KVM: Harden copying of userspace-array against overflow

[thirdparty/kernel/stable.git] / arch / arm64 / kvm / arch_timer.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 ARM Ltd.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/uaccess.h>

#include <clocksource/arm_arch_timer.h>
#include <asm/arch_timer.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_nested.h>

#include <kvm/arm_vgic.h>
#include <kvm/arm_arch_timer.h>

#include "trace.h"

static struct timecounter *timecounter;
static unsigned int host_vtimer_irq;
static unsigned int host_ptimer_irq;
static u32 host_vtimer_irq_flags;
static u32 host_ptimer_irq_flags;

static DEFINE_STATIC_KEY_FALSE(has_gic_active_state);

static const u8 default_ppi[] = {
        [TIMER_PTIMER]  = 30,
        [TIMER_VTIMER]  = 27,
        [TIMER_HPTIMER] = 26,
        [TIMER_HVTIMER] = 28,
};

static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx);
static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
                                 struct arch_timer_context *timer_ctx);
static bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx);
static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
                                struct arch_timer_context *timer,
                                enum kvm_arch_timer_regs treg,
                                u64 val);
static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
                              struct arch_timer_context *timer,
                              enum kvm_arch_timer_regs treg);
static bool kvm_arch_timer_get_input_level(int vintid);

static struct irq_ops arch_timer_irq_ops = {
        .get_input_level = kvm_arch_timer_get_input_level,
};

static int nr_timers(struct kvm_vcpu *vcpu)
{
        if (!vcpu_has_nv(vcpu))
                return NR_KVM_EL0_TIMERS;

        return NR_KVM_TIMERS;
}

u32 timer_get_ctl(struct arch_timer_context *ctxt)
{
        struct kvm_vcpu *vcpu = ctxt->vcpu;

        switch(arch_timer_ctx_index(ctxt)) {
        case TIMER_VTIMER:
                return __vcpu_sys_reg(vcpu, CNTV_CTL_EL0);
        case TIMER_PTIMER:
                return __vcpu_sys_reg(vcpu, CNTP_CTL_EL0);
        case TIMER_HVTIMER:
                return __vcpu_sys_reg(vcpu, CNTHV_CTL_EL2);
        case TIMER_HPTIMER:
                return __vcpu_sys_reg(vcpu, CNTHP_CTL_EL2);
        default:
                WARN_ON(1);
                return 0;
        }
}

u64 timer_get_cval(struct arch_timer_context *ctxt)
{
        struct kvm_vcpu *vcpu = ctxt->vcpu;

        switch(arch_timer_ctx_index(ctxt)) {
        case TIMER_VTIMER:
                return __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0);
        case TIMER_PTIMER:
                return __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0);
        case TIMER_HVTIMER:
                return __vcpu_sys_reg(vcpu, CNTHV_CVAL_EL2);
        case TIMER_HPTIMER:
                return __vcpu_sys_reg(vcpu, CNTHP_CVAL_EL2);
        default:
                WARN_ON(1);
                return 0;
        }
}

static u64 timer_get_offset(struct arch_timer_context *ctxt)
{
        u64 offset = 0;

        if (!ctxt)
                return 0;

        if (ctxt->offset.vm_offset)
                offset += *ctxt->offset.vm_offset;
        if (ctxt->offset.vcpu_offset)
                offset += *ctxt->offset.vcpu_offset;

        return offset;
}

static void timer_set_ctl(struct arch_timer_context *ctxt, u32 ctl)
{
        struct kvm_vcpu *vcpu = ctxt->vcpu;

        switch(arch_timer_ctx_index(ctxt)) {
        case TIMER_VTIMER:
                __vcpu_sys_reg(vcpu, CNTV_CTL_EL0) = ctl;
                break;
        case TIMER_PTIMER:
                __vcpu_sys_reg(vcpu, CNTP_CTL_EL0) = ctl;
                break;
        case TIMER_HVTIMER:
                __vcpu_sys_reg(vcpu, CNTHV_CTL_EL2) = ctl;
                break;
        case TIMER_HPTIMER:
                __vcpu_sys_reg(vcpu, CNTHP_CTL_EL2) = ctl;
                break;
        default:
                WARN_ON(1);
        }
}

static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval)
{
        struct kvm_vcpu *vcpu = ctxt->vcpu;

        switch(arch_timer_ctx_index(ctxt)) {
        case TIMER_VTIMER:
                __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0) = cval;
                break;
        case TIMER_PTIMER:
                __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0) = cval;
                break;
        case TIMER_HVTIMER:
                __vcpu_sys_reg(vcpu, CNTHV_CVAL_EL2) = cval;
                break;
        case TIMER_HPTIMER:
                __vcpu_sys_reg(vcpu, CNTHP_CVAL_EL2) = cval;
                break;
        default:
                WARN_ON(1);
        }
}

static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset)
{
        if (!ctxt->offset.vm_offset) {
                WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt));
                return;
        }

        WRITE_ONCE(*ctxt->offset.vm_offset, offset);
}

u64 kvm_phys_timer_read(void)
{
        return timecounter->cc->read(timecounter->cc);
}

void get_timer_map(struct kvm_vcpu *vcpu, struct timer_map *map)
{
        if (vcpu_has_nv(vcpu)) {
                if (is_hyp_ctxt(vcpu)) {
                        map->direct_vtimer = vcpu_hvtimer(vcpu);
                        map->direct_ptimer = vcpu_hptimer(vcpu);
                        map->emul_vtimer = vcpu_vtimer(vcpu);
                        map->emul_ptimer = vcpu_ptimer(vcpu);
                } else {
                        map->direct_vtimer = vcpu_vtimer(vcpu);
                        map->direct_ptimer = vcpu_ptimer(vcpu);
                        map->emul_vtimer = vcpu_hvtimer(vcpu);
                        map->emul_ptimer = vcpu_hptimer(vcpu);
                }
        } else if (has_vhe()) {
                map->direct_vtimer = vcpu_vtimer(vcpu);
                map->direct_ptimer = vcpu_ptimer(vcpu);
                map->emul_vtimer = NULL;
                map->emul_ptimer = NULL;
        } else {
                map->direct_vtimer = vcpu_vtimer(vcpu);
                map->direct_ptimer = NULL;
                map->emul_vtimer = NULL;
                map->emul_ptimer = vcpu_ptimer(vcpu);
        }

        trace_kvm_get_timer_map(vcpu->vcpu_id, map);
}

static inline bool userspace_irqchip(struct kvm *kvm)
{
        return static_branch_unlikely(&userspace_irqchip_in_use) &&
                unlikely(!irqchip_in_kernel(kvm));
}

static void soft_timer_start(struct hrtimer *hrt, u64 ns)
{
        hrtimer_start(hrt, ktime_add_ns(ktime_get(), ns),
                      HRTIMER_MODE_ABS_HARD);
}

static void soft_timer_cancel(struct hrtimer *hrt)
{
        hrtimer_cancel(hrt);
}

static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
{
        struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
        struct arch_timer_context *ctx;
        struct timer_map map;

