Re: [PATCH] kvm: x86: fix apic_base enable check

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2014-01-15 13:40, Paolo Bonzini wrote:
> Il 15/01/2014 13:39, Andrew Jones ha scritto:
>> Commit e66d2ae7c67bd moved the assignment
>> vcpu->arch.apic_base = value above a condition with
>> (vcpu->arch.apic_base ^ value), causing that check
>> to always fail. Use old_value, vcpu->arch.apic_base's
>> old value, in the condition instead.
>>
>> Signed-off-by: Andrew Jones <drjones@redhat.com>
>> ---
>>  arch/x86/kvm/lapic.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
>> index 1673940cf9c35..775702f649ca6 100644
>> --- a/arch/x86/kvm/lapic.c
>> +++ b/arch/x86/kvm/lapic.c
>> @@ -1355,7 +1355,7 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
>>  	vcpu->arch.apic_base = value;
>>  
>>  	/* update jump label if enable bit changes */
>> -	if ((vcpu->arch.apic_base ^ value) & MSR_IA32_APICBASE_ENABLE) {
>> +	if ((old_value ^ value) & MSR_IA32_APICBASE_ENABLE) {
>>  		if (value & MSR_IA32_APICBASE_ENABLE)
>>  			static_key_slow_dec_deferred(&apic_hw_disabled);
>>  		else
>>
> 
> Thanks Drew, applying this patch to master branch.
> 

Thanks for catching this.

Paolo, please make sure this one makes it to stable as well.

Jan

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