Re: [PATCH 4/4] vfio/container: Fix vfio_container_post_load()

[Steven Sistare <steven.sistare@oracle.com>]

On 6/23/2025 6:22 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 |  1 -
>   hw/vfio/cpr-legacy.c       | 20 +++++++-------------
>   2 files changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
> index aef542e93c..71a1c1a70c 100644
> --- a/include/hw/vfio/vfio-cpr.h
> +++ b/include/hw/vfio/vfio-cpr.h
> @@ -25,7 +25,6 @@ typedef struct VFIOContainerCPR {
>       bool vaddr_unmapped;
>       NotifierWithReturn transfer_notifier;
>       MemoryListener remap_listener;
> -    DMA_MAP_FUNC saved_dma_map;
>   } VFIOContainerCPR;
>   
>   typedef struct VFIODeviceCPR {
> diff --git a/hw/vfio/cpr-legacy.c b/hw/vfio/cpr-legacy.c
> index 100a8db74d..ff45a5128f 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_FUNC 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;
>   }
>   
> @@ -180,13 +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. */
> -    if (cpr_is_incoming()) {
> -        VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
> -        container->cpr.saved_dma_map = vioc->dma_map;
> -        vioc->dma_map = vfio_legacy_cpr_dma_map;
> -    }
> -
>       migration_add_notifier_mode(&container->cpr.transfer_notifier,
>                                   vfio_cpr_fail_notifier,
>                                   MIG_MODE_CPR_TRANSFER);

Good fix, thanks. All looks good.  I will wait to see the "local save" parts
of patch 3 squashed into patch 4 before sending RB.

One nit about DMA_MAP_FUNC -- the majority of typedefs for function signatures
use lower case.  See
   git grep typedef | fgrep '(*'

- Steve