        /*
         * We may see a timer interrupt after vcpu_put() has been called which
         * sets the CPU's vcpu pointer to NULL, because even though the timer
         * has been disabled in timer_save_state(), the hardware interrupt
         * signal may not have been retired from the interrupt controller yet.
         */
        if (!vcpu)
                return IRQ_HANDLED;

        get_timer_map(vcpu, &map);

        if (irq == host_vtimer_irq)
                ctx = map.direct_vtimer;
        else
                ctx = map.direct_ptimer;

        if (kvm_timer_should_fire(ctx))
                kvm_timer_update_irq(vcpu, true, ctx);

        if (userspace_irqchip(vcpu->kvm) &&
            !static_branch_unlikely(&has_gic_active_state))
                disable_percpu_irq(host_vtimer_irq);

        return IRQ_HANDLED;
}

static u64 kvm_counter_compute_delta(struct arch_timer_context *timer_ctx,
                                     u64 val)
{
        u64 now = kvm_phys_timer_read() - timer_get_offset(timer_ctx);

        if (now < val) {
                u64 ns;

                ns = cyclecounter_cyc2ns(timecounter->cc,
                                         val - now,
                                         timecounter->mask,
                                         &timer_ctx->ns_frac);
                return ns;
        }

        return 0;
}

static u64 kvm_timer_compute_delta(struct arch_timer_context *timer_ctx)
{
        return kvm_counter_compute_delta(timer_ctx, timer_get_cval(timer_ctx));
}

static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx)
{
        WARN_ON(timer_ctx && timer_ctx->loaded);
        return timer_ctx &&
                ((timer_get_ctl(timer_ctx) &
                  (ARCH_TIMER_CTRL_IT_MASK | ARCH_TIMER_CTRL_ENABLE)) == ARCH_TIMER_CTRL_ENABLE);
}

static bool vcpu_has_wfit_active(struct kvm_vcpu *vcpu)
{
        return (cpus_have_final_cap(ARM64_HAS_WFXT) &&
                vcpu_get_flag(vcpu, IN_WFIT));
}

static u64 wfit_delay_ns(struct kvm_vcpu *vcpu)
{
        u64 val = vcpu_get_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu));
        struct arch_timer_context *ctx;

        ctx = (vcpu_has_nv(vcpu) && is_hyp_ctxt(vcpu)) ? vcpu_hvtimer(vcpu)
                                                       : vcpu_vtimer(vcpu);

        return kvm_counter_compute_delta(ctx, val);
}

/*
 * Returns the earliest expiration time in ns among guest timers.
 * Note that it will return 0 if none of timers can fire.
 */
static u64 kvm_timer_earliest_exp(struct kvm_vcpu *vcpu)
{
        u64 min_delta = ULLONG_MAX;
        int i;

        for (i = 0; i < nr_timers(vcpu); i++) {
                struct arch_timer_context *ctx = &vcpu->arch.timer_cpu.timers[i];

                WARN(ctx->loaded, "timer %d loaded\n", i);
                if (kvm_timer_irq_can_fire(ctx))
                        min_delta = min(min_delta, kvm_timer_compute_delta(ctx));
        }

        if (vcpu_has_wfit_active(vcpu))
                min_delta = min(min_delta, wfit_delay_ns(vcpu));

        /* If none of timers can fire, then return 0 */
        if (min_delta == ULLONG_MAX)
                return 0;

        return min_delta;
}

static enum hrtimer_restart kvm_bg_timer_expire(struct hrtimer *hrt)
{
        struct arch_timer_cpu *timer;
        struct kvm_vcpu *vcpu;
        u64 ns;

        timer = container_of(hrt, struct arch_timer_cpu, bg_timer);
        vcpu = container_of(timer, struct kvm_vcpu, arch.timer_cpu);

        /*
         * Check that the timer has really expired from the guest's
         * PoV (NTP on the host may have forced it to expire
         * early). If we should have slept longer, restart it.
         */
        ns = kvm_timer_earliest_exp(vcpu);
        if (unlikely(ns)) {
                hrtimer_forward_now(hrt, ns_to_ktime(ns));
                return HRTIMER_RESTART;
        }

        kvm_vcpu_wake_up(vcpu);
        return HRTIMER_NORESTART;
}

static enum hrtimer_restart kvm_hrtimer_expire(struct hrtimer *hrt)
{
        struct arch_timer_context *ctx;
        struct kvm_vcpu *vcpu;
        u64 ns;

        ctx = container_of(hrt, struct arch_timer_context, hrtimer);
        vcpu = ctx->vcpu;

        trace_kvm_timer_hrtimer_expire(ctx);

        /*
         * Check that the timer has really expired from the guest's
         * PoV (NTP on the host may have forced it to expire
         * early). If not ready, schedule for a later time.
         */
        ns = kvm_timer_compute_delta(ctx);
        if (unlikely(ns)) {
                hrtimer_forward_now(hrt, ns_to_ktime(ns));
                return HRTIMER_RESTART;
        }

        kvm_timer_update_irq(vcpu, true, ctx);
        return HRTIMER_NORESTART;
}

static bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx)
{
        enum kvm_arch_timers index;
        u64 cval, now;

        if (!timer_ctx)
                return false;

        index = arch_timer_ctx_index(timer_ctx);

        if (timer_ctx->loaded) {
                u32 cnt_ctl = 0;

                switch (index) {
                case TIMER_VTIMER:
                case TIMER_HVTIMER:
                        cnt_ctl = read_sysreg_el0(SYS_CNTV_CTL);
                        break;
                case TIMER_PTIMER:
                case TIMER_HPTIMER:
                        cnt_ctl = read_sysreg_el0(SYS_CNTP_CTL);
                        break;
                case NR_KVM_TIMERS:
                        /* GCC is braindead */
                        cnt_ctl = 0;
                        break;
                }

                return  (cnt_ctl & ARCH_TIMER_CTRL_ENABLE) &&
                        (cnt_ctl & ARCH_TIMER_CTRL_IT_STAT) &&
                       !(cnt_ctl & ARCH_TIMER_CTRL_IT_MASK);
        }

        if (!kvm_timer_irq_can_fire(timer_ctx))
                return false;

        cval = timer_get_cval(timer_ctx);
        now = kvm_phys_timer_read() - timer_get_offset(timer_ctx);

        return cval <= now;
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
        return vcpu_has_wfit_active(vcpu) && wfit_delay_ns(vcpu) == 0;
}

