Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 986 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
new file mode 100644
index 000000000..4040a33cd
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -0,0 +1,986 @@
+/*
+ * Copyright (C) 2015, 2016 ARM Ltd.
+ *
+ * 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/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/list_sort.h>
+#include <linux/nospec.h>
+
+#include <asm/kvm_hyp.h>
+
+#include "vgic.h"
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+struct vgic_global kvm_vgic_global_state __ro_after_init = {
+	.gicv3_cpuif = STATIC_KEY_FALSE_INIT,
+};
+
+/*
+ * Locking order is always:
+ * kvm->lock (mutex)
+ *   its->cmd_lock (mutex)
+ *     its->its_lock (mutex)
+ *       vgic_cpu->ap_list_lock		must be taken with IRQs disabled
+ *         kvm->lpi_list_lock		must be taken with IRQs disabled
+ *           vgic_irq->irq_lock		must be taken with IRQs disabled
+ *
+ * As the ap_list_lock might be taken from the timer interrupt handler,
+ * we have to disable IRQs before taking this lock and everything lower
+ * than it.
+ *
+ * If you need to take multiple locks, always take the upper lock first,
+ * then the lower ones, e.g. first take the its_lock, then the irq_lock.
+ * If you are already holding a lock and need to take a higher one, you
+ * have to drop the lower ranking lock first and re-aquire it after having
+ * taken the upper one.
+ *
+ * When taking more than one ap_list_lock at the same time, always take the
+ * lowest numbered VCPU's ap_list_lock first, so:
+ *   vcpuX->vcpu_id < vcpuY->vcpu_id:
+ *     spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);
+ *     spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
+ *
+ * Since the VGIC must support injecting virtual interrupts from ISRs, we have
+ * to use the spin_lock_irqsave/spin_unlock_irqrestore versions of outer
+ * spinlocks for any lock that may be taken while injecting an interrupt.
+ */
+
+/*
+ * Iterate over the VM's list of mapped LPIs to find the one with a
+ * matching interrupt ID and return a reference to the IRQ structure.
+ */
+static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct vgic_irq *irq = NULL;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+
+	list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+		if (irq->intid != intid)
+			continue;
+
+		/*
+		 * This increases the refcount, the caller is expected to
+		 * call vgic_put_irq() later once it's finished with the IRQ.
+		 */
+		vgic_get_irq_kref(irq);
+		goto out_unlock;
+	}
+	irq = NULL;
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+
+	return irq;
+}
+
+/*
+ * This looks up the virtual interrupt ID to get the corresponding
+ * struct vgic_irq. It also increases the refcount, so any caller is expected
+ * to call vgic_put_irq() once it's finished with this IRQ.
+ */
+struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
+			      u32 intid)
+{
+	/* SGIs and PPIs */
+	if (intid <= VGIC_MAX_PRIVATE) {
+		intid = array_index_nospec(intid, VGIC_MAX_PRIVATE + 1);
+		return &vcpu->arch.vgic_cpu.private_irqs[intid];
+	}
+
+	/* SPIs */
+	if (intid < (kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS)) {
+		intid = array_index_nospec(intid, kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS);
+		return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
+	}
+
+	/* LPIs */
+	if (intid >= VGIC_MIN_LPI)
+		return vgic_get_lpi(kvm, intid);
+
+	WARN(1, "Looking up struct vgic_irq for reserved INTID");
+	return NULL;
+}
+
+/*
+ * We can't do anything in here, because we lack the kvm pointer to
+ * lock and remove the item from the lpi_list. So we keep this function
+ * empty and use the return value of kref_put() to trigger the freeing.
