[PATCH V2] vhost_vdpa: no need to fetch vring base when poweroff

[Zhu Lingshan <lingshan.zhu@intel.com>]

In the poweroff routine, no need to fetch last available index.

This commit also provides a better debug message in the vhost
caller vhost_virtqueue_stop, because if vhost does not fetch
the last avail idx successfully, maybe the device does not
suspend, vhost will sync last avail idx to vring used idx as a
work around, not a failure.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 hw/virtio/vhost-vdpa.c | 10 ++++++++++
 hw/virtio/vhost.c      |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 3c575a9a6e..10b445f64e 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -26,6 +26,7 @@
 #include "cpu.h"
 #include "trace.h"
 #include "qapi/error.h"
+#include "sysemu/runstate.h"
 
 /*
  * Return one past the end of the end of section. Be careful with uint64_t
@@ -1391,6 +1392,15 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
     struct vhost_vdpa *v = dev->opaque;
     int ret;
 
+    if (runstate_check(RUN_STATE_SHUTDOWN)) {
+        /*
+         * Some devices do not support this call properly,
+         * and we don't need to retrieve the indexes
+         * if it is shutting down
+         */
+        return 0;
+    }
+
     if (v->shadow_vqs_enabled) {
         ring->num = virtio_queue_get_last_avail_idx(dev->vdev, ring->index);
         return 0;
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 82394331bf..7dd90cff3a 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1262,7 +1262,7 @@ void vhost_virtqueue_stop(struct vhost_dev *dev,
 
     r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
     if (r < 0) {
-        VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r);
+        VHOST_OPS_DEBUG(r, "sync last avail idx to the guest used idx for vhost VQ %u", idx);
         /* Connection to the backend is broken, so let's sync internal
          * last avail idx to the device used idx.
          */
-- 
2.39.3