/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.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, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/cpu_pm.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/mman.h>
#include <linux/sched.h>
#include <linux/kvm.h>
#include <linux/kvm_irqfd.h>
#include <linux/irqbypass.h>
#include <trace/events/kvm.h>
#include <kvm/arm_pmu.h>
#include <kvm/arm_psci.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/mman.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <asm/virt.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/sections.h>

#ifdef REQUIRES_VIRT
__asm__(".arch_extension        virt");
#endif

DEFINE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);

/* Per-CPU variable containing the currently running vcpu. */
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);

/* The VMID used in the VTTBR */
static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
static u32 kvm_next_vmid;
static unsigned int kvm_vmid_bits __read_mostly;
static DEFINE_SPINLOCK(kvm_vmid_lock);

static bool vgic_present;

static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);

static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
{
        __this_cpu_write(kvm_arm_running_vcpu, vcpu);
}

DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);

/**
 * kvm_arm_get_running_vcpu - get the vcpu running on the current CPU.
 * Must be called from non-preemptible context
 */
struct kvm_vcpu *kvm_arm_get_running_vcpu(void)
{
        return __this_cpu_read(kvm_arm_running_vcpu);
}

/**
 * kvm_arm_get_running_vcpus - get the per-CPU array of currently running vcpus.
 */
struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
{
        return &kvm_arm_running_vcpu;
}

int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
        return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
}

int kvm_arch_hardware_setup(void)
{
        return 0;
}

void kvm_arch_check_processor_compat(void *rtn)
{
        *(int *)rtn = 0;
}


/**
 * kvm_arch_init_vm - initializes a VM data structure
 * @kvm:        pointer to the KVM struct
 */
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
        int ret, cpu;

        if (type)
                return -EINVAL;

        kvm->arch.last_vcpu_ran = alloc_percpu(typeof(*kvm->arch.last_vcpu_ran));
        if (!kvm->arch.last_vcpu_ran)
                return -ENOMEM;

        for_each_possible_cpu(cpu)
                *per_cpu_ptr(kvm->arch.last_vcpu_ran, cpu) = -1;

        ret = kvm_alloc_stage2_pgd(kvm);
        if (ret)
                goto out_fail_alloc;

        ret = create_hyp_mappings(kvm, kvm + 1, PAGE_HYP);
        if (ret)
                goto out_free_stage2_pgd;

        kvm_vgic_early_init(kvm);

        /* Mark the initial VMID generation invalid */
        kvm->arch.vmid_gen = 0;

        /* The maximum number of VCPUs is limited by the host's GIC model */
        kvm->arch.max_vcpus = vgic_present ?
                                kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS;

        return ret;
out_free_stage2_pgd:
        kvm_free_stage2_pgd(kvm);
out_fail_alloc:
        free_percpu(kvm->arch.last_vcpu_ran);
        kvm->arch.last_vcpu_ran = NULL;
        return ret;
}

bool kvm_arch_has_vcpu_debugfs(void)
{
        return false;
}

int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
{
        return 0;
}

int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
{
        return VM_FAULT_SIGBUS;
}


/**
 * kvm_arch_destroy_vm - destroy the VM data structure
 * @kvm:        pointer to the KVM struct
 */
void kvm_arch_destroy_vm(struct kvm *kvm)
{
        int i;

        kvm_vgic_destroy(kvm);

        free_percpu(kvm->arch.last_vcpu_ran);
        kvm->arch.last_vcpu_ran = NULL;

        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
                if (kvm->vcpus[i]) {
                        kvm_arch_vcpu_free(kvm->vcpus[i]);
                        kvm->vcpus[i] = NULL;
                }
        }
        atomic_set(&kvm->online_vcpus, 0);
}

int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
{
        int r;
        switch (ext) {
        case KVM_CAP_IRQCHIP:
                r = vgic_present;
                break;
        case KVM_CAP_IOEVENTFD:
        case KVM_CAP_DEVICE_CTRL:
        case KVM_CAP_USER_MEMORY:
        case KVM_CAP_SYNC_MMU:
        case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
        case KVM_CAP_ONE_REG:
        case KVM_CAP_ARM_PSCI:
        case KVM_CAP_ARM_PSCI_0_2:
        case KVM_CAP_READONLY_MEM:
        case KVM_CAP_MP_STATE:
        case KVM_CAP_IMMEDIATE_EXIT:
                r = 1;
                break;
        case KVM_CAP_ARM_SET_DEVICE_ADDR:
                r = 1;
                break;
        case KVM_CAP_NR_VCPUS:
                r = num_online_cpus();
                break;
        case KVM_CAP_MAX_VCPUS:
                r = KVM_MAX_VCPUS;
                break;
        case KVM_CAP_NR_MEMSLOTS:
                r = KVM_USER_MEM_SLOTS;
                break;
        case KVM_CAP_MSI_DEVID:
                if (!kvm)
                        r = -EINVAL;
                else
                        r = kvm->arch.vgic.msis_require_devid;
                break;
        case KVM_CAP_ARM_USER_IRQ:
                /*
                 * 1: EL1_VTIMER, EL1_PTIMER, and PMU.
                 * (bump this number if adding more devices)
                 */
                r = 1;
                break;
        default:
                r = kvm_arch_dev_ioctl_check_extension(kvm, ext);
                break;
        }
        return r;
}

