vm-virtio: vhost-user: Send memory update to the backend

In order to keep vhost-user backend to work across guest memory resizing
happening when memory is hot-plugged or hot-unplugged, both blk, net and
fs devices are implementing the notifier to let the backend know.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vm-virtio/src/vhost_user/blk.rs

@@ -321,6 +321,10 @@ impl VirtioDevice for Blk {
     fn shutdown(&mut self) {
         let _ = unsafe { libc::close(self.vhost_user_blk.as_raw_fd()) };
     }
+
+    fn update_memory(&mut self, mem: &GuestMemoryMmap) -> std::result::Result<(), crate::Error> {
+        update_mem_table(&mut self.vhost_user_blk, mem).map_err(crate::Error::VhostUserUpdateMemory)
+    }
 }
 
 virtio_pausable!(Blk);

vm-virtio/src/vhost_user/fs.rs

@@ -1,7 +1,7 @@
 // Copyright 2019 Intel Corporation. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-use super::vu_common_ctrl::{reset_vhost_user, setup_vhost_user};
+use super::vu_common_ctrl::{reset_vhost_user, setup_vhost_user, update_mem_table};
 use super::Error as DeviceError;
 use super::{Error, Result};
 use crate::vhost_user::handler::{VhostUserEpollConfig, VhostUserEpollHandler};
@@ -529,6 +529,10 @@ impl VirtioDevice for Fs {
             None
         }
     }
+
+    fn update_memory(&mut self, mem: &GuestMemoryMmap) -> std::result::Result<(), crate::Error> {
+        update_mem_table(&mut self.vu, mem).map_err(crate::Error::VhostUserUpdateMemory)
+    }
 }
 
 virtio_pausable!(Fs);

vm-virtio/src/vhost_user/net.rs

@@ -358,6 +358,10 @@ impl VirtioDevice for Net {
     fn shutdown(&mut self) {
         let _ = unsafe { libc::close(self.vhost_user_net.as_raw_fd()) };
     }
+
+    fn update_memory(&mut self, mem: &GuestMemoryMmap) -> std::result::Result<(), crate::Error> {
+        update_mem_table(&mut self.vhost_user_net, mem).map_err(crate::Error::VhostUserUpdateMemory)
+    }
 }
 
 virtio_ctrl_q_pausable!(Net);