[mirror_ubuntu-bionic-kernel.git] / virt / kvm / arm / vgic / vgic-v4.c

/*
 * Copyright (C) 2017 ARM Ltd.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kvm_host.h>
#include <linux/irqchip/arm-gic-v3.h>

#include "vgic.h"

/*
 * How KVM uses GICv4 (insert rude comments here):
 *
 * The vgic-v4 layer acts as a bridge between several entities:
 * - The GICv4 ITS representation offered by the ITS driver
 * - VFIO, which is in charge of the PCI endpoint
 * - The virtual ITS, which is the only thing the guest sees
 *
 * The configuration of VLPIs is triggered by a callback from VFIO,
 * instructing KVM that a PCI device has been configured to deliver
 * MSIs to a vITS.
 *
 * kvm_vgic_v4_set_forwarding() is thus called with the routing entry,
 * and this is used to find the corresponding vITS data structures
 * (ITS instance, device, event and irq) using a process that is
 * extremely similar to the injection of an MSI.
 *
 * At this stage, we can link the guest's view of an LPI (uniquely
 * identified by the routing entry) and the host irq, using the GICv4
 * driver mapping operation. Should the mapping succeed, we've then
 * successfully upgraded the guest's LPI to a VLPI. We can then start
 * with updating GICv4's view of the property table and generating an
 * INValidation in order to kickstart the delivery of this VLPI to the
 * guest directly, without software intervention. Well, almost.
 *
 * When the PCI endpoint is deconfigured, this operation is reversed
 * with VFIO calling kvm_vgic_v4_unset_forwarding().
 *
 * Once the VLPI has been mapped, it needs to follow any change the
 * guest performs on its LPI through the vITS. For that, a number of
 * command handlers have hooks to communicate these changes to the HW:
 * - Any invalidation triggers a call to its_prop_update_vlpi()
 * - The INT command results in a irq_set_irqchip_state(), which
 *   generates an INT on the corresponding VLPI.
 * - The CLEAR command results in a irq_set_irqchip_state(), which
 *   generates an CLEAR on the corresponding VLPI.
 * - DISCARD translates into an unmap, similar to a call to
 *   kvm_vgic_v4_unset_forwarding().
 * - MOVI is translated by an update of the existing mapping, changing
 *   the target vcpu, resulting in a VMOVI being generated.
 * - MOVALL is translated by a string of mapping updates (similar to
 *   the handling of MOVI). MOVALL is horrible.
 *
 * Note that a DISCARD/MAPTI sequence emitted from the guest without
 * reprogramming the PCI endpoint after MAPTI does not result in a
 * VLPI being mapped, as there is no callback from VFIO (the guest
 * will get the interrupt via the normal SW injection). Fixing this is
 * not trivial, and requires some horrible messing with the VFIO
 * internals. Not fun. Don't do that.
 *
 * Then there is the scheduling. Each time a vcpu is about to run on a
 * physical CPU, KVM must tell the corresponding redistributor about
 * it. And if we've migrated our vcpu from one CPU to another, we must
 * tell the ITS (so that the messages reach the right redistributor).
 * This is done in two steps: first issue a irq_set_affinity() on the
 * irq corresponding to the vcpu, then call its_schedule_vpe(). You
 * must be in a non-preemptible context. On exit, another call to
 * its_schedule_vpe() tells the redistributor that we're done with the
 * vcpu.
 *
 * Finally, the doorbell handling: Each vcpu is allocated an interrupt
 * which will fire each time a VLPI is made pending whilst the vcpu is
 * not running. Each time the vcpu gets blocked, the doorbell
 * interrupt gets enabled. When the vcpu is unblocked (for whatever
 * reason), the doorbell interrupt is disabled.
 */