long kvm_arch_dev_ioctl(struct file *filp,
                        unsigned int ioctl, unsigned long arg)
{
        return -EINVAL;
}


struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
{
        int err;
        struct kvm_vcpu *vcpu;

        if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) {
                err = -EBUSY;
                goto out;
        }

        if (id >= kvm->arch.max_vcpus) {
                err = -EINVAL;
                goto out;
        }

        vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
        if (!vcpu) {
                err = -ENOMEM;
                goto out;
        }

        err = kvm_vcpu_init(vcpu, kvm, id);
        if (err)
                goto free_vcpu;

        err = create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP);
        if (err)
                goto vcpu_uninit;

        return vcpu;
vcpu_uninit:
        kvm_vcpu_uninit(vcpu);
free_vcpu:
        kmem_cache_free(kvm_vcpu_cache, vcpu);
out:
        return ERR_PTR(err);
}

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
        kvm_vgic_vcpu_early_init(vcpu);
}

void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
        if (vcpu->arch.has_run_once && unlikely(!irqchip_in_kernel(vcpu->kvm)))
                static_branch_dec(&userspace_irqchip_in_use);

        kvm_mmu_free_memory_caches(vcpu);
        kvm_timer_vcpu_terminate(vcpu);
        kvm_pmu_vcpu_destroy(vcpu);
        kvm_vcpu_uninit(vcpu);
        kmem_cache_free(kvm_vcpu_cache, vcpu);
}

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
        kvm_arch_vcpu_free(vcpu);
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
        return kvm_timer_is_pending(vcpu);
}

void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
{
        kvm_timer_schedule(vcpu);
        kvm_vgic_v4_enable_doorbell(vcpu);
}

void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
{
        kvm_timer_unschedule(vcpu);
        kvm_vgic_v4_disable_doorbell(vcpu);
}

int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
        /* Force users to call KVM_ARM_VCPU_INIT */
        vcpu->arch.target = -1;
        bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);

        /* Set up the timer */
        kvm_timer_vcpu_init(vcpu);

        kvm_arm_reset_debug_ptr(vcpu);

        return kvm_vgic_vcpu_init(vcpu);
}

void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
        int *last_ran;

        last_ran = this_cpu_ptr(vcpu->kvm->arch.last_vcpu_ran);

        /*
         * We might get preempted before the vCPU actually runs, but
         * over-invalidation doesn't affect correctness.
         */
        if (*last_ran != vcpu->vcpu_id) {
                kvm_call_hyp(__kvm_tlb_flush_local_vmid, vcpu);
                *last_ran = vcpu->vcpu_id;
        }

        vcpu->cpu = cpu;
        vcpu->arch.host_cpu_context = this_cpu_ptr(&kvm_host_cpu_state);

        kvm_arm_set_running_vcpu(vcpu);
        kvm_vgic_load(vcpu);
        kvm_timer_vcpu_load(vcpu);
}

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
        kvm_timer_vcpu_put(vcpu);
        kvm_vgic_put(vcpu);

        vcpu->cpu = -1;

        kvm_arm_set_running_vcpu(NULL);
}

static void vcpu_power_off(struct kvm_vcpu *vcpu)
{
        vcpu->arch.power_off = true;
        kvm_make_request(KVM_REQ_SLEEP, vcpu);
        kvm_vcpu_kick(vcpu);
}

int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
                                    struct kvm_mp_state *mp_state)
{
        if (vcpu->arch.power_off)
                mp_state->mp_state = KVM_MP_STATE_STOPPED;
        else
                mp_state->mp_state = KVM_MP_STATE_RUNNABLE;

        return 0;
}

int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
                                    struct kvm_mp_state *mp_state)
{
        int ret = 0;

        switch (mp_state->mp_state) {
        case KVM_MP_STATE_RUNNABLE:
                vcpu->arch.power_off = false;
                break;
        case KVM_MP_STATE_STOPPED:
                vcpu_power_off(vcpu);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

/**
 * kvm_arch_vcpu_runnable - determine if the vcpu can be scheduled
 * @v:          The VCPU pointer
 *
 * If the guest CPU is not waiting for interrupts or an interrupt line is
 * asserted, the CPU is by definition runnable.
 */
int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
{
        return ((!!v->arch.irq_lines || kvm_vgic_vcpu_pending_irq(v))
                && !v->arch.power_off && !v->arch.pause);
}

bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
{
        return vcpu_mode_priv(vcpu);
}

/* Just ensure a guest exit from a particular CPU */
static void exit_vm_noop(void *info)
{
}

void force_vm_exit(const cpumask_t *mask)
{
        preempt_disable();
        smp_call_function_many(mask, exit_vm_noop, NULL, true);
        preempt_enable();
}

/**
 * need_new_vmid_gen - check that the VMID is still valid
 * @kvm: The VM's VMID to check
 *
 * return true if there is a new generation of VMIDs being used
 *
 * The hardware supports only 256 values with the value zero reserved for the
 * host, so we check if an assigned value belongs to a previous generation,
 * which which requires us to assign a new value. If we're the first to use a
 * VMID for the new generation, we must flush necessary caches and TLBs on all
 * CPUs.
 */
static bool need_new_vmid_gen(struct kvm *kvm)
{
        return unlikely(kvm->arch.vmid_gen != atomic64_read(&kvm_vmid_gen));
}

