virt/kvm/arm/vgic.c

/*
 * 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/rculist.h>
#include <linux/uaccess.h>

#include <asm/kvm_emulate.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <trace/events/kvm.h>
#include <asm/kvm.h>
#include <kvm/iodev.h>

#define CREATE_TRACE_POINTS
#include "trace.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 on the CPU interface.
 * - Interrupts that are pending on the distributor are stored on the
 *   vgic.irq_pending 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).
 * - 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_pending & dist->irq_enable
 *   - SPI: dist->irq_pending & dist->irq_enable & dist->irq_spi_target
 *   - irq_spi_target is a 'formatted' version of the GICD_ITARGETSRn
 *     registers, stored on each vcpu. We only keep one bit of
 *     information per interrupt, making sure that only one vcpu can
 *     accept the interrupt.
 * - If any of the above state changes, we must recalculate the oracle.
 * - 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_queued 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_queued. This allows the
 *   interrupt line to be sampled again.
 * - Note that level-triggered interrupts can also be set to pending from
 *   writes to GICD_ISPENDRn and lowering the external input line does not
 *   cause the interrupt to become inactive in such a situation.
 *   Conversely, writes to GICD_ICPENDRn do not cause the interrupt to become
 *   inactive as long as the external input line is held high.
 *
 *
 * Initialization rules: there are multiple stages to the vgic
 * initialization, both for the distributor and the CPU interfaces.
 *
 * Distributor:
 *
 * - kvm_vgic_early_init(): initialization of static data that doesn't
 *   depend on any sizing information or emulation type. No allocation
 *   is allowed there.
 *
 * - vgic_init(): allocation and initialization of the generic data
 *   structures that depend on sizing information (number of CPUs,
 *   number of interrupts). Also initializes the vcpu specific data
 *   structures. Can be executed lazily for GICv2.
 *   [to be renamed to kvm_vgic_init??]
 *
 * CPU Interface:
 *
 * - kvm_vgic_cpu_early_init(): initialization of static data that
 *   doesn't depend on any sizing information or emulation type. No
 *   allocation is allowed there.
 */

#include "vgic.h"

static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
static void vgic_retire_lr(int lr_nr, struct kvm_vcpu *vcpu);
static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc);
static u64 vgic_get_elrsr(struct kvm_vcpu *vcpu);
static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu,
						int virt_irq);
static int compute_pending_for_cpu(struct kvm_vcpu *vcpu);

static const struct vgic_ops *vgic_ops;
static const struct vgic_params *vgic;

static void add_sgi_source(struct kvm_vcpu *vcpu, int irq, int source)
{
	vcpu->kvm->arch.vgic.vm_ops.add_sgi_source(vcpu, irq, source);
}

static bool queue_sgi(struct kvm_vcpu *vcpu, int irq)
{
	return vcpu->kvm->arch.vgic.vm_ops.queue_sgi(vcpu, irq);
}

int kvm_vgic_map_resources(struct kvm *kvm)
{
	return kvm->arch.vgic.vm_ops.map_resources(kvm, vgic);
}

/*
 * struct vgic_bitmap contains a bitmap made of unsigned longs, but
 * extracts u32s out of them.
 *
 * This does not work on 64-bit BE systems, because the bitmap access
 * will store two consecutive 32-bit words with the higher-addressed
 * register's bits at the lower index and the lower-addressed register's
 * bits at the higher index.
 *
 * Therefore, swizzle the register index when accessing the 32-bit word
 * registers to access the right register's value.
 */
#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 64
#define REG_OFFSET_SWIZZLE	1
#else
#define REG_OFFSET_SWIZZLE	0
#endif

static int vgic_init_bitmap(struct vgic_bitmap *b, int nr_cpus, int nr_irqs)
{
	int nr_longs;

	nr_longs = nr_cpus + BITS_TO_LONGS(nr_irqs - VGIC_NR_PRIVATE_IRQS);

	b->private = kzalloc(sizeof(unsigned long) * nr_longs, GFP_KERNEL);
	if (!b->private)
		return -ENOMEM;

	b->shared = b->private + nr_cpus;

	return 0;
}

static void vgic_free_bitmap(struct vgic_bitmap *b)
{
	kfree(b->private);
	b->private = NULL;
	b->shared = NULL;
}

/*
 * Call this function to convert a u64 value to an unsigned long * bitmask
 * in a way that works on both 32-bit and 64-bit LE and BE platforms.
 *
 * Warning: Calling this function may modify *val.
 */
static unsigned long *u64_to_bitmask(u64 *val)
{
#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 32
	*val = (*val >> 32) | (*val << 32);
#endif
	return (unsigned long *)val;
}

u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x, int cpuid, u32 offset)
{
	offset >>= 2;
	if (!offset)
		return (u32 *)(x->private + cpuid) + REG_OFFSET_SWIZZLE;
	else
		return (u32 *)(x->shared) + ((offset - 1) ^ REG_OFFSET_SWIZZLE);
}

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->private + cpuid);

	return test_bit(irq - VGIC_NR_PRIVATE_IRQS, x->shared);
}

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->private + cpuid;
	} else {
		reg = x->shared;
		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)
{
	return x->private + cpuid;
}

unsigned long *vgic_bitmap_get_shared_map(struct vgic_bitmap *x)
{
	return x->shared;
}

static int vgic_init_bytemap(struct vgic_bytemap *x, int nr_cpus, int nr_irqs)
{
	int size;

	size  = nr_cpus * VGIC_NR_PRIVATE_IRQS;
	size += nr_irqs - VGIC_NR_PRIVATE_IRQS;

	x->private = kzalloc(size, GFP_KERNEL);
	if (!x->private)
		return -ENOMEM;

	x->shared = x->private + nr_cpus * VGIC_NR_PRIVATE_IRQS / sizeof(u32);
	return 0;
}

static void vgic_free_bytemap(struct vgic_bytemap *b)
{
	kfree(b->private);
	b->private = NULL;
	b->shared = NULL;
}

u32 *vgic_bytemap_get_reg(struct vgic_bytemap *x, int cpuid, u32 offset)
{
	u32 *reg;

	if (offset < VGIC_NR_PRIVATE_IRQS) {
		reg = x->private;
		offset += cpuid * VGIC_NR_PRIVATE_IRQS;
	} else {
		reg = x->shared;
		offset -= VGIC_NR_PRIVATE_IRQS;
	}

	return reg + (offset / sizeof(u32));
}

#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_queued(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	return vgic_bitmap_get_irq_val(&dist->irq_queued, 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_queued(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_queued, vcpu->vcpu_id, irq, 1);
}

static void vgic_irq_clear_queued(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_queued, vcpu->vcpu_id, irq, 0);
}

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_get_level(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	return vgic_bitmap_get_irq_val(&dist->irq_level, vcpu->vcpu_id, irq);
}

static void vgic_dist_irq_set_level(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_level, vcpu->vcpu_id, irq, 1);
}

static void vgic_dist_irq_clear_level(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_level, vcpu->vcpu_id, irq, 0);
}

static int vgic_dist_irq_soft_pend(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	return vgic_bitmap_get_irq_val(&dist->irq_soft_pend, vcpu->vcpu_id, irq);
}

static void vgic_dist_irq_clear_soft_pend(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_soft_pend, vcpu->vcpu_id, irq, 0);
	if (!vgic_dist_irq_get_level(vcpu, irq)) {
		vgic_dist_irq_clear_pending(vcpu, irq);
		if (!compute_pending_for_cpu(vcpu))
			clear_bit(vcpu->vcpu_id, dist->irq_pending_on_cpu);
	}
}

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_pending, vcpu->vcpu_id, irq);
}

void vgic_dist_irq_set_pending(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_pending, vcpu->vcpu_id, irq, 1);
}

void vgic_dist_irq_clear_pending(struct kvm_vcpu *vcpu, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;

	vgic_bitmap_set_irq_val(&dist->irq_pending, 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);
}

