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Commit fd837b08 authored by Andre Przywara's avatar Andre Przywara Committed by Christoffer Dall
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KVM: arm64: ITS: return 1 on successful MSI injection 



According to the KVM API documentation a successful MSI injection
should return a value > 0 on success.
Return possible errors in vgic_its_trigger_msi() and report a
successful injection back to userland, while also reporting the
case where the MSI could not be delivered due to the guest not
having the LPI mapped, for instance.

Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 29b4817d

include/linux/irqchip/arm-gic-v3.h

+1 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ 
 */

#define E_ITS_MOVI_UNMAPPED_INTERRUPT		0x010107

#define E_ITS_MOVI_UNMAPPED_COLLECTION		0x010109

#define E_ITS_INT_UNMAPPED_INTERRUPT		0x010307

#define E_ITS_CLEAR_UNMAPPED_INTERRUPT		0x010507

#define E_ITS_MAPD_DEVICE_OOR			0x010801

#define E_ITS_MAPC_PROCNUM_OOR			0x010902

virt/kvm/arm/vgic/vgic-its.c

+37 −19
Original line number Diff line number Diff line
@@ -441,39 +441,48 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm, 
 * Find the target VCPU and the LPI number for a given devid/eventid pair

 * and make this IRQ pending, possibly injecting it.

 * Must be called with the its_lock mutex held.

 * Returns 0 on success, a positive error value for any ITS mapping

 * related errors and negative error values for generic errors.

 */

static void vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,

static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,

				u32 devid, u32 eventid)

{

	struct kvm_vcpu *vcpu;

	struct its_itte *itte;



	if (!its->enabled)

		return;

		return -EBUSY;



	itte = find_itte(its, devid, eventid);

	/* Triggering an unmapped IRQ gets silently dropped. */

	if (itte && its_is_collection_mapped(itte->collection)) {

		struct kvm_vcpu *vcpu;

	if (!itte || !its_is_collection_mapped(itte->collection))

		return E_ITS_INT_UNMAPPED_INTERRUPT;



	vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr);

		if (vcpu && vcpu->arch.vgic_cpu.lpis_enabled) {

	if (!vcpu)

		return E_ITS_INT_UNMAPPED_INTERRUPT;



	if (!vcpu->arch.vgic_cpu.lpis_enabled)

		return -EBUSY;



	spin_lock(&itte->irq->irq_lock);

	itte->irq->pending = true;

	vgic_queue_irq_unlock(kvm, itte->irq);

		}

	}



	return 0;

}



/*

 * Queries the KVM IO bus framework to get the ITS pointer from the given

 * doorbell address.

 * We then call vgic_its_trigger_msi() with the decoded data.

 * According to the KVM_SIGNAL_MSI API description returns 1 on success.

 */

int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)

{

	u64 address;

	struct kvm_io_device *kvm_io_dev;

	struct vgic_io_device *iodev;

	int ret;



	if (!vgic_has_its(kvm))

		return -ENODEV;
@@ -490,10 +499,21 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) 
	iodev = container_of(kvm_io_dev, struct vgic_io_device, dev);



	mutex_lock(&iodev->its->its_lock);

	vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data);

	ret = vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data);

	mutex_unlock(&iodev->its->its_lock);



	if (ret < 0)

		return ret;



	/*

	 * KVM_SIGNAL_MSI demands a return value > 0 for success and 0

	 * if the guest has blocked the MSI. So we map any LPI mapping

	 * related error to that.

	 */

	if (ret)

		return 0;

	else

		return 1;

}



/* Requires the its_lock to be held. */
@@ -981,9 +1001,7 @@ static int vgic_its_cmd_handle_int(struct kvm *kvm, struct vgic_its *its, 
	u32 msi_data = its_cmd_get_id(its_cmd);

	u64 msi_devid = its_cmd_get_deviceid(its_cmd);



	vgic_its_trigger_msi(kvm, its, msi_devid, msi_data);



	return 0;

	return vgic_its_trigger_msi(kvm, its, msi_devid, msi_data);

}



/*