xen.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
 * Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * KVM Xen emulation
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include "x86.h"
#include "xen.h"
#include "hyperv.h"
#include "lapic.h"
 
#include <linux/eventfd.h>
#include <linux/kvm_host.h>
#include <linux/sched/stat.h>
 
#include <trace/events/kvm.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include <xen/interface/version.h>
#include <xen/interface/event_channel.h>
#include <xen/interface/sched.h>
 
#include <asm/xen/cpuid.h>
 
#include "cpuid.h"
#include "trace.h"
 
static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
 
DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
 
static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
{
    struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
    struct pvclock_wall_clock *wc;
    gpa_t gpa = gfn_to_gpa(gfn);
    u32 *wc_sec_hi;
    u32 wc_version;
    u64 wall_nsec;
    int ret = 0;
    int idx = srcu_read_lock(&kvm->srcu);
 
    if (gfn == KVM_XEN_INVALID_GFN) {
        kvm_gpc_deactivate(gpc);
        goto out;
    }
 
    do {
        ret = kvm_gpc_activate(gpc, gpa, PAGE_SIZE);
        if (ret)
            goto out;
 
        /*
         * This code mirrors kvm_write_wall_clock() except that it writes
         * directly through the pfn cache and doesn't mark the page dirty.
         */
        wall_nsec = kvm_get_wall_clock_epoch(kvm);
 
        /* It could be invalid again already, so we need to check */
        read_lock_irq(&gpc->lock);
 
        if (gpc->valid)
            break;
 
        read_unlock_irq(&gpc->lock);
    } while (1);
 
    /* Paranoia checks on the 32-bit struct layout */
    BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
    BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
    BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
 
#ifdef CONFIG_X86_64
    /* Paranoia checks on the 64-bit struct layout */
    BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
    BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);
 
    if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
        struct shared_info *shinfo = gpc->khva;
 
        wc_sec_hi = &shinfo->wc_sec_hi;
        wc = &shinfo->wc;
    } else
#endif
    {
        struct compat_shared_info *shinfo = gpc->khva;
 
        wc_sec_hi = &shinfo->arch.wc_sec_hi;
        wc = &shinfo->wc;
    }
 
    /* Increment and ensure an odd value */
    wc_version = wc->version = (wc->version + 1) | 1;
    smp_wmb();
 
    wc->nsec = do_div(wall_nsec, NSEC_PER_SEC);
    wc->sec = (u32)wall_nsec;
    *wc_sec_hi = wall_nsec >> 32;
    smp_wmb();
 
    wc->version = wc_version + 1;
    read_unlock_irq(&gpc->lock);
 
    kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
 
out:
    srcu_read_unlock(&kvm->srcu, idx);
    return ret;
}
 
void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
{
    if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) {
        struct kvm_xen_evtchn e;
 
        e.vcpu_id = vcpu->vcpu_id;
        e.vcpu_idx = vcpu->vcpu_idx;
        e.port = vcpu->arch.xen.timer_virq;
        e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
 
        kvm_xen_set_evtchn(&e, vcpu->kvm);
 
        vcpu->arch.xen.timer_expires = 0;
        atomic_set(&vcpu->arch.xen.timer_pending, 0);
    }
}
 
static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
{
    struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
                         arch.xen.timer);
    struct kvm_xen_evtchn e;
    int rc;
 
    if (atomic_read(&vcpu->arch.xen.timer_pending))
        return HRTIMER_NORESTART;
 
    e.vcpu_id = vcpu->vcpu_id;
    e.vcpu_idx = vcpu->vcpu_idx;
    e.port = vcpu->arch.xen.timer_virq;
    e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
 
    rc = kvm_xen_set_evtchn_fast(&e, vcpu->kvm);
    if (rc != -EWOULDBLOCK) {
        vcpu->arch.xen.timer_expires = 0;
        return HRTIMER_NORESTART;
    }
 
    atomic_inc(&vcpu->arch.xen.timer_pending);
    kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
    kvm_vcpu_kick(vcpu);
 