#define DB_IRQ_FLAGS	(IRQ_NOAUTOEN | IRQ_DISABLE_UNLAZY | IRQ_NO_BALANCING)

static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
{
	struct kvm_vcpu *vcpu = info;

	vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
	kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
	kvm_vcpu_kick(vcpu);

	return IRQ_HANDLED;
}

/**
 * vgic_v4_init - Initialize the GICv4 data structures
 * @kvm:	Pointer to the VM being initialized
 *
 * We may be called each time a vITS is created, or when the
 * vgic is initialized. This relies on kvm->lock to be
 * held. In both cases, the number of vcpus should now be
 * fixed.
 */
int vgic_v4_init(struct kvm *kvm)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct kvm_vcpu *vcpu;
	int i, nr_vcpus, ret;

	if (!kvm_vgic_global_state.has_gicv4)
		return 0; /* Nothing to see here... move along. */

	if (dist->its_vm.vpes)
		return 0;

	nr_vcpus = atomic_read(&kvm->online_vcpus);

	dist->its_vm.vpes = kzalloc(sizeof(*dist->its_vm.vpes) * nr_vcpus,
				    GFP_KERNEL);
	if (!dist->its_vm.vpes)
		return -ENOMEM;

	dist->its_vm.nr_vpes = nr_vcpus;

	kvm_for_each_vcpu(i, vcpu, kvm)
		dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;

	ret = its_alloc_vcpu_irqs(&dist->its_vm);
	if (ret < 0) {
		kvm_err("VPE IRQ allocation failure\n");
		kfree(dist->its_vm.vpes);
		dist->its_vm.nr_vpes = 0;
		dist->its_vm.vpes = NULL;
		return ret;
	}

	kvm_for_each_vcpu(i, vcpu, kvm) {
		int irq = dist->its_vm.vpes[i]->irq;

		/*
		 * Don't automatically enable the doorbell, as we're
		 * flipping it back and forth when the vcpu gets
		 * blocked. Also disable the lazy disabling, as the
		 * doorbell could kick us out of the guest too
		 * early...
		 */
		irq_set_status_flags(irq, DB_IRQ_FLAGS);
		ret = request_irq(irq, vgic_v4_doorbell_handler,
				  0, "vcpu", vcpu);
		if (ret) {
			kvm_err("failed to allocate vcpu IRQ%d\n", irq);
			/*
			 * Trick: adjust the number of vpes so we know
			 * how many to nuke on teardown...
			 */
			dist->its_vm.nr_vpes = i;
			break;
		}
	}

	if (ret)
		vgic_v4_teardown(kvm);

	return ret;
}

/**
 * vgic_v4_teardown - Free the GICv4 data structures
 * @kvm:	Pointer to the VM being destroyed
 *
 * Relies on kvm->lock to be held.
 */
void vgic_v4_teardown(struct kvm *kvm)
{
	struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
	int i;

	if (!its_vm->vpes)
		return;

	for (i = 0; i < its_vm->nr_vpes; i++) {
		struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
		int irq = its_vm->vpes[i]->irq;

		irq_clear_status_flags(irq, DB_IRQ_FLAGS);
		free_irq(irq, vcpu);
	}

	its_free_vcpu_irqs(its_vm);
	kfree(its_vm->vpes);
	its_vm->nr_vpes = 0;
	its_vm->vpes = NULL;
}

int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu)
{
	if (!vgic_supports_direct_msis(vcpu->kvm))
		return 0;

	return its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, false);
}

int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu)
{
	int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
	int err;

	if (!vgic_supports_direct_msis(vcpu->kvm))
		return 0;

	/*
	 * Before making the VPE resident, make sure the redistributor
	 * corresponding to our current CPU expects us here. See the
	 * doc in drivers/irqchip/irq-gic-v4.c to understand how this
	 * turns into a VMOVP command at the ITS level.
	 */
	err = irq_set_affinity(irq, cpumask_of(smp_processor_id()));
	if (err)
		return err;

	err = its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, true);
	if (err)
		return err;

	/*
	 * Now that the VPE is resident, let's get rid of a potential
	 * doorbell interrupt that would still be pending.
	 */
	err = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, false);

	return err;
}

static struct vgic_its *vgic_get_its(struct kvm *kvm,
				     struct kvm_kernel_irq_routing_entry *irq_entry)
{
	struct kvm_msi msi  = (struct kvm_msi) {
		.address_lo	= irq_entry->msi.address_lo,
		.address_hi	= irq_entry->msi.address_hi,
		.data		= irq_entry->msi.data,
		.flags		= irq_entry->msi.flags,
		.devid		= irq_entry->msi.devid,
	};

	return vgic_msi_to_its(kvm, &msi);
}

int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
			       struct kvm_kernel_irq_routing_entry *irq_entry)
{
	struct vgic_its *its;
	struct vgic_irq *irq;
	struct its_vlpi_map map;
	int ret;

	if (!vgic_supports_direct_msis(kvm))
		return 0;

