diff options
| author | Stefano Garzarella <sgarzare@redhat.com> | 2022-11-30 11:24:36 +0000 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2022-12-01 02:30:04 -0500 |
| commit | 4daa5054c599c8aec70f1264a01341a15921c145 (patch) | |
| tree | 82e6b78fedf0a4cdb056e0727fb64e1d1cbcdcb4 /hw/block | |
| parent | 523e40022fc9522bb6bc13e4ce9eb4d1613ab5dc (diff) | |
vhost: enable vrings in vhost_dev_start() for vhost-user devices
Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user
backend, but we forgot to enable vrings as specified in
docs/interop/vhost-user.rst:
If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the
ring starts directly in the enabled state.
If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is
initialized in a disabled state and is enabled by
``VHOST_USER_SET_VRING_ENABLE`` with parameter 1.
Some vhost-user front-ends already did this by calling
vhost_ops.vhost_set_vring_enable() directly:
- backends/cryptodev-vhost.c
- hw/net/virtio-net.c
- hw/virtio/vhost-user-gpio.c
But most didn't do that, so we would leave the vrings disabled and some
backends would not work. We observed this issue with the rust version of
virtiofsd [1], which uses the event loop [2] provided by the
vhost-user-backend crate where requests are not processed if vring is
not enabled.
Let's fix this issue by enabling the vrings in vhost_dev_start() for
vhost-user front-ends that don't already do this directly. Same thing
also in vhost_dev_stop() where we disable vrings.
[1] https://gitlab.com/virtio-fs/virtiofsd
[2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217
Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features")
Reported-by: German Maglione <gmaglione@redhat.com>
Tested-by: German Maglione <gmaglione@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221123131630.52020-1-sgarzare@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/block')
| -rw-r--r-- | hw/block/vhost-user-blk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 0d5190accf..1177064631 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -178,7 +178,7 @@ static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp) } s->dev.vq_index_end = s->dev.nvqs; - ret = vhost_dev_start(&s->dev, vdev); + ret = vhost_dev_start(&s->dev, vdev, true); if (ret < 0) { error_setg_errno(errp, -ret, "Error starting vhost"); goto err_guest_notifiers; @@ -213,7 +213,7 @@ static void vhost_user_blk_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&s->dev, vdev); + vhost_dev_stop(&s->dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false); if (ret < 0) { |