    return HRTIMER_NORESTART;
}
 
static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns)
{
    /*
     * Avoid races with the old timer firing. Checking timer_expires
     * to avoid calling hrtimer_cancel() will only have false positives
     * so is fine.
     */
    if (vcpu->arch.xen.timer_expires)
        hrtimer_cancel(&vcpu->arch.xen.timer);
 
    atomic_set(&vcpu->arch.xen.timer_pending, 0);
    vcpu->arch.xen.timer_expires = guest_abs;
 
    if (delta_ns <= 0) {
        xen_timer_callback(&vcpu->arch.xen.timer);
    } else {
        ktime_t ktime_now = ktime_get();
        hrtimer_start(&vcpu->arch.xen.timer,
                  ktime_add_ns(ktime_now, delta_ns),
                  HRTIMER_MODE_ABS_HARD);
    }
}
 
static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
{
    hrtimer_cancel(&vcpu->arch.xen.timer);
    vcpu->arch.xen.timer_expires = 0;
    atomic_set(&vcpu->arch.xen.timer_pending, 0);
}
 
static void kvm_xen_init_timer(struct kvm_vcpu *vcpu)
{
    hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC,
             HRTIMER_MODE_ABS_HARD);
    vcpu->arch.xen.timer.function = xen_timer_callback;
}
 
static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic)
{
    struct kvm_vcpu_xen *vx = &v->arch.xen;
    struct gfn_to_pfn_cache *gpc1 = &vx->runstate_cache;
    struct gfn_to_pfn_cache *gpc2 = &vx->runstate2_cache;
    size_t user_len, user_len1, user_len2;
    struct vcpu_runstate_info rs;
    unsigned long flags;
    size_t times_ofs;
    uint8_t *update_bit = NULL;
    uint64_t entry_time;
    uint64_t *rs_times;
    int *rs_state;
 
    /*
     * The only difference between 32-bit and 64-bit versions of the
     * runstate struct is the alignment of uint64_t in 32-bit, which
     * means that the 64-bit version has an additional 4 bytes of
     * padding after the first field 'state'. Let's be really really
     * paranoid about that, and matching it with our internal data
     * structures that we memcpy into it...
     */
    BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
    BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
    BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
#ifdef CONFIG_X86_64
    /*
     * The 64-bit structure has 4 bytes of padding before 'state_entry_time'
     * so each subsequent field is shifted by 4, and it's 4 bytes longer.
     */
    BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
             offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
    BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
             offsetof(struct compat_vcpu_runstate_info, time) + 4);
    BUILD_BUG_ON(sizeof(struct vcpu_runstate_info) != 0x2c + 4);
#endif
    /*
     * The state field is in the same place at the start of both structs,
     * and is the same size (int) as vx->current_runstate.
     */
    BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
             offsetof(struct compat_vcpu_runstate_info, state));
    BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
             sizeof(vx->current_runstate));
    BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
             sizeof(vx->current_runstate));
 
    /*
     * The state_entry_time field is 64 bits in both versions, and the
     * XEN_RUNSTATE_UPDATE flag is in the top bit, which given that x86
     * is little-endian means that it's in the last *byte* of the word.
     * That detail is important later.
     */
    BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
             sizeof(uint64_t));
    BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
             sizeof(uint64_t));
    BUILD_BUG_ON((XEN_RUNSTATE_UPDATE >> 56) != 0x80);
 
    /*
     * The time array is four 64-bit quantities in both versions, matching
     * the vx->runstate_times and immediately following state_entry_time.
     */
    BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
             offsetof(struct vcpu_runstate_info, time) - sizeof(uint64_t));
    BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
             offsetof(struct compat_vcpu_runstate_info, time) - sizeof(uint64_t));
    BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
             sizeof_field(struct compat_vcpu_runstate_info, time));
    BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
             sizeof(vx->runstate_times));
 
    if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
        user_len = sizeof(struct vcpu_runstate_info);
        times_ofs = offsetof(struct vcpu_runstate_info,
                     state_entry_time);
    } else {
        user_len = sizeof(struct compat_vcpu_runstate_info);
        times_ofs = offsetof(struct compat_vcpu_runstate_info,
                     state_entry_time);
    }
 
