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KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hosts 

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: 1eaafe91a0 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported")
Cc: stable@vger.kernel.org
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Sean Christopherson 2019-03-07 15:43:02 -08:00 committed by Paolo Bonzini
parent ca0488aadd
commit 0cf9135b77
4 changed files with 13 additions and 14 deletions
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1
arch/x86/include/asm/kvm_host.h
View File

@ -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

13
arch/x86/kvm/vmx/vmx.c
View File

@ -1683,12 +1683,6 @@ 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;
@ -1895,11 +1889,6 @@ 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)
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 +4077,6 @@ 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 */

1
arch/x86/kvm/vmx/vmx.h
View File

@ -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;

12
arch/x86/kvm/x86.c
View File

@ -2443,6 +2443,11 @@ 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)
return 1;
vcpu->arch.arch_capabilities = data;
break;
case MSR_EFER:
return set_efer(vcpu, data);
case MSR_K7_HWCR:
@ -2747,6 +2752,12 @@ 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;
@ -8733,6 +8744,7 @@ 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);