[RFC v2 08/13] virtio: Add vhost_shadow_vq_get_vring_addr

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

It reports the shadow virtqueue address from qemu virtual address space

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |  2 ++
 hw/virtio/vhost-shadow-virtqueue.c | 24 +++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index 2ca4b92b12..d82c35bccf 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -19,6 +19,8 @@ typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
 
 void vhost_shadow_vq_mask(VhostShadowVirtqueue *svq, EventNotifier *masked);
 void vhost_shadow_vq_unmask(VhostShadowVirtqueue *svq);
+void vhost_shadow_vq_get_vring_addr(const VhostShadowVirtqueue *svq,
+                                    struct vhost_vring_addr *addr);
 
 bool vhost_shadow_vq_start(struct vhost_dev *dev,
                            unsigned idx,
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index b6bab438d6..1460d1d5d1 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -17,6 +17,9 @@
 
 /* Shadow virtqueue to relay notifications */
 typedef struct VhostShadowVirtqueue {
+    /* Shadow vring */
+    struct vring vring;
+
     /* Shadow kick notifier, sent to vhost */
     EventNotifier kick_notifier;
     /* Shadow call notifier, sent to vhost */
@@ -51,6 +54,9 @@ typedef struct VhostShadowVirtqueue {
 
     /* Virtio device */
     VirtIODevice *vdev;
+
+    /* Descriptors copied from guest */
+    vring_desc_t descs[];
 } VhostShadowVirtqueue;
 
 /* Forward guest notifications */
@@ -132,6 +138,19 @@ void vhost_shadow_vq_unmask(VhostShadowVirtqueue *svq)
     qemu_event_wait(&svq->masked_notifier.is_free);
 }
 
+/*
+ * Get the shadow vq vring address.
+ * @svq Shadow virtqueue
+ * @addr Destination to store address
+ */
+void vhost_shadow_vq_get_vring_addr(const VhostShadowVirtqueue *svq,
+                                    struct vhost_vring_addr *addr)
+{
+    addr->desc_user_addr = (uint64_t)svq->vring.desc;
+    addr->avail_user_addr = (uint64_t)svq->vring.avail;
+    addr->used_user_addr = (uint64_t)svq->vring.used;
+}
+
 /*
  * Restore the vhost guest to host notifier, i.e., disables svq effect.
  */
@@ -262,7 +281,9 @@ void vhost_shadow_vq_stop(struct vhost_dev *dev,
 VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev *dev, int idx)
 {
     int vq_idx = dev->vq_index + idx;
-    g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
+    unsigned num = virtio_queue_get_num(dev->vdev, vq_idx);
+    size_t ring_size = vring_size(num, VRING_DESC_ALIGN_SIZE);
+    g_autofree VhostShadowVirtqueue *svq = g_malloc0(sizeof(*svq) + ring_size);
     int r;
 
     r = event_notifier_init(&svq->kick_notifier, 0);
@@ -279,6 +300,7 @@ VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev *dev, int idx)
         goto err_init_call_notifier;
     }
 
+    vring_init(&svq->vring, num, svq->descs, VRING_DESC_ALIGN_SIZE);
     svq->vq = virtio_get_queue(dev->vdev, vq_idx);
     svq->vdev = dev->vdev;
     event_notifier_set_handler(&svq->call_notifier,
-- 
2.27.0