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authorStefano Garzarella2022-11-30 12:24:36 +0100
committerMichael S. Tsirkin2022-12-01 08:30:04 +0100
commit4daa5054c599c8aec70f1264a01341a15921c145 (patch)
tree82e6b78fedf0a4cdb056e0727fb64e1d1cbcdcb4 /audio/trace-events
parenttests/qtests: override "force-legacy" for gpio virtio-mmio tests (diff)
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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>
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