vfio/container: Fix vfio_container_post_load()

When there are multiple VFIO containers, vioc->dma_map is restored
multiple times, this made only first container work and remaining
containers using vioc->dma_map restored by first container.

Fix it by save and restore vioc->dma_map locally. saved_dma_map in
VFIOContainerCPR becomes useless and is removed.

Fixes: 7e9f21411302 ("vfio/container: restore DMA vaddr")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Link: https://lore.kernel.org/qemu-devel/20250627063332.5173-3-zhenzhong.duan@intel.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

2 files changed, 13 insertions, 17 deletions

diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
index 0a5d1bd..1216717 100644
--- a/hw/vfio/cpr-legacy.c
+++ b/hw/vfio/cpr-legacy.c
@@ -99,20 +99,21 @@ static int vfio_container_post_load(void *opaque, int version_id)
 {
     VFIOContainer *container = opaque;
     VFIOContainerBase *bcontainer = &container->bcontainer;
-    VFIOGroup *group;
+    VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
+    dma_map_fn saved_dma_map = vioc->dma_map;
     Error *local_err = NULL;
 
+    /* During incoming CPR, divert calls to dma_map. */
+    vioc->dma_map = vfio_legacy_cpr_dma_map;
+
     if (!vfio_listener_register(bcontainer, &local_err)) {
         error_report_err(local_err);
         return -1;
     }
 
-    QLIST_FOREACH(group, &container->group_list, container_next) {
-        VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
+    /* Restore original dma_map function */
+    vioc->dma_map = saved_dma_map;
 
-        /* Restore original dma_map function */
-        vioc->dma_map = container->cpr.saved_dma_map;
-    }
     return 0;
 }
 
@@ -148,6 +149,7 @@ static int vfio_cpr_fail_notifier(NotifierWithReturn *notifier,
          */
 
         VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
+        dma_map_fn saved_dma_map = vioc->dma_map;
         vioc->dma_map = vfio_legacy_cpr_dma_map;
 
         container->cpr.remap_listener = (MemoryListener) {
@@ -158,7 +160,7 @@ static int vfio_cpr_fail_notifier(NotifierWithReturn *notifier,
                                  bcontainer->space->as);
         memory_listener_unregister(&container->cpr.remap_listener);
         container->cpr.vaddr_unmapped = false;
-        vioc->dma_map = container->cpr.saved_dma_map;
+        vioc->dma_map = saved_dma_map;
     }
     return 0;
 }
@@ -179,13 +181,6 @@ bool vfio_legacy_cpr_register_container(VFIOContainer *container, Error **errp)
 
     vmstate_register(NULL, -1, &vfio_container_vmstate, container);
 
-    /* During incoming CPR, divert calls to dma_map. */
-    VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
-    container->cpr.saved_dma_map = vioc->dma_map;
-    if (cpr_is_incoming()) {
-        vioc->dma_map = vfio_legacy_cpr_dma_map;
-    }
-
     migration_add_notifier_mode(&container->cpr.transfer_notifier,
                                 vfio_cpr_fail_notifier,
                                 MIG_MODE_CPR_TRANSFER);
diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 8bf85b9..dbb2a16 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/include/hw/vfio/vfio-cpr.h
@@ -16,14 +16,15 @@ struct VFIOContainer;
 struct VFIOContainerBase;
 struct VFIOGroup;
 
+typedef int (*dma_map_fn)(const struct VFIOContainerBase *bcontainer,
+                          hwaddr iova, ram_addr_t size, void *vaddr,
+                          bool readonly, MemoryRegion *mr);
+
 typedef struct VFIOContainerCPR {
     Error *blocker;
     bool vaddr_unmapped;
     NotifierWithReturn transfer_notifier;
     MemoryListener remap_listener;
-    int (*saved_dma_map)(const struct VFIOContainerBase *bcontainer,
-                         hwaddr iova, ram_addr_t size,
-                         void *vaddr, bool readonly, MemoryRegion *mr);
 } VFIOContainerCPR;
 
 typedef struct VFIODeviceCPR {