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 bool vgic_can_sample_irq(struct kvm_vcpu *vcpu, int irq)
{
	return !vgic_irq_is_queued(vcpu, irq);
}

/**
 * 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)
 */
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);
		}
	}
}

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;
}

bool vgic_handle_enable_reg(struct kvm *kvm, struct kvm_exit_mmio *mmio,
			    phys_addr_t offset, int vcpu_id, int access)
{
	u32 *reg;
	int mode = ACCESS_READ_VALUE | access;
	struct kvm_vcpu *target_vcpu = kvm_get_vcpu(kvm, vcpu_id);

	reg = vgic_bitmap_get_reg(&kvm->arch.vgic.irq_enabled, vcpu_id, offset);
	vgic_reg_access(mmio, reg, offset, mode);
	if (mmio->is_write) {
		if (access & ACCESS_WRITE_CLEARBIT) {
			if (offset < 4) /* Force SGI enabled */
				*reg |= 0xffff;
			vgic_retire_disabled_irqs(target_vcpu);
		}
		vgic_update_state(kvm);
		return true;
	}

	return false;
}

bool vgic_handle_set_pending_reg(struct kvm *kvm,
				 struct kvm_exit_mmio *mmio,
				 phys_addr_t offset, int vcpu_id)
{
	u32 *reg, orig;
	u32 level_mask;
	int mode = ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT;
	struct vgic_dist *dist = &kvm->arch.vgic;

	reg = vgic_bitmap_get_reg(&dist->irq_cfg, vcpu_id, offset);
	level_mask = (~(*reg));

	/* Mark both level and edge triggered irqs as pending */
	reg = vgic_bitmap_get_reg(&dist->irq_pending, vcpu_id, offset);
	orig = *reg;
	vgic_reg_access(mmio, reg, offset, mode);

	if (mmio->is_write) {
		/* Set the soft-pending flag only for level-triggered irqs */
		reg = vgic_bitmap_get_reg(&dist->irq_soft_pend,
					  vcpu_id, offset);
		vgic_reg_access(mmio, reg, offset, mode);
		*reg &= level_mask;

		/* Ignore writes to SGIs */
		if (offset < 2) {
			*reg &= ~0xffff;
			*reg |= orig & 0xffff;
		}

		vgic_update_state(kvm);
		return true;
	}

	return false;
}

bool vgic_handle_clear_pending_reg(struct kvm *kvm,
				   struct kvm_exit_mmio *mmio,
				   phys_addr_t offset, int vcpu_id)
{
	u32 *level_active;
	u32 *reg, orig;
	int mode = ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT;
	struct vgic_dist *dist = &kvm->arch.vgic;

	reg = vgic_bitmap_get_reg(&dist->irq_pending, vcpu_id, offset);
	orig = *reg;
	vgic_reg_access(mmio, reg, offset, mode);
	if (mmio->is_write) {
		/* Re-set level triggered level-active interrupts */
		level_active = vgic_bitmap_get_reg(&dist->irq_level,
					  vcpu_id, offset);
		reg = vgic_bitmap_get_reg(&dist->irq_pending, vcpu_id, offset);
		*reg |= *level_active;

		/* Ignore writes to SGIs */
		if (offset < 2) {
			*reg &= ~0xffff;
			*reg |= orig & 0xffff;
		}

		/* Clear soft-pending flags */
		reg = vgic_bitmap_get_reg(&dist->irq_soft_pend,
					  vcpu_id, offset);
		vgic_reg_access(mmio, reg, offset, mode);

		vgic_update_state(kvm);
		return true;
	}
	return false;
}

bool vgic_handle_set_active_reg(struct kvm *kvm,
				struct kvm_exit_mmio *mmio,
				phys_addr_t offset, int vcpu_id)
{
	u32 *reg;
	struct vgic_dist *dist = &kvm->arch.vgic;

	reg = vgic_bitmap_get_reg(&dist->irq_active, vcpu_id, offset);
	vgic_reg_access(mmio, reg, offset,
			ACCESS_READ_VALUE | ACCESS_WRITE_SETBIT);

	if (mmio->is_write) {
		vgic_update_state(kvm);
		return true;
	}

	return false;
}

bool vgic_handle_clear_active_reg(struct kvm *kvm,
				  struct kvm_exit_mmio *mmio,
				  phys_addr_t offset, int vcpu_id)
{
	u32 *reg;
	struct vgic_dist *dist = &kvm->arch.vgic;

	reg = vgic_bitmap_get_reg(&dist->irq_active, vcpu_id, offset);
	vgic_reg_access(mmio, reg, offset,
			ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);

	if (mmio->is_write) {
		vgic_update_state(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
 */
bool vgic_handle_cfg_reg(u32 *reg, struct kvm_exit_mmio *mmio,
			 phys_addr_t offset)
{
	u32 val;

	if (offset & 4)
		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) {
		/* Ignore writes to read-only SGI and PPI bits */
		if (offset < 8)
			return false;

		val = vgic_cfg_compress(val);
		if (offset & 4) {
			*reg &= 0xffff;
			*reg |= val << 16;
		} else {
			*reg &= 0xffff << 16;
			*reg |= val;
		}
	}

	return false;
}

/**
 * vgic_unqueue_irqs - move pending/active IRQs from LRs to the distributor
 * @vgic_cpu: Pointer to the vgic_cpu struct holding the LRs
 *
 * Move any IRQs that have already been assigned to LRs back to the
 * emulated distributor state so that the complete emulated state can be read
 * from the main emulation structures without investigating the LRs.
 */
void vgic_unqueue_irqs(struct kvm_vcpu *vcpu)
{
	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
	u64 elrsr = vgic_get_elrsr(vcpu);
	unsigned long *elrsr_ptr = u64_to_bitmask(&elrsr);
	int i;

	for_each_clear_bit(i, elrsr_ptr, vgic_cpu->nr_lr) {
		struct vgic_lr lr = vgic_get_lr(vcpu, i);

		/*
		 * There are three options for the state bits:
		 *
		 * 01: pending
		 * 10: active
		 * 11: pending and active
		 */
		BUG_ON(!(lr.state & LR_STATE_MASK));

		/* Reestablish SGI source for pending and active IRQs */
		if (lr.irq < VGIC_NR_SGIS)
			add_sgi_source(vcpu, lr.irq, lr.source);

		/*
		 * If the LR holds an active (10) or a pending and active (11)
		 * interrupt then move the active state to the
		 * distributor tracking bit.
		 */
		if (lr.state & LR_STATE_ACTIVE)
			vgic_irq_set_active(vcpu, lr.irq);

		/*
		 * Reestablish the pending state on the distributor and the
		 * CPU interface and mark the LR as free for other use.
		 */
		vgic_retire_lr(i, vcpu);

		/* Finally update the VGIC state. */
		vgic_update_state(vcpu->kvm);
	}
}

const
struct vgic_io_range *vgic_find_range(const struct vgic_io_range *ranges,
				      int len, gpa_t offset)
{
	while (ranges->len) {
		if (offset >= ranges->base &&
		    (offset + len) <= (ranges->base + ranges->len))
			return ranges;
		ranges++;
	}

	return NULL;
}

static bool vgic_validate_access(const struct vgic_dist *dist,
				 const struct vgic_io_range *range,
				 unsigned long offset)
{
	int irq;

	if (!range->bits_per_irq)
		return true;	/* Not an irq-based access */

	irq = offset * 8 / range->bits_per_irq;
	if (irq >= dist->nr_irqs)
		return false;

	return true;
}

/*
 * Call the respective handler function for the given range.
 * We split up any 64 bit accesses into two consecutive 32 bit
 * handler calls and merge the result afterwards.
 * We do this in a little endian fashion regardless of the host's
 * or guest's endianness, because the GIC is always LE and the rest of
 * the code (vgic_reg_access) also puts it in a LE fashion already.
 * At this point we have already identified the handle function, so
 * range points to that one entry and offset is relative to this.
 */
static bool call_range_handler(struct kvm_vcpu *vcpu,
			       struct kvm_exit_mmio *mmio,
			       unsigned long offset,
			       const struct vgic_io_range *range)
{
	struct kvm_exit_mmio mmio32;
	bool ret;

	if (likely(mmio->len <= 4))
		return range->handle_mmio(vcpu, mmio, offset);

