ARM: KVM: move GIC/timer code to a common location

As KVM/arm64 is looming on the horizon, it makes sense to move some
of the common code to a single location in order to reduce duplication.

The code could live anywhere. Actually, most of KVM is already built
with a bunch of ugly ../../.. hacks in the various Makefiles, so we're
not exactly talking about style here. But maybe it is time to start
moving into a less ugly direction.

The include files must be in a "public" location, as they are accessed
from non-KVM files (arch/arm/kernel/asm-offsets.c).

For this purpose, introduce two new locations:
- virt/kvm/arm/ : x86 and ia64 already share the ioapic code in
  virt/kvm, so this could be seen as a (very ugly) precedent.
- include/kvm/  : there is already an include/xen, and while the
  intent is slightly different, this seems as good a location as
  any

Eventually, we should probably have independant Makefiles at every
levels (just like everywhere else in the kernel), but this is just
the first step.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

2 files changed, 1771 insertions, 0 deletions

diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
new file mode 100644
index 00000000000..2d00b292578
--- /dev/null
+++ b/virt/kvm/arm/arch_timer.c
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2012 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/cpu.h>
+#include <linux/of_irq.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+
+#include <clocksource/arm_arch_timer.h>
+#include <asm/arch_timer.h>
+
+#include <kvm/arm_vgic.h>
+#include <kvm/arm_arch_timer.h>
+
+static struct timecounter *timecounter;
+static struct workqueue_struct *wqueue;
+static struct kvm_irq_level timer_irq = {
+	.level	= 1,
+};
+
+static cycle_t kvm_phys_timer_read(void)
+{
+	return timecounter->cc->read(timecounter->cc);
+}
+
+static bool timer_is_armed(struct arch_timer_cpu *timer)
+{
+	return timer->armed;
+}
+
+/* timer_arm: as in "arm the timer", not as in ARM the company */
+static void timer_arm(struct arch_timer_cpu *timer, u64 ns)
+{
+	timer->armed = true;
+	hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
+		      HRTIMER_MODE_ABS);
+}
+
+static void timer_disarm(struct arch_timer_cpu *timer)
+{
+	if (timer_is_armed(timer)) {
+		hrtimer_cancel(&timer->timer);
+		cancel_work_sync(&timer->expired);
+		timer->armed = false;
+	}
+}
+
+static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
+	kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+			    vcpu->arch.timer_cpu.irq->irq,
+			    vcpu->arch.timer_cpu.irq->level);
+}
+
+static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
+{
+	struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
+
+	/*
+	 * We disable the timer in the world switch and let it be
+	 * handled by kvm_timer_sync_hwstate(). Getting a timer
+	 * interrupt at this point is a sure sign of some major
+	 * breakage.
+	 */
+	pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
+	return IRQ_HANDLED;
+}
+
+static void kvm_timer_inject_irq_work(struct work_struct *work)
+{
+	struct kvm_vcpu *vcpu;
+
+	vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired);
+	vcpu->arch.timer_cpu.armed = false;
+	kvm_timer_inject_irq(vcpu);
+}
+
+static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
+{
+	struct arch_timer_cpu *timer;
+	timer = container_of(hrt, struct arch_timer_cpu, timer);
+	queue_work(wqueue, &timer->expired);
+	return HRTIMER_NORESTART;
+}
+
+/**
+ * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Disarm any pending soft timers, since the world-switch code will write the
+ * virtual timer state back to the physical CPU.
+ */
+void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	/*
+	 * We're about to run this vcpu again, so there is no need to
+	 * keep the background timer running, as we're about to
+	 * populate the CPU timer again.
+	 */
+	timer_disarm(timer);
+}
+
+/**
+ * kvm_timer_sync_hwstate - sync timer state from cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Check if the virtual timer was armed and either schedule a corresponding
+ * soft timer or inject directly if already expired.
+ */
+void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+	cycle_t cval, now;
+	u64 ns;
+
+	if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) ||
+		!(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE))
+		return;
+
+	cval = timer->cntv_cval;
+	now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
+
+	BUG_ON(timer_is_armed(timer));
+
+	if (cval <= now) {
+		/*
+		 * Timer has already expired while we were not
+		 * looking. Inject the interrupt and carry on.
+		 */
+		kvm_timer_inject_irq(vcpu);
+		return;
+	}
+
+	ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
+	timer_arm(timer, ns);
+}
+
+void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
+	hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	timer->timer.function = kvm_timer_expire;
+	timer->irq = &timer_irq;
+}
+
+static void kvm_timer_init_interrupt(void *info)
+{
+	enable_percpu_irq(timer_irq.irq, 0);
+}
+
+
+static int kvm_timer_cpu_notify(struct notifier_block *self,
+				unsigned long action, void *cpu)
+{
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		kvm_timer_init_interrupt(NULL);
+		break;
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		disable_percpu_irq(timer_irq.irq);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kvm_timer_cpu_nb = {
+	.notifier_call = kvm_timer_cpu_notify,
+};
+
+static const struct of_device_id arch_timer_of_match[] = {
+	{ .compatible	= "arm,armv7-timer",	},
+	{},
+};
+
+int kvm_timer_hyp_init(void)
+{
+	struct device_node *np;
+	unsigned int ppi;
+	int err;
+
+	timecounter = arch_timer_get_timecounter();
+	if (!timecounter)
+		return -ENODEV;
+
+	np = of_find_matching_node(NULL, arch_timer_of_match);
+	if (!np) {
+		kvm_err("kvm_arch_timer: can't find DT node\n");
+		return -ENODEV;
+	}
+
+	ppi = irq_of_parse_and_map(np, 2);
+	if (!ppi) {
+		kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = request_percpu_irq(ppi, kvm_arch_timer_handler,
+				 "kvm guest timer", kvm_get_running_vcpus());
+	if (err) {
+		kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
+			ppi, err);
+		goto out;
+	}
+
+	timer_irq.irq = ppi;
+
+	err = register_cpu_notifier(&kvm_timer_cpu_nb);
+	if (err) {
+		kvm_err("Cannot register timer CPU notifier\n");
+		goto out_free;
+	}
+
+	wqueue = create_singlethread_workqueue("kvm_arch_timer");
+	if (!wqueue) {
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	kvm_info("%s IRQ%d\n", np->name, ppi);
+	on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
+
+	goto out;
+out_free:
+	free_percpu_irq(ppi, kvm_get_running_vcpus());
+out:
+	of_node_put(np);
+	return err;
+}
+
+void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	timer_disarm(timer);
+}
+
+int kvm_timer_init(struct kvm *kvm)
+{
+	if (timecounter && wqueue) {
+		kvm->arch.timer.cntvoff = kvm_phys_timer_read();
+		kvm->arch.timer.enabled = 1;
+	}
+
+	return 0;
+}
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
new file mode 100644
index 00000000000..17c5ac7d10e
--- /dev/null
+++ b/virt/kvm/arm/vgic.c
@@ -0,0 +1,1499 @@
+/*
+ * Copyright (C) 2012 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/cpu.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <linux/irqchip/arm-gic.h>
+
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_mmu.h>
+
+/*
+ * How the whole thing works (courtesy of Christoffer Dall):
+ *
+ * - At any time, the dist->irq_pending_on_cpu is the oracle that knows if
+ *   something is pending
+ * - VGIC pending interrupts are stored on the vgic.irq_state vgic
+ *   bitmap (this bitmap is updated by both user land ioctls and guest
+ *   mmio ops, and other in-kernel peripherals such as the
+ *   arch. timers) and indicate the 'wire' state.
