On 20/06/19 11:46, Xiaoyao Li wrote:
> You cannot put the atomic switch here. What if umwait_control_cached is changed
> at runtime? Host kernel patch exposed a sysfs interface to let it happen.
Thanks for the review, Xiaoyao. I agree with both of your remarks.
Paolo
>> + break;
>> case MSR_IA32_SPEC_CTRL:
>> if (!msr_info->host_initiated &&
>> !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
>> @@ -4126,6 +4148,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool
>> init_event)
>> vmx->rmode.vm86_active = 0;
>> vmx->spec_ctrl = 0;
>>
>> + vmx->msr_ia32_umwait_control = 0;
>> +
>> vcpu->arch.microcode_version = 0x100000000ULL;
>> vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val();
>> kvm_set_cr8(vcpu, 0);
>> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
>> index 61128b48c503..8485bec7c38a 100644
>> --- a/arch/x86/kvm/vmx/vmx.h
>> +++ b/arch/x86/kvm/vmx/vmx.h
>> @@ -14,6 +14,8 @@
>> extern const u32 vmx_msr_index[];
>> extern u64 host_efer;
>>
>> +extern u32 umwait_control_cached;
>> +
>> #define MSR_TYPE_R 1
>> #define MSR_TYPE_W 2
>> #define MSR_TYPE_RW 3
>> @@ -194,6 +196,7 @@ struct vcpu_vmx {
>> #endif
>>
>> u64 spec_ctrl;
>> + u64 msr_ia32_umwait_control;
>>
>> u32 vm_entry_controls_shadow;
>> u32 vm_exit_controls_shadow;
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 83aefd759846..4480de459bf4 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -1138,6 +1138,7 @@ static u32 msrs_to_save[] = {
>> MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
>> MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
>> MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
>> + MSR_IA32_UMWAIT_CONTROL,
>> };
>>
>> static unsigned num_msrs_to_save;
>
