From 0d2acd505d9d190cc732a4d0979631cd62c678ab Mon Sep 17 00:00:00 2001
From: Liu Jiang <gerry@linux.alibaba.com>
Date: Sun, 19 Dec 2021 12:47:47 +0800
Subject: [PATCH] vhost-user: fix SlaveReqHandler::set_config()

Fix a bug in SlaveReqHandler::set_config(), it should remove the
message header of the buffer passed to backend.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
---
 coverage_config_x86_64.json         | 2 +-
 src/vhost_user/dummy_slave.rs       | 5 +++++
 src/vhost_user/mod.rs               | 4 ++--
 src/vhost_user/slave_req_handler.rs | 3 ++-
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/coverage_config_x86_64.json b/coverage_config_x86_64.json
index d90e85d..e1314df 100644
--- a/coverage_config_x86_64.json
+++ b/coverage_config_x86_64.json
@@ -1 +1 @@
-{"coverage_score": 80.2, "exclude_path": "src/vhost_kern/", "crate_features": "vhost-user-master,vhost-user-slave"}
+{"coverage_score": 80.3, "exclude_path": "src/vhost_kern/", "crate_features": "vhost-user-master,vhost-user-slave"}
diff --git a/src/vhost_user/dummy_slave.rs b/src/vhost_user/dummy_slave.rs
index cc9a9fb..222a5bb 100644
--- a/src/vhost_user/dummy_slave.rs
+++ b/src/vhost_user/dummy_slave.rs
@@ -218,6 +218,8 @@ impl VhostUserSlaveReqHandlerMut for DummySlaveReqHandler {
         {
             return Err(Error::InvalidParam);
         }
+        assert_eq!(offset, 0x100);
+        assert_eq!(size, 4);
         Ok(vec![0xa5; size as usize])
     }
 
@@ -231,6 +233,9 @@ impl VhostUserSlaveReqHandlerMut for DummySlaveReqHandler {
         {
             return Err(Error::InvalidParam);
         }
+        assert_eq!(offset, 0x100);
+        assert_eq!(buf.len(), 4);
+        assert_eq!(buf, &[0xa5; 4]);
         Ok(())
     }
 
diff --git a/src/vhost_user/mod.rs b/src/vhost_user/mod.rs
index 605c4fc..a49cdfb 100644
--- a/src/vhost_user/mod.rs
+++ b/src/vhost_user/mod.rs
@@ -419,7 +419,7 @@ mod tests {
         master.set_mem_table(&mem).unwrap();
 
         master
-            .set_config(0x100, VhostUserConfigFlags::WRITABLE, &[0xa5u8])
+            .set_config(0x100, VhostUserConfigFlags::WRITABLE, &[0xa5u8; 4])
             .unwrap();
         let buf = [0x0u8; 4];
         let (reply_body, reply_payload) = master
@@ -427,7 +427,7 @@ mod tests {
             .unwrap();
         let offset = reply_body.offset;
         assert_eq!(offset, 0x100);
-        assert_eq!(reply_payload[0], 0xa5);
+        assert_eq!(&reply_payload, &[0xa5; 4]);
 
         master.set_slave_request_fd(&eventfd).unwrap();
         master.set_vring_enable(0, true).unwrap();
diff --git a/src/vhost_user/slave_req_handler.rs b/src/vhost_user/slave_req_handler.rs
index bbc935e..2cd9dd9 100644
--- a/src/vhost_user/slave_req_handler.rs
+++ b/src/vhost_user/slave_req_handler.rs
@@ -634,7 +634,8 @@ impl<S: VhostUserSlaveReqHandler> SlaveReqHandler<S> {
             None => return Err(Error::InvalidMessage),
         }
 
-        self.backend.set_config(msg.offset, buf, flags)
+        self.backend
+            .set_config(msg.offset, &buf[mem::size_of::<VhostUserConfig>()..], flags)
     }
 
     fn set_slave_req_fd(&mut self, files: Option<Vec<File>>) -> Result<()> {