linux-kernel - Re: [PATCH 05/19] KVM: SVM: Compute dest based on sender's x2APIC status for AVIC kick

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Message-ID: <6c0e65417ad0f38ed4207fa38331556cea2aac9f.camel@redhat.com>
Date:   Wed, 31 Aug 2022 12:38:07 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Li RongQing <lirongqing@...du.com>
Subject: Re: [PATCH 05/19] KVM: SVM: Compute dest based on sender's x2APIC
 status for AVIC kick

On Wed, 2022-08-31 at 00:34 +0000, Sean Christopherson wrote:
> Compute the destination from ICRH using the sender's x2APIC status, not
> each (potential) target's x2APIC status.
> 
> Fixes: c514d3a348ac ("KVM: SVM: Update avic_kick_target_vcpus to support 32-bit APIC ID")
> Cc: Li RongQing <lirongqing@...du.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/kvm/svm/avic.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index b59f8ee2671f..3ace0f2f52f0 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -441,6 +441,7 @@ static int avic_kick_target_vcpus_fast(struct kvm *kvm, struct kvm_lapic *source
>  static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
>  				   u32 icrl, u32 icrh, u32 index)
>  {
> +	u32 dest = apic_x2apic_mode(source) ? icrh : GET_XAPIC_DEST_FIELD(icrh);
>  	unsigned long i;
>  	struct kvm_vcpu *vcpu;
>  
> @@ -456,13 +457,6 @@ static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
>  	 * since entered the guest will have processed pending IRQs at VMRUN.
>  	 */
>  	kvm_for_each_vcpu(i, vcpu, kvm) {
> -		u32 dest;
> -
> -		if (apic_x2apic_mode(vcpu->arch.apic))
> -			dest = icrh;
> -		else
> -			dest = GET_XAPIC_DEST_FIELD(icrh);
> -
>  		if (kvm_apic_match_dest(vcpu, source, icrl & APIC_SHORT_MASK,
>  					dest, icrl & APIC_DEST_MASK)) {
>  			vcpu->arch.apic->irr_pending = true;

I didn't notice this in a review, makes sense.

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
	Maxim Levitsky