[PATCH v4 06/15] vdpa: add vhost_vdpa->suspended parameter

["Eugenio Pérez" <eperezma@redhat.com>]

This allows vhost_vdpa to track if it is safe to get vring base from the
device or not.  If it is not, vhost can fall back to fetch idx from the
guest buffer again.

No functional change intended in this patch, later patches will use this
field.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h | 2 ++
 hw/virtio/vhost-vdpa.c         | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 7997f09a8d..4a7d396674 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -42,6 +42,8 @@ typedef struct vhost_vdpa {
     bool shadow_vqs_enabled;
     /* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA */
     bool shadow_data;
+    /* Device suspended successfully */
+    bool suspended;
     /* IOVA mapping used by the Shadow Virtqueue */
     VhostIOVATree *iova_tree;
     GPtrArray *shadow_vqs;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 8cc9c98db9..228677895a 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -1227,6 +1227,14 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
         return 0;
     }
 
+    if (!v->suspended) {
+        /*
+         * Cannot trust in value returned by device, let vhost recover used
+         * idx from guest.
+         */
+        return -1;
+    }
+
     ret = vhost_vdpa_call(dev, VHOST_GET_VRING_BASE, ring);
     trace_vhost_vdpa_get_vring_base(dev, ring->index, ring->num);
     return ret;
-- 
2.31.1