/**
 * update_vttbr - Update the VTTBR with a valid VMID before the guest runs
 * @kvm The guest that we are about to run
 *
 * Called from kvm_arch_vcpu_ioctl_run before entering the guest to ensure the
 * VM has a valid VMID, otherwise assigns a new one and flushes corresponding
 * caches and TLBs.
 */
static void update_vttbr(struct kvm *kvm)
{
        phys_addr_t pgd_phys;
        u64 vmid;

        if (!need_new_vmid_gen(kvm))
                return;

        spin_lock(&kvm_vmid_lock);

        /*
         * We need to re-check the vmid_gen here to ensure that if another vcpu
         * already allocated a valid vmid for this vm, then this vcpu should
         * use the same vmid.
         */
        if (!need_new_vmid_gen(kvm)) {
                spin_unlock(&kvm_vmid_lock);
                return;
        }

        /* First user of a new VMID generation? */
        if (unlikely(kvm_next_vmid == 0)) {
                atomic64_inc(&kvm_vmid_gen);
                kvm_next_vmid = 1;

                /*
                 * On SMP we know no other CPUs can use this CPU's or each
                 * other's VMID after force_vm_exit returns since the
                 * kvm_vmid_lock blocks them from reentry to the guest.
                 */
                force_vm_exit(cpu_all_mask);
                /*
                 * Now broadcast TLB + ICACHE invalidation over the inner
                 * shareable domain to make sure all data structures are
                 * clean.
                 */
                kvm_call_hyp(__kvm_flush_vm_context);
        }

        kvm->arch.vmid_gen = atomic64_read(&kvm_vmid_gen);
        kvm->arch.vmid = kvm_next_vmid;
        kvm_next_vmid++;
        kvm_next_vmid &= (1 << kvm_vmid_bits) - 1;

        /* update vttbr to be used with the new vmid */
        pgd_phys = virt_to_phys(kvm->arch.pgd);
        BUG_ON(pgd_phys & ~VTTBR_BADDR_MASK);
        vmid = ((u64)(kvm->arch.vmid) << VTTBR_VMID_SHIFT) & VTTBR_VMID_MASK(kvm_vmid_bits);
        kvm->arch.vttbr = kvm_phys_to_vttbr(pgd_phys) | vmid;

        spin_unlock(&kvm_vmid_lock);
}

static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
{
        struct kvm *kvm = vcpu->kvm;
        int ret = 0;

        if (likely(vcpu->arch.has_run_once))
                return 0;

        vcpu->arch.has_run_once = true;

        if (likely(irqchip_in_kernel(kvm))) {
                /*
                 * Map the VGIC hardware resources before running a vcpu the
                 * first time on this VM.
                 */
                if (unlikely(!vgic_ready(kvm))) {
                        ret = kvm_vgic_map_resources(kvm);
                        if (ret)
                                return ret;
                }
        } else {
                /*
                 * Tell the rest of the code that there are userspace irqchip
                 * VMs in the wild.
                 */
                static_branch_inc(&userspace_irqchip_in_use);
        }

        ret = kvm_timer_enable(vcpu);
        if (ret)
                return ret;

        ret = kvm_arm_pmu_v3_enable(vcpu);

        return ret;
}

bool kvm_arch_intc_initialized(struct kvm *kvm)
{
        return vgic_initialized(kvm);
}

void kvm_arm_halt_guest(struct kvm *kvm)
{
        int i;
        struct kvm_vcpu *vcpu;

        kvm_for_each_vcpu(i, vcpu, kvm)
                vcpu->arch.pause = true;
        kvm_make_all_cpus_request(kvm, KVM_REQ_SLEEP);
}

void kvm_arm_resume_guest(struct kvm *kvm)
{
        int i;
        struct kvm_vcpu *vcpu;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                vcpu->arch.pause = false;
                swake_up(kvm_arch_vcpu_wq(vcpu));
        }
}

static void vcpu_req_sleep(struct kvm_vcpu *vcpu)
{
        struct swait_queue_head *wq = kvm_arch_vcpu_wq(vcpu);

        swait_event_interruptible(*wq, ((!vcpu->arch.power_off) &&
                                       (!vcpu->arch.pause)));

        if (vcpu->arch.power_off || vcpu->arch.pause) {
                /* Awaken to handle a signal, request we sleep again later. */
                kvm_make_request(KVM_REQ_SLEEP, vcpu);
        }
}

static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
{
        return vcpu->arch.target >= 0;
}

static void check_vcpu_requests(struct kvm_vcpu *vcpu)
{
        if (kvm_request_pending(vcpu)) {
                if (kvm_check_request(KVM_REQ_SLEEP, vcpu))
                        vcpu_req_sleep(vcpu);

                /*
                 * Clear IRQ_PENDING requests that were made to guarantee
                 * that a VCPU sees new virtual interrupts.
                 */
                kvm_check_request(KVM_REQ_IRQ_PENDING, vcpu);
        }
}

