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[PATCH v2 2/2] vfio/container: Fix vfio_container_post_load()

Zhenzhong Duan posted 2 patches 4 months, 3 weeks ago
Maintainers: Steve Sistare <steven.sistare@oracle.com>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>
[PATCH v2 2/2] vfio/container: Fix vfio_container_post_load()
Posted by Zhenzhong Duan 4 months, 3 weeks ago 
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>
---
 include/hw/vfio/vfio-cpr.h |  7 ++++---
 hw/vfio/cpr-legacy.c       | 23 +++++++++--------------
 2 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index 8bf85b9f4e..dbb2a16b7a 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 {
diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
index 0a5d1bd480..1216717546 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);
-- 
2.34.1
Re: [PATCH v2 2/2] vfio/container: Fix vfio_container_post_load()
Posted by Steven Sistare 4 months, 3 weeks ago 
On 6/27/2025 2:33 AM, Zhenzhong Duan wrote:
> 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>
> ---
>   include/hw/vfio/vfio-cpr.h |  7 ++++---
>   hw/vfio/cpr-legacy.c       | 23 +++++++++--------------
>   2 files changed, 13 insertions(+), 17 deletions(-)
> 
> diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
> index 8bf85b9f4e..dbb2a16b7a 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 {
> diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
> index 0a5d1bd480..1216717546 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);

Reviewed-by: Steve Sistare <steven.sistare@oracle.com>

Patchew 2.1-devel-b67e4c2

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