From: Yongji Xie <elohi...@gmail.com> Some old guests (before commit 7a11370e5: "virtio_blk: enable VQs early") kick virtqueue before setting VIRTIO_CONFIG_S_DRIVER_OK. This violates the virtio spec. But virtio 1.0 transitional devices support this behaviour. So we should start vhost when guest kicks in this case.
Signed-off-by: Yongji Xie <xieyon...@baidu.com> Signed-off-by: Chai Wen <chai...@baidu.com> Signed-off-by: Ni Xun <ni...@baidu.com> Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> Reviewed-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@redhat.com> --- hw/block/vhost-user-blk.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index d755223643..1451940845 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -217,7 +217,32 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev, static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) { + VHostUserBlk *s = VHOST_USER_BLK(vdev); + int i; + if (!(virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1) && + !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1))) { + return; + } + + if (s->dev.started) { + return; + } + + /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start + * vhost here instead of waiting for .set_status(). + */ + vhost_user_blk_start(vdev); + + /* Kick right away to begin processing requests already in vring */ + for (i = 0; i < s->dev.nvqs; i++) { + VirtQueue *kick_vq = virtio_get_queue(vdev, i); + + if (!virtio_queue_get_desc_addr(vdev, i)) { + continue; + } + event_notifier_set(virtio_queue_get_host_notifier(kick_vq)); + } } static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) -- MST