	/*
	 * Get the ITS, and escape early on error (not a valid
	 * doorbell for any of our vITSs).
	 */
	its = vgic_get_its(kvm, irq_entry);
	if (IS_ERR(its))
		return 0;

	mutex_lock(&its->its_lock);

	/* Perform then actual DevID/EventID -> LPI translation. */
	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
				   irq_entry->msi.data, &irq);
	if (ret)
		goto out;

	/*
	 * Emit the mapping request. If it fails, the ITS probably
	 * isn't v4 compatible, so let's silently bail out. Holding
	 * the ITS lock should ensure that nothing can modify the
	 * target vcpu.
	 */
	map = (struct its_vlpi_map) {
		.vm		= &kvm->arch.vgic.its_vm,
		.vpe		= &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
		.vintid		= irq->intid,
		.properties	= ((irq->priority & 0xfc) |
				   (irq->enabled ? LPI_PROP_ENABLED : 0) |
				   LPI_PROP_GROUP1),
		.db_enabled	= true,
	};

	ret = its_map_vlpi(virq, &map);
	if (ret)
		goto out;

	irq->hw		= true;
	irq->host_irq	= virq;

out:
	mutex_unlock(&its->its_lock);
	return ret;
}

int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
				 struct kvm_kernel_irq_routing_entry *irq_entry)
{
	struct vgic_its *its;
	struct vgic_irq *irq;
	int ret;

	if (!vgic_supports_direct_msis(kvm))
		return 0;

	/*
	 * Get the ITS, and escape early on error (not a valid
	 * doorbell for any of our vITSs).
	 */
	its = vgic_get_its(kvm, irq_entry);
	if (IS_ERR(its))
		return 0;

	mutex_lock(&its->its_lock);

	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
				   irq_entry->msi.data, &irq);
	if (ret)
		goto out;

	WARN_ON(!(irq->hw && irq->host_irq == virq));
	if (irq->hw) {
		irq->hw = false;
		ret = its_unmap_vlpi(virq);
	}

out:
	mutex_unlock(&its->its_lock);
	return ret;
}

void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu)
{
	if (vgic_supports_direct_msis(vcpu->kvm)) {
		int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
		if (irq)
			enable_irq(irq);
	}
}