/**
 * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
 * @vcpu:       The VCPU pointer
 * @run:        The kvm_run structure pointer used for userspace state exchange
 *
 * This function is called through the VCPU_RUN ioctl called from user space. It
 * will execute VM code in a loop until the time slice for the process is used
 * or some emulation is needed from user space in which case the function will
 * return with return value 0 and with the kvm_run structure filled in with the
 * required data for the requested emulation.
 */
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        int ret;

        if (unlikely(!kvm_vcpu_initialized(vcpu)))
                return -ENOEXEC;

        vcpu_load(vcpu);

        ret = kvm_vcpu_first_run_init(vcpu);
        if (ret)
                goto out;

        if (run->exit_reason == KVM_EXIT_MMIO) {
                ret = kvm_handle_mmio_return(vcpu, vcpu->run);
                if (ret)
                        goto out;
                if (kvm_arm_handle_step_debug(vcpu, vcpu->run)) {
                        ret = 0;
                        goto out;
                }

        }

        if (run->immediate_exit) {
                ret = -EINTR;
                goto out;
        }

        kvm_sigset_activate(vcpu);

        ret = 1;
        run->exit_reason = KVM_EXIT_UNKNOWN;
        while (ret > 0) {
                /*
                 * Check conditions before entering the guest
                 */
                cond_resched();

                update_vttbr(vcpu->kvm);

                check_vcpu_requests(vcpu);

                /*
                 * Preparing the interrupts to be injected also
                 * involves poking the GIC, which must be done in a
                 * non-preemptible context.
                 */
                preempt_disable();

                /* Flush FP/SIMD state that can't survive guest entry/exit */
                kvm_fpsimd_flush_cpu_state();

                kvm_pmu_flush_hwstate(vcpu);

                local_irq_disable();

                kvm_vgic_flush_hwstate(vcpu);

                /*
                 * Exit if we have a signal pending so that we can deliver the
                 * signal to user space.
                 */
                if (signal_pending(current)) {
                        ret = -EINTR;
                        run->exit_reason = KVM_EXIT_INTR;
                }

                /*
                 * If we're using a userspace irqchip, then check if we need
                 * to tell a userspace irqchip about timer or PMU level
                 * changes and if so, exit to userspace (the actual level
                 * state gets updated in kvm_timer_update_run and
                 * kvm_pmu_update_run below).
                 */
                if (static_branch_unlikely(&userspace_irqchip_in_use)) {
                        if (kvm_timer_should_notify_user(vcpu) ||
                            kvm_pmu_should_notify_user(vcpu)) {
                                ret = -EINTR;
                                run->exit_reason = KVM_EXIT_INTR;
                        }
                }

                /*
                 * Ensure we set mode to IN_GUEST_MODE after we disable
                 * interrupts and before the final VCPU requests check.
                 * See the comment in kvm_vcpu_exiting_guest_mode() and
                 * Documentation/virtual/kvm/vcpu-requests.rst
                 */
                smp_store_mb(vcpu->mode, IN_GUEST_MODE);

                if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) ||
                    kvm_request_pending(vcpu)) {
                        vcpu->mode = OUTSIDE_GUEST_MODE;
                        kvm_pmu_sync_hwstate(vcpu);
                        if (static_branch_unlikely(&userspace_irqchip_in_use))
                                kvm_timer_sync_hwstate(vcpu);
                        kvm_vgic_sync_hwstate(vcpu);
                        local_irq_enable();
                        preempt_enable();
                        continue;
                }

                kvm_arm_setup_debug(vcpu);

                /**************************************************************
                 * Enter the guest
                 */
                trace_kvm_entry(*vcpu_pc(vcpu));
                guest_enter_irqoff();
                if (has_vhe())
                        kvm_arm_vhe_guest_enter();

                ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);

                if (has_vhe())
                        kvm_arm_vhe_guest_exit();
                vcpu->mode = OUTSIDE_GUEST_MODE;
                vcpu->stat.exits++;
                /*
                 * Back from guest
                 *************************************************************/

                kvm_arm_clear_debug(vcpu);

                /*
                 * We must sync the PMU state before the vgic state so
                 * that the vgic can properly sample the updated state of the
                 * interrupt line.
                 */
                kvm_pmu_sync_hwstate(vcpu);

                /*
                 * Sync the vgic state before syncing the timer state because
                 * the timer code needs to know if the virtual timer
                 * interrupts are active.
                 */
                kvm_vgic_sync_hwstate(vcpu);

                /*
                 * Sync the timer hardware state before enabling interrupts as
                 * we don't want vtimer interrupts to race with syncing the
                 * timer virtual interrupt state.
                 */
                if (static_branch_unlikely(&userspace_irqchip_in_use))
                        kvm_timer_sync_hwstate(vcpu);

                /*
                 * We may have taken a host interrupt in HYP mode (ie
                 * while executing the guest). This interrupt is still
                 * pending, as we haven't serviced it yet!
                 *
                 * We're now back in SVC mode, with interrupts
                 * disabled.  Enabling the interrupts now will have
                 * the effect of taking the interrupt again, in SVC
                 * mode this time.
                 */
                local_irq_enable();

                /*
                 * We do local_irq_enable() before calling guest_exit() so
                 * that if a timer interrupt hits while running the guest we
                 * account that tick as being spent in the guest.  We enable
                 * preemption after calling guest_exit() so that if we get
                 * preempted we make sure ticks after that is not counted as
                 * guest time.
                 */
                guest_exit();
                trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));

