runtime-rs: make the resize_vcpu sync

When hot plugging vcpu in dragonball hypervisor, use the synchronization
interface and wait until the hot plug cpu is executed in the guest
before returning. This ensures that the subsequent device hot plug will
not conflict with the previous call.

Signed-off-by: Fupan Li <fupan.lfp@antgroup.com>

src/runtime-rs/crates/hypervisor/src/dragonball/inner.rs

@@ -28,7 +28,7 @@ use kata_types::{
 };
 use nix::mount::MsFlags;
 use persist::sandbox_persist::Persist;
-use std::cmp::Ordering;
+use std::{cmp::Ordering, time::Duration};
 use std::{collections::HashSet, fs::create_dir_all};
 use tokio::sync::mpsc;
 
@@ -37,6 +37,9 @@ const DRAGONBALL_INITRD: &str = "initrd";
 const DRAGONBALL_ROOT_FS: &str = "rootfs";
 const BALLOON_DEVICE_ID: &str = "balloon0";
 const MEM_DEVICE_ID: &str = "memmr0";
+/// default hotplug timeout
+const DEFAULT_HOTPLUG_TIMEOUT: u64 = 250;
+
 #[derive(Debug)]
 pub struct DragonballInner {
     /// sandbox id
@@ -391,7 +394,10 @@ impl DragonballInner {
             vcpu_count: Some(new_vcpus as u8),
         };
         self.vmm_instance
-            .resize_vcpu(&cpu_resize_info)
+            .resize_vcpu(
+                &cpu_resize_info,
+                Some(Duration::from_millis(DEFAULT_HOTPLUG_TIMEOUT)),
+            )
             .context(format!(
                 "failed to do_resize_vcpus on new_vcpus={:?}",
                 new_vcpus

src/runtime-rs/crates/hypervisor/src/dragonball/vmm_instance.rs

@@ -9,6 +9,7 @@ use std::{
     os::unix::{io::IntoRawFd, prelude::AsRawFd},
     sync::{Arc, Mutex, RwLock},
     thread,
+    time::Duration,
 };
 
 use anyhow::{anyhow, Context, Result};
@@ -292,9 +293,17 @@ impl VmmInstance {
         Ok(())
     }
 
-    pub fn resize_vcpu(&self, cfg: &VcpuResizeInfo) -> Result<()> {
-        self.handle_request(Request::Sync(VmmAction::ResizeVcpu(cfg.clone())))
+    pub fn resize_vcpu(&self, cfg: &VcpuResizeInfo, timeout: Option<Duration>) -> Result<()> {
+        let vmmdata = self
+            .handle_request(Request::Sync(VmmAction::ResizeVcpu(cfg.clone())))
             .with_context(|| format!("Failed to resize_vm(hotplug vcpu), cfg: {:?}", cfg))?;
+
+        if let Some(timeout) = timeout {
+            if let VmmData::SyncHotplug((_, receiver)) = vmmdata {
+                let _ = receiver.recv_timeout(timeout)?;
+            }
+        }
+
         Ok(())
     }