void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu)
{
	if (vgic_supports_direct_msis(vcpu->kvm)) {
		int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
		if (irq)
			disable_irq(irq);
	}
}
Commit	Line	Data
74fe55dc MZ	1	/*
	2	* Copyright (C) 2017 ARM Ltd.
	3	* Author: Marc Zyngier <marc.zyngier@arm.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	16	*/
	17
	18	#include <linux/interrupt.h>
bdb2d2cc	19	#include <linux/irq.h>
74fe55dc MZ	20	#include <linux/irqdomain.h>
74fe55dc MZ	21	#include <linux/kvm_host.h>
196b1364	22	#include <linux/irqchip/arm-gic-v3.h>
74fe55dc MZ	23
	24	#include "vgic.h"
	25
ed8703a5 MZ	26	/*
	27	* How KVM uses GICv4 (insert rude comments here):
	28	*
	29	* The vgic-v4 layer acts as a bridge between several entities:
	30	* - The GICv4 ITS representation offered by the ITS driver
	31	* - VFIO, which is in charge of the PCI endpoint
	32	* - The virtual ITS, which is the only thing the guest sees
	33	*
	34	* The configuration of VLPIs is triggered by a callback from VFIO,
	35	* instructing KVM that a PCI device has been configured to deliver
	36	* MSIs to a vITS.
	37	*
	38	* kvm_vgic_v4_set_forwarding() is thus called with the routing entry,
	39	* and this is used to find the corresponding vITS data structures
	40	* (ITS instance, device, event and irq) using a process that is
	41	* extremely similar to the injection of an MSI.
	42	*
	43	* At this stage, we can link the guest's view of an LPI (uniquely
	44	* identified by the routing entry) and the host irq, using the GICv4
	45	* driver mapping operation. Should the mapping succeed, we've then
	46	* successfully upgraded the guest's LPI to a VLPI. We can then start
	47	* with updating GICv4's view of the property table and generating an
	48	* INValidation in order to kickstart the delivery of this VLPI to the
	49	* guest directly, without software intervention. Well, almost.
	50	*
	51	* When the PCI endpoint is deconfigured, this operation is reversed
	52	* with VFIO calling kvm_vgic_v4_unset_forwarding().
	53	*
	54	* Once the VLPI has been mapped, it needs to follow any change the
	55	* guest performs on its LPI through the vITS. For that, a number of
	56	* command handlers have hooks to communicate these changes to the HW:
	57	* - Any invalidation triggers a call to its_prop_update_vlpi()
	58	* - The INT command results in a irq_set_irqchip_state(), which
	59	* generates an INT on the corresponding VLPI.
	60	* - The CLEAR command results in a irq_set_irqchip_state(), which
	61	* generates an CLEAR on the corresponding VLPI.
	62	* - DISCARD translates into an unmap, similar to a call to
	63	* kvm_vgic_v4_unset_forwarding().
	64	* - MOVI is translated by an update of the existing mapping, changing
	65	* the target vcpu, resulting in a VMOVI being generated.
	66	* - MOVALL is translated by a string of mapping updates (similar to
	67	* the handling of MOVI). MOVALL is horrible.
	68	*
	69	* Note that a DISCARD/MAPTI sequence emitted from the guest without
	70	* reprogramming the PCI endpoint after MAPTI does not result in a
	71	* VLPI being mapped, as there is no callback from VFIO (the guest
	72	* will get the interrupt via the normal SW injection). Fixing this is
	73	* not trivial, and requires some horrible messing with the VFIO
	74	* internals. Not fun. Don't do that.
	75	*
	76	* Then there is the scheduling. Each time a vcpu is about to run on a
	77	* physical CPU, KVM must tell the corresponding redistributor about
	78	* it. And if we've migrated our vcpu from one CPU to another, we must
	79	* tell the ITS (so that the messages reach the right redistributor).
	80	* This is done in two steps: first issue a irq_set_affinity() on the
	81	* irq corresponding to the vcpu, then call its_schedule_vpe(). You
	82	* must be in a non-preemptible context. On exit, another call to
	83	* its_schedule_vpe() tells the redistributor that we're done with the
	84	* vcpu.
	85	*
	86	* Finally, the doorbell handling: Each vcpu is allocated an interrupt