	/*
	 * Any access bigger than 4 bytes (that we currently handle in KVM)
	 * is actually 8 bytes long, caused by a 64-bit access
	 */

	mmio32.len = 4;
	mmio32.is_write = mmio->is_write;
	mmio32.private = mmio->private;

	mmio32.phys_addr = mmio->phys_addr + 4;
	mmio32.data = &((u32 *)mmio->data)[1];
	ret = range->handle_mmio(vcpu, &mmio32, offset + 4);

	mmio32.phys_addr = mmio->phys_addr;
	mmio32.data = &((u32 *)mmio->data)[0];
	ret |= range->handle_mmio(vcpu, &mmio32, offset);

	return ret;
}

/**
 * vgic_handle_mmio_access - handle an in-kernel MMIO access
 * This is called by the read/write KVM IO device wrappers below.
 * @vcpu:	pointer to the vcpu performing the access
 * @this:	pointer to the KVM IO device in charge
 * @addr:	guest physical address of the access
 * @len:	size of the access
 * @val:	pointer to the data region
 * @is_write:	read or write access
 *
 * returns true if the MMIO access could be performed
 */
static int vgic_handle_mmio_access(struct kvm_vcpu *vcpu,
				   struct kvm_io_device *this, gpa_t addr,
				   int len, void *val, bool is_write)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	struct vgic_io_device *iodev = container_of(this,
						    struct vgic_io_device, dev);
	struct kvm_run *run = vcpu->run;
	const struct vgic_io_range *range;
	struct kvm_exit_mmio mmio;
	bool updated_state;
	gpa_t offset;

	offset = addr - iodev->addr;
	range = vgic_find_range(iodev->reg_ranges, len, offset);
	if (unlikely(!range || !range->handle_mmio)) {
		pr_warn("Unhandled access %d %08llx %d\n", is_write, addr, len);
		return -ENXIO;
	}

	mmio.phys_addr = addr;
	mmio.len = len;
	mmio.is_write = is_write;
	mmio.data = val;
	mmio.private = iodev->redist_vcpu;

	spin_lock(&dist->lock);
	offset -= range->base;
	if (vgic_validate_access(dist, range, offset)) {
		updated_state = call_range_handler(vcpu, &mmio, offset, range);
	} else {
		if (!is_write)
			memset(val, 0, len);
		updated_state = false;
	}
	spin_unlock(&dist->lock);
	run->mmio.is_write	= is_write;
	run->mmio.len		= len;
	run->mmio.phys_addr	= addr;
	memcpy(run->mmio.data, val, len);

	kvm_handle_mmio_return(vcpu, run);

	if (updated_state)
		vgic_kick_vcpus(vcpu->kvm);

	return 0;
}

static int vgic_handle_mmio_read(struct kvm_vcpu *vcpu,
				 struct kvm_io_device *this,
				 gpa_t addr, int len, void *val)
{
	return vgic_handle_mmio_access(vcpu, this, addr, len, val, false);
}

static int vgic_handle_mmio_write(struct kvm_vcpu *vcpu,
				  struct kvm_io_device *this,
				  gpa_t addr, int len, const void *val)
{
	return vgic_handle_mmio_access(vcpu, this, addr, len, (void *)val,
				       true);
}

struct kvm_io_device_ops vgic_io_ops = {
	.read	= vgic_handle_mmio_read,
	.write	= vgic_handle_mmio_write,
};

/**
 * vgic_register_kvm_io_dev - register VGIC register frame on the KVM I/O bus
 * @kvm:            The VM structure pointer
 * @base:           The (guest) base address for the register frame
 * @len:            Length of the register frame window
 * @ranges:         Describing the handler functions for each register
 * @redist_vcpu_id: The VCPU ID to pass on to the handlers on call
 * @iodev:          Points to memory to be passed on to the handler
 *
 * @iodev stores the parameters of this function to be usable by the handler
 * respectively the dispatcher function (since the KVM I/O bus framework lacks
 * an opaque parameter). Initialization is done in this function, but the
 * reference should be valid and unique for the whole VGIC lifetime.
 * If the register frame is not mapped for a specific VCPU, pass -1 to
 * @redist_vcpu_id.
 */
int vgic_register_kvm_io_dev(struct kvm *kvm, gpa_t base, int len,
			     const struct vgic_io_range *ranges,
			     int redist_vcpu_id,
			     struct vgic_io_device *iodev)
{
	struct kvm_vcpu *vcpu = NULL;
	int ret;

	if (redist_vcpu_id >= 0)
		vcpu = kvm_get_vcpu(kvm, redist_vcpu_id);

	iodev->addr		= base;
	iodev->len		= len;
	iodev->reg_ranges	= ranges;
	iodev->redist_vcpu	= vcpu;

	kvm_iodevice_init(&iodev->dev, &vgic_io_ops);

	mutex_lock(&kvm->slots_lock);

	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, base, len,
				      &iodev->dev);
	mutex_unlock(&kvm->slots_lock);

	/* Mark the iodev as invalid if registration fails. */
	if (ret)
		iodev->dev.ops = NULL;

	return ret;
}

static int vgic_nr_shared_irqs(struct vgic_dist *dist)
{
	return dist->nr_irqs - VGIC_NR_PRIVATE_IRQS;
}

static int compute_active_for_cpu(struct kvm_vcpu *vcpu)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	unsigned long *active, *enabled, *act_percpu, *act_shared;
	unsigned long active_private, active_shared;
	int nr_shared = vgic_nr_shared_irqs(dist);
	int vcpu_id;

	vcpu_id = vcpu->vcpu_id;
	act_percpu = vcpu->arch.vgic_cpu.active_percpu;
	act_shared = vcpu->arch.vgic_cpu.active_shared;

	active = vgic_bitmap_get_cpu_map(&dist->irq_active, vcpu_id);
	enabled = vgic_bitmap_get_cpu_map(&dist->irq_enabled, vcpu_id);
	bitmap_and(act_percpu, active, enabled, VGIC_NR_PRIVATE_IRQS);

	active = vgic_bitmap_get_shared_map(&dist->irq_active);
	enabled = vgic_bitmap_get_shared_map(&dist->irq_enabled);
	bitmap_and(act_shared, active, enabled, nr_shared);
	bitmap_and(act_shared, act_shared,
		   vgic_bitmap_get_shared_map(&dist->irq_spi_target[vcpu_id]),
		   nr_shared);

	active_private = find_first_bit(act_percpu, VGIC_NR_PRIVATE_IRQS);
	active_shared = find_first_bit(act_shared, nr_shared);

	return (active_private < VGIC_NR_PRIVATE_IRQS ||
		active_shared < nr_shared);
}

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 nr_shared = vgic_nr_shared_irqs(dist);
	int vcpu_id;

	vcpu_id = vcpu->vcpu_id;
	pend_percpu = vcpu->arch.vgic_cpu.pending_percpu;
	pend_shared = vcpu->arch.vgic_cpu.pending_shared;

	if (!dist->enabled) {
		bitmap_zero(pend_percpu, VGIC_NR_PRIVATE_IRQS);
		bitmap_zero(pend_shared, nr_shared);
		return 0;
	}

	pending = vgic_bitmap_get_cpu_map(&dist->irq_pending, 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_pending);
	enabled = vgic_bitmap_get_shared_map(&dist->irq_enabled);
	bitmap_and(pend_shared, pending, enabled, nr_shared);
	bitmap_and(pend_shared, pend_shared,
		   vgic_bitmap_get_shared_map(&dist->irq_spi_target[vcpu_id]),
		   nr_shared);

	pending_private = find_first_bit(pend_percpu, VGIC_NR_PRIVATE_IRQS);
	pending_shared = find_first_bit(pend_shared, nr_shared);
	return (pending_private < VGIC_NR_PRIVATE_IRQS ||
		pending_shared < vgic_nr_shared_irqs(dist));
}