+ * - Every time the bitmap changes, the irq_pending_on_cpu oracle is
+ *   recalculated
+ * - To calculate the oracle, we need info for each cpu from
+ *   compute_pending_for_cpu, which considers:
+ *   - PPI: dist->irq_state & dist->irq_enable
+ *   - SPI: dist->irq_state & dist->irq_enable & dist->irq_spi_target
+ *   - irq_spi_target is a 'formatted' version of the GICD_ICFGR
+ *     registers, stored on each vcpu. We only keep one bit of
+ *     information per interrupt, making sure that only one vcpu can
+ *     accept the interrupt.
+ * - The same is true when injecting an interrupt, except that we only
+ *   consider a single interrupt at a time. The irq_spi_cpu array
+ *   contains the target CPU for each SPI.
+ *
+ * The handling of level interrupts adds some extra complexity. We
+ * need to track when the interrupt has been EOIed, so we can sample
+ * the 'line' again. This is achieved as such:
+ *
+ * - When a level interrupt is moved onto a vcpu, the corresponding
+ *   bit in irq_active is set. As long as this bit is set, the line
+ *   will be ignored for further interrupts. The interrupt is injected
+ *   into the vcpu with the GICH_LR_EOI bit set (generate a
+ *   maintenance interrupt on EOI).
+ * - When the interrupt is EOIed, the maintenance interrupt fires,
+ *   and clears the corresponding bit in irq_active. This allow the
+ *   interrupt line to be sampled again.
+ */
+
+#define VGIC_ADDR_UNDEF		(-1)
+#define IS_VGIC_ADDR_UNDEF(_x)  ((_x) == VGIC_ADDR_UNDEF)
+
+/* Physical address of vgic virtual cpu interface */
+static phys_addr_t vgic_vcpu_base;
+
+/* Virtual control interface base address */
+static void __iomem *vgic_vctrl_base;
+
+static struct device_node *vgic_node;
+
+#define ACCESS_READ_VALUE	(1 << 0)
+#define ACCESS_READ_RAZ		(0 << 0)
+#define ACCESS_READ_MASK(x)	((x) & (1 << 0))
+#define ACCESS_WRITE_IGNORED	(0 << 1)
+#define ACCESS_WRITE_SETBIT	(1 << 1)
+#define ACCESS_WRITE_CLEARBIT	(2 << 1)
+#define ACCESS_WRITE_VALUE	(3 << 1)
+#define ACCESS_WRITE_MASK(x)	((x) & (3 << 1))
+
+static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
+static void vgic_update_state(struct kvm *kvm);
+static void vgic_kick_vcpus(struct kvm *kvm);
+static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
+static u32 vgic_nr_lr;
+
+static unsigned int vgic_maint_irq;
+
+static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x,
+				int cpuid, u32 offset)
+{
+	offset >>= 2;
+	if (!offset)
+		return x->percpu[cpuid].reg;
+	else
+		return x->shared.reg + offset - 1;
+}
+
+static int vgic_bitmap_get_irq_val(struct vgic_bitmap *x,
+				   int cpuid, int irq)
+{
+	if (irq < VGIC_NR_PRIVATE_IRQS)
+		return test_bit(irq, x->percpu[cpuid].reg_ul);
+
+	return test_bit(irq - VGIC_NR_PRIVATE_IRQS, x->shared.reg_ul);
+}
+
+static void vgic_bitmap_set_irq_val(struct vgic_bitmap *x, int cpuid,
+				    int irq, int val)
+{
+	unsigned long *reg;
+
+	if (irq < VGIC_NR_PRIVATE_IRQS) {
+		reg = x->percpu[cpuid].reg_ul;
+	} else {
+		reg =  x->shared.reg_ul;
+		irq -= VGIC_NR_PRIVATE_IRQS;
+	}
+
+	if (val)
+		set_bit(irq, reg);
+	else
+		clear_bit(irq, reg);
+}
+
+static unsigned long *vgic_bitmap_get_cpu_map(struct vgic_bitmap *x, int cpuid)
+{
+	if (unlikely(cpuid >= VGIC_MAX_CPUS))
+		return NULL;
+	return x->percpu[cpuid].reg_ul;
+}
+
+static unsigned long *vgic_bitmap_get_shared_map(struct vgic_bitmap *x)
+{
+	return x->shared.reg_ul;
+}
+
+static u32 *vgic_bytemap_get_reg(struct vgic_bytemap *x, int cpuid, u32 offset)
+{
+	offset >>= 2;
+	BUG_ON(offset > (VGIC_NR_IRQS / 4));
+	if (offset < 4)
+		return x->percpu[cpuid] + offset;
+	else
+		return x->shared + offset - 8;
+}
+
+#define VGIC_CFG_LEVEL	0
+#define VGIC_CFG_EDGE	1
+
+static bool vgic_irq_is_edge(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int irq_val;
+
+	irq_val = vgic_bitmap_get_irq_val(&dist->irq_cfg, vcpu->vcpu_id, irq);
+	return irq_val == VGIC_CFG_EDGE;
+}
+
+static int vgic_irq_is_enabled(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	return vgic_bitmap_get_irq_val(&dist->irq_enabled, vcpu->vcpu_id, irq);
+}
+
+static int vgic_irq_is_active(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	return vgic_bitmap_get_irq_val(&dist->irq_active, vcpu->vcpu_id, irq);
+}
+
+static void vgic_irq_set_active(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	vgic_bitmap_set_irq_val(&dist->irq_active, vcpu->vcpu_id, irq, 1);
+}
+
+static void vgic_irq_clear_active(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	vgic_bitmap_set_irq_val(&dist->irq_active, vcpu->vcpu_id, irq, 0);
+}
+
+static int vgic_dist_irq_is_pending(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	return vgic_bitmap_get_irq_val(&dist->irq_state, vcpu->vcpu_id, irq);
+}
+
+static void vgic_dist_irq_set(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	vgic_bitmap_set_irq_val(&dist->irq_state, vcpu->vcpu_id, irq, 1);
+}
+
+static void vgic_dist_irq_clear(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	vgic_bitmap_set_irq_val(&dist->irq_state, vcpu->vcpu_id, irq, 0);
+}
+
+static void vgic_cpu_irq_set(struct kvm_vcpu *vcpu, int irq)
+{
+	if (irq < VGIC_NR_PRIVATE_IRQS)
+		set_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
+	else
+		set_bit(irq - VGIC_NR_PRIVATE_IRQS,
+			vcpu->arch.vgic_cpu.pending_shared);
+}
+
+static void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq)
+{
+	if (irq < VGIC_NR_PRIVATE_IRQS)
+		clear_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
+	else
+		clear_bit(irq - VGIC_NR_PRIVATE_IRQS,
+			  vcpu->arch.vgic_cpu.pending_shared);
+}
+
+static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask)
+{
+	return *((u32 *)mmio->data) & mask;
+}
+
+static void mmio_data_write(struct kvm_exit_mmio *mmio, u32 mask, u32 value)