    /*
     * There are basically no alignment constraints. The guest can set it
     * up so it crosses from one page to the next, and at arbitrary byte
     * alignment (and the 32-bit ABI doesn't align the 64-bit integers
     * anyway, even if the overall struct had been 64-bit aligned).
     */
    if ((gpc1->gpa & ~PAGE_MASK) + user_len >= PAGE_SIZE) {
        user_len1 = PAGE_SIZE - (gpc1->gpa & ~PAGE_MASK);
        user_len2 = user_len - user_len1;
    } else {
        user_len1 = user_len;
        user_len2 = 0;
    }
    BUG_ON(user_len1 + user_len2 != user_len);
 
 retry:
    /*
     * Attempt to obtain the GPC lock on *both* (if there are two)
     * gfn_to_pfn caches that cover the region.
     */
    if (atomic) {
        local_irq_save(flags);
        if (!read_trylock(&gpc1->lock)) {
            local_irq_restore(flags);
            return;
        }
    } else {
        read_lock_irqsave(&gpc1->lock, flags);
    }
    while (!kvm_gpc_check(gpc1, user_len1)) {
        read_unlock_irqrestore(&gpc1->lock, flags);
 
        /* When invoked from kvm_sched_out() we cannot sleep */
        if (atomic)
            return;
 
        if (kvm_gpc_refresh(gpc1, user_len1))
            return;
 
        read_lock_irqsave(&gpc1->lock, flags);
    }
 
    if (likely(!user_len2)) {
        /*
         * Set up three pointers directly to the runstate_info
         * struct in the guest (via the GPC).
         *
         *  • @rs_state   → state field
         *  • @rs_times   → state_entry_time field.
         *  • @update_bit → last byte of state_entry_time, which
         *                  contains the XEN_RUNSTATE_UPDATE bit.
         */
        rs_state = gpc1->khva;
        rs_times = gpc1->khva + times_ofs;
        if (v->kvm->arch.xen.runstate_update_flag)
            update_bit = ((void *)(&rs_times[1])) - 1;
    } else {
        /*
         * The guest's runstate_info is split across two pages and we
         * need to hold and validate both GPCs simultaneously. We can
         * declare a lock ordering GPC1 > GPC2 because nothing else
         * takes them more than one at a time. Set a subclass on the
         * gpc1 lock to make lockdep shut up about it.
         */
        lock_set_subclass(&gpc1->lock.dep_map, 1, _THIS_IP_);
        if (atomic) {
            if (!read_trylock(&gpc2->lock)) {
                read_unlock_irqrestore(&gpc1->lock, flags);
                return;
            }
        } else {
            read_lock(&gpc2->lock);
        }
 
        if (!kvm_gpc_check(gpc2, user_len2)) {
            read_unlock(&gpc2->lock);
            read_unlock_irqrestore(&gpc1->lock, flags);
 
            /* When invoked from kvm_sched_out() we cannot sleep */
            if (atomic)
                return;
 
            /*
             * Use kvm_gpc_activate() here because if the runstate
             * area was configured in 32-bit mode and only extends
             * to the second page now because the guest changed to
             * 64-bit mode, the second GPC won't have been set up.
             */
            if (kvm_gpc_activate(gpc2, gpc1->gpa + user_len1,
                         user_len2))
                return;
 
            /*
             * We dropped the lock on GPC1 so we have to go all the
             * way back and revalidate that too.
             */
            goto retry;
        }
 
        /*
         * In this case, the runstate_info struct will be assembled on
         * the kernel stack (compat or not as appropriate) and will
         * be copied to GPC1/GPC2 with a dual memcpy. Set up the three
         * rs pointers accordingly.
         */
        rs_times = &rs.state_entry_time;
 
        /*
         * The rs_state pointer points to the start of what we'll
         * copy to the guest, which in the case of a compat guest
         * is the 32-bit field that the compiler thinks is padding.
         */
        rs_state = ((void *)rs_times) - times_ofs;
 
