Reviewed-by: Raphael Norwitz <[email protected]>
On Sat, Oct 11, 2025 at 7:24 PM Vladimir Sementsov-Ogievskiy
<[email protected]> wrote:
>
> We call the handler almost the same way in three places:
>
> - cryptodev-vhost.c
> - vhost_net.c
> - vhost.c
>
> The only difference, is that in vhost.c we don't try to call the handler
> for old vhost-user (when VHOST_USER_F_PROTOCOL_FEATURES is not supported).
>
> cryptodev-vhost and vhost_net code will just fail in this case. Probably
> they were developed only for newer vhost-user. Anyway, it doesn't seem
> correct to rely on this error path, if these devices want to check,
> that they don't communicate to old vhost-user protocol, they should
> do that earlier.
>
> Let's create the common helper, to call .vhost_set_vring_enable and
> use in all three places. For vhost-user let's just always skip
> enable/disable if it's unsupported.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
> ---
> backends/cryptodev-vhost.c | 8 +-------
> hw/net/vhost_net.c | 7 +------
> hw/virtio/vhost-user.c | 7 ++++++-
> hw/virtio/vhost.c | 21 ---------------------
> include/hw/virtio/vhost.h | 9 +++++++++
> 5 files changed, 17 insertions(+), 35 deletions(-)
>
> diff --git a/backends/cryptodev-vhost.c b/backends/cryptodev-vhost.c
> index 943680a23a..abdfce33af 100644
> --- a/backends/cryptodev-vhost.c
> +++ b/backends/cryptodev-vhost.c
> @@ -152,7 +152,6 @@ vhost_set_vring_enable(CryptoDevBackendClient *cc,
> {
> CryptoDevBackendVhost *crypto =
> cryptodev_get_vhost(cc, b, queue);
> - const VhostOps *vhost_ops;
>
> cc->vring_enable = enable;
>
> @@ -160,12 +159,7 @@ vhost_set_vring_enable(CryptoDevBackendClient *cc,
> return 0;
> }
>
> - vhost_ops = crypto->dev.vhost_ops;
> - if (vhost_ops->vhost_set_vring_enable) {
> - return vhost_ops->vhost_set_vring_enable(&crypto->dev, enable);
> - }
> -
> - return 0;
> + return vhost_dev_set_vring_enable(&crypto->dev, enable);
> }
>
> int cryptodev_vhost_start(VirtIODevice *dev, int total_queues)
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index a8ee18a912..25e9f1fd24 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -587,7 +587,6 @@ VHostNetState *get_vhost_net(NetClientState *nc)
> int vhost_net_set_vring_enable(NetClientState *nc, int enable)
> {
> VHostNetState *net = get_vhost_net(nc);
> - const VhostOps *vhost_ops = net->dev.vhost_ops;
>
> /*
> * vhost-vdpa network devices need to enable dataplane virtqueues after
> @@ -601,11 +600,7 @@ int vhost_net_set_vring_enable(NetClientState *nc, int
> enable)
>
> nc->vring_enable = enable;
>
> - if (vhost_ops && vhost_ops->vhost_set_vring_enable) {
> - return vhost_ops->vhost_set_vring_enable(&net->dev, enable);
> - }
> -
> - return 0;
> + return vhost_dev_set_vring_enable(&net->dev, enable);
> }
>
> int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu)
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 36c9c2e04d..f367ce06ce 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -1235,7 +1235,12 @@ static int vhost_user_set_vring_enable(struct
> vhost_dev *dev, int enable)
> int i;
>
> if (!virtio_has_feature(dev->features, VHOST_USER_F_PROTOCOL_FEATURES)) {
> - return -EINVAL;
> + /*
> + * For vhost-user devices, if VHOST_USER_F_PROTOCOL_FEATURES has not
> + * been negotiated, the rings start directly in the enabled state,
> + * and can't be disabled.
> + */
> + return 0;
> }
>
> for (i = 0; i < dev->nvqs; ++i) {
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 266a11514a..414a48a218 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -2013,27 +2013,6 @@ int vhost_dev_get_inflight(struct vhost_dev *dev,
> uint16_t queue_size,
> return 0;
> }
>
> -static int vhost_dev_set_vring_enable(struct vhost_dev *hdev, int enable)
> -{
> - if (!hdev->vhost_ops->vhost_set_vring_enable) {
> - return 0;
> - }
> -
> - /*
> - * For vhost-user devices, if VHOST_USER_F_PROTOCOL_FEATURES has not
> - * been negotiated, the rings start directly in the enabled state, and
> - * .vhost_set_vring_enable callback will fail since
> - * VHOST_USER_SET_VRING_ENABLE is not supported.
> - */
> - if (hdev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER &&
> - !virtio_has_feature(hdev->backend_features,
> - VHOST_USER_F_PROTOCOL_FEATURES)) {
> - return 0;
> - }
> -
> - return hdev->vhost_ops->vhost_set_vring_enable(hdev, enable);
> -}
> -
> /*
> * Host notifiers must be enabled at this point.
> *
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 08bbb4dfe9..1ee639dd7e 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -215,6 +215,15 @@ static inline bool vhost_dev_is_started(struct vhost_dev
> *hdev)
> return hdev->started;
> }
>
> +static inline int vhost_dev_set_vring_enable(struct vhost_dev *hdev, int
> enable)
> +{
> + if (!hdev->vhost_ops->vhost_set_vring_enable) {
> + return 0;
> + }
> +
> + return hdev->vhost_ops->vhost_set_vring_enable(hdev, enable);
> +}
> +
> /**
> * vhost_dev_start() - start the vhost device
> * @hdev: common vhost_dev structure
> --
> 2.48.1
>