+ */
+static void vgic_irq_release(struct kref *ref)
+{
+}
+
+void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	unsigned long flags;
+
+	if (irq->intid < VGIC_MIN_LPI)
+		return;
+
+	raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+	if (!kref_put(&irq->refcount, vgic_irq_release)) {
+		raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+		return;
+	};
+
+	list_del(&irq->lpi_list);
+	dist->lpi_list_count--;
+	raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+
+	kfree(irq);
+}
+
+void vgic_irq_set_phys_pending(struct vgic_irq *irq, bool pending)
+{
+	WARN_ON(irq_set_irqchip_state(irq->host_irq,
+				      IRQCHIP_STATE_PENDING,
+				      pending));
+}
+
+bool vgic_get_phys_line_level(struct vgic_irq *irq)
+{
+	bool line_level;
+
+	BUG_ON(!irq->hw);
+
+	if (irq->get_input_level)
+		return irq->get_input_level(irq->intid);
+
+	WARN_ON(irq_get_irqchip_state(irq->host_irq,
+				      IRQCHIP_STATE_PENDING,
+				      &line_level));
+	return line_level;
+}
+
+/* Set/Clear the physical active state */
+void vgic_irq_set_phys_active(struct vgic_irq *irq, bool active)
+{
+
+	BUG_ON(!irq->hw);
+	WARN_ON(irq_set_irqchip_state(irq->host_irq,
+				      IRQCHIP_STATE_ACTIVE,
+				      active));
+}
+
+/**
+ * kvm_vgic_target_oracle - compute the target vcpu for an irq
+ *
+ * @irq:	The irq to route. Must be already locked.
+ *
+ * Based on the current state of the interrupt (enabled, pending,
+ * active, vcpu and target_vcpu), compute the next vcpu this should be
+ * given to. Return NULL if this shouldn't be injected at all.
+ *
+ * Requires the IRQ lock to be held.
+ */
+static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)
+{
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
+
+	/* If the interrupt is active, it must stay on the current vcpu */
+	if (irq->active)
+		return irq->vcpu ? : irq->target_vcpu;
+
+	/*
+	 * If the IRQ is not active but enabled and pending, we should direct
+	 * it to its configured target VCPU.
+	 * If the distributor is disabled, pending interrupts shouldn't be
+	 * forwarded.
+	 */
+	if (irq->enabled && irq_is_pending(irq)) {
+		if (unlikely(irq->target_vcpu &&
+			     !irq->target_vcpu->kvm->arch.vgic.enabled))
+			return NULL;
+
+		return irq->target_vcpu;
+	}
+
+	/* If neither active nor pending and enabled, then this IRQ should not
+	 * be queued to any VCPU.
+	 */
+	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;
+
+	/*
+	 * list_sort may call this function with the same element when
+	 * the list is fairly long.
+	 */
+	if (unlikely(irqa == irqb))
+		return 0;
+
+	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 && irq_is_pending(irqa);
+	pendb = irqb->enabled && irq_is_pending(irqb);
+
+	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, and in-kernel connected IRQ lines can only be controlled by
+ * their owner.
+ */
+static bool vgic_validate_injection(struct vgic_irq *irq, bool level, void *owner)
+{
+	if (irq->owner != owner)
+		return false;
+
+	switch (irq->config) {
+	case VGIC_CONFIG_LEVEL:
+		return irq->line_level != level;
+	case VGIC_CONFIG_EDGE:
+		return level;
+	}
+
+	return false;
+}
+
+/*
+ * Check whether an IRQ needs to (and can) be queued to a VCPU's ap list.
+ * Do the queuing if necessary, taking the right locks in the right order.
+ * Returns true when the IRQ was queued, false otherwise.
+ *
+ * Needs to be entered with the IRQ lock already held, but will return
+ * with all locks dropped.
+ */
+bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
+			   unsigned long flags)
+{
+	struct kvm_vcpu *vcpu;
+
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
+
+retry:
+	vcpu = vgic_target_oracle(irq);
+	if (irq->vcpu || !vcpu) {
+		/*
+		 * If this IRQ is already on a VCPU's ap_list, then it
+		 * cannot be moved or modified and there is no more work for
+		 * us to do.
+		 *
+		 * Otherwise, if the irq is not pending and enabled, it does
+		 * not need to be inserted into an ap_list and there is also
+		 * no more work for us to do.
