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Commit c6ccd30e authored by Christoffer Dall's avatar Christoffer Dall
Browse files

KVM: arm/arm64: Introduce an allocator for in-kernel irq lines 



Having multiple devices being able to signal the same interrupt line is
very confusing and almost certainly guarantees a configuration error.

Therefore, introduce a very simple allocator which allows a device to
claim an interrupt line from the vgic for a given VM.

Signed-off-by: default avatarChristoffer Dall <cdall@linaro.org>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 99a1db7a

include/kvm/arm_vgic.h

+5 −0
Original line number Diff line number Diff line
@@ -121,6 +121,9 @@ struct vgic_irq { 
	u8 source;			/* GICv2 SGIs only */

	u8 priority;

	enum vgic_irq_config config;	/* Level or edge */



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

					   for in-kernel devices. */

};



struct vgic_register_region;
@@ -340,4 +343,6 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi); 
 */

int kvm_vgic_setup_default_irq_routing(struct kvm *kvm);



int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner);



#endif /* __KVM_ARM_VGIC_H */

virt/kvm/arm/vgic/vgic.c

+33 −0
Original line number Diff line number Diff line
@@ -434,6 +434,39 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq) 
	return 0;

}



/**

 * kvm_vgic_set_owner - Set the owner of an interrupt for a VM

 *

 * @vcpu:   Pointer to the VCPU (used for PPIs)

 * @intid:  The virtual INTID identifying the interrupt (PPI or SPI)

 * @owner:  Opaque pointer to the owner

 *

 * Returns 0 if intid is not already used by another in-kernel device and the

 * owner is set, otherwise returns an error code.

 */

int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)

{

	struct vgic_irq *irq;

	int ret = 0;



	if (!vgic_initialized(vcpu->kvm))

		return -EAGAIN;



	/* SGIs and LPIs cannot be wired up to any device */

	if (!irq_is_ppi(intid) && !vgic_valid_spi(vcpu->kvm, intid))

		return -EINVAL;



	irq = vgic_get_irq(vcpu->kvm, vcpu, intid);

	spin_lock(&irq->irq_lock);

	if (irq->owner && irq->owner != owner)

		ret = -EEXIST;

	else

		irq->owner = owner;

	spin_unlock(&irq->irq_lock);



	return ret;

}



/**

 * vgic_prune_ap_list - Remove non-relevant interrupts from the list

 *