                /* Exit types that need handling before we can be preempted */
                handle_exit_early(vcpu, run, ret);

                preempt_enable();

                ret = handle_exit(vcpu, run, ret);
        }

        /* Tell userspace about in-kernel device output levels */
        if (unlikely(!irqchip_in_kernel(vcpu->kvm))) {
                kvm_timer_update_run(vcpu);
                kvm_pmu_update_run(vcpu);
        }

        kvm_sigset_deactivate(vcpu);

out:
        vcpu_put(vcpu);
        return ret;
}

static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level)
{
        int bit_index;
        bool set;
        unsigned long *ptr;

        if (number == KVM_ARM_IRQ_CPU_IRQ)
                bit_index = __ffs(HCR_VI);
        else /* KVM_ARM_IRQ_CPU_FIQ */
                bit_index = __ffs(HCR_VF);

        ptr = (unsigned long *)&vcpu->arch.irq_lines;
        if (level)
                set = test_and_set_bit(bit_index, ptr);
        else
                set = test_and_clear_bit(bit_index, ptr);

        /*
         * If we didn't change anything, no need to wake up or kick other CPUs
         */
        if (set == level)
                return 0;

        /*
         * The vcpu irq_lines field was updated, wake up sleeping VCPUs and
         * trigger a world-switch round on the running physical CPU to set the
         * virtual IRQ/FIQ fields in the HCR appropriately.
         */
        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
        kvm_vcpu_kick(vcpu);

        return 0;
}

int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level,
                          bool line_status)
{
        u32 irq = irq_level->irq;
        unsigned int irq_type, vcpu_idx, irq_num;
        int nrcpus = atomic_read(&kvm->online_vcpus);
        struct kvm_vcpu *vcpu = NULL;
        bool level = irq_level->level;

        irq_type = (irq >> KVM_ARM_IRQ_TYPE_SHIFT) & KVM_ARM_IRQ_TYPE_MASK;
        vcpu_idx = (irq >> KVM_ARM_IRQ_VCPU_SHIFT) & KVM_ARM_IRQ_VCPU_MASK;
        irq_num = (irq >> KVM_ARM_IRQ_NUM_SHIFT) & KVM_ARM_IRQ_NUM_MASK;

        trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);

        switch (irq_type) {
        case KVM_ARM_IRQ_TYPE_CPU:
                if (irqchip_in_kernel(kvm))
                        return -ENXIO;

                if (vcpu_idx >= nrcpus)
                        return -EINVAL;

                vcpu = kvm_get_vcpu(kvm, vcpu_idx);
                if (!vcpu)
                        return -EINVAL;

                if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
                        return -EINVAL;

                return vcpu_interrupt_line(vcpu, irq_num, level);
        case KVM_ARM_IRQ_TYPE_PPI:
                if (!irqchip_in_kernel(kvm))
                        return -ENXIO;

                if (vcpu_idx >= nrcpus)
                        return -EINVAL;

                vcpu = kvm_get_vcpu(kvm, vcpu_idx);
                if (!vcpu)
                        return -EINVAL;

                if (irq_num < VGIC_NR_SGIS || irq_num >= VGIC_NR_PRIVATE_IRQS)
                        return -EINVAL;

                return kvm_vgic_inject_irq(kvm, vcpu->vcpu_id, irq_num, level, NULL);
        case KVM_ARM_IRQ_TYPE_SPI:
                if (!irqchip_in_kernel(kvm))
                        return -ENXIO;

                if (irq_num < VGIC_NR_PRIVATE_IRQS)
                        return -EINVAL;

                return kvm_vgic_inject_irq(kvm, 0, irq_num, level, NULL);
        }

        return -EINVAL;
}

static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
                               const struct kvm_vcpu_init *init)
{
        unsigned int i;
        int phys_target = kvm_target_cpu();

        if (init->target != phys_target)
                return -EINVAL;

        /*
         * Secondary and subsequent calls to KVM_ARM_VCPU_INIT must
         * use the same target.
         */
        if (vcpu->arch.target != -1 && vcpu->arch.target != init->target)
                return -EINVAL;

        /* -ENOENT for unknown features, -EINVAL for invalid combinations. */
        for (i = 0; i < sizeof(init->features) * 8; i++) {
                bool set = (init->features[i / 32] & (1 << (i % 32)));

                if (set && i >= KVM_VCPU_MAX_FEATURES)
                        return -ENOENT;

                /*
                 * Secondary and subsequent calls to KVM_ARM_VCPU_INIT must
                 * use the same feature set.
                 */
                if (vcpu->arch.target != -1 && i < KVM_VCPU_MAX_FEATURES &&
                    test_bit(i, vcpu->arch.features) != set)
                        return -EINVAL;

                if (set)
                        set_bit(i, vcpu->arch.features);
        }

        vcpu->arch.target = phys_target;

        /* Now we know what it is, we can reset it. */
        return kvm_reset_vcpu(vcpu);
}


static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
                                         struct kvm_vcpu_init *init)
{
        int ret;

        ret = kvm_vcpu_set_target(vcpu, init);
        if (ret)
                return ret;

        /*
         * Ensure a rebooted VM will fault in RAM pages and detect if the
         * guest MMU is turned off and flush the caches as needed.
         */
        if (vcpu->arch.has_run_once)
                stage2_unmap_vm(vcpu->kvm);

        vcpu_reset_hcr(vcpu);

