Re: [PATCH v4 06/15] vdpa: add vhost_vdpa->suspended parameter

[Jason Wang]

在 2023/2/24 23:54, Eugenio Pérez 写道:
> This allows vhost_vdpa to track if it is safe to get vring base from the
> device or not.  If it is not, vhost can fall back to fetch idx from the
> guest buffer again.
>
> No functional change intended in this patch, later patches will use this
> field.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>


I think we probably need to re-order the patch, e.g to let this come 
before at least patch 5.


> ---
>   include/hw/virtio/vhost-vdpa.h | 2 ++
>   hw/virtio/vhost-vdpa.c         | 8 ++++++++
>   2 files changed, 10 insertions(+)
>
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index 7997f09a8d..4a7d396674 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -42,6 +42,8 @@ typedef struct vhost_vdpa {
>       bool shadow_vqs_enabled;
>       /* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA 
> */
>       bool shadow_data;
> +    /* Device suspended successfully */
> +    bool suspended;


Should we implement the set/clear in this patch as well?

Thanks


>       /* IOVA mapping used by the Shadow Virtqueue */
>       VhostIOVATree *iova_tree;
>       GPtrArray *shadow_vqs;
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 8cc9c98db9..228677895a 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -1227,6 +1227,14 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev 
> *dev,
>           return 0;
>       }
>   
> +    if (!v->suspended) {
> +        /*
> +         * Cannot trust in value returned by device, let vhost recover used
> +         * idx from guest.
> +         */
> +        return -1;
> +    }
> +
>       ret = vhost_vdpa_call(dev, VHOST_GET_VRING_BASE, ring);
>       trace_vhost_vdpa_get_vring_base(dev, ring->index, ring->num);
>       return ret;