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Commit b6909a65 authored by Christoffer Dall's avatar Christoffer Dall
Browse files

KVM: arm/arm64: Support a vgic interrupt line level sample function 



The GIC sometimes need to sample the physical line of a mapped
interrupt.  As we know this to be notoriously slow, provide a callback
function for devices (such as the timer) which can do this much faster
than talking to the distributor, for example by comparing a few
in-memory values.  Fall back to the good old method of poking the
physical GIC if no callback is provided.

Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent e40cc57b

include/kvm/arm_vgic.h

+12 −1
Original line number Diff line number Diff line
@@ -130,6 +130,17 @@ struct vgic_irq { 
	u8 priority;

	enum vgic_irq_config config;	/* Level or edge */



	/*

	 * Callback function pointer to in-kernel devices that can tell us the

	 * state of the input level of mapped level-triggered IRQ faster than

	 * peaking into the physical GIC.

	 *

	 * Always called in non-preemptible section and the functions can use

	 * kvm_arm_get_running_vcpu() to get the vcpu pointer for private

	 * IRQs.

	 */

	bool (*get_input_level)(int vintid);



	void *owner;			/* Opaque pointer to reserve an interrupt

					   for in-kernel devices. */

};
@@ -331,7 +342,7 @@ void kvm_vgic_init_cpu_hardware(void); 
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,

			bool level, void *owner);

int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,

			  u32 vintid);

			  u32 vintid, bool (*get_input_level)(int vindid));

int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);

bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);

virt/kvm/arm/arch_timer.c

+2 −1
Original line number Diff line number Diff line
@@ -834,7 +834,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) 
		return -EINVAL;

	}



	ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq);

	ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq,

				    NULL);

	if (ret)

		return ret;

virt/kvm/arm/vgic/vgic.c

+9 −4
Original line number Diff line number Diff line
@@ -144,13 +144,15 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) 
	kfree(irq);

}



/* Get the input level of a mapped IRQ directly from the physical GIC */

bool vgic_get_phys_line_level(struct vgic_irq *irq)

{

	bool line_level;



	BUG_ON(!irq->hw);



	if (irq->get_input_level)

		return irq->get_input_level(irq->intid);



	WARN_ON(irq_get_irqchip_state(irq->host_irq,

				      IRQCHIP_STATE_PENDING,

				      &line_level));
@@ -436,7 +438,8 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, 


/* @irq->irq_lock must be held */

static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,

			    unsigned int host_irq)

			    unsigned int host_irq,

			    bool (*get_input_level)(int vindid))

{

	struct irq_desc *desc;

	struct irq_data *data;
@@ -456,6 +459,7 @@ static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq, 
	irq->hw = true;

	irq->host_irq = host_irq;

	irq->hwintid = data->hwirq;

	irq->get_input_level = get_input_level;

	return 0;

}
@@ -464,10 +468,11 @@ static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq) 
{

	irq->hw = false;

	irq->hwintid = 0;

	irq->get_input_level = NULL;

}



int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,

			  u32 vintid)

			  u32 vintid, bool (*get_input_level)(int vindid))

{

	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);

	unsigned long flags;
@@ -476,7 +481,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, 
	BUG_ON(!irq);



	spin_lock_irqsave(&irq->irq_lock, flags);

	ret = kvm_vgic_map_irq(vcpu, irq, host_irq);

	ret = kvm_vgic_map_irq(vcpu, irq, host_irq, get_input_level);

	spin_unlock_irqrestore(&irq->irq_lock, flags);

	vgic_put_irq(vcpu->kvm, irq);