/*
 * Update the interrupt state and determine which CPUs have pending
 * or active interrupts. Must be called with distributor lock held.
 */
void vgic_update_state(struct kvm *kvm)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct kvm_vcpu *vcpu;
	int c;

	kvm_for_each_vcpu(c, vcpu, kvm) {
		if (compute_pending_for_cpu(vcpu))
			set_bit(c, dist->irq_pending_on_cpu);

		if (compute_active_for_cpu(vcpu))
			set_bit(c, dist->irq_active_on_cpu);
		else
			clear_bit(c, dist->irq_active_on_cpu);
	}
}

static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr)
{
	return vgic_ops->get_lr(vcpu, lr);
}

static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr,
			       struct vgic_lr vlr)
{
	vgic_ops->set_lr(vcpu, lr, vlr);
}

static void vgic_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr,
			       struct vgic_lr vlr)
{
	vgic_ops->sync_lr_elrsr(vcpu, lr, vlr);
}

static inline u64 vgic_get_elrsr(struct kvm_vcpu *vcpu)
{
	return vgic_ops->get_elrsr(vcpu);
}

static inline u64 vgic_get_eisr(struct kvm_vcpu *vcpu)
{
	return vgic_ops->get_eisr(vcpu);
}

static inline void vgic_clear_eisr(struct kvm_vcpu *vcpu)
{
	vgic_ops->clear_eisr(vcpu);
}

static inline u32 vgic_get_interrupt_status(struct kvm_vcpu *vcpu)
{
	return vgic_ops->get_interrupt_status(vcpu);
}

static inline void vgic_enable_underflow(struct kvm_vcpu *vcpu)
{
	vgic_ops->enable_underflow(vcpu);
}

static inline void vgic_disable_underflow(struct kvm_vcpu *vcpu)
{
	vgic_ops->disable_underflow(vcpu);
}

void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
{
	vgic_ops->get_vmcr(vcpu, vmcr);
}

void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
{
	vgic_ops->set_vmcr(vcpu, vmcr);
}

static inline void vgic_enable(struct kvm_vcpu *vcpu)
{
	vgic_ops->enable(vcpu);
}

static void vgic_retire_lr(int lr_nr, struct kvm_vcpu *vcpu)
{
	struct vgic_lr vlr = vgic_get_lr(vcpu, lr_nr);

	vgic_irq_clear_queued(vcpu, vlr.irq);

	/*
	 * We must transfer the pending state back to the distributor before
	 * retiring the LR, otherwise we may loose edge-triggered interrupts.
	 */
	if (vlr.state & LR_STATE_PENDING) {
		vgic_dist_irq_set_pending(vcpu, vlr.irq);
		vlr.hwirq = 0;
	}

	vlr.state = 0;
	vgic_set_lr(vcpu, lr_nr, vlr);
	vgic_sync_lr_elrsr(vcpu, lr_nr, vlr);
}

/*
 * 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)
{
	u64 elrsr = vgic_get_elrsr(vcpu);
	unsigned long *elrsr_ptr = u64_to_bitmask(&elrsr);
	int lr;

	for_each_clear_bit(lr, elrsr_ptr, vgic->nr_lr) {
		struct vgic_lr vlr = vgic_get_lr(vcpu, lr);

		if (!vgic_irq_is_enabled(vcpu, vlr.irq))
			vgic_retire_lr(lr, vcpu);
	}
}

static void vgic_queue_irq_to_lr(struct kvm_vcpu *vcpu, int irq,
				 int lr_nr, struct vgic_lr vlr)
{
	if (vgic_irq_is_active(vcpu, irq)) {
		vlr.state |= LR_STATE_ACTIVE;
		kvm_debug("Set active, clear distributor: 0x%x\n", vlr.state);
		vgic_irq_clear_active(vcpu, irq);
		vgic_update_state(vcpu->kvm);
	} else {
		WARN_ON(!vgic_dist_irq_is_pending(vcpu, irq));
		vlr.state |= LR_STATE_PENDING;
		kvm_debug("Set pending: 0x%x\n", vlr.state);
	}

	if (!vgic_irq_is_edge(vcpu, irq))
		vlr.state |= LR_EOI_INT;

	if (vlr.irq >= VGIC_NR_SGIS) {
		struct irq_phys_map *map;
		map = vgic_irq_map_search(vcpu, irq);

		if (map) {
			vlr.hwirq = map->phys_irq;
			vlr.state |= LR_HW;
			vlr.state &= ~LR_EOI_INT;

			/*
			 * Make sure we're not going to sample this
			 * again, as a HW-backed interrupt cannot be
			 * in the PENDING_ACTIVE stage.
			 */
			vgic_irq_set_queued(vcpu, irq);
		}
	}

	vgic_set_lr(vcpu, lr_nr, vlr);
	vgic_sync_lr_elrsr(vcpu, lr_nr, vlr);
}

/*
 * Queue an interrupt to a CPU virtual interface. Return true on success,
 * or false if it wasn't possible to queue it.
 * sgi_source must be zero for any non-SGI interrupts.
 */
bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	u64 elrsr = vgic_get_elrsr(vcpu);
	unsigned long *elrsr_ptr = u64_to_bitmask(&elrsr);
	struct vgic_lr vlr;
	int lr;

	/* Sanitize the input... */
	BUG_ON(sgi_source_id & ~7);
	BUG_ON(sgi_source_id && irq >= VGIC_NR_SGIS);
	BUG_ON(irq >= dist->nr_irqs);

	kvm_debug("Queue IRQ%d\n", irq);

	/* Do we have an active interrupt for the same CPUID? */
	for_each_clear_bit(lr, elrsr_ptr, vgic->nr_lr) {
		vlr = vgic_get_lr(vcpu, lr);
		if (vlr.irq == irq && vlr.source == sgi_source_id) {
			kvm_debug("LR%d piggyback for IRQ%d\n", lr, vlr.irq);
			vgic_queue_irq_to_lr(vcpu, irq, lr, vlr);
			return true;
		}
	}

	/* Try to use another LR for this interrupt */
	lr = find_first_bit(elrsr_ptr, vgic->nr_lr);
	if (lr >= vgic->nr_lr)
		return false;

	kvm_debug("LR%d allocated for IRQ%d %x\n", lr, irq, sgi_source_id);

	vlr.irq = irq;
	vlr.source = sgi_source_id;
	vlr.state = 0;
	vgic_queue_irq_to_lr(vcpu, irq, lr, vlr);

	return true;
}

static bool vgic_queue_hwirq(struct kvm_vcpu *vcpu, int irq)
{
	if (!vgic_can_sample_irq(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_pending(vcpu, irq);
			vgic_cpu_irq_clear(vcpu, irq);
		} else {
			vgic_irq_set_queued(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;
	unsigned long *pa_percpu, *pa_shared;
	int i, vcpu_id;
	int overflow = 0;
	int nr_shared = vgic_nr_shared_irqs(dist);

	vcpu_id = vcpu->vcpu_id;

	pa_percpu = vcpu->arch.vgic_cpu.pend_act_percpu;
	pa_shared = vcpu->arch.vgic_cpu.pend_act_shared;

	bitmap_or(pa_percpu, vgic_cpu->pending_percpu, vgic_cpu->active_percpu,
		  VGIC_NR_PRIVATE_IRQS);
	bitmap_or(pa_shared, vgic_cpu->pending_shared, vgic_cpu->active_shared,
		  nr_shared);
	/*
	 * 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) && !kvm_vgic_vcpu_active_irq(vcpu))
		goto epilog;