/*
 * Reflect the timer output level into the kvm_run structure
 */
void kvm_timer_update_run(struct kvm_vcpu *vcpu)
{
        struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
        struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
        struct kvm_sync_regs *regs = &vcpu->run->s.regs;

        /* Populate the device bitmap with the timer states */
        regs->device_irq_level &= ~(KVM_ARM_DEV_EL1_VTIMER |
                                    KVM_ARM_DEV_EL1_PTIMER);
        if (kvm_timer_should_fire(vtimer))
                regs->device_irq_level |= KVM_ARM_DEV_EL1_VTIMER;
        if (kvm_timer_should_fire(ptimer))
                regs->device_irq_level |= KVM_ARM_DEV_EL1_PTIMER;
}

static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
                                 struct arch_timer_context *timer_ctx)
{
        int ret;

        timer_ctx->irq.level = new_level;
        trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_irq(timer_ctx),
                                   timer_ctx->irq.level);

        if (!userspace_irqchip(vcpu->kvm)) {
                ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu,
                                          timer_irq(timer_ctx),
                                          timer_ctx->irq.level,
                                          timer_ctx);
                WARN_ON(ret);
        }
}

/* Only called for a fully emulated timer */
static void timer_emulate(struct arch_timer_context *ctx)
{
        bool should_fire = kvm_timer_should_fire(ctx);

        trace_kvm_timer_emulate(ctx, should_fire);

        if (should_fire != ctx->irq.level) {
                kvm_timer_update_irq(ctx->vcpu, should_fire, ctx);
                return;
        }

        /*
         * If the timer can fire now, we don't need to have a soft timer
         * scheduled for the future.  If the timer cannot fire at all,
         * then we also don't need a soft timer.
         */
        if (should_fire || !kvm_timer_irq_can_fire(ctx))
                return;

        soft_timer_start(&ctx->hrtimer, kvm_timer_compute_delta(ctx));
}

static void set_cntvoff(u64 cntvoff)
{
        kvm_call_hyp(__kvm_timer_set_cntvoff, cntvoff);
}

static void set_cntpoff(u64 cntpoff)
{
        if (has_cntpoff())
                write_sysreg_s(cntpoff, SYS_CNTPOFF_EL2);
}

static void timer_save_state(struct arch_timer_context *ctx)
{
        struct arch_timer_cpu *timer = vcpu_timer(ctx->vcpu);
        enum kvm_arch_timers index = arch_timer_ctx_index(ctx);
        unsigned long flags;

        if (!timer->enabled)
                return;

        local_irq_save(flags);

        if (!ctx->loaded)
                goto out;

        switch (index) {
                u64 cval;

        case TIMER_VTIMER:
        case TIMER_HVTIMER:
                timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTV_CTL));
                timer_set_cval(ctx, read_sysreg_el0(SYS_CNTV_CVAL));

                /* Disable the timer */
                write_sysreg_el0(0, SYS_CNTV_CTL);
                isb();

                /*
                 * The kernel may decide to run userspace after
                 * calling vcpu_put, so we reset cntvoff to 0 to
                 * ensure a consistent read between user accesses to
                 * the virtual counter and kernel access to the
                 * physical counter of non-VHE case.
                 *
                 * For VHE, the virtual counter uses a fixed virtual
                 * offset of zero, so no need to zero CNTVOFF_EL2
                 * register, but this is actually useful when switching
                 * between EL1/vEL2 with NV.
                 *
                 * Do it unconditionally, as this is either unavoidable
                 * or dirt cheap.
                 */
                set_cntvoff(0);
                break;
        case TIMER_PTIMER:
        case TIMER_HPTIMER:
                timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTP_CTL));
                cval = read_sysreg_el0(SYS_CNTP_CVAL);

                cval -= timer_get_offset(ctx);

                timer_set_cval(ctx, cval);

                /* Disable the timer */
                write_sysreg_el0(0, SYS_CNTP_CTL);
                isb();

                set_cntpoff(0);
                break;
        case NR_KVM_TIMERS:
                BUG();
        }

        trace_kvm_timer_save_state(ctx);

        ctx->loaded = false;
out:
        local_irq_restore(flags);
}

/*
 * Schedule the background timer before calling kvm_vcpu_halt, so that this
 * thread is removed from its waitqueue and made runnable when there's a timer
 * interrupt to handle.
 */
static void kvm_timer_blocking(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);
        struct timer_map map;

        get_timer_map(vcpu, &map);

        /*
         * If no timers are capable of raising interrupts (disabled or
         * masked), then there's no more work for us to do.
         */
        if (!kvm_timer_irq_can_fire(map.direct_vtimer) &&
            !kvm_timer_irq_can_fire(map.direct_ptimer) &&
            !kvm_timer_irq_can_fire(map.emul_vtimer) &&
            !kvm_timer_irq_can_fire(map.emul_ptimer) &&
            !vcpu_has_wfit_active(vcpu))
                return;