	87	* which will fire each time a VLPI is made pending whilst the vcpu is
	88	* not running. Each time the vcpu gets blocked, the doorbell
	89	* interrupt gets enabled. When the vcpu is unblocked (for whatever
90	* reason), the doorbell interrupt is disabled.
91	*/
92
d3d83f7f MZ	93	#define DB_IRQ_FLAGS (IRQ_NOAUTOEN \| IRQ_DISABLE_UNLAZY \| IRQ_NO_BALANCING)
d3d83f7f MZ	94
bdb2d2cc MZ	95	static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
	96	{
	97	struct kvm_vcpu *vcpu = info;
	98
	99	vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
	100	kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
	101	kvm_vcpu_kick(vcpu);
	102
	103	return IRQ_HANDLED;
	104	}
	105
74fe55dc MZ	106	/**
	107	* vgic_v4_init - Initialize the GICv4 data structures
	108	* @kvm: Pointer to the VM being initialized
	109	*
	110	* We may be called each time a vITS is created, or when the
	111	* vgic is initialized. This relies on kvm->lock to be
	112	* held. In both cases, the number of vcpus should now be
	113	* fixed.
	114	*/
	115	int vgic_v4_init(struct kvm *kvm)
	116	{
	117	struct vgic_dist *dist = &kvm->arch.vgic;
	118	struct kvm_vcpu *vcpu;
	119	int i, nr_vcpus, ret;
	120
f8f85dc0	121	if (!kvm_vgic_global_state.has_gicv4)
3d1ad640 CD	122	return 0; /* Nothing to see here... move along. */
3d1ad640 CD	123
74fe55dc MZ	124	if (dist->its_vm.vpes)
	125	return 0;
	126
	127	nr_vcpus = atomic_read(&kvm->online_vcpus);
	128
	129	dist->its_vm.vpes = kzalloc(sizeof(dist->its_vm.vpes) nr_vcpus,
	130	GFP_KERNEL);
	131	if (!dist->its_vm.vpes)
	132	return -ENOMEM;
	133
	134	dist->its_vm.nr_vpes = nr_vcpus;
	135
	136	kvm_for_each_vcpu(i, vcpu, kvm)
	137	dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
	138
	139	ret = its_alloc_vcpu_irqs(&dist->its_vm);
	140	if (ret < 0) {
	141	kvm_err("VPE IRQ allocation failure\n");
	142	kfree(dist->its_vm.vpes);
	143	dist->its_vm.nr_vpes = 0;
	144	dist->its_vm.vpes = NULL;
	145	return ret;
	146	}
	147
bdb2d2cc MZ	148	kvm_for_each_vcpu(i, vcpu, kvm) {
	149	int irq = dist->its_vm.vpes[i]->irq;
	150
	151	/*
	152	* Don't automatically enable the doorbell, as we're
	153	* flipping it back and forth when the vcpu gets
	154	* blocked. Also disable the lazy disabling, as the
	155	* doorbell could kick us out of the guest too
	156	* early...
	157	*/
d3d83f7f	158	irq_set_status_flags(irq, DB_IRQ_FLAGS);
bdb2d2cc MZ	159	ret = request_irq(irq, vgic_v4_doorbell_handler,
	160	0, "vcpu", vcpu);
	161	if (ret) {
	162	kvm_err("failed to allocate vcpu IRQ%d\n", irq);
	163	/*
	164	* Trick: adjust the number of vpes so we know
	165	* how many to nuke on teardown...
	166	*/
	167	dist->its_vm.nr_vpes = i;
	168	break;
	169	}
	170	}
	171
	172	if (ret)
	173	vgic_v4_teardown(kvm);
	174
74fe55dc MZ	175	return ret;
	176	}
	177
	178	/**
	179	* vgic_v4_teardown - Free the GICv4 data structures
	180	* @kvm: Pointer to the VM being destroyed
	181	*
	182	* Relies on kvm->lock to be held.
	183	*/
	184	void vgic_v4_teardown(struct kvm *kvm)
	185	{
	186	struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
bdb2d2cc	187	int i;
74fe55dc MZ	188
	189	if (!its_vm->vpes)
	190	return;
	191
bdb2d2cc MZ	192	for (i = 0; i < its_vm->nr_vpes; i++) {
	193	struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
	194	int irq = its_vm->vpes[i]->irq;
	195
d3d83f7f	196	irq_clear_status_flags(irq, DB_IRQ_FLAGS);
bdb2d2cc MZ	197	free_irq(irq, vcpu);
	198	}
	199
74fe55dc MZ	200	its_free_vcpu_irqs(its_vm);
	201	kfree(its_vm->vpes);
	202	its_vm->nr_vpes = 0;
	203	its_vm->vpes = NULL;
	204	}
196b1364	205
62775797 MZ	206	int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu)
	207	{
	208	if (!vgic_supports_direct_msis(vcpu->kvm))
	209	return 0;
	210
	211	return its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, false);
	212	}
	213
	214	int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu)
	215	{
	216	int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
	217	int err;
	218
