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SubjectRe: [PATCH v2] KVM: x86: Prevent exposing TSC deadline timer feature in the absence of in-kernel APIC
On 2011-12-21 12:45, Avi Kivity wrote:
> On 12/21/2011 01:28 PM, Jan Kiszka wrote:
>>>
>>> timer_mode_mask can just be slaved to the bit (as received by
>>> KVM_SET_CPUID); that's exactly kvm_update_cpuid()'s role.
>>
>> Like
>
> Ugh, the facebook generation invades lkml.

I'm not on facebook. Does anyone sell shirts with that?

>
>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>> index 230f713..89b02bf 100644
>> --- a/arch/x86/kvm/cpuid.c
>> +++ b/arch/x86/kvm/cpuid.c
>> @@ -27,7 +27,6 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
>> {
>> struct kvm_cpuid_entry2 *best;
>> struct kvm_lapic *apic = vcpu->arch.apic;
>> - u32 timer_mode_mask;
>>
>> best = kvm_find_cpuid_entry(vcpu, 1, 0);
>> if (!best)
>> @@ -40,15 +39,12 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
>> best->ecx |= bit(X86_FEATURE_OSXSAVE);
>> }
>>
>> - if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
>> - best->function == 0x1) {
>> - best->ecx |= bit(X86_FEATURE_TSC_DEADLINE_TIMER);
>> - timer_mode_mask = 3 << 17;
>> - } else
>> - timer_mode_mask = 1 << 17;
>> -
>> - if (apic)
>> - apic->lapic_timer.timer_mode_mask = timer_mode_mask;
>> + if (apic) {
>> + if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
>> + apic->lapic_timer.timer_mode_mask = 3 << 17;
>> + else
>> + apic->lapic_timer.timer_mode_mask = 1 << 17;
>> + }
>>
>> kvm_pmu_cpuid_update(vcpu);
>> }
>>
>>
>> + the KVM_CAP thing?
>>
>
> +1

Ah, the adult crowd that trusts the other side.

OK, will see that I can cook up a proper patch later.

Jan

--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux


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