tests: Add integration test for CPU affinity

This new integration test validates the vCPUs are running on the
expected set of CPUs on the host.

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

tests/integration.rs

@@ -2498,6 +2498,48 @@ mod tests {
             handle_child_output(r, &output);
         }
 
+        #[test]
+        fn test_cpu_affinity() {
+            let focal = UbuntuDiskConfig::new(FOCAL_IMAGE_NAME.to_string());
+            let guest = Guest::new(Box::new(focal));
+
+            // We need the host to have at least 4 CPUs if we want to be able
+            // to run this test.
+            let host_cpus_count = exec_host_command_output("nproc");
+            assert!(
+                String::from_utf8_lossy(&host_cpus_count.stdout)
+                    .trim()
+                    .parse::<u8>()
+                    .unwrap_or(0)
+                    >= 4
+            );
+
+            let mut child = GuestCommand::new(&guest)
+                .args(&["--cpus", "boot=2,affinity=[0@[0,2],1@[1,3]]"])
+                .args(&["--memory", "size=512M"])
+                .args(&["--kernel", direct_kernel_boot_path().to_str().unwrap()])
+                .args(&["--cmdline", DIRECT_KERNEL_BOOT_CMDLINE])
+                .default_disks()
+                .default_net()
+                .capture_output()
+                .spawn()
+                .unwrap();
+
+            let r = std::panic::catch_unwind(|| {
+                guest.wait_vm_boot(None).unwrap();
+                let pid = child.id();
+                let taskset_vcpu0 = exec_host_command_output(format!("taskset -pc $(ps -T -p {} | grep vcpu0 | xargs | cut -f 2 -d \" \") | cut -f 6 -d \" \"", pid).as_str());
+                assert_eq!(String::from_utf8_lossy(&taskset_vcpu0.stdout).trim(), "0,2");
+                let taskset_vcpu1 = exec_host_command_output(format!("taskset -pc $(ps -T -p {} | grep vcpu1 | xargs | cut -f 2 -d \" \") | cut -f 6 -d \" \"", pid).as_str());
+                assert_eq!(String::from_utf8_lossy(&taskset_vcpu1.stdout).trim(), "1,3");
+            });
+
+            let _ = child.kill();
+            let output = child.wait_with_output().unwrap();
+
+            handle_child_output(r, &output);
+        }
+
         #[test]
         #[cfg(not(feature = "mshv"))]
         fn test_large_vm() {