        /*
         * Handle the "start in power-off" case.
         */
        if (test_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features))
                vcpu_power_off(vcpu);
        else
                vcpu->arch.power_off = false;

        return 0;
}

static int kvm_arm_vcpu_set_attr(struct kvm_vcpu *vcpu,
                                 struct kvm_device_attr *attr)
{
        int ret = -ENXIO;

        switch (attr->group) {
        default:
                ret = kvm_arm_vcpu_arch_set_attr(vcpu, attr);
                break;
        }

        return ret;
}

static int kvm_arm_vcpu_get_attr(struct kvm_vcpu *vcpu,
                                 struct kvm_device_attr *attr)
{
        int ret = -ENXIO;

        switch (attr->group) {
        default:
                ret = kvm_arm_vcpu_arch_get_attr(vcpu, attr);
                break;
        }

        return ret;
}

static int kvm_arm_vcpu_has_attr(struct kvm_vcpu *vcpu,
                                 struct kvm_device_attr *attr)
{
        int ret = -ENXIO;

        switch (attr->group) {
        default:
                ret = kvm_arm_vcpu_arch_has_attr(vcpu, attr);
                break;
        }

        return ret;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
                         unsigned int ioctl, unsigned long arg)
{
        struct kvm_vcpu *vcpu = filp->private_data;
        void __user *argp = (void __user *)arg;
        struct kvm_device_attr attr;
        long r;

        switch (ioctl) {
        case KVM_ARM_VCPU_INIT: {
                struct kvm_vcpu_init init;

                r = -EFAULT;
                if (copy_from_user(&init, argp, sizeof(init)))
                        break;

                r = kvm_arch_vcpu_ioctl_vcpu_init(vcpu, &init);
                break;
        }
        case KVM_SET_ONE_REG:
        case KVM_GET_ONE_REG: {
                struct kvm_one_reg reg;

                r = -ENOEXEC;
                if (unlikely(!kvm_vcpu_initialized(vcpu)))
                        break;

                r = -EFAULT;
                if (copy_from_user(&reg, argp, sizeof(reg)))
                        break;

                if (ioctl == KVM_SET_ONE_REG)
                        r = kvm_arm_set_reg(vcpu, &reg);
                else
                        r = kvm_arm_get_reg(vcpu, &reg);
                break;
        }
        case KVM_GET_REG_LIST: {
                struct kvm_reg_list __user *user_list = argp;
                struct kvm_reg_list reg_list;
                unsigned n;

                r = -ENOEXEC;
                if (unlikely(!kvm_vcpu_initialized(vcpu)))
                        break;

                r = -EFAULT;
                if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
                        break;
                n = reg_list.n;
                reg_list.n = kvm_arm_num_regs(vcpu);
                if (copy_to_user(user_list, &reg_list, sizeof(reg_list)))
                        break;
                r = -E2BIG;
                if (n < reg_list.n)
                        break;
                r = kvm_arm_copy_reg_indices(vcpu, user_list->reg);
                break;
        }
        case KVM_SET_DEVICE_ATTR: {
                r = -EFAULT;
                if (copy_from_user(&attr, argp, sizeof(attr)))
                        break;
                r = kvm_arm_vcpu_set_attr(vcpu, &attr);
                break;
        }
        case KVM_GET_DEVICE_ATTR: {
                r = -EFAULT;
                if (copy_from_user(&attr, argp, sizeof(attr)))
                        break;
                r = kvm_arm_vcpu_get_attr(vcpu, &attr);
                break;
        }
        case KVM_HAS_DEVICE_ATTR: {
                r = -EFAULT;
                if (copy_from_user(&attr, argp, sizeof(attr)))
                        break;
                r = kvm_arm_vcpu_has_attr(vcpu, &attr);
                break;
        }
        default:
                r = -EINVAL;
        }

        return r;
}

/**
 * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
 * @kvm: kvm instance
 * @log: slot id and address to which we copy the log
 *
 * Steps 1-4 below provide general overview of dirty page logging. See
 * kvm_get_dirty_log_protect() function description for additional details.
 *
 * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
 * always flush the TLB (step 4) even if previous step failed  and the dirty
 * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
 * does not preclude user space subsequent dirty log read. Flushing TLB ensures
 * writes will be marked dirty for next log read.
 *
 *   1. Take a snapshot of the bit and clear it if needed.
 *   2. Write protect the corresponding page.
 *   3. Copy the snapshot to the userspace.
 *   4. Flush TLB's if needed.
 */
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
{
        bool is_dirty = false;
        int r;

        mutex_lock(&kvm->slots_lock);

        r = kvm_get_dirty_log_protect(kvm, log, &is_dirty);

        if (is_dirty)
                kvm_flush_remote_tlbs(kvm);

        mutex_unlock(&kvm->slots_lock);
        return r;
}

static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
                                        struct kvm_arm_device_addr *dev_addr)
{
        unsigned long dev_id, type;

        dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
                KVM_ARM_DEVICE_ID_SHIFT;
        type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
                KVM_ARM_DEVICE_TYPE_SHIFT;

        switch (dev_id) {
        case KVM_ARM_DEVICE_VGIC_V2:
                if (!vgic_present)
                        return -ENXIO;
                return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
        default:
                return -ENODEV;
        }
}

long kvm_arch_vm_ioctl(struct file *filp,
                       unsigned int ioctl, unsigned long arg)
{
        struct kvm *kvm = filp->private_data;
        void __user *argp = (void __user *)arg;

