfio_container_dma_map(bcontainer, iova, int128_get64(llsize),

-                                 vaddr, section->readonly);
+                                 vaddr, section->readonly, section->mr);
      if (ret) {
          error_setg(&err, "vfio_container_dma_map(%p, 0x%"HWADDR_PRIx", "
                     "0x%"HWADDR_PRIx", %p) = %d (%s)",