        /*
         * At least one guest time will expire. Schedule a background timer.
         * Set the earliest expiration time among the guest timers.
         */
        soft_timer_start(&timer->bg_timer, kvm_timer_earliest_exp(vcpu));
}

static void kvm_timer_unblocking(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);

        soft_timer_cancel(&timer->bg_timer);
}

static void timer_restore_state(struct arch_timer_context *ctx)
{
        struct arch_timer_cpu *timer = vcpu_timer(ctx->vcpu);
        enum kvm_arch_timers index = arch_timer_ctx_index(ctx);
        unsigned long flags;

        if (!timer->enabled)
                return;

        local_irq_save(flags);

        if (ctx->loaded)
                goto out;

        switch (index) {
                u64 cval, offset;

        case TIMER_VTIMER:
        case TIMER_HVTIMER:
                set_cntvoff(timer_get_offset(ctx));
                write_sysreg_el0(timer_get_cval(ctx), SYS_CNTV_CVAL);
                isb();
                write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
                break;
        case TIMER_PTIMER:
        case TIMER_HPTIMER:
                cval = timer_get_cval(ctx);
                offset = timer_get_offset(ctx);
                set_cntpoff(offset);
                cval += offset;
                write_sysreg_el0(cval, SYS_CNTP_CVAL);
                isb();
                write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTP_CTL);
                break;
        case NR_KVM_TIMERS:
                BUG();
        }

        trace_kvm_timer_restore_state(ctx);

        ctx->loaded = true;
out:
        local_irq_restore(flags);
}

static inline void set_timer_irq_phys_active(struct arch_timer_context *ctx, bool active)
{
        int r;
        r = irq_set_irqchip_state(ctx->host_timer_irq, IRQCHIP_STATE_ACTIVE, active);
        WARN_ON(r);
}

static void kvm_timer_vcpu_load_gic(struct arch_timer_context *ctx)
{
        struct kvm_vcpu *vcpu = ctx->vcpu;
        bool phys_active = false;

        /*
         * Update the timer output so that it is likely to match the
         * state we're about to restore. If the timer expires between
         * this point and the register restoration, we'll take the
         * interrupt anyway.
         */
        kvm_timer_update_irq(ctx->vcpu, kvm_timer_should_fire(ctx), ctx);

        if (irqchip_in_kernel(vcpu->kvm))
                phys_active = kvm_vgic_map_is_active(vcpu, timer_irq(ctx));

        phys_active |= ctx->irq.level;

        set_timer_irq_phys_active(ctx, phys_active);
}

static void kvm_timer_vcpu_load_nogic(struct kvm_vcpu *vcpu)
{
        struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);

        /*
         * Update the timer output so that it is likely to match the
         * state we're about to restore. If the timer expires between
         * this point and the register restoration, we'll take the
         * interrupt anyway.
         */
        kvm_timer_update_irq(vcpu, kvm_timer_should_fire(vtimer), vtimer);

        /*
         * When using a userspace irqchip with the architected timers and a
         * host interrupt controller that doesn't support an active state, we
         * must still prevent continuously exiting from the guest, and
         * therefore mask the physical interrupt by disabling it on the host
         * interrupt controller when the virtual level is high, such that the
         * guest can make forward progress.  Once we detect the output level
         * being de-asserted, we unmask the interrupt again so that we exit
         * from the guest when the timer fires.
         */
        if (vtimer->irq.level)
                disable_percpu_irq(host_vtimer_irq);
        else
                enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
}

/* If _pred is true, set bit in _set, otherwise set it in _clr */
#define assign_clear_set_bit(_pred, _bit, _clr, _set)                   \
        do {                                                            \
                if (_pred)                                              \
                        (_set) |= (_bit);                               \
                else                                                    \
                        (_clr) |= (_bit);                               \
        } while (0)

static void kvm_timer_vcpu_load_nested_switch(struct kvm_vcpu *vcpu,
                                              struct timer_map *map)
{
        int hw, ret;

        if (!irqchip_in_kernel(vcpu->kvm))
                return;

        /*
         * We only ever unmap the vtimer irq on a VHE system that runs nested
         * virtualization, in which case we have both a valid emul_vtimer,
         * emul_ptimer, direct_vtimer, and direct_ptimer.
         *
         * Since this is called from kvm_timer_vcpu_load(), a change between
         * vEL2 and vEL1/0 will have just happened, and the timer_map will
         * represent this, and therefore we switch the emul/direct mappings
         * below.
         */
        hw = kvm_vgic_get_map(vcpu, timer_irq(map->direct_vtimer));
        if (hw < 0) {
                kvm_vgic_unmap_phys_irq(vcpu, timer_irq(map->emul_vtimer));
                kvm_vgic_unmap_phys_irq(vcpu, timer_irq(map->emul_ptimer));

                ret = kvm_vgic_map_phys_irq(vcpu,
                                            map->direct_vtimer->host_timer_irq,
                                            timer_irq(map->direct_vtimer),
                                            &arch_timer_irq_ops);
                WARN_ON_ONCE(ret);
                ret = kvm_vgic_map_phys_irq(vcpu,
                                            map->direct_ptimer->host_timer_irq,
                                            timer_irq(map->direct_ptimer),
                                            &arch_timer_irq_ops);
                WARN_ON_ONCE(ret);

                /*
                 * The virtual offset behaviour is "interresting", as it
                 * always applies when HCR_EL2.E2H==0, but only when
                 * accessed from EL1 when HCR_EL2.E2H==1. So make sure we
                 * track E2H when putting the HV timer in "direct" mode.
                 */
                if (map->direct_vtimer == vcpu_hvtimer(vcpu)) {
                        struct arch_timer_offset *offs = &map->direct_vtimer->offset;

                        if (vcpu_el2_e2h_is_set(vcpu))
                                offs->vcpu_offset = NULL;
                        else
                                offs->vcpu_offset = &__vcpu_sys_reg(vcpu, CNTVOFF_EL2);
                }
        }
}

static void timer_set_traps(struct kvm_vcpu *vcpu, struct timer_map *map)
{
        bool tpt, tpc;
        u64 clr, set;

        /*
         * No trapping gets configured here with nVHE. See
         * __timer_enable_traps(), which is where the stuff happens.
         */
        if (!has_vhe())
                return;

        /*
         * Our default policy is not to trap anything. As we progress
         * within this function, reality kicks in and we start adding
         * traps based on emulation requirements.
         */
        tpt = tpc = false;

        /*
         * We have two possibility to deal with a physical offset:
         *
         * - Either we have CNTPOFF (yay!) or the offset is 0:
         *   we let the guest freely access the HW
         *
         * - or neither of these condition apply:
         *   we trap accesses to the HW, but still use it
         *   after correcting the physical offset
         */
        if (!has_cntpoff() && timer_get_offset(map->direct_ptimer))
                tpt = tpc = true;

        /*
         * Apply the enable bits that the guest hypervisor has requested for
         * its own guest. We can only add traps that wouldn't have been set
         * above.
         */
        if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) {
                u64 val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);

