tests: Add integration test for hotplugging vCPUs

Resize the VM to increase the number of vCPUs.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

src/main.rs

@@ -934,6 +934,10 @@ mod tests {
             }
         }
 
+        fn api_resize_body(&self, desired_vcpus: u8) -> String {
+            format!("{{\"desired_vcpus\":{}}}", desired_vcpus)
+        }
+
         fn get_cpu_count(&self) -> Result<u32, Error> {
             Ok(self
                 .ssh_command("grep -c processor /proc/cpuinfo")?
@@ -3209,4 +3213,69 @@ mod tests {
     fn test_memory_mergeable_off() {
         test_memory_mergeable(false)
     }
+
+    #[cfg_attr(not(feature = "mmio"), test)]
+    fn test_cpu_hotplug() {
+        test_block!(tb, "", {
+            let mut clear = ClearDiskConfig::new();
+            let guest = Guest::new(&mut clear);
+            let api_socket = temp_api_path(&guest.tmp_dir);
+            let mut workload_path = dirs::home_dir().unwrap();
+            workload_path.push("workloads");
+            let mut kernel_path = workload_path.clone();
+            kernel_path.push("vmlinux");
+
+            let mut child = Command::new("target/release/cloud-hypervisor")
+                .args(&["--cpus", "boot=2,max=4"])
+                .args(&["--memory", "size=512M"])
+                .args(&["--kernel", kernel_path.to_str().unwrap()])
+                .args(&["--cmdline", "root=PARTUUID=8d93774b-e12c-4ac5-aa35-77bfa7168767 console=tty0 console=ttyS0,115200n8 console=hvc0 quiet init=/usr/lib/systemd/systemd-bootchart initcall_debug tsc=reliable no_timer_check noreplace-smp cryptomgr.notests rootfstype=ext4,btrfs,xfs kvm-intel.nested=1 rw"])
+                .args(&[
+                    "--disk",
+                    format!(
+                        "path={}",
+                        guest.disk_config.disk(DiskType::OperatingSystem).unwrap()
+                    )
+                    .as_str(),
+                    format!(
+                        "path={}",
+                        guest.disk_config.disk(DiskType::CloudInit).unwrap()
+                    )
+                    .as_str(),
+                ])
+                .args(&["--net", guest.default_net_string().as_str()])
+                .args(&["--api-socket", &api_socket])
+                .spawn()
+                .unwrap();
+
+            thread::sleep(std::time::Duration::new(20, 0));
+
+            aver_eq!(tb, guest.get_cpu_count().unwrap_or_default(), 2);
+
+            // Resize the VM
+            let desired_vcpus = 4;
+            let http_body = guest.api_resize_body(desired_vcpus);
+            curl_command(
+                &api_socket,
+                "PUT",
+                "http://localhost/api/v1/vm.resize",
+                Some(&http_body),
+            );
+
+            guest.ssh_command("echo 1 | sudo tee /sys/bus/cpu/devices/cpu2/online")?;
+            guest.ssh_command("echo 1 | sudo tee /sys/bus/cpu/devices/cpu3/online")?;
+            thread::sleep(std::time::Duration::new(10, 0));
+            aver_eq!(
+                tb,
+                guest.get_cpu_count().unwrap_or_default(),
+                u32::from(desired_vcpus)
+            );
+
+            guest.ssh_command("sudo shutdown -h now")?;
+            thread::sleep(std::time::Duration::new(10, 0));
+            let _ = child.kill();
+            let _ = child.wait();
+            Ok(())
+        });
+    }
 }