2018-02-26 19:42 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
> On 26/02/2018 11:17, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>>
>> Linux (among the others) has checks to make sure that certain features
>> aren't enabled on a certain family/model/stepping if the microcode version
>> isn't greater than or equal to a known good version.
>>
>> By exposing the real microcode version, we're preventing buggy guests that
>> don't check that they are running virtualized (i.e., they should trust the
>> hypervisor) from disabling features that are effectively not buggy.
>>
>> Suggested-by: Filippo Sironi <sironi@xxxxxxxxx>
>> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
>> Cc: Liran Alon <liran.alon@xxxxxxxxxx>
>> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>> ---
>> v1 -> v2:
>> * add MSR_IA32_UCODE_REV to emulated_msrs
>>
>> arch/x86/include/asm/kvm_host.h | 1 +
>> arch/x86/kvm/x86.c | 9 +++++++--
>> 2 files changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 938d453..6e13f2f 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -507,6 +507,7 @@ struct kvm_vcpu_arch {
>> u64 smi_count;
>> bool tpr_access_reporting;
>> u64 ia32_xss;
>> + u32 microcode_version;
>>
>> /*
>> * Paging state of the vcpu
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 1a3ed81..4ae9517 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -1047,6 +1047,7 @@ static u32 emulated_msrs[] = {
>> MSR_SMI_COUNT,
>> MSR_PLATFORM_INFO,
>> MSR_MISC_FEATURES_ENABLES,
>> + MSR_IA32_UCODE_REV,
>> };
>>
>> static unsigned num_emulated_msrs;
>> @@ -2247,7 +2248,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>
>> switch (msr) {
>> case MSR_AMD64_NB_CFG:
>> - case MSR_IA32_UCODE_REV:
>> case MSR_IA32_UCODE_WRITE:
>> case MSR_VM_HSAVE_PA:
>> case MSR_AMD64_PATCH_LOADER:
>> @@ -2255,6 +2255,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>> case MSR_AMD64_DC_CFG:
>> break;
>>
>> + case MSR_IA32_UCODE_REV:
>> + if (msr_info->host_initiated)
>> + vcpu->arch.microcode_version = data >> 32;
>
> Please remove the shifts, and add the MSR_IA32_UCODE_REV version to the
> "feature MSRs" recently added by Tom Lendacky.
Do it in v3, thanks for the review. :)
Regards,
Wanpeng Li
>
> Thanks,
>
> Paolo
>
>> + break;
>> case MSR_EFER:
>> return set_efer(vcpu, data);
>> case MSR_K7_HWCR:
>> @@ -2550,7 +2554,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>> msr_info->data = 0;
>> break;
>> case MSR_IA32_UCODE_REV:
>> - msr_info->data = 0x100000000ULL;
>> + msr_info->data = (u64)vcpu->arch.microcode_version << 32;
>> break;
>> case MSR_MTRRcap:
>> case 0x200 ... 0x2ff:
>> @@ -8232,6 +8236,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
>> vcpu->arch.regs_dirty = ~0;
>>
>> vcpu->arch.ia32_xss = 0;
>> + vcpu->arch.microcode_version = 0x1;
>>
>> kvm_x86_ops->vcpu_reset(vcpu, init_event);
>> }
>>
>
