Add unit test for KVM_CREATE_IRQCHIP on ARM.

On ARM, KVM_CREATE_IRQCHIP is a bit more complex than on X86.
KVM_CREATE_IRQCHIP only creates VGICv2. It usually succeed with a
GICv2 hardware. But if the hardware is GICv3, it's probable that
GICv2 can't be emulated, so KVM_CREATE_IRQCHIP would fail.

An issue was created for the problem:
#79

To avoid hardware dependency, in the test we'd better check the
ability of creating VGICv2 in advance, and assert the result of
KVM_CREATE_IRQCHIP correspondingly.

Change-Id: Id17339dde28dbb4abd68bf09fe7f8f0d88c14edb
Signed-off-by: Michael Zhao <[email protected]>

Author: michael2012z

src/ioctls/vm.rs

@@ -146,12 +146,25 @@ impl VmFd {
     ///
     /// ```rust
     /// # extern crate kvm_ioctls;
+    /// # extern crate kvm_bindings;
     /// # use kvm_ioctls::Kvm;
     /// let kvm = Kvm::new().unwrap();
     /// let vm = kvm.create_vm().unwrap();
     ///
     /// #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     /// vm.create_irq_chip().unwrap();
+    /// #[cfg(any(target_arch = "arm", target_arch = "aarch64"))] {
+    ///     use kvm_bindings::{kvm_create_device,
+    ///         kvm_device_type_KVM_DEV_TYPE_ARM_VGIC_V2, KVM_CREATE_DEVICE_TEST};
+    ///     let mut gic_device = kvm_bindings::kvm_create_device {
+    ///         type_: kvm_device_type_KVM_DEV_TYPE_ARM_VGIC_V2,
+    ///         fd: 0,
+    ///         flags: KVM_CREATE_DEVICE_TEST,
+    ///     };
+    ///     if vm.create_device(&mut gic_device).is_ok() {
+    ///         vm.create_irq_chip().unwrap();
+    ///     }
+    /// }
     /// ```
     ///
     #[cfg(any(
@@ -1189,6 +1202,28 @@ mod tests {
         unsafe { assert_eq!(irqchip.chip.pic, other_irqchip.chip.pic) };
     }
 
+    #[test]
+    #[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
+    fn test_irq_chip() {
+        use Cap;
+
+        let kvm = Kvm::new().unwrap();
+        assert!(kvm.check_extension(Cap::Irqchip));
+
+        let vm = kvm.create_vm().unwrap();
+
+        // On ARM/arm64, a GICv2 is created. It's better to check ahead whether GICv2
+        // can be emulated or not.
+        let mut gic_device = kvm_bindings::kvm_create_device {
+            type_: kvm_device_type_KVM_DEV_TYPE_ARM_VGIC_V2,
+            fd: 0,
+            flags: KVM_CREATE_DEVICE_TEST,
+        };
+
+        let vgic_v2_supported = vm.create_device(&mut gic_device).is_ok();
+        assert_eq!(vm.create_irq_chip().is_ok(), vgic_v2_supported);
+    }
+
     #[test]
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     fn test_pit2() {