	/* SGIs */
	for_each_set_bit(i, pa_percpu, VGIC_NR_SGIS) {
		if (!queue_sgi(vcpu, i))
			overflow = 1;
	}

	/* PPIs */
	for_each_set_bit_from(i, pa_percpu, VGIC_NR_PRIVATE_IRQS) {
		if (!vgic_queue_hwirq(vcpu, i))
			overflow = 1;
	}

	/* SPIs */
	for_each_set_bit(i, pa_shared, nr_shared) {
		if (!vgic_queue_hwirq(vcpu, i + VGIC_NR_PRIVATE_IRQS))
			overflow = 1;
	}




epilog:
	if (overflow) {
		vgic_enable_underflow(vcpu);
	} else {
		vgic_disable_underflow(vcpu);
		/*
		 * 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 int process_queued_irq(struct kvm_vcpu *vcpu,
				   int lr, struct vgic_lr vlr)
{
	int pending = 0;

	/*
	 * If the IRQ was EOIed (called from vgic_process_maintenance) or it
	 * went from active to non-active (called from vgic_sync_hwirq) it was
	 * also ACKed and we we therefore assume we can clear the soft pending
	 * state (should it had been set) for this interrupt.
	 *
	 * Note: if the IRQ soft pending state was set after the IRQ was
	 * acked, it actually shouldn't be cleared, but we have no way of
	 * knowing that unless we start trapping ACKs when the soft-pending
	 * state is set.
	 */
	vgic_dist_irq_clear_soft_pend(vcpu, vlr.irq);

	/*
	 * Tell the gic to start sampling this interrupt again.
	 */
	vgic_irq_clear_queued(vcpu, vlr.irq);

	/* Any additional pending interrupt? */
	if (vgic_irq_is_edge(vcpu, vlr.irq)) {
		BUG_ON(!(vlr.state & LR_HW));
		pending = vgic_dist_irq_is_pending(vcpu, vlr.irq);
	} else {
		if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
			vgic_cpu_irq_set(vcpu, vlr.irq);
			pending = 1;
		} else {
			vgic_dist_irq_clear_pending(vcpu, vlr.irq);
			vgic_cpu_irq_clear(vcpu, vlr.irq);
		}
	}

	/*
	 * Despite being EOIed, the LR may not have
	 * been marked as empty.
	 */
	vlr.state = 0;
	vlr.hwirq = 0;
	vgic_set_lr(vcpu, lr, vlr);

	vgic_sync_lr_elrsr(vcpu, lr, vlr);

	return pending;
}

static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
{
	u32 status = vgic_get_interrupt_status(vcpu);
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	struct kvm *kvm = vcpu->kvm;
	int level_pending = 0;

	kvm_debug("STATUS = %08x\n", status);

	if (status & INT_STATUS_EOI) {
		/*
		 * Some level interrupts have been EOIed. Clear their
		 * active bit.
		 */
		u64 eisr = vgic_get_eisr(vcpu);
		unsigned long *eisr_ptr = u64_to_bitmask(&eisr);
		int lr;

		for_each_set_bit(lr, eisr_ptr, vgic->nr_lr) {
			struct vgic_lr vlr = vgic_get_lr(vcpu, lr);

			WARN_ON(vgic_irq_is_edge(vcpu, vlr.irq));
			WARN_ON(vlr.state & LR_STATE_MASK);


			/*
			 * kvm_notify_acked_irq calls kvm_set_irq()
			 * to reset the IRQ level, which grabs the dist->lock
			 * so we call this before taking the dist->lock.
			 */
			kvm_notify_acked_irq(kvm, 0,
					     vlr.irq - VGIC_NR_PRIVATE_IRQS);

			spin_lock(&dist->lock);
			level_pending |= process_queued_irq(vcpu, lr, vlr);
			spin_unlock(&dist->lock);
		}
	}

	if (status & INT_STATUS_UNDERFLOW)
		vgic_disable_underflow(vcpu);

	/*
	 * In the next iterations of the vcpu loop, if we sync the vgic state
	 * after flushing it, but before entering the guest (this happens for
	 * pending signals and vmid rollovers), then make sure we don't pick
	 * up any old maintenance interrupts here.
	 */
	vgic_clear_eisr(vcpu);

	return level_pending;
}

/*
 * Save the physical active state, and reset it to inactive.
 *
 * Return true if there's a pending forwarded interrupt to queue.
 */
static bool vgic_sync_hwirq(struct kvm_vcpu *vcpu, int lr, struct vgic_lr vlr)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	struct irq_phys_map *map;
	bool phys_active;
	bool level_pending;
	int ret;

	if (!(vlr.state & LR_HW))
		return false;

	map = vgic_irq_map_search(vcpu, vlr.irq);
	BUG_ON(!map);

	ret = irq_get_irqchip_state(map->irq,
				    IRQCHIP_STATE_ACTIVE,
				    &phys_active);

	WARN_ON(ret);

	if (phys_active)
		return 0;

	spin_lock(&dist->lock);
	level_pending = process_queued_irq(vcpu, lr, vlr);
	spin_unlock(&dist->lock);
	return level_pending;
}

/* Sync back the VGIC state after a guest run */
static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	u64 elrsr;
	unsigned long *elrsr_ptr;
	int lr, pending;
	bool level_pending;

	level_pending = vgic_process_maintenance(vcpu);
	elrsr = vgic_get_elrsr(vcpu);
	elrsr_ptr = u64_to_bitmask(&elrsr);

	/* Deal with HW interrupts, and clear mappings for empty LRs */
	for (lr = 0; lr < vgic->nr_lr; lr++) {
		struct vgic_lr vlr = vgic_get_lr(vcpu, lr);

		level_pending |= vgic_sync_hwirq(vcpu, lr, vlr);
		BUG_ON(vlr.irq >= dist->nr_irqs);
	}

	/* Check if we still have something up our sleeve... */
	pending = find_first_zero_bit(elrsr_ptr, vgic->nr_lr);
	if (level_pending || pending < vgic->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)
{
	if (!irqchip_in_kernel(vcpu->kvm))
		return;

	__kvm_vgic_sync_hwstate(vcpu);
}

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);
}

int kvm_vgic_vcpu_active_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_active_on_cpu);
}


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 edge_triggered = vgic_irq_is_edge(vcpu, irq);

	/*
	 * Only inject an interrupt if:
	 * - edge triggered and we have a rising edge
	 * - level triggered and we change level
	 */
	if (edge_triggered) {
		int state = vgic_dist_irq_is_pending(vcpu, irq);
		return level > state;
	} else {
		int state = vgic_dist_irq_get_level(vcpu, irq);
		return level != state;
	}
}

static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
				   struct irq_phys_map *map,
				   unsigned int irq_num, bool level)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct kvm_vcpu *vcpu;
	int edge_triggered, level_triggered;
	int enabled;
	bool ret = true, can_inject = true;

	trace_vgic_update_irq_pending(cpuid, irq_num, level);

	if (irq_num >= min(kvm->arch.vgic.nr_irqs, 1020))
		return -EINVAL;

	spin_lock(&dist->lock);

	vcpu = kvm_get_vcpu(kvm, cpuid);
	edge_triggered = vgic_irq_is_edge(vcpu, irq_num);
	level_triggered = !edge_triggered;

