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From: Maxim Levitsky <mlevitsk@redhat.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: pbonzini@redhat.com, seanjc@google.com, joro@8bytes.org,
	jon.grimm@amd.com, wei.huang2@amd.com, terry.bowman@amd.com
Subject: Re: [PATCH v4 08/15] KVM: x86: Deactivate APICv on vCPU with APIC disabled
Date: Mon, 09 May 2022 13:30:05 +0300	[thread overview]
Message-ID: <815c41ebfbe8876d2f2e8bbc779a035b66eeeafd.camel@redhat.com> (raw)
In-Reply-To: <b553737e9f7b587cd1ce598e276c1c9117fa2a98.camel@redhat.com>

On Mon, 2022-05-09 at 13:18 +0300, Maxim Levitsky wrote:
> On Sat, 2022-05-07 at 21:39 -0500, Suravee Suthikulpanit wrote:
> > APICv should be deactivated on vCPU that has APIC disabled.
> > Therefore, call kvm_vcpu_update_apicv() when changing
> > APIC mode, and add additional check for APIC disable mode
> > when determine APICV activation,
> > 
> > Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
> > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> > ---
> >  arch/x86/kvm/lapic.c | 4 +++-
> >  arch/x86/kvm/x86.c   | 4 +++-
> >  2 files changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> > index 8b8c4a905976..680824d7aa0d 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -2346,8 +2346,10 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
> >  	if (((old_value ^ value) & X2APIC_ENABLE) && (value & X2APIC_ENABLE))
> >  		kvm_apic_set_x2apic_id(apic, vcpu->vcpu_id);
> >  
> > -	if ((old_value ^ value) & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE))
> > +	if ((old_value ^ value) & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)) {
> > +		kvm_vcpu_update_apicv(vcpu);
> >  		static_call_cond(kvm_x86_set_virtual_apic_mode)(vcpu);
> 
> As futher optimization, we might even get rid of .set_virtual_apic_mode
> and do all of this in kvm_vcpu_update_apicv.
> But no need to this now.
> 
> 
> > +	}
> >  
> >  	apic->base_address = apic->vcpu->arch.apic_base &
> >  			     MSR_IA32_APICBASE_BASE;
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 8ee8c91fa762..77e49892dea1 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -9836,7 +9836,9 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
> >  
> >  	down_read(&vcpu->kvm->arch.apicv_update_lock);
> >  
> > -	activate = kvm_vcpu_apicv_activated(vcpu);
> > +	/* Do not activate APICV when APIC is disabled */
> > +	activate = kvm_vcpu_apicv_activated(vcpu) &&
> > +		   (kvm_get_apic_mode(vcpu) != LAPIC_MODE_DISABLED);
> >  
> >  	if (vcpu->arch.apicv_active == activate)
> >  		goto out;
> 
> Looks good!
> 
> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
> 
> Best regards,
> 	Maxim Levitsky
> 

Sorry for a duplicated reply - I tried to cancel it
to correct a typo, but I was too late I see.

Best regards,
	Maxim Levitsky


  reply	other threads:[~2022-05-09 10:31 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-08  2:39 [PATCH v4 00/15] Introducing AMD x2AVIC and hybrid-AVIC modes Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 01/15] x86/cpufeatures: Introduce x2AVIC CPUID bit Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 02/15] KVM: x86: lapic: Rename [GET/SET]_APIC_DEST_FIELD to [GET/SET]_XAPIC_DEST_FIELD Suravee Suthikulpanit
2022-05-09 14:27   ` Gupta, Pankaj
2022-05-08  2:39 ` [PATCH v4 03/15] KVM: SVM: Detect X2APIC virtualization (x2AVIC) support Suravee Suthikulpanit
2022-05-09 10:15   ` Maxim Levitsky
2022-05-08  2:39 ` [PATCH v4 04/15] KVM: SVM: Update max number of vCPUs supported for x2AVIC mode Suravee Suthikulpanit
2022-05-09 13:35   ` Gupta, Pankaj
2022-05-08  2:39 ` [PATCH v4 05/15] KVM: SVM: Update avic_kick_target_vcpus to support 32-bit APIC ID Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 06/15] KVM: SVM: Do not support updating APIC ID when in x2APIC mode Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 07/15] KVM: SVM: Adding support for configuring x2APIC MSRs interception Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 08/15] KVM: x86: Deactivate APICv on vCPU with APIC disabled Suravee Suthikulpanit
2022-05-09 10:18   ` Maxim Levitsky
2022-05-09 10:30     ` Maxim Levitsky [this message]
2022-05-09 10:19   ` Maxim Levitsky
2022-05-08  2:39 ` [PATCH v4 09/15] KVM: SVM: Refresh AVIC configuration when changing APIC mode Suravee Suthikulpanit
2022-05-09 10:22   ` Maxim Levitsky
2022-05-08  2:39 ` [PATCH v4 10/15] KVM: SVM: Introduce helper functions to (de)activate AVIC and x2AVIC Suravee Suthikulpanit
2022-05-09 13:42   ` Maxim Levitsky
2022-05-11 15:37     ` Suravee Suthikulpanit
2022-05-11 16:26       ` Maxim Levitsky
2022-05-08  2:39 ` [PATCH v4 11/15] KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu Suravee Suthikulpanit
2022-05-09 13:40   ` Gupta, Pankaj
2022-05-08  2:39 ` [PATCH v4 12/15] KVM: SVM: Introduce hybrid-AVIC mode Suravee Suthikulpanit
2022-05-09 11:23   ` Suthikulpanit, Suravee
2022-05-08  2:39 ` [PATCH v4 13/15] KVM: x86: Warning APICv inconsistency only when vcpu APIC mode is valid Suravee Suthikulpanit
2022-05-09 13:38   ` Gupta, Pankaj
2022-05-08  2:39 ` [PATCH v4 14/15] KVM: SVM: Use target APIC ID to complete x2AVIC IRQs when possible Suravee Suthikulpanit
2022-05-08  2:39 ` [PATCH v4 15/15] KVM: SVM: Add AVIC doorbell tracepoint Suravee Suthikulpanit
2022-05-09 10:28 ` [PATCH v4 00/15] Introducing AMD x2AVIC and hybrid-AVIC modes Maxim Levitsky

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