        switch (ioctl) {
        case KVM_CREATE_IRQCHIP: {
                int ret;
                if (!vgic_present)
                        return -ENXIO;
                mutex_lock(&kvm->lock);
                ret = kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
                mutex_unlock(&kvm->lock);
                return ret;
        }
        case KVM_ARM_SET_DEVICE_ADDR: {
                struct kvm_arm_device_addr dev_addr;

                if (copy_from_user(&dev_addr, argp, sizeof(dev_addr)))
                        return -EFAULT;
                return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr);
        }
        case KVM_ARM_PREFERRED_TARGET: {
                int err;
                struct kvm_vcpu_init init;

                err = kvm_vcpu_preferred_target(&init);
                if (err)
                        return err;

                if (copy_to_user(argp, &init, sizeof(init)))
                        return -EFAULT;

                return 0;
        }
        default:
                return -EINVAL;
        }
}

static void cpu_init_hyp_mode(void *dummy)
{
        phys_addr_t pgd_ptr;
        unsigned long hyp_stack_ptr;
        unsigned long stack_page;
        unsigned long vector_ptr;

        /* Switch from the HYP stub to our own HYP init vector */
        __hyp_set_vectors(kvm_get_idmap_vector());

        pgd_ptr = kvm_mmu_get_httbr();
        stack_page = __this_cpu_read(kvm_arm_hyp_stack_page);
        hyp_stack_ptr = stack_page + PAGE_SIZE;
        vector_ptr = (unsigned long)kvm_get_hyp_vector();

        __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
        __cpu_init_stage2();

        kvm_arm_init_debug();
}

static void cpu_hyp_reset(void)
{
        if (!is_kernel_in_hyp_mode())
                __hyp_reset_vectors();
}

static void cpu_hyp_reinit(void)
{
        cpu_hyp_reset();

        if (is_kernel_in_hyp_mode()) {
                /*
                 * __cpu_init_stage2() is safe to call even if the PM
                 * event was cancelled before the CPU was reset.
                 */
                __cpu_init_stage2();
                kvm_timer_init_vhe();
        } else {
                cpu_init_hyp_mode(NULL);
        }

        if (vgic_present)
                kvm_vgic_init_cpu_hardware();
}

static void _kvm_arch_hardware_enable(void *discard)
{
        if (!__this_cpu_read(kvm_arm_hardware_enabled)) {
                cpu_hyp_reinit();
                __this_cpu_write(kvm_arm_hardware_enabled, 1);
        }
}

int kvm_arch_hardware_enable(void)
{
        _kvm_arch_hardware_enable(NULL);
        return 0;
}

static void _kvm_arch_hardware_disable(void *discard)
{
        if (__this_cpu_read(kvm_arm_hardware_enabled)) {
                cpu_hyp_reset();
                __this_cpu_write(kvm_arm_hardware_enabled, 0);
        }
}

void kvm_arch_hardware_disable(void)
{
        _kvm_arch_hardware_disable(NULL);
}

#ifdef CONFIG_CPU_PM
static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
                                    unsigned long cmd,
                                    void *v)
{
        /*
         * kvm_arm_hardware_enabled is left with its old value over
         * PM_ENTER->PM_EXIT. It is used to indicate PM_EXIT should
         * re-enable hyp.
         */
        switch (cmd) {
        case CPU_PM_ENTER:
                if (__this_cpu_read(kvm_arm_hardware_enabled))
                        /*
                         * don't update kvm_arm_hardware_enabled here
                         * so that the hardware will be re-enabled
                         * when we resume. See below.
                         */
                        cpu_hyp_reset();

                return NOTIFY_OK;
        case CPU_PM_ENTER_FAILED:
        case CPU_PM_EXIT:
                if (__this_cpu_read(kvm_arm_hardware_enabled))
                        /* The hardware was enabled before suspend. */
                        cpu_hyp_reinit();

                return NOTIFY_OK;

        default:
                return NOTIFY_DONE;
        }
}

static struct notifier_block hyp_init_cpu_pm_nb = {
        .notifier_call = hyp_init_cpu_pm_notifier,
};

static void __init hyp_cpu_pm_init(void)
{
        cpu_pm_register_notifier(&hyp_init_cpu_pm_nb);
}
static void __init hyp_cpu_pm_exit(void)
{
        cpu_pm_unregister_notifier(&hyp_init_cpu_pm_nb);
}
#else
static inline void hyp_cpu_pm_init(void)
{
}
static inline void hyp_cpu_pm_exit(void)
{
}
#endif

static int init_common_resources(void)
{
        /* set size of VMID supported by CPU */
        kvm_vmid_bits = kvm_get_vmid_bits();
        kvm_info("%d-bit VMID\n", kvm_vmid_bits);

        return 0;
}

static int init_subsystems(void)
{
        int err = 0;

        /*
         * Enable hardware so that subsystem initialisation can access EL2.
         */
        on_each_cpu(_kvm_arch_hardware_enable, NULL, 1);

        /*
         * Register CPU lower-power notifier
         */
        hyp_cpu_pm_init();

        /*
         * Init HYP view of VGIC
         */
        err = kvm_vgic_hyp_init();
        switch (err) {
        case 0:
                vgic_present = true;
                break;
        case -ENODEV:
        case -ENXIO:
                vgic_present = false;
                err = 0;
                break;
        default:
                goto out;
        }