        /*
         * The update_bit is still directly in the guest memory,
         * via one GPC or the other.
         */
        if (v->kvm->arch.xen.runstate_update_flag) {
            if (user_len1 >= times_ofs + sizeof(uint64_t))
                update_bit = gpc1->khva + times_ofs +
                    sizeof(uint64_t) - 1;
            else
                update_bit = gpc2->khva + times_ofs +
                    sizeof(uint64_t) - 1 - user_len1;
        }
 
#ifdef CONFIG_X86_64
        /*
         * Don't leak kernel memory through the padding in the 64-bit
         * version of the struct.
         */
        memset(&rs, 0, offsetof(struct vcpu_runstate_info, state_entry_time));
#endif
    }
 
    /*
     * First, set the XEN_RUNSTATE_UPDATE bit in the top bit of the
     * state_entry_time field, directly in the guest. We need to set
     * that (and write-barrier) before writing to the rest of the
     * structure, and clear it last. Just as Xen does, we address the
     * single *byte* in which it resides because it might be in a
     * different cache line to the rest of the 64-bit word, due to
     * the (lack of) alignment constraints.
     */
    entry_time = vx->runstate_entry_time;
    if (update_bit) {
        entry_time |= XEN_RUNSTATE_UPDATE;
        *update_bit = (vx->runstate_entry_time | XEN_RUNSTATE_UPDATE) >> 56;
        smp_wmb();
    }
 
    /*
     * Now assemble the actual structure, either on our kernel stack
     * or directly in the guest according to how the rs_state and
     * rs_times pointers were set up above.
     */
    *rs_state = vx->current_runstate;
    rs_times[0] = entry_time;
    memcpy(rs_times + 1, vx->runstate_times, sizeof(vx->runstate_times));
 
    /* For the split case, we have to then copy it to the guest. */
    if (user_len2) {
        memcpy(gpc1->khva, rs_state, user_len1);
        memcpy(gpc2->khva, ((void *)rs_state) + user_len1, user_len2);
    }
    smp_wmb();
 
    /* Finally, clear the XEN_RUNSTATE_UPDATE bit. */
    if (update_bit) {
        entry_time &= ~XEN_RUNSTATE_UPDATE;
        *update_bit = entry_time >> 56;
        smp_wmb();
    }
 
    if (user_len2)
        read_unlock(&gpc2->lock);
 
    read_unlock_irqrestore(&gpc1->lock, flags);
 
    mark_page_dirty_in_slot(v->kvm, gpc1->memslot, gpc1->gpa >> PAGE_SHIFT);
    if (user_len2)
        mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT);
}
 
void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
{
    struct kvm_vcpu_xen *vx = &v->arch.xen;
    u64 now = get_kvmclock_ns(v->kvm);
    u64 delta_ns = now - vx->runstate_entry_time;
    u64 run_delay = current->sched_info.run_delay;
 
    if (unlikely(!vx->runstate_entry_time))
        vx->current_runstate = RUNSTATE_offline;
 
    /*
     * Time waiting for the scheduler isn't "stolen" if the
     * vCPU wasn't running anyway.
     */
    if (vx->current_runstate == RUNSTATE_running) {
        u64 steal_ns = run_delay - vx->last_steal;
 
        delta_ns -= steal_ns;
 
        vx->runstate_times[RUNSTATE_runnable] += steal_ns;
    }
    vx->last_steal = run_delay;
 
    vx->runstate_times[vx->current_runstate] += delta_ns;
    vx->current_runstate = state;
    vx->runstate_entry_time = now;
 
    if (vx->runstate_cache.active)
        kvm_xen_update_runstate_guest(v, state == RUNSTATE_runnable);
}
 
void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
{
    struct kvm_lapic_irq irq = { };
    int r;
 
    irq.dest_id = v->vcpu_id;
    irq.vector = v->arch.xen.upcall_vector;
    irq.dest_mode = APIC_DEST_PHYSICAL;
    irq.shorthand = APIC_DEST_NOSHORT;
    irq.delivery_mode = APIC_DM_FIXED;
    irq.level = 1;
 