                /* Use the VHE format for mental sanity */
                if (!vcpu_el2_e2h_is_set(vcpu))
                        val = (val & (CNTHCTL_EL1PCEN | CNTHCTL_EL1PCTEN)) << 10;

                tpt |= !(val & (CNTHCTL_EL1PCEN << 10));
                tpc |= !(val & (CNTHCTL_EL1PCTEN << 10));
        }

        /*
         * Now that we have collected our requirements, compute the
         * trap and enable bits.
         */
        set = 0;
        clr = 0;

        assign_clear_set_bit(tpt, CNTHCTL_EL1PCEN << 10, set, clr);
        assign_clear_set_bit(tpc, CNTHCTL_EL1PCTEN << 10, set, clr);

        /* This only happens on VHE, so use the CNTHCTL_EL2 accessor. */
        sysreg_clear_set(cnthctl_el2, clr, set);
}

void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);
        struct timer_map map;

        if (unlikely(!timer->enabled))
                return;

        get_timer_map(vcpu, &map);

        if (static_branch_likely(&has_gic_active_state)) {
                if (vcpu_has_nv(vcpu))
                        kvm_timer_vcpu_load_nested_switch(vcpu, &map);

                kvm_timer_vcpu_load_gic(map.direct_vtimer);
                if (map.direct_ptimer)
                        kvm_timer_vcpu_load_gic(map.direct_ptimer);
        } else {
                kvm_timer_vcpu_load_nogic(vcpu);
        }

        kvm_timer_unblocking(vcpu);

        timer_restore_state(map.direct_vtimer);
        if (map.direct_ptimer)
                timer_restore_state(map.direct_ptimer);
        if (map.emul_vtimer)
                timer_emulate(map.emul_vtimer);
        if (map.emul_ptimer)
                timer_emulate(map.emul_ptimer);

        timer_set_traps(vcpu, &map);
}

bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu)
{
        struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
        struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
        struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
        bool vlevel, plevel;

        if (likely(irqchip_in_kernel(vcpu->kvm)))
                return false;

        vlevel = sregs->device_irq_level & KVM_ARM_DEV_EL1_VTIMER;
        plevel = sregs->device_irq_level & KVM_ARM_DEV_EL1_PTIMER;

        return kvm_timer_should_fire(vtimer) != vlevel ||
               kvm_timer_should_fire(ptimer) != plevel;
}

void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);
        struct timer_map map;

        if (unlikely(!timer->enabled))
                return;

        get_timer_map(vcpu, &map);

        timer_save_state(map.direct_vtimer);
        if (map.direct_ptimer)
                timer_save_state(map.direct_ptimer);

        /*
         * Cancel soft timer emulation, because the only case where we
         * need it after a vcpu_put is in the context of a sleeping VCPU, and
         * in that case we already factor in the deadline for the physical
         * timer when scheduling the bg_timer.
         *
         * In any case, we re-schedule the hrtimer for the physical timer when
         * coming back to the VCPU thread in kvm_timer_vcpu_load().
         */
        if (map.emul_vtimer)
                soft_timer_cancel(&map.emul_vtimer->hrtimer);
        if (map.emul_ptimer)
                soft_timer_cancel(&map.emul_ptimer->hrtimer);

        if (kvm_vcpu_is_blocking(vcpu))
                kvm_timer_blocking(vcpu);
}

/*
 * With a userspace irqchip we have to check if the guest de-asserted the
 * timer and if so, unmask the timer irq signal on the host interrupt
 * controller to ensure that we see future timer signals.
 */
static void unmask_vtimer_irq_user(struct kvm_vcpu *vcpu)
{
        struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);

        if (!kvm_timer_should_fire(vtimer)) {
                kvm_timer_update_irq(vcpu, false, vtimer);
                if (static_branch_likely(&has_gic_active_state))
                        set_timer_irq_phys_active(vtimer, false);
                else
                        enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
        }
}

void kvm_timer_sync_user(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);

        if (unlikely(!timer->enabled))
                return;

        if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
                unmask_vtimer_irq_user(vcpu);
}

void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);
        struct timer_map map;

        get_timer_map(vcpu, &map);

        /*
         * The bits in CNTV_CTL are architecturally reset to UNKNOWN for ARMv8
         * and to 0 for ARMv7.  We provide an implementation that always
         * resets the timer to be disabled and unmasked and is compliant with
         * the ARMv7 architecture.
         */
        for (int i = 0; i < nr_timers(vcpu); i++)
                timer_set_ctl(vcpu_get_timer(vcpu, i), 0);

        /*
         * A vcpu running at EL2 is in charge of the offset applied to
         * the virtual timer, so use the physical VM offset, and point
         * the vcpu offset to CNTVOFF_EL2.
         */
        if (vcpu_has_nv(vcpu)) {
                struct arch_timer_offset *offs = &vcpu_vtimer(vcpu)->offset;

                offs->vcpu_offset = &__vcpu_sys_reg(vcpu, CNTVOFF_EL2);
                offs->vm_offset = &vcpu->kvm->arch.timer_data.poffset;
        }

        if (timer->enabled) {
                for (int i = 0; i < nr_timers(vcpu); i++)
                        kvm_timer_update_irq(vcpu, false,
                                             vcpu_get_timer(vcpu, i));

                if (irqchip_in_kernel(vcpu->kvm)) {
                        kvm_vgic_reset_mapped_irq(vcpu, timer_irq(map.direct_vtimer));
                        if (map.direct_ptimer)
                                kvm_vgic_reset_mapped_irq(vcpu, timer_irq(map.direct_ptimer));
                }
        }

        if (map.emul_vtimer)
                soft_timer_cancel(&map.emul_vtimer->hrtimer);
        if (map.emul_ptimer)
                soft_timer_cancel(&map.emul_ptimer->hrtimer);
}

static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
{
        struct arch_timer_context *ctxt = vcpu_get_timer(vcpu, timerid);
        struct kvm *kvm = vcpu->kvm;

        ctxt->vcpu = vcpu;

        if (timerid == TIMER_VTIMER)
                ctxt->offset.vm_offset = &kvm->arch.timer_data.voffset;
        else
                ctxt->offset.vm_offset = &kvm->arch.timer_data.poffset;

        hrtimer_init(&ctxt->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
        ctxt->hrtimer.function = kvm_hrtimer_expire;

        switch (timerid) {
        case TIMER_PTIMER:
        case TIMER_HPTIMER:
                ctxt->host_timer_irq = host_ptimer_irq;
                break;
        case TIMER_VTIMER:
        case TIMER_HVTIMER:
                ctxt->host_timer_irq = host_vtimer_irq;
                break;
        }
}

void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);

        for (int i = 0; i < NR_KVM_TIMERS; i++)
                timer_context_init(vcpu, i);

