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Commit 8e444745 authored by Christoffer Dall's avatar Christoffer Dall
Browse files

KVM: arm/arm64: vgic-new: Add IRQ sorting 



Adds the sorting function to cover the case where you have more IRQs
to consider than you have LRs. We now consider priorities.

Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 81eeb95d

virt/kvm/arm/vgic/vgic.c

+57 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 


#include <linux/kvm.h>

#include <linux/kvm_host.h>

#include <linux/list_sort.h>



#include "vgic.h"
@@ -102,6 +103,62 @@ static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq) 
	return NULL;

}



/*

 * The order of items in the ap_lists defines how we'll pack things in LRs as

 * well, the first items in the list being the first things populated in the

 * LRs.

 *

 * A hard rule is that active interrupts can never be pushed out of the LRs

 * (and therefore take priority) since we cannot reliably trap on deactivation

 * of IRQs and therefore they have to be present in the LRs.

 *

 * Otherwise things should be sorted by the priority field and the GIC

 * hardware support will take care of preemption of priority groups etc.

 *

 * Return negative if "a" sorts before "b", 0 to preserve order, and positive

 * to sort "b" before "a".

 */

static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)

{

	struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);

	struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);

	bool penda, pendb;

	int ret;



	spin_lock(&irqa->irq_lock);

	spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING);



	if (irqa->active || irqb->active) {

		ret = (int)irqb->active - (int)irqa->active;

		goto out;

	}



	penda = irqa->enabled && irqa->pending;

	pendb = irqb->enabled && irqb->pending;



	if (!penda || !pendb) {

		ret = (int)pendb - (int)penda;

		goto out;

	}



	/* Both pending and enabled, sort by priority */

	ret = irqa->priority - irqb->priority;

out:

	spin_unlock(&irqb->irq_lock);

	spin_unlock(&irqa->irq_lock);

	return ret;

}



/* Must be called with the ap_list_lock held */

static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)

{

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



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



	list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);

}



/*

 * Only valid injection if changing level for level-triggered IRQs or for a

 * rising edge.