Messages in this thread | | | Date | Tue, 1 Mar 2022 16:59:23 +0700 | Subject | Re: [RFC PATCH 04/13] KVM: SVM: Only call vcpu_(un)blocking when AVIC is enabled. | From | Suravee Suthikulpanit <> |
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Hi Maxim,
On 2/24/22 11:54 PM, Maxim Levitsky wrote: > On Sun, 2022-02-20 at 20:19 -0600, Suravee Suthikulpanit wrote: >> The kvm_x86_ops.vcpu_(un)blocking are needed by AVIC only. >> Therefore, set the ops only when AVIC is enabled. >> >> Suggested-by: Sean Christopherson<seanjc@google.com> >> Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpanit@amd.com> >> --- >> arch/x86/kvm/svm/avic.c | 12 ++++++++++-- >> arch/x86/kvm/svm/svm.c | 7 ------- >> arch/x86/kvm/svm/svm.h | 2 -- >> 3 files changed, 10 insertions(+), 11 deletions(-) >> >> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c >> index abde08ca23ab..0040824e4376 100644 >> --- a/arch/x86/kvm/svm/avic.c >> +++ b/arch/x86/kvm/svm/avic.c >> @@ -996,7 +996,7 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) >> WRITE_ONCE(*(svm->avic_physical_id_cache), entry); >> } >> >> -void avic_vcpu_blocking(struct kvm_vcpu *vcpu) >> +static void avic_vcpu_blocking(struct kvm_vcpu *vcpu) >> { >> if (!kvm_vcpu_apicv_active(vcpu)) >> return; >> @@ -1021,7 +1021,7 @@ void avic_vcpu_blocking(struct kvm_vcpu *vcpu) >> preempt_enable(); >> } >> >> -void avic_vcpu_unblocking(struct kvm_vcpu *vcpu) >> +static void avic_vcpu_unblocking(struct kvm_vcpu *vcpu) >> { >> int cpu; >> >> @@ -1057,6 +1057,14 @@ bool avic_hardware_setup(struct kvm_x86_ops *x86_ops) >> pr_info("x2AVIC enabled\n"); >> } >> >> + if (avic_mode) { >> + x86_ops->vcpu_blocking = avic_vcpu_blocking; >> + x86_ops->vcpu_unblocking = avic_vcpu_unblocking; >> + } else { >> + x86_ops->vcpu_blocking = NULL; >> + x86_ops->vcpu_unblocking = NULL; >> + } >> + >> amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier); >> return !!avic_mode; >> } >> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c >> index 3048f4b758d6..3687026f2859 100644 >> --- a/arch/x86/kvm/svm/svm.c >> +++ b/arch/x86/kvm/svm/svm.c >> @@ -4531,8 +4531,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { >> .prepare_guest_switch = svm_prepare_guest_switch, >> .vcpu_load = svm_vcpu_load, >> .vcpu_put = svm_vcpu_put, >> - .vcpu_blocking = avic_vcpu_blocking, >> - .vcpu_unblocking = avic_vcpu_unblocking, >> >> .update_exception_bitmap = svm_update_exception_bitmap, >> .get_msr_feature = svm_get_msr_feature, >> @@ -4819,11 +4817,6 @@ static __init int svm_hardware_setup(void) >> >> enable_apicv = avic = avic && avic_hardware_setup(&svm_x86_ops); >> >> - if (!enable_apicv) { >> - svm_x86_ops.vcpu_blocking = NULL; >> - svm_x86_ops.vcpu_unblocking = NULL; >> - } > Isn't this code already zeros these callbacks when avic is not enabled?
Ah, right. I'll remove the setting to NULL.
> I am not sure why this patch is needed to be honest.
It's not related to x2AVIC. It was recommended by Sean earlier in another patch series:
https://lore.kernel.org/lkml/Yc3r1U6WFVDtJCZn@google.com/
Since this series introduces the helper function avic_hardware_setup(), and re-factor the AVIC setup code into the function. So, I am including his recommendation in this series instead..
Regards, Suravee
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