    /* The fast version will always work for physical unicast */
    WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL));
}
 
/*
 * On event channel delivery, the vcpu_info may not have been accessible.
 * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which
 * need to be marked into the vcpu_info (and evtchn_upcall_pending set).
 * Do so now that we can sleep in the context of the vCPU to bring the
 * page in, and refresh the pfn cache for it.
 */
void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
{
    unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
    struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
    unsigned long flags;
 
    if (!evtchn_pending_sel)
        return;
 
    /*
     * Yes, this is an open-coded loop. But that's just what put_user()
     * does anyway. Page it in and retry the instruction. We're just a
     * little more honest about it.
     */
    read_lock_irqsave(&gpc->lock, flags);
    while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
        read_unlock_irqrestore(&gpc->lock, flags);
 
        if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info)))
            return;
 
        read_lock_irqsave(&gpc->lock, flags);
    }
 
    /* Now gpc->khva is a valid kernel address for the vcpu_info */
    if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
        struct vcpu_info *vi = gpc->khva;
 
        asm volatile(LOCK_PREFIX "orq %0, %1\n"
                 "notq %0\n"
                 LOCK_PREFIX "andq %0, %2\n"
                 : "=r" (evtchn_pending_sel),
                   "+m" (vi->evtchn_pending_sel),
                   "+m" (v->arch.xen.evtchn_pending_sel)
                 : "0" (evtchn_pending_sel));
        WRITE_ONCE(vi->evtchn_upcall_pending, 1);
    } else {
        u32 evtchn_pending_sel32 = evtchn_pending_sel;
        struct compat_vcpu_info *vi = gpc->khva;
 
        asm volatile(LOCK_PREFIX "orl %0, %1\n"
                 "notl %0\n"
                 LOCK_PREFIX "andl %0, %2\n"
                 : "=r" (evtchn_pending_sel32),
                   "+m" (vi->evtchn_pending_sel),
                   "+m" (v->arch.xen.evtchn_pending_sel)
                 : "0" (evtchn_pending_sel32));
        WRITE_ONCE(vi->evtchn_upcall_pending, 1);
    }
    read_unlock_irqrestore(&gpc->lock, flags);
 
    /* For the per-vCPU lapic vector, deliver it as MSI. */
    if (v->arch.xen.upcall_vector)
        kvm_xen_inject_vcpu_vector(v);
 
    mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
}
 
int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
{
    struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
    unsigned long flags;
    u8 rc = 0;
 
    /*
     * If the global upcall vector (HVMIRQ_callback_vector) is set and
     * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
     */
 
    /* No need for compat handling here */
    BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
             offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
    BUILD_BUG_ON(sizeof(rc) !=
             sizeof_field(struct vcpu_info, evtchn_upcall_pending));
    BUILD_BUG_ON(sizeof(rc) !=
             sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
 
    read_lock_irqsave(&gpc->lock, flags);
    while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
        read_unlock_irqrestore(&gpc->lock, flags);
 
        /*
         * This function gets called from kvm_vcpu_block() after setting the
         * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
         * from a HLT. So we really mustn't sleep. If the page ended up absent
         * at that point, just return 1 in order to trigger an immediate wake,
         * and we'll end up getting called again from a context where we *can*
         * fault in the page and wait for it.
         */
        if (in_atomic() || !task_is_running(current))
            return 1;
 
        if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info))) {
            /*
             * If this failed, userspace has screwed up the
             * vcpu_info mapping. No interrupts for you.
             */
            return 0;
        }
        read_lock_irqsave(&gpc->lock, flags);
    }
 
    rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending;
    read_unlock_irqrestore(&gpc->lock, flags);
    return rc;
}
 
int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
    int r = -ENOENT;
 
 
    switch (data->type) {
    case KVM_XEN_ATTR_TYPE_LONG_MODE:
        if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
            r = -EINVAL;
        } else {
            mutex_lock(&kvm->arch.xen.xen_lock);
            kvm->arch.xen.long_mode = !!data->u.long_mode;
            mutex_unlock(&kvm->arch.xen.xen_lock);
            r = 0;
        }
        break;
 
