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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: Christoffer Dall <cdall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Christoffer Dall 2017-05-04 13:24:20 +02:00
parent 99a1db7a2c
commit c6ccd30e0d
2 changed files with 38 additions and 0 deletions
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5
include/kvm/arm_vgic.h
View File

@ -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 */

33
virt/kvm/arm/vgic/vgic.c
View File

@ -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
*