3 files changed, 22 insertions, 6 deletions
diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index a1539dbb69..7d47f1364a 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -136,7 +136,7 @@ typedef struct VhostUserMemory {
 } VhostUserMemory;
 
 typedef struct VhostUserMemRegMsg {
-    uint32_t padding;
+    uint64_t padding;
     VhostUserMemoryRegion region;
 } VhostUserMemRegMsg;
 
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 988f154144..6d4025ba6a 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -131,6 +131,23 @@ A region is:
 
 :mmap offset: 64-bit offset where region starts in the mapped memory
 
+Single memory region description
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
++---------+---------------+------+--------------+-------------+
+| padding | guest address | size | user address | mmap offset |
++---------+---------------+------+--------------+-------------+
+
+:padding: 64-bit
+
+:guest address: a 64-bit guest address of the region
+
+:size: a 64-bit size
+
+:user address: a 64-bit user address
+
+:mmap offset: 64-bit offset where region starts in the mapped memory
+
 Log description
 ^^^^^^^^^^^^^^^
 
@@ -1281,7 +1298,7 @@ Master message types
 ``VHOST_USER_ADD_MEM_REG``
   :id: 37
   :equivalent ioctl: N/A
-  :slave payload: memory region
+  :slave payload: single memory region description
 
   When the ``VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS`` protocol
   feature has been successfully negotiated, this message is submitted
@@ -1296,7 +1313,7 @@ Master message types
 ``VHOST_USER_REM_MEM_REG``
   :id: 38
   :equivalent ioctl: N/A
-  :slave payload: memory region
+  :slave payload: single memory region description
 
   When the ``VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS`` protocol
   feature has been successfully negotiated, this message is submitted
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 9c5b4f7fbc..2fdd5daf74 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -149,7 +149,7 @@ typedef struct VhostUserMemory {
 } VhostUserMemory;
 
 typedef struct VhostUserMemRegMsg {
-    uint32_t padding;
+    uint64_t padding;
     VhostUserMemoryRegion region;
 } VhostUserMemRegMsg;
 
@@ -800,8 +800,7 @@ static int vhost_user_add_remove_regions(struct vhost_dev *dev,
     uint64_t shadow_pcb[VHOST_USER_MAX_RAM_SLOTS] = {};
     int nr_add_reg, nr_rem_reg;
 
-    msg->hdr.size = sizeof(msg->payload.mem_reg.padding) +
-        sizeof(VhostUserMemoryRegion);
+    msg->hdr.size = sizeof(msg->payload.mem_reg);
 
     /* Find the regions which need to be removed or added. */
     scrub_shadow_regions(dev, add_reg, &nr_add_reg, rem_reg, &nr_rem_reg,