    case KVM_XEN_ATTR_TYPE_SHARED_INFO:
        mutex_lock(&kvm->arch.xen.xen_lock);
        r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
        mutex_unlock(&kvm->arch.xen.xen_lock);
        break;
 
    case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
        if (data->u.vector && data->u.vector < 0x10)
            r = -EINVAL;
        else {
            mutex_lock(&kvm->arch.xen.xen_lock);
            kvm->arch.xen.upcall_vector = data->u.vector;
            mutex_unlock(&kvm->arch.xen.xen_lock);
            r = 0;
        }
        break;
 
    case KVM_XEN_ATTR_TYPE_EVTCHN:
        r = kvm_xen_setattr_evtchn(kvm, data);
        break;
 
    case KVM_XEN_ATTR_TYPE_XEN_VERSION:
        mutex_lock(&kvm->arch.xen.xen_lock);
        kvm->arch.xen.xen_version = data->u.xen_version;
        mutex_unlock(&kvm->arch.xen.xen_lock);
        r = 0;
        break;
 
    case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        mutex_lock(&kvm->arch.xen.xen_lock);
        kvm->arch.xen.runstate_update_flag = !!data->u.runstate_update_flag;
        mutex_unlock(&kvm->arch.xen.xen_lock);
        r = 0;
        break;
 
    default:
        break;
    }
 
    return r;
}
 
int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
    int r = -ENOENT;
 
    mutex_lock(&kvm->arch.xen.xen_lock);
 
    switch (data->type) {
    case KVM_XEN_ATTR_TYPE_LONG_MODE:
        data->u.long_mode = kvm->arch.xen.long_mode;
        r = 0;
        break;
 
    case KVM_XEN_ATTR_TYPE_SHARED_INFO:
        if (kvm->arch.xen.shinfo_cache.active)
            data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
        else
            data->u.shared_info.gfn = KVM_XEN_INVALID_GFN;
        r = 0;
        break;
 
    case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
        data->u.vector = kvm->arch.xen.upcall_vector;
        r = 0;
        break;
 
    case KVM_XEN_ATTR_TYPE_XEN_VERSION:
        data->u.xen_version = kvm->arch.xen.xen_version;
        r = 0;
        break;
 
    case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        data->u.runstate_update_flag = kvm->arch.xen.runstate_update_flag;
        r = 0;
        break;
 
    default:
        break;
    }
 
    mutex_unlock(&kvm->arch.xen.xen_lock);
    return r;
}
 
int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
{
    int idx, r = -ENOENT;
 
    mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
    idx = srcu_read_lock(&vcpu->kvm->srcu);
 
    switch (data->type) {
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
        /* No compat necessary here. */
        BUILD_BUG_ON(sizeof(struct vcpu_info) !=
                 sizeof(struct compat_vcpu_info));
        BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
                 offsetof(struct compat_vcpu_info, time));
 
        if (data->u.gpa == KVM_XEN_INVALID_GPA) {
            kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
            r = 0;
            break;
        }
 
        r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_info_cache,
                     data->u.gpa, sizeof(struct vcpu_info));
        if (!r)
            kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
        if (data->u.gpa == KVM_XEN_INVALID_GPA) {
            kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
            r = 0;
            break;
        }
 
        r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_time_info_cache,
                     data->u.gpa,
                     sizeof(struct pvclock_vcpu_time_info));
        if (!r)
            kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: {
        size_t sz, sz1, sz2;
 
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        if (data->u.gpa == KVM_XEN_INVALID_GPA) {
            r = 0;
        deactivate_out:
            kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
            kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
            break;
        }
 
        /*
         * If the guest switches to 64-bit mode after setting the runstate
         * address, that's actually OK. kvm_xen_update_runstate_guest()
         * will cope.
         */
        if (IS_ENABLED(CONFIG_64BIT) && vcpu->kvm->arch.xen.long_mode)
            sz = sizeof(struct vcpu_runstate_info);
        else
            sz = sizeof(struct compat_vcpu_runstate_info);
 
