Fixes KVM_CAP_ONE_REG is not supported on x86-64 (#1000)

obhq · Sep 28, 2024 · 165fd9d · 165fd9d
1 parent 80dde69
commit 165fd9d
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Showing 3 changed files with 16 additions and 8 deletions.
diff --git a/src/core/src/vmm/hv/linux/ffi.rs b/src/core/src/vmm/hv/linux/ffi.rs
@@ -5,6 +5,7 @@ pub const KVM_CREATE_VM: c_ulong = _IO(KVMIO, 0x01);
 pub const KVM_CHECK_EXTENSION: c_ulong = _IO(KVMIO, 0x03);
 pub const KVM_GET_VCPU_MMAP_SIZE: c_ulong = _IO(KVMIO, 0x04);
 pub const KVM_CREATE_VCPU: c_ulong = _IO(KVMIO, 0x41);
+#[cfg(target_arch = "aarch64")]
 pub const KVM_GET_ONE_REG: c_ulong = _IOW::<KvmOneReg<()>>(KVMIO, 0xab);
 #[cfg(target_arch = "aarch64")]
 pub const KVM_ARM_VCPU_INIT: c_ulong = _IOW::<KvmVcpuInit>(KVMIO, 0xae);
@@ -14,6 +15,7 @@ pub const KVM_ARM_PREFERRED_TARGET: c_ulong = _IOR::<KvmVcpuInit>(KVMIO, 0xaf);
 pub const KVM_API_VERSION: c_int = 12;
 
 pub const KVM_CAP_MAX_VCPUS: c_int = 66;
+#[cfg(target_arch = "aarch64")]
 pub const KVM_CAP_ONE_REG: c_int = 70;
 #[cfg(target_arch = "aarch64")]
 pub const KVM_CAP_ARM_VM_IPA_SIZE: c_int = 165;
@@ -74,6 +76,7 @@ const fn _IOC(dir: c_ulong, ty: c_ulong, nr: c_ulong, size: c_ulong) -> c_ulong
         | (size << _IOC_SIZESHIFT)
 }
 
+#[cfg(target_arch = "aarch64")]
 #[repr(C)]
 pub struct KvmOneReg<'a, T> {
     pub id: u64,

diff --git a/src/core/src/vmm/hv/linux/mod.rs b/src/core/src/vmm/hv/linux/mod.rs
@@ -1,9 +1,8 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 use self::cpu::KvmCpu;
 use self::ffi::{
-    kvm_set_user_memory_region, KvmOneReg, KVM_API_VERSION, KVM_CAP_MAX_VCPUS, KVM_CAP_ONE_REG,
-    KVM_CHECK_EXTENSION, KVM_CREATE_VCPU, KVM_CREATE_VM, KVM_GET_API_VERSION, KVM_GET_ONE_REG,
-    KVM_GET_VCPU_MMAP_SIZE,
+    kvm_set_user_memory_region, KVM_API_VERSION, KVM_CAP_MAX_VCPUS, KVM_CHECK_EXTENSION,
+    KVM_CREATE_VCPU, KVM_CREATE_VM, KVM_GET_API_VERSION, KVM_GET_VCPU_MMAP_SIZE,
 };
 use super::{CpuFeats, Hypervisor};
 use crate::vmm::ram::Ram;
@@ -48,9 +47,15 @@ pub fn new(cpu: usize, ram: Ram) -> Result<impl Hypervisor, VmmError> {
         return Err(VmmError::MaxCpuTooLow);
     }
 
-    // Check KVM_CAP_ONE_REG. KVM_SET_ONE_REG and KVM_GET_ONE_REG are the only API that support all
-    // architectures.
-    if unsafe { ioctl(kvm.as_raw_fd(), KVM_CHECK_EXTENSION, KVM_CAP_ONE_REG) <= 0 } {
+    // On AArch64 we need KVM_SET_ONE_REG and KVM_GET_ONE_REG.
+    #[cfg(target_arch = "aarch64")]
+    if unsafe {
+        ioctl(
+            kvm.as_raw_fd(),
+            KVM_CHECK_EXTENSION,
+            self::ffi::KVM_CAP_ONE_REG,
+        ) <= 0
+    } {
         return Err(VmmError::NoKvmOneReg);
     }
 
@@ -189,7 +194,7 @@ impl Hypervisor for Kvm {
 
     #[cfg(target_arch = "aarch64")]
     fn cpu_features(&mut self) -> Result<CpuFeats, Self::CpuErr> {
-        use self::ffi::ARM64_SYS_REG;
+        use self::ffi::{KvmOneReg, ARM64_SYS_REG, KVM_GET_ONE_REG};
         use crate::vmm::hv::{Mmfr0, Mmfr1, Mmfr2};
         use std::arch::asm;
 

diff --git a/src/core/src/vmm/mod.rs b/src/core/src/vmm/mod.rs
@@ -698,7 +698,7 @@ enum VmmError {
     #[error("unexpected KVM version")]
     KvmVersionMismatched,
 
-    #[cfg(target_os = "linux")]
+    #[cfg(all(target_os = "linux", target_arch = "aarch64"))]
     #[error("your OS does not support KVM_CAP_ONE_REG")]
     NoKvmOneReg,