* [PATCH] kvm: x86: fix apic_base enable check
@ 2014-01-15 12:39 Andrew Jones
2014-01-15 12:40 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Jones @ 2014-01-15 12:39 UTC (permalink / raw)
To: jan.kiszka, pbonzini, mtosatti; +Cc: kvm
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
--
1.8.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] kvm: x86: fix apic_base enable check
2014-01-15 12:39 [PATCH] kvm: x86: fix apic_base enable check Andrew Jones
@ 2014-01-15 12:40 ` Paolo Bonzini
2014-01-16 7:38 ` Jan Kiszka
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2014-01-15 12:40 UTC (permalink / raw)
To: Andrew Jones; +Cc: jan.kiszka, mtosatti, kvm
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.
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] kvm: x86: fix apic_base enable check
2014-01-15 12:40 ` Paolo Bonzini
@ 2014-01-16 7:38 ` Jan Kiszka
0 siblings, 0 replies; 3+ messages in thread
From: Jan Kiszka @ 2014-01-16 7:38 UTC (permalink / raw)
To: Paolo Bonzini, Andrew Jones; +Cc: mtosatti, kvm
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
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-01-15 12:40 ` Paolo Bonzini
2014-01-16 7:38 ` Jan Kiszka
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