        /* How much fits in the (first) page? */
        sz1 = PAGE_SIZE - (data->u.gpa & ~PAGE_MASK);
        r = kvm_gpc_activate(&vcpu->arch.xen.runstate_cache,
                     data->u.gpa, sz1);
        if (r)
            goto deactivate_out;
 
        /* Either map the second page, or deactivate the second GPC */
        if (sz1 >= sz) {
            kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
        } else {
            sz2 = sz - sz1;
            BUG_ON((data->u.gpa + sz1) & ~PAGE_MASK);
            r = kvm_gpc_activate(&vcpu->arch.xen.runstate2_cache,
                         data->u.gpa + sz1, sz2);
            if (r)
                goto deactivate_out;
        }
 
        kvm_xen_update_runstate_guest(vcpu, false);
        break;
    }
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        if (data->u.runstate.state > RUNSTATE_offline) {
            r = -EINVAL;
            break;
        }
 
        kvm_xen_update_runstate(vcpu, data->u.runstate.state);
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        if (data->u.runstate.state > RUNSTATE_offline) {
            r = -EINVAL;
            break;
        }
        if (data->u.runstate.state_entry_time !=
            (data->u.runstate.time_running +
             data->u.runstate.time_runnable +
             data->u.runstate.time_blocked +
             data->u.runstate.time_offline)) {
            r = -EINVAL;
            break;
        }
        if (get_kvmclock_ns(vcpu->kvm) <
            data->u.runstate.state_entry_time) {
            r = -EINVAL;
            break;
        }
 
        vcpu->arch.xen.current_runstate = data->u.runstate.state;
        vcpu->arch.xen.runstate_entry_time =
            data->u.runstate.state_entry_time;
        vcpu->arch.xen.runstate_times[RUNSTATE_running] =
            data->u.runstate.time_running;
        vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
            data->u.runstate.time_runnable;
        vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
            data->u.runstate.time_blocked;
        vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
            data->u.runstate.time_offline;
        vcpu->arch.xen.last_steal = current->sched_info.run_delay;
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        if (data->u.runstate.state > RUNSTATE_offline &&
            data->u.runstate.state != (u64)-1) {
            r = -EINVAL;
            break;
        }
        /* The adjustment must add up */
        if (data->u.runstate.state_entry_time !=
            (data->u.runstate.time_running +
             data->u.runstate.time_runnable +
             data->u.runstate.time_blocked +
             data->u.runstate.time_offline)) {
            r = -EINVAL;
            break;
        }
 
        if (get_kvmclock_ns(vcpu->kvm) <
            (vcpu->arch.xen.runstate_entry_time +
             data->u.runstate.state_entry_time)) {
            r = -EINVAL;
            break;
        }
 
        vcpu->arch.xen.runstate_entry_time +=
            data->u.runstate.state_entry_time;
        vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
            data->u.runstate.time_running;
        vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
            data->u.runstate.time_runnable;
        vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
            data->u.runstate.time_blocked;
        vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
            data->u.runstate.time_offline;
 
        if (data->u.runstate.state <= RUNSTATE_offline)
            kvm_xen_update_runstate(vcpu, data->u.runstate.state);
        else if (vcpu->arch.xen.runstate_cache.active)
            kvm_xen_update_runstate_guest(vcpu, false);
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
        if (data->u.vcpu_id >= KVM_MAX_VCPUS)
            r = -EINVAL;
        else {
            vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
            r = 0;
        }
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
        if (data->u.timer.port &&
            data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
            r = -EINVAL;
            break;
        }
 
        if (!vcpu->arch.xen.timer.function)
            kvm_xen_init_timer(vcpu);
 
        /* Stop the timer (if it's running) before changing the vector */
        kvm_xen_stop_timer(vcpu);
        vcpu->arch.xen.timer_virq = data->u.timer.port;
 
        /* Start the timer if the new value has a valid vector+expiry. */
        if (data->u.timer.port && data->u.timer.expires_ns)
            kvm_xen_start_timer(vcpu, data->u.timer.expires_ns,
                        data->u.timer.expires_ns -
                        get_kvmclock_ns(vcpu->kvm));
 
