tests: add test case for testing PMU on direct kernel boot

Add integration tests for "pmu=on". It depends on checking if there
is "arm-pmu" item in "/proc/interrupts". As PMU info has not been added
to ACPI, the tests are only for dt.

Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>

tests/integration.rs

@@ -76,6 +76,7 @@ mod aarch64 {
     pub const FOCAL_IMAGE_NAME_VHD: &str = "focal-server-cloudimg-arm64-custom-20210929-0.vhd";
     pub const FOCAL_IMAGE_NAME_VHDX: &str = "focal-server-cloudimg-arm64-custom-20210929-0.vhdx";
     pub const GREP_SERIAL_IRQ_CMD: &str = "grep -c 'GICv3.*uart-pl011' /proc/interrupts || true";
+    pub const GREP_PMU_IRQ_CMD: &str = "grep -c 'GICv3.*arm-pmu' /proc/interrupts || true";
 }
 
 #[cfg(target_arch = "aarch64")]
@@ -3516,6 +3517,43 @@ mod parallel {
         handle_child_output(r, &output);
     }
 
+    #[test]
+    #[cfg(target_arch = "aarch64")]
+    fn test_pmu_on() {
+        let focal = UbuntuDiskConfig::new(FOCAL_IMAGE_NAME.to_string());
+        let guest = Guest::new(Box::new(focal));
+        let mut child = GuestCommand::new(&guest)
+            .args(&["--cpus", "boot=1"])
+            .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();
+
+            // Test that PMU exists.
+            assert_eq!(
+                guest
+                    .ssh_command(GREP_PMU_IRQ_CMD)
+                    .unwrap()
+                    .trim()
+                    .parse::<u32>()
+                    .unwrap_or_default(),
+                1
+            );
+        });
+
+        let _ = child.kill();
+        let output = child.wait_with_output().unwrap();
+
+        handle_child_output(r, &output);
+    }
+
     #[test]
     fn test_serial_off() {
         let focal = UbuntuDiskConfig::new(FOCAL_IMAGE_NAME.to_string());