Re: [PATCH] vdpa: do not save failed dma maps in SVQ iova tree

[Jason Wang <jasowang@redhat.com>]

On Tue, Aug 2, 2022 at 10:39 PM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> If a map fails for whatever reason, it must not be saved in the tree.
> Otherwise, qemu will try to unmap it in cleanup, leaving to more errors.
>
> Fixes: 34e3c94eda ("vdpa: Add custom IOTLB translations to SVQ")
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>  hw/virtio/vhost-vdpa.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 3ff9ce3501..e44c23dce5 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -176,6 +176,7 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener)
>  static void vhost_vdpa_listener_region_add(MemoryListener *listener,
>                                             MemoryRegionSection *section)
>  {
> +    DMAMap mem_region = {};
>      struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
>      hwaddr iova;
>      Int128 llend, llsize;
> @@ -212,13 +213,13 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
>
>      llsize = int128_sub(llend, int128_make64(iova));
>      if (v->shadow_vqs_enabled) {
> -        DMAMap mem_region = {
> -            .translated_addr = (hwaddr)(uintptr_t)vaddr,
> -            .size = int128_get64(llsize) - 1,
> -            .perm = IOMMU_ACCESS_FLAG(true, section->readonly),
> -        };

Nit: can we keep this part unchanged?

Thanks

> +        int r;
>
> -        int r = vhost_iova_tree_map_alloc(v->iova_tree, &mem_region);
> +        mem_region.translated_addr = (hwaddr)(uintptr_t)vaddr,
> +        mem_region.size = int128_get64(llsize) - 1,
> +        mem_region.perm = IOMMU_ACCESS_FLAG(true, section->readonly),
> +
> +        r = vhost_iova_tree_map_alloc(v->iova_tree, &mem_region);
>          if (unlikely(r != IOVA_OK)) {
>              error_report("Can't allocate a mapping (%d)", r);
>              goto fail;
> @@ -232,11 +233,16 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
>                               vaddr, section->readonly);
>      if (ret) {
>          error_report("vhost vdpa map fail!");
> -        goto fail;
> +        goto fail_map;
>      }
>
>      return;
>
> +fail_map:
> +    if (v->shadow_vqs_enabled) {
> +        vhost_iova_tree_remove(v->iova_tree, &mem_region);
> +    }
> +
>  fail:
>      /*
>       * On the initfn path, store the first error in the container so we
> --
> 2.31.1
>