qemu/contrib/vhost-user-blk
Stefan Hajnoczi a9a5c473d2 libvhost-user: advertise vring features
libvhost-user implements several vring features without advertising
them. There is no way for the vhost-user master to detect support for
these features.

Things more or less work today because QEMU assumes the vhost-user
backend always implements certain feature bits like
VIRTIO_RING_F_EVENT_IDX. This is not documented anywhere.

This patch explicitly advertises features implemented in libvhost-user
so that the vhost-user master does not need to make undocumented
assumptions.

Feature bits that libvhost-user now advertises can be removed from
vhost-user-blk.c. Devices should not be responsible for advertising
vring feature bits, that is libvhost-user's job.

Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200529161338.456017-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2020-06-12 10:17:06 -04:00
..
Makefile.objs contrib/vhost-user-blk: introduce a vhost-user-blk sample application 2018-01-18 21:52:37 +02:00
vhost-user-blk.c libvhost-user: advertise vring features 2020-06-12 10:17:06 -04:00