+{
+	*((u32 *)mmio->data) = value & mask;
+}
+
+/**
+ * vgic_reg_access - access vgic register
+ * @mmio:   pointer to the data describing the mmio access
+ * @reg:    pointer to the virtual backing of vgic distributor data
+ * @offset: least significant 2 bits used for word offset
+ * @mode:   ACCESS_ mode (see defines above)
+ *
+ * Helper to make vgic register access easier using one of the access
+ * modes defined for vgic register access
+ * (read,raz,write-ignored,setbit,clearbit,write)
+ */
+static void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
+			    phys_addr_t offset, int mode)
+{
+	int word_offset = (offset & 3) * 8;
+	u32 mask = (1UL << (mmio->len * 8)) - 1;
+	u32 regval;
+
+	/*
+	 * Any alignment fault should have been delivered to the guest
+	 * directly (ARM ARM B3.12.7 "Prioritization of aborts").
+	 */
+
+	if (reg) {
+		regval = *reg;
+	} else {
+		BUG_ON(mode != (ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED));
+		regval = 0;
+	}
+
+	if (mmio->is_write) {
+		u32 data = mmio_data_read(mmio, mask) << word_offset;
+		switch (ACCESS_WRITE_MASK(mode)) {
+		case ACCESS_WRITE_IGNORED:
+			return;
+
+		case ACCESS_WRITE_SETBIT:
+			regval |= data;
+			break;
+
+		case ACCESS_WRITE_CLEARBIT:
+			regval &= ~data;
+			break;
+
+		case ACCESS_WRITE_VALUE:
+			regval = (regval & ~(mask << word_offset)) | data;
+			break;
+		}
+		*reg = regval;
+	} else {
+		switch (ACCESS_READ_MASK(mode)) {
+		case ACCESS_READ_RAZ:
+			regval = 0;
+			/* fall through */
+
+		case ACCESS_READ_VALUE:
+			mmio_data_write(mmio, mask, regval >> word_offset);
+		}
+	}
+}
+
+static bool handle_mmio_misc(struct kvm_vcpu *vcpu,
+			     struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+	u32 reg;
+	u32 word_offset = offset & 3;
+
+	switch (offset & ~3) {
+	case 0:			/* CTLR */
+		reg = vcpu->kvm->arch.vgic.enabled;
+		vgic_reg_access(mmio, &reg, word_offset,
+				ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
+		if (mmio->is_write) {
+			vcpu->kvm->arch.vgic.enabled = reg & 1;
+			vgic_update_state(vcpu->kvm);
+			return true;
+		}
+		break;
+
+	case 4:			/* TYPER */
+		reg  = (atomic_read(&vcpu->kvm->online_vcpus) - 1) << 5;
+		reg |= (VGIC_NR_IRQS >> 5) - 1;
+		vgic_reg_access(mmio, &reg, word_offset,
+				ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
+		break;
+
+	case 8:			/* IIDR */
+		reg = 0x4B00043B;
+		vgic_reg_access(mmio, &reg, word_offset,
+				ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
+		break;
+	}
+
+	return false;
+}
+
+static bool handle_mmio_raz_wi(struct kvm_vcpu *vcpu,
+			       struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+	vgic_reg_access(mmio, NULL, offset,
+			ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED);
+	return false;
+}
+
+static bool handle_mmio_set_enable_reg(struct kvm_vcpu *vcpu,
+				       struct kvm_exit_mmio *mmio,
+				       phys_addr_t offset)
+{
+	u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_enabled,
+				       vcpu->vcpu_id, offset);
+	vgic_reg_access(mmio, reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT);
+	if (mmio->is_write) {
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+static bool handle_mmio_clear_enable_reg(struct kvm_vcpu *vcpu,
+					 struct kvm_exit_mmio *mmio,
+					 phys_addr_t offset)
+{
+	u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_enabled,
+				       vcpu->vcpu_id, offset);
+	vgic_reg_access(mmio, reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);
+	if (mmio->is_write) {
+		if (offset < 4) /* Force SGI enabled */
+			*reg |= 0xffff;
+		vgic_retire_disabled_irqs(vcpu);
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+static bool handle_mmio_set_pending_reg(struct kvm_vcpu *vcpu,
+					struct kvm_exit_mmio *mmio,
+					phys_addr_t offset)
+{
+	u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_state,
+				       vcpu->vcpu_id, offset);
+	vgic_reg_access(mmio, reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT);
+	if (mmio->is_write) {
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+static bool handle_mmio_clear_pending_reg(struct kvm_vcpu *vcpu,
+					  struct kvm_exit_mmio *mmio,
+					  phys_addr_t offset)
+{
+	u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_state,
+				       vcpu->vcpu_id, offset);
+	vgic_reg_access(mmio, reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);
+	if (mmio->is_write) {
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+static bool handle_mmio_priority_reg(struct kvm_vcpu *vcpu,
+				     struct kvm_exit_mmio *mmio,
+				     phys_addr_t offset)
+{
+	u32 *reg = vgic_bytemap_get_reg(&vcpu->kvm->arch.vgic.irq_priority,
+					vcpu->vcpu_id, offset);
+	vgic_reg_access(mmio, reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
+	return false;
+}
+
+#define GICD_ITARGETSR_SIZE	32
+#define GICD_CPUTARGETS_BITS	8
+#define GICD_IRQS_PER_ITARGETSR	(GICD_ITARGETSR_SIZE / GICD_CPUTARGETS_BITS)
+static u32 vgic_get_target_reg(struct kvm *kvm, int irq)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int i, c;
+	unsigned long *bmap;
+	u32 val = 0;
+
+	irq -= VGIC_NR_PRIVATE_IRQS;
+
+	kvm_for_each_vcpu(c, vcpu, kvm) {
+		bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
+		for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
+			if (test_bit(irq + i, bmap))
+				val |= 1 << (c + i * 8);
+	}
+
+	return val;
+}
+
+static void vgic_set_target_reg(struct kvm *kvm, u32 val, int irq)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int i, c;
+	unsigned long *bmap;
+	u32 target;
+
+	irq -= VGIC_NR_PRIVATE_IRQS;
+
+	/*
+	 * Pick the LSB in each byte. This ensures we target exactly
+	 * one vcpu per IRQ. If the byte is null, assume we target
+	 * CPU0.