+		 */
+		spin_unlock_irqrestore(&irq->irq_lock, flags);
+
+		/*
+		 * We have to kick the VCPU here, because we could be
+		 * queueing an edge-triggered interrupt for which we
+		 * get no EOI maintenance interrupt. In that case,
+		 * while the IRQ is already on the VCPU's AP list, the
+		 * VCPU could have EOI'ed the original interrupt and
+		 * won't see this one until it exits for some other
+		 * reason.
+		 */
+		if (vcpu) {
+			kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+			kvm_vcpu_kick(vcpu);
+		}
+		return false;
+	}
+
+	/*
+	 * We must unlock the irq lock to take the ap_list_lock where
+	 * we are going to insert this new pending interrupt.
+	 */
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+
+	/* someone can do stuff here, which we re-check below */
+
+	spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
+	spin_lock(&irq->irq_lock);
+
+	/*
+	 * Did something change behind our backs?
+	 *
+	 * There are two cases:
+	 * 1) The irq lost its pending state or was disabled behind our
+	 *    backs and/or it was queued to another VCPU's ap_list.
+	 * 2) Someone changed the affinity on this irq behind our
+	 *    backs and we are now holding the wrong ap_list_lock.
+	 *
+	 * In both cases, drop the locks and retry.
+	 */
+
+	if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {
+		spin_unlock(&irq->irq_lock);
+		spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
+
+		spin_lock_irqsave(&irq->irq_lock, flags);
+		goto retry;
+	}
+
+	/*
+	 * Grab a reference to the irq to reflect the fact that it is
+	 * now in the ap_list.
+	 */
+	vgic_get_irq_kref(irq);
+	list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
+	irq->vcpu = vcpu;
+
+	spin_unlock(&irq->irq_lock);
+	spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
+
+	kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+	kvm_vcpu_kick(vcpu);
+
+	return true;
+}
+
+/**
+ * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
+ * @kvm:     The VM structure pointer
+ * @cpuid:   The CPU for PPIs
+ * @intid:   The INTID to inject a new state to.
+ * @level:   Edge-triggered:  true:  to trigger the interrupt
+ *			      false: to ignore the call
+ *	     Level-sensitive  true:  raise the input signal
+ *			      false: lower the input signal
+ * @owner:   The opaque pointer to the owner of the IRQ being raised to verify
+ *           that the caller is allowed to inject this IRQ.  Userspace
+ *           injections will have owner == NULL.
+ *
+ * The VGIC is not concerned with devices being active-LOW or active-HIGH for
+ * level-sensitive interrupts.  You can think of the level parameter as 1
+ * being HIGH and 0 being LOW and all devices being active-HIGH.
+ */
+int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
+			bool level, void *owner)
+{
+	struct kvm_vcpu *vcpu;
+	struct vgic_irq *irq;
+	unsigned long flags;
+	int ret;
+
+	trace_vgic_update_irq_pending(cpuid, intid, level);
+
+	ret = vgic_lazy_init(kvm);
+	if (ret)
+		return ret;
+
+	vcpu = kvm_get_vcpu(kvm, cpuid);
+	if (!vcpu && intid < VGIC_NR_PRIVATE_IRQS)
+		return -EINVAL;
+
+	irq = vgic_get_irq(kvm, vcpu, intid);
+	if (!irq)
+		return -EINVAL;
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+
+	if (!vgic_validate_injection(irq, level, owner)) {
+		/* Nothing to see here, move along... */
+		spin_unlock_irqrestore(&irq->irq_lock, flags);
+		vgic_put_irq(kvm, irq);
+		return 0;
+	}
+
+	if (irq->config == VGIC_CONFIG_LEVEL)
+		irq->line_level = level;
+	else
+		irq->pending_latch = true;
+
+	vgic_queue_irq_unlock(kvm, irq, flags);
+	vgic_put_irq(kvm, irq);
+
+	return 0;
+}
+
+/* @irq->irq_lock must be held */
+static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
+			    unsigned int host_irq,
+			    bool (*get_input_level)(int vindid))
+{
+	struct irq_desc *desc;
+	struct irq_data *data;
+
+	/*
+	 * Find the physical IRQ number corresponding to @host_irq
+	 */
+	desc = irq_to_desc(host_irq);