        /* Synchronize offsets across timers of a VM if not already provided */
        if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &vcpu->kvm->arch.flags)) {
                timer_set_offset(vcpu_vtimer(vcpu), kvm_phys_timer_read());
                timer_set_offset(vcpu_ptimer(vcpu), 0);
        }

        hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
        timer->bg_timer.function = kvm_bg_timer_expire;
}

void kvm_timer_init_vm(struct kvm *kvm)
{
        for (int i = 0; i < NR_KVM_TIMERS; i++)
                kvm->arch.timer_data.ppi[i] = default_ppi[i];
}

void kvm_timer_cpu_up(void)
{
        enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
        if (host_ptimer_irq)
                enable_percpu_irq(host_ptimer_irq, host_ptimer_irq_flags);
}

void kvm_timer_cpu_down(void)
{
        disable_percpu_irq(host_vtimer_irq);
        if (host_ptimer_irq)
                disable_percpu_irq(host_ptimer_irq);
}

int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
{
        struct arch_timer_context *timer;

        switch (regid) {
        case KVM_REG_ARM_TIMER_CTL:
                timer = vcpu_vtimer(vcpu);
                kvm_arm_timer_write(vcpu, timer, TIMER_REG_CTL, value);
                break;
        case KVM_REG_ARM_TIMER_CNT:
                if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET,
                              &vcpu->kvm->arch.flags)) {
                        timer = vcpu_vtimer(vcpu);
                        timer_set_offset(timer, kvm_phys_timer_read() - value);
                }
                break;
        case KVM_REG_ARM_TIMER_CVAL:
                timer = vcpu_vtimer(vcpu);
                kvm_arm_timer_write(vcpu, timer, TIMER_REG_CVAL, value);
                break;
        case KVM_REG_ARM_PTIMER_CTL:
                timer = vcpu_ptimer(vcpu);
                kvm_arm_timer_write(vcpu, timer, TIMER_REG_CTL, value);
                break;
        case KVM_REG_ARM_PTIMER_CNT:
                if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET,
                              &vcpu->kvm->arch.flags)) {
                        timer = vcpu_ptimer(vcpu);
                        timer_set_offset(timer, kvm_phys_timer_read() - value);
                }
                break;
        case KVM_REG_ARM_PTIMER_CVAL:
                timer = vcpu_ptimer(vcpu);
                kvm_arm_timer_write(vcpu, timer, TIMER_REG_CVAL, value);
                break;

        default:
                return -1;
        }

        return 0;
}

static u64 read_timer_ctl(struct arch_timer_context *timer)
{
        /*
         * Set ISTATUS bit if it's expired.
         * Note that according to ARMv8 ARM Issue A.k, ISTATUS bit is
         * UNKNOWN when ENABLE bit is 0, so we chose to set ISTATUS bit
         * regardless of ENABLE bit for our implementation convenience.
         */
        u32 ctl = timer_get_ctl(timer);

        if (!kvm_timer_compute_delta(timer))
                ctl |= ARCH_TIMER_CTRL_IT_STAT;

        return ctl;
}

u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
{
        switch (regid) {
        case KVM_REG_ARM_TIMER_CTL:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_vtimer(vcpu), TIMER_REG_CTL);
        case KVM_REG_ARM_TIMER_CNT:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_vtimer(vcpu), TIMER_REG_CNT);
        case KVM_REG_ARM_TIMER_CVAL:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_vtimer(vcpu), TIMER_REG_CVAL);
        case KVM_REG_ARM_PTIMER_CTL:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_ptimer(vcpu), TIMER_REG_CTL);
        case KVM_REG_ARM_PTIMER_CNT:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_ptimer(vcpu), TIMER_REG_CNT);
        case KVM_REG_ARM_PTIMER_CVAL:
                return kvm_arm_timer_read(vcpu,
                                          vcpu_ptimer(vcpu), TIMER_REG_CVAL);
        }
        return (u64)-1;
}

static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
                              struct arch_timer_context *timer,
                              enum kvm_arch_timer_regs treg)
{
        u64 val;

        switch (treg) {
        case TIMER_REG_TVAL:
                val = timer_get_cval(timer) - kvm_phys_timer_read() + timer_get_offset(timer);
                val = lower_32_bits(val);
                break;

        case TIMER_REG_CTL:
                val = read_timer_ctl(timer);
                break;

        case TIMER_REG_CVAL:
                val = timer_get_cval(timer);
                break;

        case TIMER_REG_CNT:
                val = kvm_phys_timer_read() - timer_get_offset(timer);
                break;

        case TIMER_REG_VOFF:
                val = *timer->offset.vcpu_offset;
                break;

        default:
                BUG();
        }

        return val;
}

u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
                              enum kvm_arch_timers tmr,
                              enum kvm_arch_timer_regs treg)
{
        struct arch_timer_context *timer;
        struct timer_map map;
        u64 val;

        get_timer_map(vcpu, &map);
        timer = vcpu_get_timer(vcpu, tmr);

        if (timer == map.emul_vtimer || timer == map.emul_ptimer)
                return kvm_arm_timer_read(vcpu, timer, treg);

        preempt_disable();
        timer_save_state(timer);

        val = kvm_arm_timer_read(vcpu, timer, treg);

        timer_restore_state(timer);
        preempt_enable();

        return val;
}

static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
                                struct arch_timer_context *timer,
                                enum kvm_arch_timer_regs treg,
                                u64 val)
{
        switch (treg) {
        case TIMER_REG_TVAL:
                timer_set_cval(timer, kvm_phys_timer_read() - timer_get_offset(timer) + (s32)val);
                break;

        case TIMER_REG_CTL:
                timer_set_ctl(timer, val & ~ARCH_TIMER_CTRL_IT_STAT);
                break;

        case TIMER_REG_CVAL:
                timer_set_cval(timer, val);
                break;

        case TIMER_REG_VOFF:
                *timer->offset.vcpu_offset = val;
                break;

        default:
                BUG();
        }
}

void kvm_arm_timer_write_sysreg(struct kvm_vcpu *vcpu,
                                enum kvm_arch_timers tmr,
                                enum kvm_arch_timer_regs treg,
                                u64 val)
{
        struct arch_timer_context *timer;
        struct timer_map map;

