Commit 424c989b authored by Andrew Jones's avatar Andrew Jones Committed by Christoffer Dall
Browse files

KVM: arm/arm64: optimize VCPU RUN 



We can make a small optimization by not checking the state of
the power_off field on each run. This is done by treating
power_off like pause, only checking it when we get the EXIT
VCPU request. When a VCPU powers off another VCPU the EXIT
request is already made, so we just need to make sure the
request is also made on self power off. kvm_vcpu_kick() isn't
necessary for these cases, as the VCPU would just be kicking
itself, but we add it anyway as a self kick doesn't cost much,
and it makes the code more future-proof.

Signed-off-by: default avatarAndrew Jones <drjones@redhat.com>
Reviewed-by: default avatarChristoffer Dall <cdall@linaro.org>
Signed-off-by: default avatarChristoffer Dall <cdall@linaro.org>
parent cc9b43f9

virt/kvm/arm/arm.c

+11 −8
Original line number Diff line number Diff line
@@ -368,6 +368,13 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) 
	kvm_timer_vcpu_put(vcpu);

}



static void vcpu_power_off(struct kvm_vcpu *vcpu)

{

	vcpu->arch.power_off = true;

	kvm_make_request(KVM_REQ_VCPU_EXIT, vcpu);

	kvm_vcpu_kick(vcpu);

}



int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,

				    struct kvm_mp_state *mp_state)

{
@@ -387,7 +394,7 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, 
		vcpu->arch.power_off = false;

		break;

	case KVM_MP_STATE_STOPPED:

		vcpu->arch.power_off = true;

		vcpu_power_off(vcpu);

		break;

	default:

		return -EINVAL;
@@ -557,7 +564,7 @@ static void vcpu_sleep(struct kvm_vcpu *vcpu) 
	swait_event_interruptible(*wq, ((!vcpu->arch.power_off) &&

				       (!vcpu->arch.pause)));



	if (vcpu->arch.pause) {

	if (vcpu->arch.power_off || vcpu->arch.pause) {

		/* Awaken to handle a signal, request we sleep again later. */

		kvm_make_request(KVM_REQ_VCPU_EXIT, vcpu);

	}
@@ -623,9 +630,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) 


		check_vcpu_requests(vcpu);



		if (vcpu->arch.power_off)

			vcpu_sleep(vcpu);



		/*

		 * Preparing the interrupts to be injected also

		 * involves poking the GIC, which must be done in a
@@ -662,8 +666,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) 
		smp_store_mb(vcpu->mode, IN_GUEST_MODE);



		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) ||

		    kvm_request_pending(vcpu) ||

		    vcpu->arch.power_off) {

		    kvm_request_pending(vcpu)) {

			vcpu->mode = OUTSIDE_GUEST_MODE;

			local_irq_enable();

			kvm_pmu_sync_hwstate(vcpu);
@@ -896,7 +899,7 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, 
	 * Handle the "start in power-off" case.

	 */

	if (test_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features))

		vcpu->arch.power_off = true;

		vcpu_power_off(vcpu);

	else

		vcpu->arch.power_off = false;

virt/kvm/arm/psci.c

+2 −0
Original line number Diff line number Diff line
@@ -65,6 +65,8 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu) 
static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)

{

	vcpu->arch.power_off = true;

	kvm_make_request(KVM_REQ_VCPU_EXIT, vcpu);

	kvm_vcpu_kick(vcpu);

}



static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)

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