+	if (!desc) {
+		kvm_err("%s: no interrupt descriptor\n", __func__);
+		return -EINVAL;
+	}
+	data = irq_desc_get_irq_data(desc);
+	while (data->parent_data)
+		data = data->parent_data;
+
+	irq->hw = true;
+	irq->host_irq = host_irq;
+	irq->hwintid = data->hwirq;
+	irq->get_input_level = get_input_level;
+	return 0;
+}
+
+/* @irq->irq_lock must be held */
+static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
+{
+	irq->hw = false;
+	irq->hwintid = 0;
+	irq->get_input_level = NULL;
+}
+
+int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
+			  u32 vintid, bool (*get_input_level)(int vindid))
+{
+	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
+	unsigned long flags;
+	int ret;
+
+	BUG_ON(!irq);
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	ret = kvm_vgic_map_irq(vcpu, irq, host_irq, get_input_level);
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+	vgic_put_irq(vcpu->kvm, irq);
+
+	return ret;
+}
+
+/**
+ * kvm_vgic_reset_mapped_irq - Reset a mapped IRQ
+ * @vcpu: The VCPU pointer
+ * @vintid: The INTID of the interrupt
+ *
+ * Reset the active and pending states of a mapped interrupt.  Kernel
+ * subsystems injecting mapped interrupts should reset their interrupt lines
+ * when we are doing a reset of the VM.
+ */
+void kvm_vgic_reset_mapped_irq(struct kvm_vcpu *vcpu, u32 vintid)
+{
+	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
+	unsigned long flags;
+
+	if (!irq->hw)
+		goto out;
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	irq->active = false;
+	irq->pending_latch = false;
+	irq->line_level = false;
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+out:
+	vgic_put_irq(vcpu->kvm, irq);
+}
+
+int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
+{
+	struct vgic_irq *irq;
+	unsigned long flags;
+
+	if (!vgic_initialized(vcpu->kvm))
+		return -EAGAIN;
+
+	irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
+	BUG_ON(!irq);
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	kvm_vgic_unmap_irq(irq);
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+	vgic_put_irq(vcpu->kvm, 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;
+	unsigned long flags;
+	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_irqsave(&irq->irq_lock, flags);
+	if (irq->owner && irq->owner != owner)
+		ret = -EEXIST;
+	else
+		irq->owner = owner;
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+
+	return ret;
+}
+
+/**
+ * vgic_prune_ap_list - Remove non-relevant interrupts from the list
+ *
+ * @vcpu: The VCPU pointer
+ *
+ * Go over the list of "interesting" interrupts, and prune those that we
+ * won't have to consider in the near future.
+ */
+static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_irq *irq, *tmp;
+
+	DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
+
+retry:
+	spin_lock(&vgic_cpu->ap_list_lock);
+
+	list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
+		struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
+		bool target_vcpu_needs_kick = false;
+
+		spin_lock(&irq->irq_lock);
+
+		BUG_ON(vcpu != irq->vcpu);
+
+		target_vcpu = vgic_target_oracle(irq);
+
+		if (!target_vcpu) {
+			/*
+			 * We don't need to process this interrupt any
+			 * further, move it off the list.
+			 */
+			list_del(&irq->ap_list);
+			irq->vcpu = NULL;
+			spin_unlock(&irq->irq_lock);
+
+			/*
+			 * This vgic_put_irq call matches the
+			 * vgic_get_irq_kref in vgic_queue_irq_unlock,
+			 * where we added the LPI to the ap_list. As
+			 * we remove the irq from the list, we drop
+			 * also drop the refcount.
+			 */
+			vgic_put_irq(vcpu->kvm, irq);
+			continue;
+		}
+
+		if (target_vcpu == vcpu) {
+			/* We're on the right CPU */
+			spin_unlock(&irq->irq_lock);
+			continue;
+		}
+
+		/* This interrupt looks like it has to be migrated. */
+
+		spin_unlock(&irq->irq_lock);
+		spin_unlock(&vgic_cpu->ap_list_lock);
+
+		/*
+		 * Ensure locking order by always locking the smallest
+		 * ID first.