+	 */
+	for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++) {
+		int shift = i * GICD_CPUTARGETS_BITS;
+		target = ffs((val >> shift) & 0xffU);
+		target = target ? (target - 1) : 0;
+		dist->irq_spi_cpu[irq + i] = target;
+		kvm_for_each_vcpu(c, vcpu, kvm) {
+			bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
+			if (c == target)
+				set_bit(irq + i, bmap);
+			else
+				clear_bit(irq + i, bmap);
+		}
+	}
+}
+
+static bool handle_mmio_target_reg(struct kvm_vcpu *vcpu,
+				   struct kvm_exit_mmio *mmio,
+				   phys_addr_t offset)
+{
+	u32 reg;
+
+	/* We treat the banked interrupts targets as read-only */
+	if (offset < 32) {
+		u32 roreg = 1 << vcpu->vcpu_id;
+		roreg |= roreg << 8;
+		roreg |= roreg << 16;
+
+		vgic_reg_access(mmio, &roreg, offset,
+				ACCESS_READ_VALUE | ACCESS_WRITE_IGNORED);
+		return false;
+	}
+
+	reg = vgic_get_target_reg(vcpu->kvm, offset & ~3U);
+	vgic_reg_access(mmio, &reg, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
+	if (mmio->is_write) {
+		vgic_set_target_reg(vcpu->kvm, reg, offset & ~3U);
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+static u32 vgic_cfg_expand(u16 val)
+{
+	u32 res = 0;
+	int i;
+
+	/*
+	 * Turn a 16bit value like abcd...mnop into a 32bit word
+	 * a0b0c0d0...m0n0o0p0, which is what the HW cfg register is.
+	 */
+	for (i = 0; i < 16; i++)
+		res |= ((val >> i) & VGIC_CFG_EDGE) << (2 * i + 1);
+
+	return res;
+}
+
+static u16 vgic_cfg_compress(u32 val)
+{
+	u16 res = 0;
+	int i;
+
+	/*
+	 * Turn a 32bit word a0b0c0d0...m0n0o0p0 into 16bit value like
+	 * abcd...mnop which is what we really care about.
+	 */
+	for (i = 0; i < 16; i++)
+		res |= ((val >> (i * 2 + 1)) & VGIC_CFG_EDGE) << i;
+
+	return res;
+}
+
+/*
+ * The distributor uses 2 bits per IRQ for the CFG register, but the
+ * LSB is always 0. As such, we only keep the upper bit, and use the
+ * two above functions to compress/expand the bits
+ */
+static bool handle_mmio_cfg_reg(struct kvm_vcpu *vcpu,
+				struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+	u32 val;
+	u32 *reg = vgic_bitmap_get_reg(&vcpu->kvm->arch.vgic.irq_cfg,
+				       vcpu->vcpu_id, offset >> 1);
+	if (offset & 2)
+		val = *reg >> 16;
+	else
+		val = *reg & 0xffff;
+
+	val = vgic_cfg_expand(val);
+	vgic_reg_access(mmio, &val, offset,
+			ACCESS_READ_VALUE | ACCESS_WRITE_VALUE);
+	if (mmio->is_write) {
+		if (offset < 4) {
+			*reg = ~0U; /* Force PPIs/SGIs to 1 */
+			return false;
+		}
+
+		val = vgic_cfg_compress(val);
+		if (offset & 2) {
+			*reg &= 0xffff;
+			*reg |= val << 16;
+		} else {
+			*reg &= 0xffff << 16;
+			*reg |= val;
+		}
+	}
+
+	return false;
+}
+
+static bool handle_mmio_sgi_reg(struct kvm_vcpu *vcpu,
+				struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+	u32 reg;
+	vgic_reg_access(mmio, &reg, offset,
+			ACCESS_READ_RAZ | ACCESS_WRITE_VALUE);
+	if (mmio->is_write) {
+		vgic_dispatch_sgi(vcpu, reg);
+		vgic_update_state(vcpu->kvm);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * I would have liked to use the kvm_bus_io_*() API instead, but it
+ * cannot cope with banked registers (only the VM pointer is passed
+ * around, and we need the vcpu). One of these days, someone please
+ * fix it!
+ */
+struct mmio_range {
+	phys_addr_t base;
+	unsigned long len;
+	bool (*handle_mmio)(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
+			    phys_addr_t offset);
+};
+
+static const struct mmio_range vgic_ranges[] = {
+	{
+		.base		= GIC_DIST_CTRL,
+		.len		= 12,
+		.handle_mmio	= handle_mmio_misc,
+	},
+	{
+		.base		= GIC_DIST_IGROUP,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_raz_wi,
+	},
+	{
+		.base		= GIC_DIST_ENABLE_SET,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_set_enable_reg,
+	},
+	{
+		.base		= GIC_DIST_ENABLE_CLEAR,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_clear_enable_reg,
+	},
+	{
+		.base		= GIC_DIST_PENDING_SET,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_set_pending_reg,
+	},
+	{
+		.base		= GIC_DIST_PENDING_CLEAR,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_clear_pending_reg,
+	},
+	{
+		.base		= GIC_DIST_ACTIVE_SET,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_raz_wi,
+	},
+	{
+		.base		= GIC_DIST_ACTIVE_CLEAR,
+		.len		= VGIC_NR_IRQS / 8,
+		.handle_mmio	= handle_mmio_raz_wi,
+	},
+	{
+		.base		= GIC_DIST_PRI,
+		.len		= VGIC_NR_IRQS,
+		.handle_mmio	= handle_mmio_priority_reg,
+	},
+	{
+		.base		= GIC_DIST_TARGET,
+		.len		= VGIC_NR_IRQS,
+		.handle_mmio	= handle_mmio_target_reg,
+	},
+	{
+		.base		= GIC_DIST_CONFIG,
+		.len		= VGIC_NR_IRQS / 4,
+		.handle_mmio	= handle_mmio_cfg_reg,
+	},
+	{
+		.base		= GIC_DIST_SOFTINT,
+		.len		= 4,
+		.handle_mmio	= handle_mmio_sgi_reg,
+	},
+	{}
+};
+
+static const
+struct mmio_range *find_matching_range(const struct mmio_range *ranges,
+				       struct kvm_exit_mmio *mmio,
+				       phys_addr_t base)
+{
+	const struct mmio_range *r = ranges;
+	phys_addr_t addr = mmio->phys_addr - base;
+
+	while (r->len) {
+		if (addr >= r->base &&
+		    (addr + mmio->len) <= (r->base + r->len))
+			return r;
+		r++;
+	}
+
+	return NULL;
+}
+
+/**
+ * vgic_handle_mmio - handle an in-kernel MMIO access
+ * @vcpu:	pointer to the vcpu performing the access
+ * @run:	pointer to the kvm_run structure
+ * @mmio:	pointer to the data describing the access
+ *
+ * returns true if the MMIO access has been performed in kernel space,
+ * and false if it needs to be emulated in user space.
