The CPUID flag ARCH_CAPABILITIES is unconditioinally exposed to host
userspace for all x86 hosts, i.e. KVM advertises ARCH_CAPABILITIES
regardless of hardware support under the pretense that KVM fully
emulates MSR_IA32_ARCH_CAPABILITIES. Unfortunately, only VMX hosts
handle accesses to MSR_IA32_ARCH_CAPABILITIES (despite KVM_GET_MSRS
also reporting MSR_IA32_ARCH_CAPABILITIES for all hosts).
Move the MSR_IA32_ARCH_CAPABILITIES handling to common x86 code so
that it's emulated on AMD hosts.
Fixes: 1eaafe91a0df4 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported")
Reported-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/vmx.c | 14 --------------
arch/x86/kvm/vmx/vmx.h | 1 -
arch/x86/kvm/x86.c | 13 +++++++++++++
4 files changed, 14 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7712b4ed8aa1..3d10ff38cbdb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -568,6 +568,7 @@ struct kvm_vcpu_arch {
bool tpr_access_reporting;
u64 ia32_xss;
u64 microcode_version;
+ u64 arch_capabilities;
/*
* Paging state of the vcpu
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2a86d296c90f..02cf8a551bd1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1682,12 +1682,6 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = to_vmx(vcpu)->spec_ctrl;
break;
- case MSR_IA32_ARCH_CAPABILITIES:
- if (!msr_info->host_initiated &&
- !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES))
- return 1;
- msr_info->data = to_vmx(vcpu)->arch_capabilities;
- break;
case MSR_IA32_SYSENTER_CS:
msr_info->data = vmcs_read32(GUEST_SYSENTER_CS);
break;
@@ -1894,12 +1888,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
vmx_disable_intercept_for_msr(vmx->vmcs01.msr_bitmap, MSR_IA32_PRED_CMD,
MSR_TYPE_W);
break;
- case MSR_IA32_ARCH_CAPABILITIES:
- if (!msr_info->host_initiated ||
- (data & ~kvm_get_arch_capabilities()))
- return 1;
- vmx->arch_capabilities = data;
- break;
case MSR_IA32_CR_PAT:
if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
@@ -4088,8 +4076,6 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
++vmx->nmsrs;
}
- vmx->arch_capabilities = kvm_get_arch_capabilities();
-
vm_exit_controls_init(vmx, vmx_vmexit_ctrl());
/* 22.2.1, 20.8.1 */
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 1554cb45b393..a1e00d0a2482 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -190,7 +190,6 @@ struct vcpu_vmx {
u64 msr_guest_kernel_gs_base;
#endif
- u64 arch_capabilities;
u64 spec_ctrl;
u32 vm_entry_controls_shadow;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d90f011f3e32..7bfeebc482c4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2443,6 +2443,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (msr_info->host_initiated)
vcpu->arch.microcode_version = data;
break;
+ case MSR_IA32_ARCH_CAPABILITIES:
+ if (!msr_info->host_initiated ||
+ (data & ~kvm_get_arch_capabilities()))
+ return 1;
+ vcpu->arch.arch_capabilities = data;
+ break;
case MSR_EFER:
return set_efer(vcpu, data);
case MSR_K7_HWCR:
@@ -2747,6 +2753,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_UCODE_REV:
msr_info->data = vcpu->arch.microcode_version;
break;
+ case MSR_IA32_ARCH_CAPABILITIES:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES))
+ return 1;
+ msr_info->data = vcpu->arch.arch_capabilities;
+ break;
case MSR_IA32_TSC:
msr_info->data = kvm_scale_tsc(vcpu, rdtsc()) + vcpu->arch.tsc_offset;
break;
@@ -8743,6 +8755,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
+ vcpu->arch.arch_capabilities = kvm_get_arch_capabilities();
vcpu->arch.msr_platform_info = MSR_PLATFORM_INFO_CPUID_FAULT;
kvm_vcpu_mtrr_init(vcpu);
vcpu_load(vcpu);
--
2.21.0