+		 */
+		if (vcpu->vcpu_id < target_vcpu->vcpu_id) {
+			vcpuA = vcpu;
+			vcpuB = target_vcpu;
+		} else {
+			vcpuA = target_vcpu;
+			vcpuB = vcpu;
+		}
+
+		spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
+		spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
+				 SINGLE_DEPTH_NESTING);
+		spin_lock(&irq->irq_lock);
+
+		/*
+		 * If the affinity has been preserved, move the
+		 * interrupt around. Otherwise, it means things have
+		 * changed while the interrupt was unlocked, and we
+		 * need to replay this.
+		 *
+		 * In all cases, we cannot trust the list not to have
+		 * changed, so we restart from the beginning.
+		 */
+		if (target_vcpu == vgic_target_oracle(irq)) {
+			struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
+
+			list_del(&irq->ap_list);
+			irq->vcpu = target_vcpu;
+			list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
+			target_vcpu_needs_kick = true;
+		}
+
+		spin_unlock(&irq->irq_lock);
+		spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
+		spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
+
+		if (target_vcpu_needs_kick) {
+			kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
+			kvm_vcpu_kick(target_vcpu);
+		}
+
+		goto retry;
+	}
+
+	spin_unlock(&vgic_cpu->ap_list_lock);
+}
+
+static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
+{
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_fold_lr_state(vcpu);
+	else
+		vgic_v3_fold_lr_state(vcpu);
+}
+
+/* Requires the irq_lock to be held. */
+static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
+				    struct vgic_irq *irq, int lr)
+{
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
+
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_populate_lr(vcpu, irq, lr);
+	else
+		vgic_v3_populate_lr(vcpu, irq, lr);
+}
+
+static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)
+{
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_clear_lr(vcpu, lr);
+	else
+		vgic_v3_clear_lr(vcpu, lr);
+}
+
+static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
+{
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_set_underflow(vcpu);
+	else
+		vgic_v3_set_underflow(vcpu);
+}
+
+/* Requires the ap_list_lock to be held. */
+static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
+				 bool *multi_sgi)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_irq *irq;
+	int count = 0;
+
+	*multi_sgi = false;
+
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
+
+	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
+		int w;
+
+		spin_lock(&irq->irq_lock);
+		/* GICv2 SGIs can count for more than one... */
+		w = vgic_irq_get_lr_count(irq);
+		spin_unlock(&irq->irq_lock);
+
+		count += w;
+		*multi_sgi |= (w > 1);
+	}
+	return count;
+}
+
+/* Requires the VCPU's ap_list_lock to be held. */
+static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_irq *irq;
+	int count;
+	bool multi_sgi;
+	u8 prio = 0xff;
+
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
+
+	count = compute_ap_list_depth(vcpu, &multi_sgi);
+	if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
+		vgic_sort_ap_list(vcpu);
+
+	count = 0;
+
+	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
+		spin_lock(&irq->irq_lock);
+
+		/*
+		 * If we have multi-SGIs in the pipeline, we need to
+		 * guarantee that they are all seen before any IRQ of
+		 * lower priority. In that case, we need to filter out
+		 * these interrupts by exiting early. This is easy as
+		 * the AP list has been sorted already.
+		 */
+		if (multi_sgi && irq->priority > prio) {
+			spin_unlock(&irq->irq_lock);
+			break;
+		}
+
+		if (likely(vgic_target_oracle(irq) == vcpu)) {
+			vgic_populate_lr(vcpu, irq, count++);
+
+			if (irq->source)
+				prio = irq->priority;
+		}
+
+		spin_unlock(&irq->irq_lock);
+
+		if (count == kvm_vgic_global_state.nr_lr) {
+			if (!list_is_last(&irq->ap_list,
+					  &vgic_cpu->ap_list_head))
+				vgic_set_underflow(vcpu);
+			break;
+		}
+	}
+
+	vcpu->arch.vgic_cpu.used_lrs = count;
+
+	/* Nuke remaining LRs */
+	for ( ; count < kvm_vgic_global_state.nr_lr; count++)
+		vgic_clear_lr(vcpu, count);
+}
+
+static inline bool can_access_vgic_from_kernel(void)
+{
+	/*
+	 * GICv2 can always be accessed from the kernel because it is
+	 * memory-mapped, and VHE systems can access GICv3 EL2 system
+	 * registers.
