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Re: [Qemu-devel] [PATCH v2 5/5] vhost: send VHOST_USER_SET_VRING_ENABLE
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2 5/5] vhost: send VHOST_USER_SET_VRING_ENABLE at start/stop |
Date: |
Wed, 21 Oct 2015 13:39:11 +0300 |
On Wed, Oct 21, 2015 at 05:07:18PM +0800, Yuanhan Liu wrote:
> Send VHOST_USER_SET_VRING_ENABLE at start/stop when multiple queue
> is negotiated, to inform the backend that we are ready or not.
OK but that's only if MQ is set. If now, we need to do
RESET_OWNER followed by SET_OWNER.
> And exclude VHOST_USER_GET_QUEUE_NUM as one time request, as we need
> to get max_queues for each vhost_dev.
Pls split this part out.
> Suggested-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Yuanhan Liu <address@hidden>
> ---
> hw/virtio/vhost-user.c | 1 -
> hw/virtio/vhost.c | 18 ++++++++++++++++++
> 2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 12a9104..6532a73 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -194,7 +194,6 @@ static bool vhost_user_one_time_request(VhostUserRequest
> request)
> case VHOST_USER_SET_OWNER:
> case VHOST_USER_RESET_OWNER:
> case VHOST_USER_SET_MEM_TABLE:
> - case VHOST_USER_GET_QUEUE_NUM:
> return true;
> default:
> return false;
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index c0ed5b2..54a4633 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -1146,6 +1146,19 @@ int vhost_dev_start(struct vhost_dev *hdev,
> VirtIODevice *vdev)
> }
> }
>
> + /*
> + * Send VHOST_USER_SET_VRING_ENABLE message when multiple queue
> + * is negotiated to inform the back end that we are ready.
> + *
> + * Only set enable to 1 for first queue pair, as we enable one
> + * queue pair by default.
> + */
> + if (hdev->max_queues > 1 &&
this makes no sense in the generic code.
This is a work around for a protocol bug - belongs in
vhost user internally.
And that's not the way to test this. MQ could be negotiated
even if there is a single pair of queues.
> + hdev->vhost_ops->vhost_backend_set_vring_enable) {
> + hdev->vhost_ops->vhost_backend_set_vring_enable(hdev,
> + hdev->vq_index == 0);
> + }
> +
> return 0;
> fail_log:
> vhost_log_put(hdev, false);
> @@ -1180,5 +1193,10 @@ void vhost_dev_stop(struct vhost_dev *hdev,
> VirtIODevice *vdev)
> hdev->started = false;
> hdev->log = NULL;
> hdev->log_size = 0;
> +
> + if (hdev->max_queues > 1 &&
> + hdev->vhost_ops->vhost_backend_set_vring_enable) {
> + hdev->vhost_ops->vhost_backend_set_vring_enable(hdev, 0);
> + }
> }
>
> --
> 1.9.0
>
[Qemu-devel] [PATCH v2 4/5] Revert "vhost-user: Send VHOST_RESET_OWNER on vhost stop", Yuanhan Liu, 2015/10/21
Re: [Qemu-devel] [PATCH v2 1/5] Revert "vhost: rename VHOST_RESET_OWNER to VHOST_RESET_DEVICE", Michael S. Tsirkin, 2015/10/21