+ */
+bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
+		      struct kvm_exit_mmio *mmio)
+{
+	const struct mmio_range *range;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	unsigned long base = dist->vgic_dist_base;
+	bool updated_state;
+	unsigned long offset;
+
+	if (!irqchip_in_kernel(vcpu->kvm) ||
+	    mmio->phys_addr < base ||
+	    (mmio->phys_addr + mmio->len) > (base + KVM_VGIC_V2_DIST_SIZE))
+		return false;
+
+	/* We don't support ldrd / strd or ldm / stm to the emulated vgic */
+	if (mmio->len > 4) {
+		kvm_inject_dabt(vcpu, mmio->phys_addr);
+		return true;
+	}
+
+	range = find_matching_range(vgic_ranges, mmio, base);
+	if (unlikely(!range || !range->handle_mmio)) {
+		pr_warn("Unhandled access %d %08llx %d\n",
+			mmio->is_write, mmio->phys_addr, mmio->len);
+		return false;
+	}
+
+	spin_lock(&vcpu->kvm->arch.vgic.lock);
+	offset = mmio->phys_addr - range->base - base;
+	updated_state = range->handle_mmio(vcpu, mmio, offset);
+	spin_unlock(&vcpu->kvm->arch.vgic.lock);
+	kvm_prepare_mmio(run, mmio);
+	kvm_handle_mmio_return(vcpu, run);
+
+	if (updated_state)
+		vgic_kick_vcpus(vcpu->kvm);
+
+	return true;
+}
+
+static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	int nrcpus = atomic_read(&kvm->online_vcpus);
+	u8 target_cpus;
+	int sgi, mode, c, vcpu_id;
+
+	vcpu_id = vcpu->vcpu_id;
+
+	sgi = reg & 0xf;
+	target_cpus = (reg >> 16) & 0xff;
+	mode = (reg >> 24) & 3;
+
+	switch (mode) {
+	case 0:
+		if (!target_cpus)
+			return;
+
+	case 1:
+		target_cpus = ((1 << nrcpus) - 1) & ~(1 << vcpu_id) & 0xff;
+		break;
+
+	case 2:
+		target_cpus = 1 << vcpu_id;
+		break;
+	}
+
+	kvm_for_each_vcpu(c, vcpu, kvm) {
+		if (target_cpus & 1) {
+			/* Flag the SGI as pending */
+			vgic_dist_irq_set(vcpu, sgi);
+			dist->irq_sgi_sources[c][sgi] |= 1 << vcpu_id;
+			kvm_debug("SGI%d from CPU%d to CPU%d\n", sgi, vcpu_id, c);
+		}
+
+		target_cpus >>= 1;
+	}
+}
+
+static int compute_pending_for_cpu(struct kvm_vcpu *vcpu)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	unsigned long *pending, *enabled, *pend_percpu, *pend_shared;
+	unsigned long pending_private, pending_shared;
+	int vcpu_id;
+
+	vcpu_id = vcpu->vcpu_id;
+	pend_percpu = vcpu->arch.vgic_cpu.pending_percpu;
+	pend_shared = vcpu->arch.vgic_cpu.pending_shared;
+
+	pending = vgic_bitmap_get_cpu_map(&dist->irq_state, vcpu_id);
+	enabled = vgic_bitmap_get_cpu_map(&dist->irq_enabled, vcpu_id);
+	bitmap_and(pend_percpu, pending, enabled, VGIC_NR_PRIVATE_IRQS);
+
+	pending = vgic_bitmap_get_shared_map(&dist->irq_state);
+	enabled = vgic_bitmap_get_shared_map(&dist->irq_enabled);
+	bitmap_and(pend_shared, pending, enabled, VGIC_NR_SHARED_IRQS);
+	bitmap_and(pend_shared, pend_shared,
+		   vgic_bitmap_get_shared_map(&dist->irq_spi_target[vcpu_id]),
+		   VGIC_NR_SHARED_IRQS);
+
+	pending_private = find_first_bit(pend_percpu, VGIC_NR_PRIVATE_IRQS);
+	pending_shared = find_first_bit(pend_shared, VGIC_NR_SHARED_IRQS);
+	return (pending_private < VGIC_NR_PRIVATE_IRQS ||
+		pending_shared < VGIC_NR_SHARED_IRQS);
+}
+
+/*
+ * Update the interrupt state and determine which CPUs have pending
+ * interrupts. Must be called with distributor lock held.
+ */
+static void vgic_update_state(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int c;
+
+	if (!dist->enabled) {
+		set_bit(0, &dist->irq_pending_on_cpu);
+		return;
+	}
+
+	kvm_for_each_vcpu(c, vcpu, kvm) {
+		if (compute_pending_for_cpu(vcpu)) {
+			pr_debug("CPU%d has pending interrupts\n", c);
+			set_bit(c, &dist->irq_pending_on_cpu);
+		}
+	}
+}
+
+#define LR_CPUID(lr)	\
+	(((lr) & GICH_LR_PHYSID_CPUID) >> GICH_LR_PHYSID_CPUID_SHIFT)
+#define MK_LR_PEND(src, irq)	\
+	(GICH_LR_PENDING_BIT | ((src) << GICH_LR_PHYSID_CPUID_SHIFT) | (irq))
+
+/*
+ * An interrupt may have been disabled after being made pending on the
+ * CPU interface (the classic case is a timer running while we're
+ * rebooting the guest - the interrupt would kick as soon as the CPU
+ * interface gets enabled, with deadly consequences).
+ *
+ * The solution is to examine already active LRs, and check the
+ * interrupt is still enabled. If not, just retire it.