	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];
		if (cpuid == VCPU_NOT_ALLOCATED) {
			/* Pretend we use CPU0, and prevent injection */
			cpuid = 0;
			can_inject = false;
		}
		vcpu = kvm_get_vcpu(kvm, cpuid);
	}

	kvm_debug("Inject IRQ%d level %d CPU%d\n", irq_num, level, cpuid);

	if (level) {
		if (level_triggered)
			vgic_dist_irq_set_level(vcpu, irq_num);
		vgic_dist_irq_set_pending(vcpu, irq_num);
	} else {
		if (level_triggered) {
			vgic_dist_irq_clear_level(vcpu, irq_num);
			if (!vgic_dist_irq_soft_pend(vcpu, irq_num)) {
				vgic_dist_irq_clear_pending(vcpu, irq_num);
				vgic_cpu_irq_clear(vcpu, irq_num);
				if (!compute_pending_for_cpu(vcpu))
					clear_bit(cpuid, dist->irq_pending_on_cpu);
			}
		}

		ret = false;
		goto out;
	}

	enabled = vgic_irq_is_enabled(vcpu, irq_num);

	if (!enabled || !can_inject) {
		ret = false;
		goto out;
	}

	if (!vgic_can_sample_irq(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);

	if (ret) {
		/* kick the specified vcpu */
		kvm_vcpu_kick(kvm_get_vcpu(kvm, cpuid));
	}

	return 0;
}

static int vgic_lazy_init(struct kvm *kvm)
{
	int ret = 0;

	if (unlikely(!vgic_initialized(kvm))) {
		/*
		 * We only provide the automatic initialization of the VGIC
		 * for the legacy case of a GICv2. Any other type must
		 * be explicitly initialized once setup with the respective
		 * KVM device call.
		 */
		if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
			return -EBUSY;

		mutex_lock(&kvm->lock);
		ret = vgic_init(kvm);
		mutex_unlock(&kvm->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. This IRQ
 *           must not be mapped to a HW interrupt.
 * @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
 *
 * 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)
{
	struct irq_phys_map *map;
	int ret;

	ret = vgic_lazy_init(kvm);
	if (ret)
		return ret;

	map = vgic_irq_map_search(kvm_get_vcpu(kvm, cpuid), irq_num);
	if (map)
		return -EINVAL;

	return vgic_update_irq_pending(kvm, cpuid, NULL, irq_num, level);
}

/**
 * kvm_vgic_inject_mapped_irq - Inject a physically mapped IRQ to the vgic
 * @kvm:     The VM structure pointer
 * @cpuid:   The CPU for PPIs
 * @map:     Pointer to a irq_phys_map structure describing the mapping
 * @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
 *
 * 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_mapped_irq(struct kvm *kvm, int cpuid,
			       struct irq_phys_map *map, bool level)
{
	int ret;

	ret = vgic_lazy_init(kvm);
	if (ret)
		return ret;

	return vgic_update_irq_pending(kvm, cpuid, map, map->virt_irq, level);
}

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;
}

static struct list_head *vgic_get_irq_phys_map_list(struct kvm_vcpu *vcpu,
						    int virt_irq)
{
	if (virt_irq < VGIC_NR_PRIVATE_IRQS)
		return &vcpu->arch.vgic_cpu.irq_phys_map_list;
	else
		return &vcpu->kvm->arch.vgic.irq_phys_map_list;
}

/**
 * kvm_vgic_map_phys_irq - map a virtual IRQ to a physical IRQ
 * @vcpu: The VCPU pointer
 * @virt_irq: The virtual irq number
 * @irq: The Linux IRQ number
 *
 * Establish a mapping between a guest visible irq (@virt_irq) and a
 * Linux irq (@irq). On injection, @virt_irq will be associated with
 * the physical interrupt represented by @irq. This mapping can be
 * established multiple times as long as the parameters are the same.
 *
 * Returns a valid pointer on success, and an error pointer otherwise
 */
struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
					   int virt_irq, int irq)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	struct list_head *root = vgic_get_irq_phys_map_list(vcpu, virt_irq);
	struct irq_phys_map *map;
	struct irq_phys_map_entry *entry;
	struct irq_desc *desc;
	struct irq_data *data;
	int phys_irq;

	desc = irq_to_desc(irq);
	if (!desc) {
		kvm_err("%s: no interrupt descriptor\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	data = irq_desc_get_irq_data(desc);
	while (data->parent_data)
		data = data->parent_data;

	phys_irq = data->hwirq;

	/* Create a new mapping */
	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return ERR_PTR(-ENOMEM);

	spin_lock(&dist->irq_phys_map_lock);

	/* Try to match an existing mapping */
	map = vgic_irq_map_search(vcpu, virt_irq);
	if (map) {
		/* Make sure this mapping matches */
		if (map->phys_irq != phys_irq	||
		    map->irq      != irq)
			map = ERR_PTR(-EINVAL);

		/* Found an existing, valid mapping */
		goto out;
	}

	map           = &entry->map;
	map->virt_irq = virt_irq;
	map->phys_irq = phys_irq;
	map->irq      = irq;

	list_add_tail_rcu(&entry->entry, root);

out:
	spin_unlock(&dist->irq_phys_map_lock);
	/* If we've found a hit in the existing list, free the useless
	 * entry */
	if (IS_ERR(map) || map != &entry->map)
		kfree(entry);
	return map;
}

static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu,
						int virt_irq)
{
	struct list_head *root = vgic_get_irq_phys_map_list(vcpu, virt_irq);
	struct irq_phys_map_entry *entry;
	struct irq_phys_map *map;

	rcu_read_lock();

	list_for_each_entry_rcu(entry, root, entry) {
		map = &entry->map;
		if (map->virt_irq == virt_irq) {
			rcu_read_unlock();
			return map;
		}
	}

	rcu_read_unlock();

	return NULL;
}

static void vgic_free_phys_irq_map_rcu(struct rcu_head *rcu)
{
	struct irq_phys_map_entry *entry;

	entry = container_of(rcu, struct irq_phys_map_entry, rcu);
	kfree(entry);
}

/**
 * kvm_vgic_unmap_phys_irq - Remove a virtual to physical IRQ mapping
 * @vcpu: The VCPU pointer
 * @map: The pointer to a mapping obtained through kvm_vgic_map_phys_irq
 *
 * Remove an existing mapping between virtual and physical interrupts.
 */
int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, struct irq_phys_map *map)
{
	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
	struct irq_phys_map_entry *entry;
	struct list_head *root;

	if (!map)
		return -EINVAL;

	root = vgic_get_irq_phys_map_list(vcpu, map->virt_irq);

	spin_lock(&dist->irq_phys_map_lock);

	list_for_each_entry(entry, root, entry) {
		if (&entry->map == map) {
			list_del_rcu(&entry->entry);
			call_rcu(&entry->rcu, vgic_free_phys_irq_map_rcu);
			break;
		}
	}

	spin_unlock(&dist->irq_phys_map_lock);

	return 0;
}

static void vgic_destroy_irq_phys_map(struct kvm *kvm, struct list_head *root)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct irq_phys_map_entry *entry;

	spin_lock(&dist->irq_phys_map_lock);

	list_for_each_entry(entry, root, entry) {
		list_del_rcu(&entry->entry);
		call_rcu(&entry->rcu, vgic_free_phys_irq_map_rcu);
	}

	spin_unlock(&dist->irq_phys_map_lock);
}

void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
{
	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

	kfree(vgic_cpu->pending_shared);
	kfree(vgic_cpu->active_shared);
	kfree(vgic_cpu->pend_act_shared);
	vgic_destroy_irq_phys_map(vcpu->kvm, &vgic_cpu->irq_phys_map_list);
	vgic_cpu->pending_shared = NULL;
	vgic_cpu->active_shared = NULL;
	vgic_cpu->pend_act_shared = NULL;
}

static int vgic_vcpu_init_maps(struct kvm_vcpu *vcpu, int nr_irqs)
{
	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

	int sz = (nr_irqs - VGIC_NR_PRIVATE_IRQS) / 8;
	vgic_cpu->pending_shared = kzalloc(sz, GFP_KERNEL);
	vgic_cpu->active_shared = kzalloc(sz, GFP_KERNEL);
	vgic_cpu->pend_act_shared = kzalloc(sz, GFP_KERNEL);

	if (!vgic_cpu->pending_shared
		|| !vgic_cpu->active_shared
		|| !vgic_cpu->pend_act_shared) {
		kvm_vgic_vcpu_destroy(vcpu);
		return -ENOMEM;
	}

