hypervisor, vmm: introduce trait functions for aarch64 PMU

The original code uses kvm_device_attr directly outside of the
hyeprvisor crate. That leaks hypervisor details.

No functional change intended.

Signed-off-by: Wei Liu <liuwe@microsoft.com>

hypervisor/src/cpu.rs

@@ -236,6 +236,12 @@ pub enum HypervisorCpuError {
     #[cfg(feature = "tdx")]
     #[error("Unknown TDX VM call")]
     UnknownTdxVmCall,
+    #[cfg(target_arch = "aarch64")]
+    ///
+    /// Failed to intialize PMU
+    ///
+    #[error("Failed to initialize PMU")]
+    InitializePmu,
 }
 
 #[derive(Debug)]
@@ -400,6 +406,16 @@ pub trait Vcpu: Send + Sync {
     #[cfg(target_arch = "aarch64")]
     fn setup_regs(&self, cpu_id: u8, boot_ip: u64, fdt_start: u64) -> Result<()>;
     ///
+    /// Check if the CPU supports PMU
+    ///
+    #[cfg(target_arch = "aarch64")]
+    fn has_pmu_support(&self) -> bool;
+    ///
+    /// Initialize PMU
+    ///
+    #[cfg(target_arch = "aarch64")]
+    fn init_pmu(&self, irq: u32) -> Result<()>;
+    ///
     /// Retrieve the vCPU state.
     /// This function is necessary to snapshot the VM
     ///

hypervisor/src/kvm/mod.rs

@@ -2063,6 +2063,35 @@ impl cpu::Vcpu for KvmVcpu {
         ]
         .to_vec()
     }
+    #[cfg(target_arch = "aarch64")]
+    fn has_pmu_support(&self) -> bool {
+        let cpu_attr = kvm_bindings::kvm_device_attr {
+            group: kvm_bindings::KVM_ARM_VCPU_PMU_V3_CTRL,
+            attr: u64::from(kvm_bindings::KVM_ARM_VCPU_PMU_V3_INIT),
+            addr: 0x0,
+            flags: 0,
+        };
+        self.has_vcpu_attr(&cpu_attr).is_ok()
+    }
+    #[cfg(target_arch = "aarch64")]
+    fn init_pmu(&self, irq: u32) -> cpu::Result<()> {
+        let cpu_attr = kvm_bindings::kvm_device_attr {
+            group: kvm_bindings::KVM_ARM_VCPU_PMU_V3_CTRL,
+            attr: u64::from(kvm_bindings::KVM_ARM_VCPU_PMU_V3_INIT),
+            addr: 0x0,
+            flags: 0,
+        };
+        let cpu_attr_irq = kvm_bindings::kvm_device_attr {
+            group: kvm_bindings::KVM_ARM_VCPU_PMU_V3_CTRL,
+            attr: u64::from(kvm_bindings::KVM_ARM_VCPU_PMU_V3_IRQ),
+            addr: &irq as *const u32 as u64,
+            flags: 0,
+        };
+        self.set_vcpu_attr(&cpu_attr_irq)
+            .map_err(|_| cpu::HypervisorCpuError::InitializePmu)?;
+        self.set_vcpu_attr(&cpu_attr)
+            .map_err(|_| cpu::HypervisorCpuError::InitializePmu)
+    }
 }
 
 impl KvmVcpu {