	219	if (!vgic_supports_direct_msis(vcpu->kvm))
	220	return 0;
	221
	222	/*
	223	* Before making the VPE resident, make sure the redistributor
	224	* corresponding to our current CPU expects us here. See the
	225	* doc in drivers/irqchip/irq-gic-v4.c to understand how this
	226	* turns into a VMOVP command at the ITS level.
	227	*/
	228	err = irq_set_affinity(irq, cpumask_of(smp_processor_id()));
	229	if (err)
	230	return err;
	231
	232	err = its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, true);
	233	if (err)
	234	return err;
	235
	236	/*
	237	* Now that the VPE is resident, let's get rid of a potential
	238	* doorbell interrupt that would still be pending.
	239	*/
	240	err = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, false);
	241
	242	return err;
	243	}
	244
196b1364 MZ	245	static struct vgic_its vgic_get_its(struct kvm kvm,
	246	struct kvm_kernel_irq_routing_entry *irq_entry)
	247	{
	248	struct kvm_msi msi = (struct kvm_msi) {
	249	.address_lo = irq_entry->msi.address_lo,
	250	.address_hi = irq_entry->msi.address_hi,
	251	.data = irq_entry->msi.data,
	252	.flags = irq_entry->msi.flags,
	253	.devid = irq_entry->msi.devid,
	254	};
	255
	256	return vgic_msi_to_its(kvm, &msi);
	257	}
	258
	259	int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
	260	struct kvm_kernel_irq_routing_entry *irq_entry)
	261	{
	262	struct vgic_its *its;
	263	struct vgic_irq *irq;
	264	struct its_vlpi_map map;
	265	int ret;
	266
	267	if (!vgic_supports_direct_msis(kvm))
	268	return 0;
	269
	270	/*
	271	* Get the ITS, and escape early on error (not a valid
	272	* doorbell for any of our vITSs).
	273	*/
	274	its = vgic_get_its(kvm, irq_entry);
	275	if (IS_ERR(its))
	276	return 0;
	277
	278	mutex_lock(&its->its_lock);
	279
	280	/* Perform then actual DevID/EventID -> LPI translation. */
	281	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
	282	irq_entry->msi.data, &irq);
	283	if (ret)
	284	goto out;
	285
	286	/*
	287	* Emit the mapping request. If it fails, the ITS probably
	288	* isn't v4 compatible, so let's silently bail out. Holding
	289	* the ITS lock should ensure that nothing can modify the
	290	* target vcpu.
	291	*/
	292	map = (struct its_vlpi_map) {
	293	.vm = &kvm->arch.vgic.its_vm,
	294	.vpe = &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
	295	.vintid = irq->intid,
	296	.properties = ((irq->priority & 0xfc) \|
	297	(irq->enabled ? LPI_PROP_ENABLED : 0) \|
	298	LPI_PROP_GROUP1),
	299	.db_enabled = true,
	300	};
	301
	302	ret = its_map_vlpi(virq, &map);
	303	if (ret)
	304	goto out;
	305
	306	irq->hw = true;
	307	irq->host_irq = virq;
	308
309	out:
310	mutex_unlock(&its->its_lock);
311	return ret;
312	}
313
314	int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
315	struct kvm_kernel_irq_routing_entry *irq_entry)
316	{
317	struct vgic_its *its;
318	struct vgic_irq *irq;
319	int ret;
320
321	if (!vgic_supports_direct_msis(kvm))
322	return 0;
323
324	/*
325	* Get the ITS, and escape early on error (not a valid
326	* doorbell for any of our vITSs).
327	*/
328	its = vgic_get_its(kvm, irq_entry);
329	if (IS_ERR(its))
330	return 0;
331
332	mutex_lock(&its->its_lock);
333
334	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
335	irq_entry->msi.data, &irq);
336	if (ret)
337	goto out;
338
339	WARN_ON(!(irq->hw && irq->host_irq == virq));
a05d1c0d MZ	340	if (irq->hw) {
	341	irq->hw = false;
	342	ret = its_unmap_vlpi(virq);
	343	}
196b1364 MZ	344
	345	out:
	346	mutex_unlock(&its->its_lock);
	347	return ret;
	348	}
df9ba959 MZ	349
	350	void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu)
	351	{
	352	if (vgic_supports_direct_msis(vcpu->kvm)) {
	353	int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
	354	if (irq)
	355	enable_irq(irq);
	356	}
	357	}
	358
	359	void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu)
	360	{
	361	if (vgic_supports_direct_msis(vcpu->kvm)) {
	362	int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
	363	if (irq)
	364	disable_irq(irq);
	365	}
	366	}