	/*
	 * Store the number of LRs per vcpu, so we don't have to go
	 * all the way to the distributor structure to find out. Only
	 * assembly code should use this one.
	 */
	vgic_cpu->nr_lr = vgic->nr_lr;

	return 0;
}

/**
 * kvm_vgic_vcpu_early_init - Earliest possible per-vcpu vgic init stage
 *
 * No memory allocation should be performed here, only static init.
 */
void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
{
	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
	INIT_LIST_HEAD(&vgic_cpu->irq_phys_map_list);
}

/**
 * kvm_vgic_get_max_vcpus - Get the maximum number of VCPUs allowed by HW
 *
 * The host's GIC naturally limits the maximum amount of VCPUs a guest
 * can use.
 */
int kvm_vgic_get_max_vcpus(void)
{
	return vgic->max_gic_vcpus;
}

void kvm_vgic_destroy(struct kvm *kvm)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct kvm_vcpu *vcpu;
	int i;

	kvm_for_each_vcpu(i, vcpu, kvm)
		kvm_vgic_vcpu_destroy(vcpu);

	vgic_free_bitmap(&dist->irq_enabled);
	vgic_free_bitmap(&dist->irq_level);
	vgic_free_bitmap(&dist->irq_pending);
	vgic_free_bitmap(&dist->irq_soft_pend);
	vgic_free_bitmap(&dist->irq_queued);
	vgic_free_bitmap(&dist->irq_cfg);
	vgic_free_bytemap(&dist->irq_priority);
	if (dist->irq_spi_target) {
		for (i = 0; i < dist->nr_cpus; i++)
			vgic_free_bitmap(&dist->irq_spi_target[i]);
	}
	kfree(dist->irq_sgi_sources);
	kfree(dist->irq_spi_cpu);
	kfree(dist->irq_spi_mpidr);
	kfree(dist->irq_spi_target);
	kfree(dist->irq_pending_on_cpu);
	kfree(dist->irq_active_on_cpu);
	vgic_destroy_irq_phys_map(kvm, &dist->irq_phys_map_list);
	dist->irq_sgi_sources = NULL;
	dist->irq_spi_cpu = NULL;
	dist->irq_spi_target = NULL;
	dist->irq_pending_on_cpu = NULL;
	dist->irq_active_on_cpu = NULL;
	dist->nr_cpus = 0;
}

/*
 * Allocate and initialize the various data structures. Must be called
 * with kvm->lock held!
 */
int vgic_init(struct kvm *kvm)
{
	struct vgic_dist *dist = &kvm->arch.vgic;
	struct kvm_vcpu *vcpu;
	int nr_cpus, nr_irqs;
	int ret, i, vcpu_id;

	if (vgic_initialized(kvm))
		return 0;

	nr_cpus = dist->nr_cpus = atomic_read(&kvm->online_vcpus);
	if (!nr_cpus)		/* No vcpus? Can't be good... */
		return -ENODEV;

	/*
	 * If nobody configured the number of interrupts, use the
	 * legacy one.
	 */
	if (!dist->nr_irqs)
		dist->nr_irqs = VGIC_NR_IRQS_LEGACY;

	nr_irqs = dist->nr_irqs;

	ret  = vgic_init_bitmap(&dist->irq_enabled, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_level, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_pending, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_soft_pend, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_queued, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_active, nr_cpus, nr_irqs);
	ret |= vgic_init_bitmap(&dist->irq_cfg, nr_cpus, nr_irqs);
	ret |= vgic_init_bytemap(&dist->irq_priority, nr_cpus, nr_irqs);

	if (ret)
		goto out;

	dist->irq_sgi_sources = kzalloc(nr_cpus * VGIC_NR_SGIS, GFP_KERNEL);
	dist->irq_spi_cpu = kzalloc(nr_irqs - VGIC_NR_PRIVATE_IRQS, GFP_KERNEL);
	dist->irq_spi_target = kzalloc(sizeof(*dist->irq_spi_target) * nr_cpus,
				       GFP_KERNEL);
	dist->irq_pending_on_cpu = kzalloc(BITS_TO_LONGS(nr_cpus) * sizeof(long),
					   GFP_KERNEL);
	dist->irq_active_on_cpu = kzalloc(BITS_TO_LONGS(nr_cpus) * sizeof(long),
					   GFP_KERNEL);
	if (!dist->irq_sgi_sources ||
	    !dist->irq_spi_cpu ||
	    !dist->irq_spi_target ||
	    !dist->irq_pending_on_cpu ||
	    !dist->irq_active_on_cpu) {
		ret = -ENOMEM;
		goto out;
	}

	for (i = 0; i < nr_cpus; i++)
		ret |= vgic_init_bitmap(&dist->irq_spi_target[i],
					nr_cpus, nr_irqs);

	if (ret)
		goto out;

	ret = kvm->arch.vgic.vm_ops.init_model(kvm);
	if (ret)
		goto out;

	kvm_for_each_vcpu(vcpu_id, vcpu, kvm) {
		ret = vgic_vcpu_init_maps(vcpu, nr_irqs);
		if (ret) {
			kvm_err("VGIC: Failed to allocate vcpu memory\n");
			break;
		}

		/*
		 * Enable and configure all SGIs to be edge-triggere and
		 * configure all PPIs as level-triggered.
		 */
		for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
			if (i < VGIC_NR_SGIS) {
				/* SGIs */
				vgic_bitmap_set_irq_val(&dist->irq_enabled,
							vcpu->vcpu_id, i, 1);
				vgic_bitmap_set_irq_val(&dist->irq_cfg,
							vcpu->vcpu_id, i,
							VGIC_CFG_EDGE);
			} else if (i < VGIC_NR_PRIVATE_IRQS) {
				/* PPIs */
				vgic_bitmap_set_irq_val(&dist->irq_cfg,
							vcpu->vcpu_id, i,
							VGIC_CFG_LEVEL);
			}
		}

		vgic_enable(vcpu);
	}

out:
	if (ret)
		kvm_vgic_destroy(kvm);

	return ret;
}

static int init_vgic_model(struct kvm *kvm, int type)
{
	switch (type) {
	case KVM_DEV_TYPE_ARM_VGIC_V2:
		vgic_v2_init_emulation(kvm);
		break;
#ifdef CONFIG_ARM_GIC_V3
	case KVM_DEV_TYPE_ARM_VGIC_V3:
		vgic_v3_init_emulation(kvm);
		break;
#endif
	default:
		return -ENODEV;
	}

	if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus)
		return -E2BIG;

	return 0;
}

/**
 * kvm_vgic_early_init - Earliest possible vgic initialization stage
 *
 * No memory allocation should be performed here, only static init.
 */
void kvm_vgic_early_init(struct kvm *kvm)
{
	spin_lock_init(&kvm->arch.vgic.lock);
	spin_lock_init(&kvm->arch.vgic.irq_phys_map_lock);
	INIT_LIST_HEAD(&kvm->arch.vgic.irq_phys_map_list);
}

int kvm_vgic_create(struct kvm *kvm, u32 type)
{
	int i, vcpu_lock_idx = -1, ret;
	struct kvm_vcpu *vcpu;

	mutex_lock(&kvm->lock);

	if (irqchip_in_kernel(kvm)) {
		ret = -EEXIST;
		goto out;
	}

	/*
	 * This function is also called by the KVM_CREATE_IRQCHIP handler,
	 * which had no chance yet to check the availability of the GICv2
	 * emulation. So check this here again. KVM_CREATE_DEVICE does
	 * the proper checks already.
	 */
	if (type == KVM_DEV_TYPE_ARM_VGIC_V2 && !vgic->can_emulate_gicv2) {
		ret = -ENODEV;
		goto out;
	}

