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Re: [PATCH 1/3] vhost-user: do not send RESET_OWNER on device reset
From: |
Raphael Norwitz |
Subject: |
Re: [PATCH 1/3] vhost-user: do not send RESET_OWNER on device reset |
Date: |
Thu, 28 Sep 2023 03:01:01 +0000 |
> On Sep 27, 2023, at 3:27 PM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> The VHOST_USER_RESET_OWNER message is deprecated in the spec:
>
> This is no longer used. Used to be sent to request disabling all
> rings, but some back-ends interpreted it to also discard connection
> state (this interpretation would lead to bugs). It is recommended
> that back-ends either ignore this message, or use it to disable all
> rings.
>
> The only caller of vhost_user_reset_device() is vhost_user_scsi_reset().
> It checks that F_RESET_DEVICE was negotiated before calling it:
>
> static void vhost_user_scsi_reset(VirtIODevice *vdev)
> {
> VHostSCSICommon *vsc = VHOST_SCSI_COMMON(vdev);
> struct vhost_dev *dev = &vsc->dev;
>
> /*
> * Historically, reset was not implemented so only reset devices
> * that are expecting it.
> */
> if (!virtio_has_feature(dev->protocol_features,
> VHOST_USER_PROTOCOL_F_RESET_DEVICE)) {
> return;
> }
>
> if (dev->vhost_ops->vhost_reset_device) {
> dev->vhost_ops->vhost_reset_device(dev);
> }
> }
>
> Therefore VHOST_USER_RESET_OWNER is actually never sent by
> vhost_user_reset_device(). Remove the dead code. This effectively moves
> the vhost-user protocol specific code from vhost-user-scsi.c into
> vhost-user.c where it belongs.
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> hw/scsi/vhost-user-scsi.c | 9 ---------
> hw/virtio/vhost-user.c | 13 +++++++++----
> 2 files changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
> index ee99b19e7a..8582b2e8ab 100644
> --- a/hw/scsi/vhost-user-scsi.c
> +++ b/hw/scsi/vhost-user-scsi.c
> @@ -71,15 +71,6 @@ static void vhost_user_scsi_reset(VirtIODevice *vdev)
> VHostSCSICommon *vsc = VHOST_SCSI_COMMON(vdev);
> struct vhost_dev *dev = &vsc->dev;
>
> - /*
> - * Historically, reset was not implemented so only reset devices
> - * that are expecting it.
> - */
> - if (!virtio_has_feature(dev->protocol_features,
> - VHOST_USER_PROTOCOL_F_RESET_DEVICE)) {
> - return;
> - }
> -
> if (dev->vhost_ops->vhost_reset_device) {
> dev->vhost_ops->vhost_reset_device(dev);
> }
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 8dcf049d42..7bed9ad7d5 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -1492,12 +1492,17 @@ static int vhost_user_reset_device(struct vhost_dev
> *dev)
> {
> VhostUserMsg msg = {
> .hdr.flags = VHOST_USER_VERSION,
> + .hdr.request = VHOST_USER_RESET_DEVICE,
> };
>
> - msg.hdr.request = virtio_has_feature(dev->protocol_features,
> - VHOST_USER_PROTOCOL_F_RESET_DEVICE)
> - ? VHOST_USER_RESET_DEVICE
> - : VHOST_USER_RESET_OWNER;
> + /*
> + * Historically, reset was not implemented so only reset devices
> + * that are expecting it.
> + */
> + if (!virtio_has_feature(dev->protocol_features,
> + VHOST_USER_PROTOCOL_F_RESET_DEVICE)) {
> + return -ENOSYS;
> + }
>
> return vhost_user_write(dev, &msg, NULL, 0);
> }
> --
> 2.41.0
>