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Commit 219b65dc authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
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KVM: SVM: Improve nested interrupt injection 



While trying to get Hyper-V running, I realized that the interrupt injection
mechanisms that are in place right now are not 100% correct.

This patch makes nested SVM's interrupt injection behave more like on a
real machine.

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent ff092385

arch/x86/kvm/svm.c

+24 −15
Original line number Diff line number Diff line
@@ -1612,7 +1612,8 @@ static int nested_svm_vmexit_real(struct vcpu_svm *svm, void *arg1, 
	/* Kill any pending exceptions */

	if (svm->vcpu.arch.exception.pending == true)

		nsvm_printk("WARNING: Pending Exception\n");

	svm->vcpu.arch.exception.pending = false;

	kvm_clear_exception_queue(&svm->vcpu);

	kvm_clear_interrupt_queue(&svm->vcpu);



	/* Restore selected save entries */

	svm->vmcb->save.es = hsave->save.es;
@@ -1680,7 +1681,8 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1, 
	svm->nested_vmcb = svm->vmcb->save.rax;



	/* Clear internal status */

	svm->vcpu.arch.exception.pending = false;

	kvm_clear_exception_queue(&svm->vcpu);

	kvm_clear_interrupt_queue(&svm->vcpu);



	/* Save the old vmcb, so we don't need to pick what we save, but

	   can restore everything when a VMEXIT occurs */
@@ -2362,21 +2364,14 @@ static inline void svm_inject_irq(struct vcpu_svm *svm, int irq) 
		((/*control->int_vector >> 4*/ 0xf) << V_INTR_PRIO_SHIFT);

}



static void svm_queue_irq(struct kvm_vcpu *vcpu, unsigned nr)

{

	struct vcpu_svm *svm = to_svm(vcpu);



	svm->vmcb->control.event_inj = nr |

		SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;

}



static void svm_set_irq(struct kvm_vcpu *vcpu)

{

	struct vcpu_svm *svm = to_svm(vcpu);



	nested_svm_intr(svm);

	BUG_ON(!(svm->vcpu.arch.hflags & HF_GIF_MASK));



	svm_queue_irq(vcpu, vcpu->arch.interrupt.nr);

	svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |

		SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;

}



static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
@@ -2404,13 +2399,25 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu) 
	struct vmcb *vmcb = svm->vmcb;

	return (vmcb->save.rflags & X86_EFLAGS_IF) &&

		!(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&

		(svm->vcpu.arch.hflags & HF_GIF_MASK);

		(svm->vcpu.arch.hflags & HF_GIF_MASK) &&

		!is_nested(svm);

}



static void enable_irq_window(struct kvm_vcpu *vcpu)

{

	svm_set_vintr(to_svm(vcpu));

	svm_inject_irq(to_svm(vcpu), 0x0);

	struct vcpu_svm *svm = to_svm(vcpu);

	nsvm_printk("Trying to open IRQ window\n");



	nested_svm_intr(svm);



	/* In case GIF=0 we can't rely on the CPU to tell us when

	 * GIF becomes 1, because that's a separate STGI/VMRUN intercept.

	 * The next time we get that intercept, this function will be

	 * called again though and we'll get the vintr intercept. */

	if (svm->vcpu.arch.hflags & HF_GIF_MASK) {

		svm_set_vintr(svm);

		svm_inject_irq(svm, 0x0);

	}

}



static void enable_nmi_window(struct kvm_vcpu *vcpu)
@@ -2489,6 +2496,8 @@ static void svm_complete_interrupts(struct vcpu_svm *svm) 
	case SVM_EXITINTINFO_TYPE_EXEPT:

		/* In case of software exception do not reinject an exception

		   vector, but re-execute and instruction instead */

		if (is_nested(svm))

			break;

		if (kvm_exception_is_soft(vector))

			break;

		if (exitintinfo & SVM_EXITINTINFO_VALID_ERR) {