+	 */
+	return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
+}
+
+static inline void vgic_save_state(struct kvm_vcpu *vcpu)
+{
+	if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+		vgic_v2_save_state(vcpu);
+	else
+		__vgic_v3_save_state(vcpu);
+}
+
+/* Sync back the hardware VGIC state into our emulation after a guest's run. */
+void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+	WARN_ON(vgic_v4_sync_hwstate(vcpu));
+
+	/* An empty ap_list_head implies used_lrs == 0 */
+	if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
+		return;
+
+	if (can_access_vgic_from_kernel())
+		vgic_save_state(vcpu);
+
+	if (vgic_cpu->used_lrs)
+		vgic_fold_lr_state(vcpu);
+	vgic_prune_ap_list(vcpu);
+}
+
+static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
+{
+	if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+		vgic_v2_restore_state(vcpu);
+	else
+		__vgic_v3_restore_state(vcpu);
+}
+
+/* Flush our emulation state into the GIC hardware before entering the guest. */
+void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	WARN_ON(vgic_v4_flush_hwstate(vcpu));
+
+	/*
+	 * If there are no virtual interrupts active or pending for this
+	 * VCPU, then there is no work to do and we can bail out without
+	 * taking any lock.  There is a potential race with someone injecting
+	 * interrupts to the VCPU, but it is a benign race as the VCPU will
+	 * either observe the new interrupt before or after doing this check,
+	 * and introducing additional synchronization mechanism doesn't change
+	 * this.
+	 */
+	if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
+		return;
+
+	DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
+
+	spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
+	vgic_flush_lr_state(vcpu);
+	spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
+
+	if (can_access_vgic_from_kernel())
+		vgic_restore_state(vcpu);
+}
+
+void kvm_vgic_load(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(!vgic_initialized(vcpu->kvm)))
+		return;
+
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_load(vcpu);
+	else
+		vgic_v3_load(vcpu);
+}
+
+void kvm_vgic_put(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(!vgic_initialized(vcpu->kvm)))
+		return;
+
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_put(vcpu);
+	else
+		vgic_v3_put(vcpu);
+}
+
+void kvm_vgic_vmcr_sync(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
+		return;
+
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_vmcr_sync(vcpu);
+	else
+		vgic_v3_vmcr_sync(vcpu);
+}
+
+int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_irq *irq;
+	bool pending = false;
+	unsigned long flags;
+
+	if (!vcpu->kvm->arch.vgic.enabled)
+		return false;
+
+	if (vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last)
+		return true;
+
+	spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
+
+	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
+		spin_lock(&irq->irq_lock);
+		pending = irq_is_pending(irq) && irq->enabled;
+		spin_unlock(&irq->irq_lock);
+
+		if (pending)
+			break;
+	}
+
+	spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
+
+	return pending;
+}
+
+void vgic_kick_vcpus(struct kvm *kvm)
+{
+	struct kvm_vcpu *vcpu;
+	int c;
+
+	/*
+	 * We've injected an interrupt, time to find out who deserves
+	 * a good kick...
+	 */
+	kvm_for_each_vcpu(c, vcpu, kvm) {
+		if (kvm_vgic_vcpu_pending_irq(vcpu)) {
+			kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+			kvm_vcpu_kick(vcpu);
+		}
+	}
+}
+
+bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
+{
+	struct vgic_irq *irq;
+	bool map_is_active;
+	unsigned long flags;
+
+	if (!vgic_initialized(vcpu->kvm))
+		return false;
+
+	irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	map_is_active = irq->hw && irq->active;
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+	vgic_put_irq(vcpu->kvm, irq);
+
+	return map_is_active;
+}
+