diff options
| author | Stefano Garzarella | 2022-11-30 12:24:36 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin | 2022-12-01 08:30:04 +0100 |
| commit | 4daa5054c599c8aec70f1264a01341a15921c145 (patch) | |
| tree | 82e6b78fedf0a4cdb056e0727fb64e1d1cbcdcb4 /include | |
| parent | tests/qtests: override "force-legacy" for gpio virtio-mmio tests (diff) | |
| download | qemu-4daa5054c599c8aec70f1264a01341a15921c145.tar.gz qemu-4daa5054c599c8aec70f1264a01341a15921c145.tar.xz qemu-4daa5054c599c8aec70f1264a01341a15921c145.zip | |
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 'include')
| -rw-r--r-- | include/hw/virtio/vhost.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index 353252ac3e..67a6807fac 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -184,24 +184,26 @@ static inline bool vhost_dev_is_started(struct vhost_dev *hdev) * vhost_dev_start() - start the vhost device * @hdev: common vhost_dev structure * @vdev: the VirtIODevice structure + * @vrings: true to have vrings enabled in this call * * Starts the vhost device. From this point VirtIO feature negotiation * can start and the device can start processing VirtIO transactions. * * Return: 0 on success, < 0 on error. */ -int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev); +int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings); /** * vhost_dev_stop() - stop the vhost device * @hdev: common vhost_dev structure * @vdev: the VirtIODevice structure + * @vrings: true to have vrings disabled in this call * * Stop the vhost device. After the device is stopped the notifiers * can be disabled (@vhost_dev_disable_notifiers) and the device can * be torn down (@vhost_dev_cleanup). */ -void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev); +void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings); /** * DOC: vhost device configuration handling |