From 7ff82af4b2ccbd77b84f5c3eda7752b1a951ca05 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Mon, 23 Mar 2020 13:21:39 +0100
Subject: [PATCH] vm-virtio: vhost-user: Factorize SET_MEM_TABLE setup

By factorizing the setup of the memory table for vhost-user, we
anticipate the fact that vhost-user devices are going to reuse this
function when the guest memory will be updated.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 vm-virtio/src/vhost_user/vu_common_ctrl.rs | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/vm-virtio/src/vhost_user/vu_common_ctrl.rs b/vm-virtio/src/vhost_user/vu_common_ctrl.rs
index 89318a2cf..67b177f0b 100644
--- a/vm-virtio/src/vhost_user/vu_common_ctrl.rs
+++ b/vm-virtio/src/vhost_user/vu_common_ctrl.rs
@@ -27,13 +27,7 @@ pub struct VhostUserConfig {
     pub queue_size: u16,
 }
 
-pub fn setup_vhost_user_vring(
-    vu: &mut Master,
-    mem: &GuestMemoryMmap,
-    queues: Vec<Queue>,
-    queue_evts: Vec<EventFd>,
-    virtio_interrupt: &Arc<dyn VirtioInterrupt>,
-) -> Result<Vec<(Option<EventFd>, Queue)>> {
+pub fn update_mem_table(vu: &mut Master, mem: &GuestMemoryMmap) -> Result<()> {
     let mut regions: Vec<VhostUserMemoryRegionInfo> = Vec::new();
     mem.with_regions_mut(|_, region| {
         let (mmap_handle, mmap_offset) = match region.file_offset() {
@@ -58,6 +52,19 @@ pub fn setup_vhost_user_vring(
     vu.set_mem_table(regions.as_slice())
         .map_err(Error::VhostUserSetMemTable)?;
 
+    Ok(())
+}
+
+pub fn setup_vhost_user_vring(
+    vu: &mut Master,
+    mem: &GuestMemoryMmap,
+    queues: Vec<Queue>,
+    queue_evts: Vec<EventFd>,
+    virtio_interrupt: &Arc<dyn VirtioInterrupt>,
+) -> Result<Vec<(Option<EventFd>, Queue)>> {
+    // Let's first provide the memory table to the backend.
+    update_mem_table(vu, mem)?;
+
     let mut vu_interrupt_list = Vec::new();
 
     for (queue_index, queue) in queues.into_iter().enumerate() {