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Commit 0919e84c authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
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KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework 



Implement the framework for syncing IRQs between our emulation and
the list registers, which represent the guest's view of IRQs.
This is done in kvm_vgic_flush_hwstate and kvm_vgic_sync_hwstate,
which gets called on guest entry and exit.
The code talking to the actual GICv2/v3 hardware is added in the
following patches.

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarEric Auger <eric.auger@linaro.org>
Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 8e444745

include/kvm/vgic/vgic.h

+4 −0
Original line number Diff line number Diff line
@@ -190,6 +190,10 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, 
#define vgic_valid_spi(k, i)	(((i) >= VGIC_NR_PRIVATE_IRQS) && \

			((i) < (k)->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS))



bool kvm_vcpu_has_pending_irqs(struct kvm_vcpu *vcpu);

void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu);

void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu);



/**

 * kvm_vgic_get_max_vcpus - Get the maximum number of VCPUs allowed by HW

 *

virt/kvm/arm/vgic/vgic.c

+192 −0
Original line number Diff line number Diff line
@@ -307,3 +307,195 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, 
{

	return vgic_update_irq_pending(kvm, cpuid, intid, level, false);

}



/**

 * vgic_prune_ap_list - Remove non-relevant interrupts from the list

 *

 * @vcpu: The VCPU pointer

 *

 * Go over the list of "interesting" interrupts, and prune those that we

 * won't have to consider in the near future.

 */

static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)

{

	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

	struct vgic_irq *irq, *tmp;



retry:

	spin_lock(&vgic_cpu->ap_list_lock);



	list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {

		struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;



		spin_lock(&irq->irq_lock);



		BUG_ON(vcpu != irq->vcpu);



		target_vcpu = vgic_target_oracle(irq);



		if (!target_vcpu) {

			/*

			 * We don't need to process this interrupt any

			 * further, move it off the list.

			 */

			list_del(&irq->ap_list);

			irq->vcpu = NULL;

			spin_unlock(&irq->irq_lock);

			continue;

		}



		if (target_vcpu == vcpu) {

			/* We're on the right CPU */

			spin_unlock(&irq->irq_lock);

			continue;

		}



		/* This interrupt looks like it has to be migrated. */



		spin_unlock(&irq->irq_lock);

		spin_unlock(&vgic_cpu->ap_list_lock);



		/*

		 * Ensure locking order by always locking the smallest

		 * ID first.

		 */

		if (vcpu->vcpu_id < target_vcpu->vcpu_id) {

			vcpuA = vcpu;

			vcpuB = target_vcpu;

		} else {

			vcpuA = target_vcpu;

			vcpuB = vcpu;

		}



		spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);

		spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,

				 SINGLE_DEPTH_NESTING);

		spin_lock(&irq->irq_lock);



		/*

		 * If the affinity has been preserved, move the

		 * interrupt around. Otherwise, it means things have

		 * changed while the interrupt was unlocked, and we

		 * need to replay this.

		 *

		 * In all cases, we cannot trust the list not to have

		 * changed, so we restart from the beginning.

		 */

		if (target_vcpu == vgic_target_oracle(irq)) {

			struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;



			list_del(&irq->ap_list);

			irq->vcpu = target_vcpu;

			list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);

		}



		spin_unlock(&irq->irq_lock);

		spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);

		spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);

		goto retry;

	}



	spin_unlock(&vgic_cpu->ap_list_lock);

}



static inline void vgic_process_maintenance_interrupt(struct kvm_vcpu *vcpu)

{

}



static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)

{

}



/* Requires the irq_lock to be held. */

static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,

				    struct vgic_irq *irq, int lr)

{

	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));

}



static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)

{

}



static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)

{

}



/* Requires the ap_list_lock to be held. */

static int compute_ap_list_depth(struct kvm_vcpu *vcpu)

{

	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

	struct vgic_irq *irq;

	int count = 0;



	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));



	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {

		spin_lock(&irq->irq_lock);

		/* GICv2 SGIs can count for more than one... */

		if (vgic_irq_is_sgi(irq->intid) && irq->source)

			count += hweight8(irq->source);

		else

			count++;

		spin_unlock(&irq->irq_lock);

	}

	return count;

}



/* Requires the VCPU's ap_list_lock to be held. */

static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)

{

	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

	struct vgic_irq *irq;

	int count = 0;



	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));



	if (compute_ap_list_depth(vcpu) > kvm_vgic_global_state.nr_lr) {

		vgic_set_underflow(vcpu);

		vgic_sort_ap_list(vcpu);

	}



	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {

		spin_lock(&irq->irq_lock);



		if (unlikely(vgic_target_oracle(irq) != vcpu))

			goto next;



		/*

		 * If we get an SGI with multiple sources, try to get

		 * them in all at once.

		 */

		do {

			vgic_populate_lr(vcpu, irq, count++);

		} while (irq->source && count < kvm_vgic_global_state.nr_lr);



next:

		spin_unlock(&irq->irq_lock);



		if (count == kvm_vgic_global_state.nr_lr)

			break;

	}



	vcpu->arch.vgic_cpu.used_lrs = count;



	/* Nuke remaining LRs */

	for ( ; count < kvm_vgic_global_state.nr_lr; count++)

		vgic_clear_lr(vcpu, count);

}



/* Sync back the hardware VGIC state into our emulation after a guest's run. */

void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)

{

	vgic_process_maintenance_interrupt(vcpu);

	vgic_fold_lr_state(vcpu);

	vgic_prune_ap_list(vcpu);

}



/* Flush our emulation state into the GIC hardware before entering the guest. */

void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)

{

	spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);

	vgic_flush_lr_state(vcpu);

	spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);

}

virt/kvm/arm/vgic/vgic.h

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#ifndef __KVM_ARM_VGIC_NEW_H__

#define __KVM_ARM_VGIC_NEW_H__



#define vgic_irq_is_sgi(intid) ((intid) < VGIC_NR_SGIS)



struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,

			      u32 intid);

bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);