	/*
	 * Any time a vcpu is run, vcpu_load is called which tries to grab the
	 * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
	 * that no other VCPUs are run while we create the vgic.
	 */
	ret = -EBUSY;
	kvm_for_each_vcpu(i, vcpu, kvm) {
		if (!mutex_trylock(&vcpu->mutex))
			goto out_unlock;
		vcpu_lock_idx = i;
	}

	kvm_for_each_vcpu(i, vcpu, kvm) {
		if (vcpu->arch.has_run_once)
			goto out_unlock;
	}
	ret = 0;

	ret = init_vgic_model(kvm, type);
	if (ret)
		goto out_unlock;

	kvm->arch.vgic.in_kernel = true;
	kvm->arch.vgic.vgic_model = type;
	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;
	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;

out_unlock:
	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
		vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
		mutex_unlock(&vcpu->mutex);
	}

out:
	mutex_unlock(&kvm->lock);
	return ret;
}

static int 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 (addr & ~KVM_PHYS_MASK)
		return -E2BIG;

	if (addr & (SZ_4K - 1))
		return -EINVAL;

	if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
		return -EEXIST;
	if (addr + size < addr)
		return -EINVAL;

	*ioaddr = addr;
	ret = vgic_ioaddr_overlap(kvm);
	if (ret)
		*ioaddr = VGIC_ADDR_UNDEF;

	return ret;
}

/**
 * kvm_vgic_addr - set or get vgic VM base addresses
 * @kvm:   pointer to the vm struct
 * @type:  the VGIC addr type, one of KVM_VGIC_V[23]_ADDR_TYPE_XXX
 * @addr:  pointer to address value
 * @write: if true set the address in the VM address space, if false read the
 *          address
 *
 * Set or get the vgic base addresses for the distributor and the virtual CPU
 * interface in the VM physical address space.  These addresses are properties
 * of the emulated core/SoC and therefore user space initially knows this
 * information.
 */
int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
{
	int r = 0;
	struct vgic_dist *vgic = &kvm->arch.vgic;
	int type_needed;
	phys_addr_t *addr_ptr, block_size;
	phys_addr_t alignment;

	mutex_lock(&kvm->lock);
	switch (type) {
	case KVM_VGIC_V2_ADDR_TYPE_DIST:
		type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
		addr_ptr = &vgic->vgic_dist_base;
		block_size = KVM_VGIC_V2_DIST_SIZE;
		alignment = SZ_4K;
		break;
	case KVM_VGIC_V2_ADDR_TYPE_CPU:
		type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
		addr_ptr = &vgic->vgic_cpu_base;
		block_size = KVM_VGIC_V2_CPU_SIZE;
		alignment = SZ_4K;
		break;
#ifdef CONFIG_ARM_GIC_V3
	case KVM_VGIC_V3_ADDR_TYPE_DIST:
		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
		addr_ptr = &vgic->vgic_dist_base;
		block_size = KVM_VGIC_V3_DIST_SIZE;
		alignment = SZ_64K;
		break;
	case KVM_VGIC_V3_ADDR_TYPE_REDIST:
		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
		addr_ptr = &vgic->vgic_redist_base;
		block_size = KVM_VGIC_V3_REDIST_SIZE;
		alignment = SZ_64K;
		break;
#endif
	default:
		r = -ENODEV;
		goto out;
	}

	if (vgic->vgic_model != type_needed) {
		r = -ENODEV;
		goto out;
	}

	if (write) {
		if (!IS_ALIGNED(*addr, alignment))
			r = -EINVAL;
		else
			r = vgic_ioaddr_assign(kvm, addr_ptr, *addr,
					       block_size);
	} else {
		*addr = *addr_ptr;
	}

out:
	mutex_unlock(&kvm->lock);
	return r;
}

int vgic_set_common_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
	int r;

	switch (attr->group) {
	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
		u64 addr;
		unsigned long type = (unsigned long)attr->attr;

		if (copy_from_user(&addr, uaddr, sizeof(addr)))
			return -EFAULT;

		r = kvm_vgic_addr(dev->kvm, type, &addr, true);
		return (r == -ENODEV) ? -ENXIO : r;
	}
	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS: {
		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
		u32 val;
		int ret = 0;

		if (get_user(val, uaddr))
			return -EFAULT;

		/*
		 * We require:
		 * - at least 32 SPIs on top of the 16 SGIs and 16 PPIs
		 * - at most 1024 interrupts
		 * - a multiple of 32 interrupts
		 */
		if (val < (VGIC_NR_PRIVATE_IRQS + 32) ||
		    val > VGIC_MAX_IRQS ||
		    (val & 31))
			return -EINVAL;

		mutex_lock(&dev->kvm->lock);

		if (vgic_ready(dev->kvm) || dev->kvm->arch.vgic.nr_irqs)
			ret = -EBUSY;
		else
			dev->kvm->arch.vgic.nr_irqs = val;

		mutex_unlock(&dev->kvm->lock);

		return ret;
	}
	case KVM_DEV_ARM_VGIC_GRP_CTRL: {
		switch (attr->attr) {
		case KVM_DEV_ARM_VGIC_CTRL_INIT:
			r = vgic_init(dev->kvm);
			return r;
		}
		break;
	}
	}

	return -ENXIO;
}

int vgic_get_common_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
	int r = -ENXIO;

	switch (attr->group) {
	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
		u64 addr;
		unsigned long type = (unsigned long)attr->attr;

		r = kvm_vgic_addr(dev->kvm, type, &addr, false);
		if (r)
			return (r == -ENODEV) ? -ENXIO : r;

		if (copy_to_user(uaddr, &addr, sizeof(addr)))
			return -EFAULT;
		break;
	}
	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS: {
		u32 __user *uaddr = (u32 __user *)(long)attr->addr;

		r = put_user(dev->kvm->arch.vgic.nr_irqs, uaddr);
		break;
	}

	}

	return r;
}

int vgic_has_attr_regs(const struct vgic_io_range *ranges, phys_addr_t offset)
{
	if (vgic_find_range(ranges, 4, offset))
		return 0;
	else
		return -ENXIO;
}

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,
};

static const struct of_device_id vgic_ids[] = {
	{ .compatible = "arm,cortex-a15-gic",	.data = vgic_v2_probe, },
	{ .compatible = "arm,cortex-a7-gic",	.data = vgic_v2_probe, },
	{ .compatible = "arm,gic-400",		.data = vgic_v2_probe, },
	{ .compatible = "arm,gic-v3",		.data = vgic_v3_probe, },
	{},
};

int kvm_vgic_hyp_init(void)
{
	const struct of_device_id *matched_id;
	const int (*vgic_probe)(struct device_node *,const struct vgic_ops **,
				const struct vgic_params **);
	struct device_node *vgic_node;
	int ret;

	vgic_node = of_find_matching_node_and_match(NULL,
						    vgic_ids, &matched_id);
	if (!vgic_node) {
		kvm_err("error: no compatible GIC node found\n");
		return -ENODEV;
	}

	vgic_probe = matched_id->data;
	ret = vgic_probe(vgic_node, &vgic_ops, &vgic);
	if (ret)
		return ret;

	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);
		return ret;
	}

	ret = __register_cpu_notifier(&vgic_cpu_nb);
	if (ret) {
		kvm_err("Cannot register vgic CPU notifier\n");
		goto out_free_irq;
	}

	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);

	return 0;

out_free_irq:
	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
	return ret;
}

int kvm_irq_map_gsi(struct kvm *kvm,
		    struct kvm_kernel_irq_routing_entry *entries,
		    int gsi)
{
	return 0;
}

int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
	return pin;
}

int kvm_set_irq(struct kvm *kvm, int irq_source_id,
		u32 irq, int level, bool line_status)
{
	unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;

	trace_kvm_set_irq(irq, level, irq_source_id);

	BUG_ON(!vgic_initialized(kvm));

	return kvm_vgic_inject_irq(kvm, 0, spi, level);
}

/* MSI not implemented yet */
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
		struct kvm *kvm, int irq_source_id,
		int level, bool line_status)
{
	return 0;
}