I think others should weigh in on the higher level abstractions you're
adding for vhost_user_blk_force_stop() - I don't have a strong
perspective on them. I'm ok with this for vhost-user-blk.
Acked-by: Raphael Norwitz <raph...@enfabrica.net>
On Mon, Jun 9, 2025 at 5:26 PM Daniil Tatianin
<d-tatia...@yandex-team.ru> wrote:
>
> If we have a server running disk requests that is for whatever reason
> hanging or not able to process any more IO requests but still has some
> in-flight requests previously issued by the guest OS, QEMU will still
> try to drain the vring before shutting down even if it was explicitly
> asked to do a "force shutdown" via SIGTERM or QMP quit. This is not
> useful since the guest is no longer running at this point since it was
> killed by QEMU earlier in the process. At this point, we don't care
> about whatever in-flight IO it might have pending, we just want QEMU
> to shut down.
>
> Add an option called "skip-get-vring-base-on-force-shutdown" to allow
> SIGTERM/QMP quit() to actually act like a "force shutdown" at least
> for vhost-user-blk devices since those require the drain operation
> to shut down gracefully unlike, for example, network devices.
>
> Signed-off-by: Daniil Tatianin <d-tatia...@yandex-team.ru>
> ---
> hw/block/vhost-user-blk.c | 9 ++++++++-
> include/hw/virtio/vhost-user-blk.h | 2 ++
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index 0eebbcd80d..c0cc5f6942 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -210,6 +210,7 @@ static int vhost_user_blk_stop(VirtIODevice *vdev)
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> int ret;
> + bool force_stop = false;
>
> if (!s->started_vu) {
> return 0;
> @@ -220,7 +221,11 @@ static int vhost_user_blk_stop(VirtIODevice *vdev)
> return 0;
> }
>
> - ret = vhost_dev_stop(&s->dev, vdev, true);
> + force_stop = s->skip_get_vring_base_on_force_shutdown &&
> + qemu_force_shutdown_requested();
> +
> + ret = force_stop ? vhost_dev_force_stop(&s->dev, vdev, true) :
> + vhost_dev_stop(&s->dev, vdev, true);
>
> if (k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false) < 0) {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> @@ -584,6 +589,8 @@ static const Property vhost_user_blk_properties[] = {
> VIRTIO_BLK_F_DISCARD, true),
> DEFINE_PROP_BIT64("write-zeroes", VHostUserBlk, parent_obj.host_features,
> VIRTIO_BLK_F_WRITE_ZEROES, true),
> + DEFINE_PROP_BOOL("skip-get-vring-base-on-force-shutdown", VHostUserBlk,
> + skip_get_vring_base_on_force_shutdown, false),
> };
>
> static void vhost_user_blk_class_init(ObjectClass *klass, const void *data)
> diff --git a/include/hw/virtio/vhost-user-blk.h
> b/include/hw/virtio/vhost-user-blk.h
> index ea085ee1ed..a10f785672 100644
> --- a/include/hw/virtio/vhost-user-blk.h
> +++ b/include/hw/virtio/vhost-user-blk.h
> @@ -50,6 +50,8 @@ struct VHostUserBlk {
> bool connected;
> /* vhost_user_blk_start/vhost_user_blk_stop */
> bool started_vu;
> +
> + bool skip_get_vring_base_on_force_shutdown;
> };
>
> #endif
> --
> 2.34.1
>
