On Thu, Mar 07, 2019 at 03:43:02PM -0800, Sean Christopherson wrote:
> 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")
And this one should have:
Cc: stable@xxxxxxxxxxxxxxx
> 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
>