+ */
+static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	int lr;
+
+	for_each_set_bit(lr, vgic_cpu->lr_used, vgic_cpu->nr_lr) {
+		int irq = vgic_cpu->vgic_lr[lr] & GICH_LR_VIRTUALID;
+
+		if (!vgic_irq_is_enabled(vcpu, irq)) {
+			vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
+			clear_bit(lr, vgic_cpu->lr_used);
+			vgic_cpu->vgic_lr[lr] &= ~GICH_LR_STATE;
+			if (vgic_irq_is_active(vcpu, irq))
+				vgic_irq_clear_active(vcpu, irq);
+		}
+	}
+}
+
+/*
+ * Queue an interrupt to a CPU virtual interface. Return true on success,
+ * or false if it wasn't possible to queue it.
+ */
+static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	int lr;
+
+	/* Sanitize the input... */
+	BUG_ON(sgi_source_id & ~7);
+	BUG_ON(sgi_source_id && irq >= VGIC_NR_SGIS);
+	BUG_ON(irq >= VGIC_NR_IRQS);
+
+	kvm_debug("Queue IRQ%d\n", irq);
+
+	lr = vgic_cpu->vgic_irq_lr_map[irq];
+
+	/* Do we have an active interrupt for the same CPUID? */
+	if (lr != LR_EMPTY &&
+	    (LR_CPUID(vgic_cpu->vgic_lr[lr]) == sgi_source_id)) {
+		kvm_debug("LR%d piggyback for IRQ%d %x\n",
+			  lr, irq, vgic_cpu->vgic_lr[lr]);
+		BUG_ON(!test_bit(lr, vgic_cpu->lr_used));
+		vgic_cpu->vgic_lr[lr] |= GICH_LR_PENDING_BIT;
+		return true;
+	}
+
+	/* Try to use another LR for this interrupt */
+	lr = find_first_zero_bit((unsigned long *)vgic_cpu->lr_used,
+			       vgic_cpu->nr_lr);
+	if (lr >= vgic_cpu->nr_lr)
+		return false;
+
+	kvm_debug("LR%d allocated for IRQ%d %x\n", lr, irq, sgi_source_id);
+	vgic_cpu->vgic_lr[lr] = MK_LR_PEND(sgi_source_id, irq);
+	vgic_cpu->vgic_irq_lr_map[irq] = lr;
+	set_bit(lr, vgic_cpu->lr_used);
+
+	if (!vgic_irq_is_edge(vcpu, irq))
+		vgic_cpu->vgic_lr[lr] |= GICH_LR_EOI;
+
+	return true;
+}
+
+static bool vgic_queue_sgi(struct kvm_vcpu *vcpu, int irq)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	unsigned long sources;
+	int vcpu_id = vcpu->vcpu_id;
+	int c;
+
+	sources = dist->irq_sgi_sources[vcpu_id][irq];
+
+	for_each_set_bit(c, &sources, VGIC_MAX_CPUS) {
+		if (vgic_queue_irq(vcpu, c, irq))
+			clear_bit(c, &sources);
+	}
+
+	dist->irq_sgi_sources[vcpu_id][irq] = sources;
+
+	/*
+	 * If the sources bitmap has been cleared it means that we
+	 * could queue all the SGIs onto link registers (see the
+	 * clear_bit above), and therefore we are done with them in
+	 * our emulated gic and can get rid of them.
+	 */
+	if (!sources) {
+		vgic_dist_irq_clear(vcpu, irq);
+		vgic_cpu_irq_clear(vcpu, irq);
+		return true;
+	}
+
+	return false;
+}
+
+static bool vgic_queue_hwirq(struct kvm_vcpu *vcpu, int irq)
+{
+	if (vgic_irq_is_active(vcpu, irq))
+		return true; /* level interrupt, already queued */
+
+	if (vgic_queue_irq(vcpu, 0, irq)) {
+		if (vgic_irq_is_edge(vcpu, irq)) {
+			vgic_dist_irq_clear(vcpu, irq);
+			vgic_cpu_irq_clear(vcpu, irq);
+		} else {
+			vgic_irq_set_active(vcpu, irq);
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Fill the list registers with pending interrupts before running the
+ * guest.
+ */
+static void __kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int i, vcpu_id;
+	int overflow = 0;
+
+	vcpu_id = vcpu->vcpu_id;
+
+	/*
+	 * We may not have any pending interrupt, or the interrupts
+	 * may have been serviced from another vcpu. In all cases,
+	 * move along.
+	 */
+	if (!kvm_vgic_vcpu_pending_irq(vcpu)) {
+		pr_debug("CPU%d has no pending interrupt\n", vcpu_id);
+		goto epilog;
+	}
+
+	/* SGIs */
+	for_each_set_bit(i, vgic_cpu->pending_percpu, VGIC_NR_SGIS) {
+		if (!vgic_queue_sgi(vcpu, i))
+			overflow = 1;
+	}
+
+	/* PPIs */
+	for_each_set_bit_from(i, vgic_cpu->pending_percpu, VGIC_NR_PRIVATE_IRQS) {
+		if (!vgic_queue_hwirq(vcpu, i))
+			overflow = 1;
+	}
+
+	/* SPIs */
+	for_each_set_bit(i, vgic_cpu->pending_shared, VGIC_NR_SHARED_IRQS) {
+		if (!vgic_queue_hwirq(vcpu, i + VGIC_NR_PRIVATE_IRQS))
+			overflow = 1;
+	}
+
+epilog:
+	if (overflow) {
+		vgic_cpu->vgic_hcr |= GICH_HCR_UIE;
+	} else {
+		vgic_cpu->vgic_hcr &= ~GICH_HCR_UIE;
+		/*
+		 * We're about to run this VCPU, and we've consumed
+		 * everything the distributor had in store for
+		 * us. Claim we don't have anything pending. We'll
+		 * adjust that if needed while exiting.
+		 */
+		clear_bit(vcpu_id, &dist->irq_pending_on_cpu);
+	}
+}
+
+static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	bool level_pending = false;
+
+	kvm_debug("MISR = %08x\n", vgic_cpu->vgic_misr);
+
+	if (vgic_cpu->vgic_misr & GICH_MISR_EOI) {
+		/*
+		 * Some level interrupts have been EOIed. Clear their
+		 * active bit.
+		 */
+		int lr, irq;
+
+		for_each_set_bit(lr, (unsigned long *)vgic_cpu->vgic_eisr,
+				 vgic_cpu->nr_lr) {
+			irq = vgic_cpu->vgic_lr[lr] & GICH_LR_VIRTUALID;
+
+			vgic_irq_clear_active(vcpu, irq);
+			vgic_cpu->vgic_lr[lr] &= ~GICH_LR_EOI;
+
+			/* Any additional pending interrupt? */
+			if (vgic_dist_irq_is_pending(vcpu, irq)) {
+				vgic_cpu_irq_set(vcpu, irq);
+				level_pending = true;
+			} else {
+				vgic_cpu_irq_clear(vcpu, irq);
+			}
+
+			/*
+			 * Despite being EOIed, the LR may not have
+			 * been marked as empty.
