arm/arm64: KVM: Use appropriate define in VGIC reset code

[deliverable/linux.git] / 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>

/*
 * 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, int irq, 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 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;
}

/*
 * If a mapped interrupt's state has been modified by the guest such that it
 * is no longer active or pending, without it have gone through the sync path,
 * then the map->active field must be cleared so the interrupt can be taken
 * again.
 */
static void vgic_handle_clear_mapped_irq(struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct list_head *root;
        struct irq_phys_map_entry *entry;
        struct irq_phys_map *map;

        rcu_read_lock();

        /* Check for PPIs */
        root = &vgic_cpu->irq_phys_map_list;
        list_for_each_entry_rcu(entry, root, entry) {
                map = &entry->map;

                if (!vgic_dist_irq_is_pending(vcpu, map->virt_irq) &&
                    !vgic_irq_is_active(vcpu, map->virt_irq))
                        map->active = false;
        }

        rcu_read_unlock();
}

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_handle_clear_mapped_irq(kvm_get_vcpu(kvm, vcpu_id));
                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_handle_clear_mapped_irq(kvm_get_vcpu(kvm, vcpu_id));
                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;
        int i;

        for_each_set_bit(i, vgic_cpu->lr_used, 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);
                        lr.state &= ~LR_STATE_ACTIVE;
                }

                /*
                 * Reestablish the pending state on the distributor and the
                 * CPU interface.  It may have already been pending, but that
                 * is fine, then we are only setting a few bits that were
                 * already set.
                 */
                if (lr.state & LR_STATE_PENDING) {
                        vgic_dist_irq_set_pending(vcpu, lr.irq);
                        lr.state &= ~LR_STATE_PENDING;
                }

                vgic_set_lr(vcpu, i, lr);

                /*
                 * Mark the LR as free for other use.
                 */
                BUG_ON(lr.state & LR_STATE_MASK);
                vgic_retire_lr(i, lr.irq, vcpu);
                vgic_irq_clear_queued(vcpu, lr.irq);

                /* 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, int irq, struct kvm_vcpu *vcpu)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_lr vlr = vgic_get_lr(vcpu, lr_nr);

        /*
         * 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, irq);
                vlr.hwirq = 0;
        }

        vlr.state = 0;
        vgic_set_lr(vcpu, lr_nr, vlr);
        clear_bit(lr_nr, vgic_cpu->lr_used);
        vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
        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)
{
        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        int lr;

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

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

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_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
        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);

        lr = vgic_cpu->vgic_irq_lr_map[irq];

        /* Do we have an active interrupt for the same CPUID? */
        if (lr != LR_EMPTY) {
                vlr = vgic_get_lr(vcpu, lr);
                if (vlr.source == sgi_source_id) {
                        kvm_debug("LR%d piggyback for IRQ%d\n", lr, vlr.irq);
                        BUG_ON(!test_bit(lr, vgic_cpu->lr_used));
                        vgic_queue_irq_to_lr(vcpu, irq, lr, vlr);
                        return true;
                }
        }

        /* Try to use another LR for this interrupt */
        lr = find_first_zero_bit((unsigned long *)vgic_cpu->lr_used,
                               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);
        vgic_cpu->vgic_irq_lr_map[irq] = lr;
        set_bit(lr, vgic_cpu->lr_used);

        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_level_irq(struct kvm_vcpu *vcpu, int lr, struct vgic_lr vlr)
{
        int level_pending = 0;

        vlr.state = 0;
        vlr.hwirq = 0;
        vgic_set_lr(vcpu, lr, vlr);

        /*
         * 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 the line of this interrupt again.
         */
        vgic_irq_clear_queued(vcpu, vlr.irq);

        /* Any additional pending interrupt? */
        if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
                vgic_cpu_irq_set(vcpu, vlr.irq);
                level_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.
         */
        vgic_sync_lr_elrsr(vcpu, lr, vlr);

        return level_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_level_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 1 if HW interrupt went from active to inactive, and 0 otherwise.
 */
static int vgic_sync_hwirq(struct kvm_vcpu *vcpu, struct vgic_lr vlr)
{
        struct irq_phys_map *map;
        int ret;

        if (!(vlr.state & LR_HW))
                return 0;

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

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

        WARN_ON(ret);

        if (map->active)
                return 0;

        return 1;
}

/* Sync back the VGIC state after a guest run */
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;
        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;

                if (!test_bit(lr, vgic_cpu->lr_used))
                        continue;

                vlr = vgic_get_lr(vcpu, lr);
                if (vgic_sync_hwirq(vcpu, vlr)) {
                        /*
                         * So this is a HW interrupt that the guest
                         * EOI-ed. Clean the LR state and allow the
                         * interrupt to be sampled again.
                         */
                        vlr.state = 0;
                        vlr.hwirq = 0;
                        vgic_set_lr(vcpu, lr, vlr);
                        vgic_irq_clear_queued(vcpu, vlr.irq);
                        set_bit(lr, elrsr_ptr);
                }

                if (!test_bit(lr, elrsr_ptr))
                        continue;

                clear_bit(lr, vgic_cpu->lr_used);

                BUG_ON(vlr.irq >= dist->nr_irqs);
                vgic_cpu->vgic_irq_lr_map[vlr.irq] = LR_EMPTY;
        }

        /* 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;

        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_get_phys_irq_active - Return the active state of a mapped IRQ
 *
 * Return the logical active state of a mapped interrupt. This doesn't
 * necessarily reflects the current HW state.
 */
bool kvm_vgic_get_phys_irq_active(struct irq_phys_map *map)
{
        BUG_ON(!map);
        return map->active;
}

/**
 * kvm_vgic_set_phys_irq_active - Set the active state of a mapped IRQ
 *
 * Set the logical active state of a mapped interrupt. This doesn't
 * immediately affects the HW state.
 */
void kvm_vgic_set_phys_irq_active(struct irq_phys_map *map, bool active)
{
        BUG_ON(!map);
        map->active = active;
}

/**
 * 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);
        kfree(vgic_cpu->vgic_irq_lr_map);
        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;
        vgic_cpu->vgic_irq_lr_map = 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);
        vgic_cpu->vgic_irq_lr_map = kmalloc(nr_irqs, GFP_KERNEL);

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

        memset(vgic_cpu->vgic_irq_lr_map, LR_EMPTY, nr_irqs);

        /*
         * 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 all SGIs and configure all private IRQs as
                 * edge-triggered.
                 */
                for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
                        if (i < VGIC_NR_SGIS)
                                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_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;
}