        get_timer_map(vcpu, &map);
        timer = vcpu_get_timer(vcpu, tmr);
        if (timer == map.emul_vtimer || timer == map.emul_ptimer) {
                soft_timer_cancel(&timer->hrtimer);
                kvm_arm_timer_write(vcpu, timer, treg, val);
                timer_emulate(timer);
        } else {
                preempt_disable();
                timer_save_state(timer);
                kvm_arm_timer_write(vcpu, timer, treg, val);
                timer_restore_state(timer);
                preempt_enable();
        }
}

static int timer_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu)
{
        if (vcpu)
                irqd_set_forwarded_to_vcpu(d);
        else
                irqd_clr_forwarded_to_vcpu(d);

        return 0;
}

static int timer_irq_set_irqchip_state(struct irq_data *d,
                                       enum irqchip_irq_state which, bool val)
{
        if (which != IRQCHIP_STATE_ACTIVE || !irqd_is_forwarded_to_vcpu(d))
                return irq_chip_set_parent_state(d, which, val);

        if (val)
                irq_chip_mask_parent(d);
        else
                irq_chip_unmask_parent(d);

        return 0;
}

static void timer_irq_eoi(struct irq_data *d)
{
        if (!irqd_is_forwarded_to_vcpu(d))
                irq_chip_eoi_parent(d);
}

static void timer_irq_ack(struct irq_data *d)
{
        d = d->parent_data;
        if (d->chip->irq_ack)
                d->chip->irq_ack(d);
}

static struct irq_chip timer_chip = {
        .name                   = "KVM",
        .irq_ack                = timer_irq_ack,
        .irq_mask               = irq_chip_mask_parent,
        .irq_unmask             = irq_chip_unmask_parent,
        .irq_eoi                = timer_irq_eoi,
        .irq_set_type           = irq_chip_set_type_parent,
        .irq_set_vcpu_affinity  = timer_irq_set_vcpu_affinity,
        .irq_set_irqchip_state  = timer_irq_set_irqchip_state,
};

static int timer_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                  unsigned int nr_irqs, void *arg)
{
        irq_hw_number_t hwirq = (uintptr_t)arg;

        return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
                                             &timer_chip, NULL);
}

static void timer_irq_domain_free(struct irq_domain *domain, unsigned int virq,
                                  unsigned int nr_irqs)
{
}

static const struct irq_domain_ops timer_domain_ops = {
        .alloc  = timer_irq_domain_alloc,
        .free   = timer_irq_domain_free,
};

static void kvm_irq_fixup_flags(unsigned int virq, u32 *flags)
{
        *flags = irq_get_trigger_type(virq);
        if (*flags != IRQF_TRIGGER_HIGH && *flags != IRQF_TRIGGER_LOW) {
                kvm_err("Invalid trigger for timer IRQ%d, assuming level low\n",
                        virq);
                *flags = IRQF_TRIGGER_LOW;
        }
}

static int kvm_irq_init(struct arch_timer_kvm_info *info)
{
        struct irq_domain *domain = NULL;

        if (info->virtual_irq <= 0) {
                kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
                        info->virtual_irq);
                return -ENODEV;
        }

        host_vtimer_irq = info->virtual_irq;
        kvm_irq_fixup_flags(host_vtimer_irq, &host_vtimer_irq_flags);

        if (kvm_vgic_global_state.no_hw_deactivation) {
                struct fwnode_handle *fwnode;
                struct irq_data *data;

                fwnode = irq_domain_alloc_named_fwnode("kvm-timer");
                if (!fwnode)
                        return -ENOMEM;

                /* Assume both vtimer and ptimer in the same parent */
                data = irq_get_irq_data(host_vtimer_irq);
                domain = irq_domain_create_hierarchy(data->domain, 0,
                                                     NR_KVM_TIMERS, fwnode,
                                                     &timer_domain_ops, NULL);
                if (!domain) {
                        irq_domain_free_fwnode(fwnode);
                        return -ENOMEM;
                }

                arch_timer_irq_ops.flags |= VGIC_IRQ_SW_RESAMPLE;
                WARN_ON(irq_domain_push_irq(domain, host_vtimer_irq,
                                            (void *)TIMER_VTIMER));
        }

        if (info->physical_irq > 0) {
                host_ptimer_irq = info->physical_irq;
                kvm_irq_fixup_flags(host_ptimer_irq, &host_ptimer_irq_flags);

                if (domain)
                        WARN_ON(irq_domain_push_irq(domain, host_ptimer_irq,
                                                    (void *)TIMER_PTIMER));
        }

        return 0;
}

int __init kvm_timer_hyp_init(bool has_gic)
{
        struct arch_timer_kvm_info *info;
        int err;

        info = arch_timer_get_kvm_info();
        timecounter = &info->timecounter;

        if (!timecounter->cc) {
                kvm_err("kvm_arch_timer: uninitialized timecounter\n");
                return -ENODEV;
        }

        err = kvm_irq_init(info);
        if (err)
                return err;

        /* First, do the virtual EL1 timer irq */

        err = request_percpu_irq(host_vtimer_irq, kvm_arch_timer_handler,
                                 "kvm guest vtimer", kvm_get_running_vcpus());
        if (err) {
                kvm_err("kvm_arch_timer: can't request vtimer interrupt %d (%d)\n",
                        host_vtimer_irq, err);
                return err;
        }

        if (has_gic) {
                err = irq_set_vcpu_affinity(host_vtimer_irq,
                                            kvm_get_running_vcpus());
                if (err) {
                        kvm_err("kvm_arch_timer: error setting vcpu affinity\n");
                        goto out_free_vtimer_irq;
                }

                static_branch_enable(&has_gic_active_state);
        }

        kvm_debug("virtual timer IRQ%d\n", host_vtimer_irq);