+			 */
+			set_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr);
+			vgic_cpu->vgic_lr[lr] &= ~GICH_LR_ACTIVE_BIT;
+		}
+	}
+
+	if (vgic_cpu->vgic_misr & GICH_MISR_U)
+		vgic_cpu->vgic_hcr &= ~GICH_HCR_UIE;
+
+	return level_pending;
+}
+
+/*
+ * Sync back the VGIC state after a guest run. The distributor lock is
+ * needed so we don't get preempted in the middle of the state processing.
+ */
+static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int lr, pending;
+	bool level_pending;
+
+	level_pending = vgic_process_maintenance(vcpu);
+
+	/* Clear mappings for empty LRs */
+	for_each_set_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr,
+			 vgic_cpu->nr_lr) {
+		int irq;
+
+		if (!test_and_clear_bit(lr, vgic_cpu->lr_used))
+			continue;
+
+		irq = vgic_cpu->vgic_lr[lr] & GICH_LR_VIRTUALID;
+
+		BUG_ON(irq >= VGIC_NR_IRQS);
+		vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
+	}
+
+	/* Check if we still have something up our sleeve... */
+	pending = find_first_zero_bit((unsigned long *)vgic_cpu->vgic_elrsr,
+				      vgic_cpu->nr_lr);
+	if (level_pending || pending < vgic_cpu->nr_lr)
+		set_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
+}
+
+void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	if (!irqchip_in_kernel(vcpu->kvm))
+		return;
+
+	spin_lock(&dist->lock);
+	__kvm_vgic_flush_hwstate(vcpu);
+	spin_unlock(&dist->lock);
+}
+
+void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	if (!irqchip_in_kernel(vcpu->kvm))
+		return;
+
+	spin_lock(&dist->lock);
+	__kvm_vgic_sync_hwstate(vcpu);
+	spin_unlock(&dist->lock);
+}
+
+int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	if (!irqchip_in_kernel(vcpu->kvm))
+		return 0;
+
+	return test_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
+}
+
+static 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_vcpu_kick(vcpu);
+	}
+}
+
+static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level)
+{
+	int is_edge = vgic_irq_is_edge(vcpu, irq);
+	int state = vgic_dist_irq_is_pending(vcpu, irq);
+
+	/*
+	 * Only inject an interrupt if:
+	 * - edge triggered and we have a rising edge
+	 * - level triggered and we change level
+	 */
+	if (is_edge)
+		return level > state;
+	else
+		return level != state;
+}
+
+static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
+				  unsigned int irq_num, bool level)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int is_edge, is_level;
+	int enabled;
+	bool ret = true;
+
+	spin_lock(&dist->lock);
+
+	vcpu = kvm_get_vcpu(kvm, cpuid);
+	is_edge = vgic_irq_is_edge(vcpu, irq_num);
+	is_level = !is_edge;
+
+	if (!vgic_validate_injection(vcpu, irq_num, level)) {
+		ret = false;
+		goto out;
+	}
+
+	if (irq_num >= VGIC_NR_PRIVATE_IRQS) {
+		cpuid = dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS];
+		vcpu = kvm_get_vcpu(kvm, cpuid);
+	}
+
+	kvm_debug("Inject IRQ%d level %d CPU%d\n", irq_num, level, cpuid);
+
+	if (level)
+		vgic_dist_irq_set(vcpu, irq_num);
+	else
+		vgic_dist_irq_clear(vcpu, irq_num);
+
+	enabled = vgic_irq_is_enabled(vcpu, irq_num);
+
+	if (!enabled) {
+		ret = false;
+		goto out;
+	}
+
+	if (is_level && vgic_irq_is_active(vcpu, irq_num)) {
+		/*
+		 * Level interrupt in progress, will be picked up
+		 * when EOId.
+		 */
+		ret = false;
+		goto out;
+	}
+
+	if (level) {
+		vgic_cpu_irq_set(vcpu, irq_num);
+		set_bit(cpuid, &dist->irq_pending_on_cpu);
+	}
+
+out:
+	spin_unlock(&dist->lock);
+
+	return ret;
+}
+
+/**
+ * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
+ * @kvm:     The VM structure pointer
+ * @cpuid:   The CPU for PPIs
+ * @irq_num: The IRQ number that is assigned to the device
+ * @level:   Edge-triggered:  true:  to trigger the interrupt
+ *			      false: to ignore the call
+ *	     Level-sensitive  true:  activates an interrupt
+ *			      false: deactivates an interrupt
+ *
+ * The GIC 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 irq_num,
+			bool level)
+{
+	if (vgic_update_irq_state(kvm, cpuid, irq_num, level))
+		vgic_kick_vcpus(kvm);
+
+	return 0;
+}
+
+static irqreturn_t vgic_maintenance_handler(int irq, void *data)
+{
+	/*
+	 * We cannot rely on the vgic maintenance interrupt to be
+	 * delivered synchronously. This means we can only use it to
+	 * exit the VM, and we perform the handling of EOIed
+	 * interrupts on the exit path (see vgic_process_maintenance).
+	 */
+	return IRQ_HANDLED;
+}
+
+int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int i;
+
+	if (!irqchip_in_kernel(vcpu->kvm))
+		return 0;
+
+	if (vcpu->vcpu_id >= VGIC_MAX_CPUS)
+		return -EBUSY;
+
+	for (i = 0; i < VGIC_NR_IRQS; i++) {
+		if (i < VGIC_NR_PPIS)
+			vgic_bitmap_set_irq_val(&dist->irq_enabled,
+						vcpu->vcpu_id, i, 1);
+		if (i < VGIC_NR_PRIVATE_IRQS)
+			vgic_bitmap_set_irq_val(&dist->irq_cfg,
+						vcpu->vcpu_id, i, VGIC_CFG_EDGE);
+
+		vgic_cpu->vgic_irq_lr_map[i] = LR_EMPTY;
+	}
+
+	/*
+	 * By forcing VMCR to zero, the GIC will restore the binary
+	 * points to their reset values. Anything else resets to zero
+	 * anyway.
