make test_irq_chip x86 specific

The test was previously marked as x86_64 and aarch64 compatible.

On aarch64 we were testing only the error case. On older kernel
versions, creating an irqchip before creating the vCPU would return
an error. This restrictions is not in place anymore on Linux Kernel
4.15.

Since we cannot test this error path anymore on aarch64, the test is
now labeled as x86 specific.

Also updated the test to set the irq_base of the PIC and check that
this value is appropriately updated.

Signed-off-by: Andreea Florescu <[email protected]>

Author: andreeaflorescu

src/ioctls/vm.rs

@@ -1109,7 +1109,7 @@ impl AsRawFd for VmFd {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use {Cap, Kvm};
+    use Kvm;
 
     use libc::EFD_NONBLOCK;
 
@@ -1136,34 +1136,31 @@ mod tests {
     }
 
     #[test]
-    #[cfg(any(
-        target_arch = "x86",
-        target_arch = "x86_64",
-        target_arch = "arm",
-        target_arch = "aarch64"
-    ))]
+    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     fn test_irq_chip() {
+        use Cap;
+
         let kvm = Kvm::new().unwrap();
         assert!(kvm.check_extension(Cap::Irqchip));
         let vm = kvm.create_vm().unwrap();
-        if cfg!(any(target_arch = "x86", target_arch = "x86_64")) {
-            assert!(vm.create_irq_chip().is_ok());
-        } else if cfg!(any(target_arch = "arm", target_arch = "aarch64")) {
-            // On arm, we expect this to fail as the irq chip needs to be created after the vcpus.
-            assert!(vm.create_irq_chip().is_err());
-        }
+        assert!(vm.create_irq_chip().is_ok());
 
-        #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-        {
-            let mut irqchip = kvm_irqchip::default();
-            irqchip.chip_id = KVM_IRQCHIP_PIC_MASTER;
-            vm.get_irqchip(&mut irqchip).unwrap();
-            vm.set_irqchip(&irqchip).unwrap();
-            let mut other_irqchip = kvm_irqchip::default();
-            other_irqchip.chip_id = KVM_IRQCHIP_PIC_MASTER;
-            vm.get_irqchip(&mut other_irqchip).unwrap();
-            unsafe { assert_eq!(irqchip.chip.dummy[..], other_irqchip.chip.dummy[..]) };
+        let mut irqchip = kvm_irqchip::default();
+        irqchip.chip_id = KVM_IRQCHIP_PIC_MASTER;
+        // Set the irq_base to a non-default value to check that set & get work.
+        unsafe {
+            irqchip.chip.pic.irq_base = 10;
         }
+        assert!(vm.set_irqchip(&irqchip).is_ok());
+
+        // We initialize a dummy irq chip (`other_irqchip`) in which the
+        // function `get_irqchip` returns its result.
+        let mut other_irqchip = kvm_irqchip::default();
+        other_irqchip.chip_id = KVM_IRQCHIP_PIC_MASTER;
+        assert!(vm.get_irqchip(&mut other_irqchip).is_ok());
+
+        // Safe because we know that the irqchip type is PIC.
+        unsafe { assert_eq!(irqchip.chip.pic, other_irqchip.chip.pic) };
     }
 
     #[test]