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* [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request()
@ 2020-02-07 15:22 linmiaohe
  2020-02-07 15:40 ` Sean Christopherson
  2020-02-12 11:55 ` Paolo Bonzini
  0 siblings, 2 replies; 3+ messages in thread
From: linmiaohe @ 2020-02-07 15:22 UTC (permalink / raw)
  To: pbonzini, rkrcmar, sean.j.christopherson, vkuznets, wanpengli,
	jmattson, joro, tglx, mingo, bp, hpa
  Cc: linmiaohe, kvm, linux-kernel, x86

From: Miaohe Lin <linmiaohe@huawei.com>

kvm_make_request() provides smp_wmb() so pending_events changes are
guaranteed to be visible.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
v1->v2:
Collected Vitaly's R-b
Use Vitaly's alternative wording
Drop unnecessary comment as suggested by Sean Christopherson
---
 arch/x86/kvm/lapic.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index eafc631d305c..afcd30d44cbb 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1080,9 +1080,6 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 			result = 1;
 			/* assumes that there are only KVM_APIC_INIT/SIPI */
 			apic->pending_events = (1UL << KVM_APIC_INIT);
-			/* make sure pending_events is visible before sending
-			 * the request */
-			smp_wmb();
 			kvm_make_request(KVM_REQ_EVENT, vcpu);
 			kvm_vcpu_kick(vcpu);
 		}
-- 
2.19.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request()
  2020-02-07 15:22 [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request() linmiaohe
@ 2020-02-07 15:40 ` Sean Christopherson
  2020-02-12 11:55 ` Paolo Bonzini
  1 sibling, 0 replies; 3+ messages in thread
From: Sean Christopherson @ 2020-02-07 15:40 UTC (permalink / raw)
  To: linmiaohe
  Cc: pbonzini, rkrcmar, vkuznets, wanpengli, jmattson, joro, tglx,
	mingo, bp, hpa, kvm, linux-kernel, x86

On Fri, Feb 07, 2020 at 11:22:07PM +0800, linmiaohe wrote:
> From: Miaohe Lin <linmiaohe@huawei.com>
> 
> kvm_make_request() provides smp_wmb() so pending_events changes are
> guaranteed to be visible.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---

Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request()
  2020-02-07 15:22 [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request() linmiaohe
  2020-02-07 15:40 ` Sean Christopherson
@ 2020-02-12 11:55 ` Paolo Bonzini
  1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2020-02-12 11:55 UTC (permalink / raw)
  To: linmiaohe, rkrcmar, sean.j.christopherson, vkuznets, wanpengli,
	jmattson, joro, tglx, mingo, bp, hpa
  Cc: kvm, linux-kernel, x86

On 07/02/20 16:22, linmiaohe wrote:
> From: Miaohe Lin <linmiaohe@huawei.com>
> 
> kvm_make_request() provides smp_wmb() so pending_events changes are
> guaranteed to be visible.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> v1->v2:
> Collected Vitaly's R-b
> Use Vitaly's alternative wording
> Drop unnecessary comment as suggested by Sean Christopherson
> ---
>  arch/x86/kvm/lapic.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index eafc631d305c..afcd30d44cbb 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1080,9 +1080,6 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
>  			result = 1;
>  			/* assumes that there are only KVM_APIC_INIT/SIPI */
>  			apic->pending_events = (1UL << KVM_APIC_INIT);
> -			/* make sure pending_events is visible before sending
> -			 * the request */
> -			smp_wmb();
>  			kvm_make_request(KVM_REQ_EVENT, vcpu);
>  			kvm_vcpu_kick(vcpu);
>  		}
> 


Queued, thanks.

Paolo


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2020-02-12 11:55 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-02-07 15:22 [PATCH v2] KVM: apic: reuse smp_wmb() in kvm_make_request() linmiaohe
2020-02-07 15:40 ` Sean Christopherson
2020-02-12 11:55 ` Paolo Bonzini

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