+	 */
+	vgic_cpu->vgic_vmcr = 0;
+
+	vgic_cpu->nr_lr = vgic_nr_lr;
+	vgic_cpu->vgic_hcr = GICH_HCR_EN; /* Get the show on the road... */
+
+	return 0;
+}
+
+static void vgic_init_maintenance_interrupt(void *info)
+{
+	enable_percpu_irq(vgic_maint_irq, 0);
+}
+
+static int vgic_cpu_notify(struct notifier_block *self,
+			   unsigned long action, void *cpu)
+{
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		vgic_init_maintenance_interrupt(NULL);
+		break;
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		disable_percpu_irq(vgic_maint_irq);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block vgic_cpu_nb = {
+	.notifier_call = vgic_cpu_notify,
+};
+
+int kvm_vgic_hyp_init(void)
+{
+	int ret;
+	struct resource vctrl_res;
+	struct resource vcpu_res;
+
+	vgic_node = of_find_compatible_node(NULL, NULL, "arm,cortex-a15-gic");
+	if (!vgic_node) {
+		kvm_err("error: no compatible vgic node in DT\n");
+		return -ENODEV;
+	}
+
+	vgic_maint_irq = irq_of_parse_and_map(vgic_node, 0);
+	if (!vgic_maint_irq) {
+		kvm_err("error getting vgic maintenance irq from DT\n");
+		ret = -ENXIO;
+		goto out;
+	}
+
+	ret = request_percpu_irq(vgic_maint_irq, vgic_maintenance_handler,
+				 "vgic", kvm_get_running_vcpus());
+	if (ret) {
+		kvm_err("Cannot register interrupt %d\n", vgic_maint_irq);
+		goto out;
+	}
+
+	ret = register_cpu_notifier(&vgic_cpu_nb);
+	if (ret) {
+		kvm_err("Cannot register vgic CPU notifier\n");
+		goto out_free_irq;
+	}
+
+	ret = of_address_to_resource(vgic_node, 2, &vctrl_res);
+	if (ret) {
+		kvm_err("Cannot obtain VCTRL resource\n");
+		goto out_free_irq;
+	}
+
+	vgic_vctrl_base = of_iomap(vgic_node, 2);
+	if (!vgic_vctrl_base) {
+		kvm_err("Cannot ioremap VCTRL\n");
+		ret = -ENOMEM;
+		goto out_free_irq;
+	}
+
+	vgic_nr_lr = readl_relaxed(vgic_vctrl_base + GICH_VTR);
+	vgic_nr_lr = (vgic_nr_lr & 0x3f) + 1;
+
+	ret = create_hyp_io_mappings(vgic_vctrl_base,
+				     vgic_vctrl_base + resource_size(&vctrl_res),
+				     vctrl_res.start);
+	if (ret) {
+		kvm_err("Cannot map VCTRL into hyp\n");
+		goto out_unmap;
+	}
+
+	kvm_info("%s@%llx IRQ%d\n", vgic_node->name,
+		 vctrl_res.start, vgic_maint_irq);
+	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
+
+	if (of_address_to_resource(vgic_node, 3, &vcpu_res)) {
+		kvm_err("Cannot obtain VCPU resource\n");
+		ret = -ENXIO;
+		goto out_unmap;
+	}
+	vgic_vcpu_base = vcpu_res.start;
+
+	goto out;
+
+out_unmap:
+	iounmap(vgic_vctrl_base);
+out_free_irq:
+	free_percpu_irq(vgic_maint_irq, kvm_get_running_vcpus());
+out:
+	of_node_put(vgic_node);
+	return ret;
+}
+
+int kvm_vgic_init(struct kvm *kvm)
+{
+	int ret = 0, i;
+
+	mutex_lock(&kvm->lock);
+
+	if (vgic_initialized(kvm))
+		goto out;
+
+	if (IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_dist_base) ||
+	    IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_cpu_base)) {
+		kvm_err("Need to set vgic cpu and dist addresses first\n");
+		ret = -ENXIO;
+		goto out;
+	}
+
+	ret = kvm_phys_addr_ioremap(kvm, kvm->arch.vgic.vgic_cpu_base,
+				    vgic_vcpu_base, KVM_VGIC_V2_CPU_SIZE);
+	if (ret) {
+		kvm_err("Unable to remap VGIC CPU to VCPU\n");
+		goto out;
+	}
+
+	for (i = VGIC_NR_PRIVATE_IRQS; i < VGIC_NR_IRQS; i += 4)
+		vgic_set_target_reg(kvm, 0, i);
+
+	kvm_timer_init(kvm);
+	kvm->arch.vgic.ready = true;
+out:
+	mutex_unlock(&kvm->lock);
+	return ret;
+}
+
+int kvm_vgic_create(struct kvm *kvm)
+{
+	int ret = 0;
+
+	mutex_lock(&kvm->lock);
+
+	if (atomic_read(&kvm->online_vcpus) || kvm->arch.vgic.vctrl_base) {
+		ret = -EEXIST;
+		goto out;
+	}
+
+	spin_lock_init(&kvm->arch.vgic.lock);
+	kvm->arch.vgic.vctrl_base = vgic_vctrl_base;
+	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
+	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
+
+out:
+	mutex_unlock(&kvm->lock);
+	return ret;
+}
+
+static bool vgic_ioaddr_overlap(struct kvm *kvm)
+{
+	phys_addr_t dist = kvm->arch.vgic.vgic_dist_base;
+	phys_addr_t cpu = kvm->arch.vgic.vgic_cpu_base;
+
+	if (IS_VGIC_ADDR_UNDEF(dist) || IS_VGIC_ADDR_UNDEF(cpu))
+		return 0;
+	if ((dist <= cpu && dist + KVM_VGIC_V2_DIST_SIZE > cpu) ||
+	    (cpu <= dist && cpu + KVM_VGIC_V2_CPU_SIZE > dist))
+		return -EBUSY;
+	return 0;
+}
+
+static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
+			      phys_addr_t addr, phys_addr_t size)
+{
+	int ret;
+
+	if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
+		return -EEXIST;
+	if (addr + size < addr)
+		return -EINVAL;
+
+	ret = vgic_ioaddr_overlap(kvm);
+	if (ret)
+		return ret;
+	*ioaddr = addr;
+	return ret;
+}
+
+int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
+{
+	int r = 0;
+	struct vgic_dist *vgic = &kvm->arch.vgic;
+
+	if (addr & ~KVM_PHYS_MASK)
+		return -E2BIG;
+
+	if (addr & (SZ_4K - 1))
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+	switch (type) {
+	case KVM_VGIC_V2_ADDR_TYPE_DIST:
+		r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
+				       addr, KVM_VGIC_V2_DIST_SIZE);
+		break;
+	case KVM_VGIC_V2_ADDR_TYPE_CPU:
+		r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
+				       addr, KVM_VGIC_V2_CPU_SIZE);
+		break;
+	default:
+		r = -ENODEV;
+	}
+
+	mutex_unlock(&kvm->lock);
+	return r;
+}