        /*
         * Init HYP architected timer support
         */
        err = kvm_timer_hyp_init(vgic_present);
        if (err)
                goto out;

        kvm_perf_init();
        kvm_coproc_table_init();

out:
        on_each_cpu(_kvm_arch_hardware_disable, NULL, 1);

        return err;
}

static void teardown_hyp_mode(void)
{
        int cpu;

        free_hyp_pgds();
        for_each_possible_cpu(cpu)
                free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
        hyp_cpu_pm_exit();
}

/**
 * Inits Hyp-mode on all online CPUs
 */
static int init_hyp_mode(void)
{
        int cpu;
        int err = 0;

        /*
         * Allocate Hyp PGD and setup Hyp identity mapping
         */
        err = kvm_mmu_init();
        if (err)
                goto out_err;

        /*
         * Allocate stack pages for Hypervisor-mode
         */
        for_each_possible_cpu(cpu) {
                unsigned long stack_page;

                stack_page = __get_free_page(GFP_KERNEL);
                if (!stack_page) {
                        err = -ENOMEM;
                        goto out_err;
                }

                per_cpu(kvm_arm_hyp_stack_page, cpu) = stack_page;
        }

        /*
         * Map the Hyp-code called directly from the host
         */
        err = create_hyp_mappings(kvm_ksym_ref(__hyp_text_start),
                                  kvm_ksym_ref(__hyp_text_end), PAGE_HYP_EXEC);
        if (err) {
                kvm_err("Cannot map world-switch code\n");
                goto out_err;
        }

        err = create_hyp_mappings(kvm_ksym_ref(__start_rodata),
                                  kvm_ksym_ref(__end_rodata), PAGE_HYP_RO);
        if (err) {
                kvm_err("Cannot map rodata section\n");
                goto out_err;
        }

        err = create_hyp_mappings(kvm_ksym_ref(__bss_start),
                                  kvm_ksym_ref(__bss_stop), PAGE_HYP_RO);
        if (err) {
                kvm_err("Cannot map bss section\n");
                goto out_err;
        }

        err = kvm_map_vectors();
        if (err) {
                kvm_err("Cannot map vectors\n");
                goto out_err;
        }

        /*
         * Map the Hyp stack pages
         */
        for_each_possible_cpu(cpu) {
                char *stack_page = (char *)per_cpu(kvm_arm_hyp_stack_page, cpu);
                err = create_hyp_mappings(stack_page, stack_page + PAGE_SIZE,
                                          PAGE_HYP);

                if (err) {
                        kvm_err("Cannot map hyp stack\n");
                        goto out_err;
                }
        }

        for_each_possible_cpu(cpu) {
                kvm_cpu_context_t *cpu_ctxt;

                cpu_ctxt = per_cpu_ptr(&kvm_host_cpu_state, cpu);
                err = create_hyp_mappings(cpu_ctxt, cpu_ctxt + 1, PAGE_HYP);

                if (err) {
                        kvm_err("Cannot map host CPU state: %d\n", err);
                        goto out_err;
                }
        }

        return 0;

out_err:
        teardown_hyp_mode();
        kvm_err("error initializing Hyp mode: %d\n", err);
        return err;
}

static void check_kvm_target_cpu(void *ret)
{
        *(int *)ret = kvm_target_cpu();
}

struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
{
        struct kvm_vcpu *vcpu;
        int i;

        mpidr &= MPIDR_HWID_BITMASK;
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (mpidr == kvm_vcpu_get_mpidr_aff(vcpu))
                        return vcpu;
        }
        return NULL;
}

bool kvm_arch_has_irq_bypass(void)
{
        return true;
}

int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
                                      struct irq_bypass_producer *prod)
{
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);

        return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
                                          &irqfd->irq_entry);
}
void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
                                      struct irq_bypass_producer *prod)
{
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);

        kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
                                     &irqfd->irq_entry);
}

void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)
{
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);

        kvm_arm_halt_guest(irqfd->kvm);
}

void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *cons)
{
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);

        kvm_arm_resume_guest(irqfd->kvm);
}

/**
 * Initialize Hyp-mode and memory mappings on all CPUs.
 */
int kvm_arch_init(void *opaque)
{
        int err;
        int ret, cpu;
        bool in_hyp_mode;

        if (!is_hyp_mode_available()) {
                kvm_info("HYP mode not available\n");
                return -ENODEV;
        }

        for_each_online_cpu(cpu) {
                smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1);
                if (ret < 0) {
                        kvm_err("Error, CPU %d not supported!\n", cpu);
                        return -ENODEV;
                }
        }

        err = init_common_resources();
        if (err)
                return err;

        in_hyp_mode = is_kernel_in_hyp_mode();

        if (!in_hyp_mode) {
                err = init_hyp_mode();
                if (err)
                        goto out_err;
        }

        err = init_subsystems();
        if (err)
                goto out_hyp;

        if (in_hyp_mode)
                kvm_info("VHE mode initialized successfully\n");
        else
                kvm_info("Hyp mode initialized successfully\n");

        return 0;

out_hyp:
        if (!in_hyp_mode)
                teardown_hyp_mode();
out_err:
        return err;
}

/* NOP: Compiling as a module not supported */
void kvm_arch_exit(void)
{
        kvm_perf_teardown();
}

static int arm_init(void)
{
        int rc = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
        return rc;
}

module_init(arm_init);