Messages in this thread | | | Subject | Re: [PATCH 1/2] vdpa/mlx5: Avoid unnecessary query virtqueue | From | Jason Wang <> | Date | Tue, 2 Feb 2021 11:12:51 +0800 |
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On 2021/2/2 上午3:17, Si-Wei Liu wrote: > On Mon, Feb 1, 2021 at 10:51 AM Si-Wei Liu <siwliu.kernel@gmail.com> wrote: >> On Thu, Jan 28, 2021 at 5:46 AM Eli Cohen <elic@nvidia.com> wrote: >>> suspend_vq should only suspend the VQ on not save the current available >>> index. This is done when a change of map occurs when the driver calls >>> save_channel_info(). >> Hmmm, suspend_vq() is also called by teardown_vq(), the latter of >> which doesn't save the available index as save_channel_info() doesn't >> get called in that path at all. How does it handle the case that >> aget_vq_state() is called from userspace (e.g. QEMU) while the >> hardware VQ object was torn down, but userspace still wants to access >> the queue index? >> >> Refer to https://lore.kernel.org/netdev/1601583511-15138-1-git-send-email-si-wei.liu@oracle.com/ >> >> vhost VQ 0 ring restore failed: -1: Resource temporarily unavailable (11) >> vhost VQ 1 ring restore failed: -1: Resource temporarily unavailable (11) >> >> QEMU will complain with the above warning while VM is being rebooted >> or shut down. >> >> Looks to me either the kernel driver should cover this requirement, or >> the userspace has to bear the burden in saving the index and not call >> into kernel if VQ is destroyed. > Actually, the userspace doesn't have the insights whether virt queue > will be destroyed if just changing the device status via set_status(). > Looking at other vdpa driver in tree i.e. ifcvf it doesn't behave like > so. Hence this still looks to me to be Mellanox specifics and > mlx5_vdpa implementation detail that shouldn't expose to userspace.
So I think we can simply drop this patch?
Thanks
>> -Siwei >> >> >>> Signed-off-by: Eli Cohen <elic@nvidia.com> >>> --- >>> drivers/vdpa/mlx5/net/mlx5_vnet.c | 8 -------- >>> 1 file changed, 8 deletions(-) >>> >>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c >>> index 88dde3455bfd..549ded074ff3 100644 >>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c >>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c >>> @@ -1148,8 +1148,6 @@ static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq) >>> >>> static void suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq) >>> { >>> - struct mlx5_virtq_attr attr; >>> - >>> if (!mvq->initialized) >>> return; >>> >>> @@ -1158,12 +1156,6 @@ static void suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *m >>> >>> if (modify_virtqueue(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND)) >>> mlx5_vdpa_warn(&ndev->mvdev, "modify to suspend failed\n"); >>> - >>> - if (query_virtqueue(ndev, mvq, &attr)) { >>> - mlx5_vdpa_warn(&ndev->mvdev, "failed to query virtqueue\n"); >>> - return; >>> - } >>> - mvq->avail_idx = attr.available_index; >>> } >>> >>> static void suspend_vqs(struct mlx5_vdpa_net *ndev) >>> -- >>> 2.29.2 >>>
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