diff mbox

[PART1,RFC,v3,11/12] svm: Do not intercept CR8 when enable AVIC

Message ID 1458281388-14452-12-git-send-email-Suravee.Suthikulpanit@amd.com (mailing list archive)
State New, archived
Headers show

Commit Message

Suthikulpanit, Suravee March 18, 2016, 6:09 a.m. UTC
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(-)

Comments

Radim Krčmář March 18, 2016, 9:10 p.m. UTC | #1
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.

>  	} else {
>  		svm_x86_ops.deliver_posted_interrupt = NULL;
>  	}
> @@ -1097,7 +1099,8 @@ static void init_vmcb(struct vcpu_svm *svm)
>  	set_cr_intercept(svm, INTERCEPT_CR0_WRITE);
>  	set_cr_intercept(svm, INTERCEPT_CR3_WRITE);
>  	set_cr_intercept(svm, INTERCEPT_CR4_WRITE);
> -	set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
> +	if (!svm_vcpu_avic_enabled(svm))
> +		set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
>  
>  	set_dr_intercepts(svm);
>  
> @@ -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().

>  
> -	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.

>  }
>  
>  static void svm_complete_interrupts(struct vcpu_svm *svm)
> -- 
> 1.9.1
> 
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Suthikulpanit, Suravee March 30, 2016, 12:15 p.m. UTC | #2
Hi Radim,

On 3/19/16 04:10, Radim Kr?má? 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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diff mbox

Patch

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;
 	} else {
 		svm_x86_ops.deliver_posted_interrupt = NULL;
 	}
@@ -1097,7 +1099,8 @@  static void init_vmcb(struct vcpu_svm *svm)
 	set_cr_intercept(svm, INTERCEPT_CR0_WRITE);
 	set_cr_intercept(svm, INTERCEPT_CR3_WRITE);
 	set_cr_intercept(svm, INTERCEPT_CR4_WRITE);
-	set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
+	if (!svm_vcpu_avic_enabled(svm))
+		set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
 
 	set_dr_intercepts(svm);
 
@@ -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;
 
-	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);
 }
 
 static void svm_complete_interrupts(struct vcpu_svm *svm)