vhost-user: frontend: Read the full reply for set_log_base

This code was incorrectly assuming that it was a plain ack but instead
the backend code in this repository (and the QEMU behaviour) is to
expect a full struct of reply.

Fixes: #217

Signed-off-by: Rob Bradford <rbradford@meta.com>

vhost/CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Deprecated
 ### Fixed
 - [[#338]](https://github.com/rust-vmm/vhost/pull/338) vhost: fix double-locking in Backend to Frontend request handlers
+- [[#342]](https://github.com/rust-vmm/vhost/pull/342) vhost-user: frontend: Read the full reply for set_log_base
 
 ## v0.15.0
 

vhost/src/vhost_user/frontend.rs

@@ -258,7 +258,8 @@ impl VhostBackend for Frontend {
                 &log,
                 Some(&[region.mmap_handle]),
             )?;
-            node.wait_for_ack(&hdr).map_err(|e| e.into())
+            let _ = node.recv_reply::<VhostUserLog>(&hdr)?;
+            Ok(())
         } else {
             let _ = node.send_request_with_body(FrontendReq::SET_LOG_BASE, &val, None)?;
             Ok(())