        /* Now let's do the physical EL1 timer irq */

        if (info->physical_irq > 0) {
                err = request_percpu_irq(host_ptimer_irq, kvm_arch_timer_handler,
                                         "kvm guest ptimer", kvm_get_running_vcpus());
                if (err) {
                        kvm_err("kvm_arch_timer: can't request ptimer interrupt %d (%d)\n",
                                host_ptimer_irq, err);
                        goto out_free_vtimer_irq;
                }

                if (has_gic) {
                        err = irq_set_vcpu_affinity(host_ptimer_irq,
                                                    kvm_get_running_vcpus());
                        if (err) {
                                kvm_err("kvm_arch_timer: error setting vcpu affinity\n");
                                goto out_free_ptimer_irq;
                        }
                }

                kvm_debug("physical timer IRQ%d\n", host_ptimer_irq);
        } else if (has_vhe()) {
                kvm_err("kvm_arch_timer: invalid physical timer IRQ: %d\n",
                        info->physical_irq);
                err = -ENODEV;
                goto out_free_vtimer_irq;
        }

        return 0;

out_free_ptimer_irq:
        if (info->physical_irq > 0)
                free_percpu_irq(host_ptimer_irq, kvm_get_running_vcpus());
out_free_vtimer_irq:
        free_percpu_irq(host_vtimer_irq, kvm_get_running_vcpus());
        return err;
}

void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);

        soft_timer_cancel(&timer->bg_timer);
}

static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
{
        u32 ppis = 0;
        bool valid;

        mutex_lock(&vcpu->kvm->arch.config_lock);

        for (int i = 0; i < nr_timers(vcpu); i++) {
                struct arch_timer_context *ctx;
                int irq;

                ctx = vcpu_get_timer(vcpu, i);
                irq = timer_irq(ctx);
                if (kvm_vgic_set_owner(vcpu, irq, ctx))
                        break;

                /*
                 * We know by construction that we only have PPIs, so
                 * all values are less than 32.
                 */
                ppis |= BIT(irq);
        }

        valid = hweight32(ppis) == nr_timers(vcpu);

        if (valid)
                set_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE, &vcpu->kvm->arch.flags);

        mutex_unlock(&vcpu->kvm->arch.config_lock);

        return valid;
}

static bool kvm_arch_timer_get_input_level(int vintid)
{
        struct kvm_vcpu *vcpu = kvm_get_running_vcpu();

        if (WARN(!vcpu, "No vcpu context!\n"))
                return false;

        for (int i = 0; i < nr_timers(vcpu); i++) {
                struct arch_timer_context *ctx;

                ctx = vcpu_get_timer(vcpu, i);
                if (timer_irq(ctx) == vintid)
                        return kvm_timer_should_fire(ctx);
        }

        /* A timer IRQ has fired, but no matching timer was found? */
        WARN_RATELIMIT(1, "timer INTID%d unknown\n", vintid);

        return false;
}

int kvm_timer_enable(struct kvm_vcpu *vcpu)
{
        struct arch_timer_cpu *timer = vcpu_timer(vcpu);
        struct timer_map map;
        int ret;

        if (timer->enabled)
                return 0;

        /* Without a VGIC we do not map virtual IRQs to physical IRQs */
        if (!irqchip_in_kernel(vcpu->kvm))
                goto no_vgic;

        /*
         * At this stage, we have the guarantee that the vgic is both
         * available and initialized.
         */
        if (!timer_irqs_are_valid(vcpu)) {
                kvm_debug("incorrectly configured timer irqs\n");
                return -EINVAL;
        }

        get_timer_map(vcpu, &map);

        ret = kvm_vgic_map_phys_irq(vcpu,
                                    map.direct_vtimer->host_timer_irq,
                                    timer_irq(map.direct_vtimer),
                                    &arch_timer_irq_ops);
        if (ret)
                return ret;

        if (map.direct_ptimer) {
                ret = kvm_vgic_map_phys_irq(vcpu,
                                            map.direct_ptimer->host_timer_irq,
                                            timer_irq(map.direct_ptimer),
                                            &arch_timer_irq_ops);
        }

        if (ret)
                return ret;

no_vgic:
        timer->enabled = 1;
        return 0;
}

/* If we have CNTPOFF, permanently set ECV to enable it */
void kvm_timer_init_vhe(void)
{
        if (cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF))
                sysreg_clear_set(cnthctl_el2, 0, CNTHCTL_ECV);
}

int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
        int __user *uaddr = (int __user *)(long)attr->addr;
        int irq, idx, ret = 0;

        if (!irqchip_in_kernel(vcpu->kvm))
                return -EINVAL;

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

        if (!(irq_is_ppi(irq)))
                return -EINVAL;

        mutex_lock(&vcpu->kvm->arch.config_lock);

        if (test_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE,
                     &vcpu->kvm->arch.flags)) {
                ret = -EBUSY;
                goto out;
        }

        switch (attr->attr) {
        case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
                idx = TIMER_VTIMER;
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
                idx = TIMER_PTIMER;
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
                idx = TIMER_HVTIMER;
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
                idx = TIMER_HPTIMER;
                break;
        default:
                ret = -ENXIO;
                goto out;
        }

        /*
         * We cannot validate the IRQ unicity before we run, so take it at
         * face value. The verdict will be given on first vcpu run, for each
         * vcpu. Yes this is late. Blame it on the stupid API.
         */
        vcpu->kvm->arch.timer_data.ppi[idx] = irq;

out:
        mutex_unlock(&vcpu->kvm->arch.config_lock);
        return ret;
}

int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
        int __user *uaddr = (int __user *)(long)attr->addr;
        struct arch_timer_context *timer;
        int irq;

        switch (attr->attr) {
        case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
                timer = vcpu_vtimer(vcpu);
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
                timer = vcpu_ptimer(vcpu);
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
                timer = vcpu_hvtimer(vcpu);
                break;
        case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
                timer = vcpu_hptimer(vcpu);
                break;
        default:
                return -ENXIO;
        }

        irq = timer_irq(timer);
        return put_user(irq, uaddr);
}

int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
        switch (attr->attr) {
        case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
        case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
        case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
        case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
                return 0;
        }

        return -ENXIO;
}

int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
                                    struct kvm_arm_counter_offset *offset)
{
        int ret = 0;

        if (offset->reserved)
                return -EINVAL;

        mutex_lock(&kvm->lock);

        if (lock_all_vcpus(kvm)) {
                set_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &kvm->arch.flags);

                /*
                 * If userspace decides to set the offset using this
                 * API rather than merely restoring the counter
                 * values, the offset applies to both the virtual and
                 * physical views.
                 */
                kvm->arch.timer_data.voffset = offset->counter_offset;
                kvm->arch.timer_data.poffset = offset->counter_offset;

                unlock_all_vcpus(kvm);
        } else {
                ret = -EBUSY;
        }

        mutex_unlock(&kvm->lock);

        return ret;
}