hypervisor: Implement hypervisor agnostic Register interface

This will help in fixing the build issue for MSHV on ARM64.

Signed-off-by: Jinank Jain <jinankjain@microsoft.com>

hypervisor/src/kvm/aarch64/gic/redist_regs.rs

@@ -7,11 +7,11 @@ use kvm_ioctls::DeviceFd;
 use crate::arch::aarch64::gic::{Error, Result};
 use crate::device::HypervisorDeviceError;
 use crate::kvm::kvm_bindings::{
-    kvm_device_attr, KVM_DEV_ARM_VGIC_GRP_REDIST_REGS, KVM_REG_ARM64, KVM_REG_ARM64_SYSREG,
-    KVM_REG_ARM64_SYSREG_OP0_MASK, KVM_REG_ARM64_SYSREG_OP0_SHIFT, KVM_REG_ARM64_SYSREG_OP2_MASK,
-    KVM_REG_ARM64_SYSREG_OP2_SHIFT, KVM_REG_SIZE_U64,
+    kvm_device_attr, kvm_one_reg, KVM_DEV_ARM_VGIC_GRP_REDIST_REGS, KVM_REG_ARM64,
+    KVM_REG_ARM64_SYSREG, KVM_REG_ARM64_SYSREG_OP0_MASK, KVM_REG_ARM64_SYSREG_OP0_SHIFT,
+    KVM_REG_ARM64_SYSREG_OP2_MASK, KVM_REG_ARM64_SYSREG_OP2_SHIFT, KVM_REG_SIZE_U64,
 };
-use crate::kvm::{Register, VcpuKvmState};
+use crate::kvm::VcpuKvmState;
 use crate::CpuState;
 
 // Relevant redistributor registers that we want to save/restore.
@@ -213,7 +213,7 @@ pub fn construct_gicr_typers(vcpu_states: &[CpuState]) -> Vec<u64> {
         let state: VcpuKvmState = state.clone().into();
         let last = (index == vcpu_states.len() - 1) as u64;
         // state.sys_regs is a big collection of system registers, including MIPDR_EL1
-        let mpidr: Vec<Register> = state
+        let mpidr: Vec<kvm_one_reg> = state
             .sys_regs
             .into_iter()
             .filter(|reg| reg.id == KVM_ARM64_SYSREG_MPIDR_EL1)

hypervisor/src/kvm/aarch64/mod.rs

@@ -14,7 +14,7 @@ use kvm_bindings::{
     kvm_mp_state, kvm_one_reg, kvm_regs, KVM_REG_ARM_COPROC_MASK, KVM_REG_ARM_CORE,
     KVM_REG_SIZE_MASK, KVM_REG_SIZE_U32, KVM_REG_SIZE_U64,
 };
-pub use kvm_bindings::{kvm_one_reg as Register, kvm_vcpu_init as VcpuInit, RegList};
+pub use kvm_bindings::{kvm_vcpu_init as VcpuInit, RegList};
 pub use kvm_ioctls::{Cap, Kvm};
 use serde::{Deserialize, Serialize};
 

hypervisor/src/kvm/mod.rs

@@ -54,14 +54,14 @@ use crate::{offset_of, riscv64_reg_id};
 #[cfg(target_arch = "x86_64")]
 pub mod x86_64;
 #[cfg(target_arch = "aarch64")]
-use aarch64::{RegList, Register};
+use aarch64::RegList;
 #[cfg(target_arch = "x86_64")]
 use kvm_bindings::{
     kvm_enable_cap, kvm_msr_entry, MsrList, KVM_CAP_HYPERV_SYNIC, KVM_CAP_SPLIT_IRQCHIP,
     KVM_GUESTDBG_USE_HW_BP,
 };
 #[cfg(target_arch = "riscv64")]
-use riscv64::{RegList, Register};
+use riscv64::RegList;
 #[cfg(target_arch = "x86_64")]
 use x86_64::check_required_kvm_extensions;
 #[cfg(target_arch = "x86_64")]
@@ -353,6 +353,23 @@ impl From<ClockData> for kvm_clock_data {
     }
 }
 
+impl From<kvm_bindings::kvm_one_reg> for crate::Register {
+    fn from(s: kvm_bindings::kvm_one_reg) -> Self {
+        crate::Register::Kvm(s)
+    }
+}
+
+impl From<crate::Register> for kvm_bindings::kvm_one_reg {
+    fn from(e: crate::Register) -> Self {
+        match e {
+            crate::Register::Kvm(e) => e,
+            /* Needed in case other hypervisors are enabled */
+            #[allow(unreachable_patterns)]
+            _ => panic!("Register is not valid"),
+        }
+    }
+}
+
 #[cfg(not(target_arch = "riscv64"))]
 impl From<kvm_bindings::kvm_regs> for crate::StandardRegisters {
     fn from(s: kvm_bindings::kvm_regs) -> Self {
@@ -2917,7 +2934,7 @@ impl cpu::Vcpu for KvmVcpu {
         // Get systerm register
         // Call KVM_GET_REG_LIST to get all registers available to the guest.
         // For ArmV8 there are around 500 registers.
-        let mut sys_regs: Vec<Register> = Vec::new();
+        let mut sys_regs: Vec<kvm_bindings::kvm_one_reg> = Vec::new();
         let mut reg_list = RegList::new(500).unwrap();
         self.fd
             .lock()
@@ -2970,7 +2987,7 @@ impl cpu::Vcpu for KvmVcpu {
         // Get non-core register
         // Call KVM_GET_REG_LIST to get all registers available to the guest.
         // For RISC-V 64-bit there are around 200 registers.
-        let mut sys_regs: Vec<Register> = Vec::new();
+        let mut sys_regs: Vec<kvm_bindings::kvm_one_reg> = Vec::new();
         let mut reg_list = RegList::new(200).unwrap();
         self.fd
             .lock()

hypervisor/src/kvm/riscv64/mod.rs

@@ -4,11 +4,11 @@
 
 pub mod aia;
 
+pub use kvm_bindings::RegList;
 use kvm_bindings::{
     kvm_mp_state, kvm_one_reg, kvm_riscv_core, KVM_REG_RISCV_CORE, KVM_REG_RISCV_TYPE_MASK,
     KVM_REG_SIZE_MASK, KVM_REG_SIZE_U64,
 };
-pub use kvm_bindings::{kvm_one_reg as Register, RegList};
 pub use kvm_ioctls::{Cap, Kvm};
 use serde::{Deserialize, Serialize};
 

hypervisor/src/lib.rs

@@ -196,6 +196,11 @@ pub enum IrqRoutingEntry {
     Mshv(mshv_bindings::mshv_user_irq_entry),
 }
 
+pub enum Register {
+    #[cfg(feature = "kvm")]
+    Kvm(kvm_bindings::kvm_one_reg),
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, serde::Serialize, serde::Deserialize)]
 pub enum StandardRegisters {
     #[cfg(all(feature = "kvm", not(target_arch = "riscv64")))]