From 0cf9135b773bf32fba9dd8e6699c1b331ee4b749 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Thu, 7 Mar 2019 15:43:02 -0800
Subject: [PATCH] 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: 1eaafe91a0df4 ("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>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/vmx.c | 13 -------------
arch/x86/kvm/vmx/vmx.h | 1 -
arch/x86/kvm/x86.c | 12 ++++++++++++
4 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 679168931c400..264814f26ce0d 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 6aa84e09217bc..ab432a930ae86 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -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 */
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 1554cb45b3931..a1e00d0a2482c 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 491e92383da81..9fc378531ca76 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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);
--
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