Messages in this thread | | | Subject | Re: [PART1 RFC v3 11/12] svm: Do not intercept CR8 when enable AVIC | From | Suravee Suthikulpanit <> | Date | Wed, 30 Mar 2016 19:15:21 +0700 |
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Hi Radim,
On 3/19/16 04:10, Radim Krčmář wrote: > 2016-03-18 01:09-0500, Suravee Suthikulpanit: >> When enable AVIC: >> * Do not intercept CR8 since this should be handled by AVIC HW. >> * Also update TPR in APIC backing page when syncing CR8 before VMRUN >> >> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> >> --- >> arch/x86/kvm/svm.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >> index ba84d57..d5418c3 100644 >> --- a/arch/x86/kvm/svm.c >> +++ b/arch/x86/kvm/svm.c >> @@ -984,6 +984,8 @@ static __init int svm_hardware_setup(void) >> >> if (avic) { >> printk(KERN_INFO "kvm: AVIC enabled\n"); >> + >> + svm_x86_ops.update_cr8_intercept = NULL; > > This doesn't look right.
Actually, I don't think this change isn't necessary since we don't even call kvm_x86_ops->update_cr8_intercept() if vcpu->arch.apicv_active (See arch/x86/kvm/x86.c: update_cr8_intercept()).
> [....] >> @@ -4080,7 +4083,8 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) >> { >> struct vcpu_svm *svm = to_svm(vcpu); >> >> - if (is_guest_mode(vcpu) && (vcpu->arch.hflags & HF_VINTR_MASK)) >> + if ((is_guest_mode(vcpu) && (vcpu->arch.hflags & HF_VINTR_MASK)) || >> + svm_vcpu_avic_enabled(svm)) >> return; >> >> clr_cr_intercept(svm, INTERCEPT_CR8_WRITE); >> @@ -4271,9 +4275,12 @@ static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu) >> if (is_guest_mode(vcpu) && (vcpu->arch.hflags & HF_VINTR_MASK)) >> return; > > I think we can exit early with svm_vcpu_avic_enabled().
Right.
> >> >> - cr8 = kvm_get_cr8(vcpu); >> + cr8 = kvm_get_cr8(vcpu) & V_TPR_MASK; >> svm->vmcb->control.int_ctl &= ~V_TPR_MASK; >> - svm->vmcb->control.int_ctl |= cr8 & V_TPR_MASK; >> + svm->vmcb->control.int_ctl |= cr8; >> + >> + if (svm_vcpu_avic_enabled(svm)) >> + kvm_lapic_set_reg(svm->vcpu.arch.apic, APIC_TASKPRI, (u32)cr8 << 4); > > kvm_get_cr8() == kvm_lapic_get_reg(APIC_TASKPRI) >> 4.
Good point. I'll clean up and simplify this function.
Thanks, Suravee
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