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
        if (data->u.vector && data->u.vector < 0x10)
            r = -EINVAL;
        else {
            vcpu->arch.xen.upcall_vector = data->u.vector;
            r = 0;
        }
        break;
 
    default:
        break;
    }
 
    srcu_read_unlock(&vcpu->kvm->srcu, idx);
    mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
    return r;
}
 
int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
{
    int r = -ENOENT;
 
    mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
 
    switch (data->type) {
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
        if (vcpu->arch.xen.vcpu_info_cache.active)
            data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
        else
            data->u.gpa = KVM_XEN_INVALID_GPA;
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
        if (vcpu->arch.xen.vcpu_time_info_cache.active)
            data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
        else
            data->u.gpa = KVM_XEN_INVALID_GPA;
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        if (vcpu->arch.xen.runstate_cache.active) {
            data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
            r = 0;
        }
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        data->u.runstate.state = vcpu->arch.xen.current_runstate;
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
        if (!sched_info_on()) {
            r = -EOPNOTSUPP;
            break;
        }
        data->u.runstate.state = vcpu->arch.xen.current_runstate;
        data->u.runstate.state_entry_time =
            vcpu->arch.xen.runstate_entry_time;
        data->u.runstate.time_running =
            vcpu->arch.xen.runstate_times[RUNSTATE_running];
        data->u.runstate.time_runnable =
            vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
        data->u.runstate.time_blocked =
            vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
        data->u.runstate.time_offline =
            vcpu->arch.xen.runstate_times[RUNSTATE_offline];
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
        r = -EINVAL;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
        data->u.vcpu_id = vcpu->arch.xen.vcpu_id;
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
        /*
         * Ensure a consistent snapshot of state is captured, with a
         * timer either being pending, or the event channel delivered
         * to the corresponding bit in the shared_info. Not still
         * lurking in the timer_pending flag for deferred delivery.
         * Purely as an optimisation, if the timer_expires field is
         * zero, that means the timer isn't active (or even in the
         * timer_pending flag) and there is no need to cancel it.
         */
        if (vcpu->arch.xen.timer_expires) {
            hrtimer_cancel(&vcpu->arch.xen.timer);
            kvm_xen_inject_timer_irqs(vcpu);
        }
 
        data->u.timer.port = vcpu->arch.xen.timer_virq;
        data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
        data->u.timer.expires_ns = vcpu->arch.xen.timer_expires;
 
        /*
         * The hrtimer may trigger and raise the IRQ immediately,
         * while the returned state causes it to be set up and
         * raised again on the destination system after migration.
         * That's fine, as the guest won't even have had a chance
         * to run and handle the interrupt. Asserting an already
         * pending event channel is idempotent.
         */
        if (vcpu->arch.xen.timer_expires)
            hrtimer_start_expires(&vcpu->arch.xen.timer,
                          HRTIMER_MODE_ABS_HARD);
 
        r = 0;
        break;
 
    case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
        data->u.vector = vcpu->arch.xen.upcall_vector;
        r = 0;
        break;
 
    default:
        break;
    }
 
    mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
    return r;
}
 
int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
{
    struct kvm *kvm = vcpu->kvm;
    u32 page_num = data & ~PAGE_MASK;
    u64 page_addr = data & PAGE_MASK;
    bool lm = is_long_mode(vcpu);
 
    /* Latch long_mode for shared_info pages etc. */
    vcpu->kvm->arch.xen.long_mode = lm;
 
    /*
     * If Xen hypercall intercept is enabled, fill the hypercall
     * page with VMCALL/VMMCALL instructions since that's what
     * we catch. Else the VMM has provided the hypercall pages
     * with instructions of its own choosing, so use those.
     */
    if (kvm_xen_hypercall_enabled(kvm)) {
        u8 instructions[32];
        int i;
 
        if (page_num)
            return 1;
 
        /* mov imm32, %eax */
        instructions[0] = 0xb8;
 
        /* vmcall / vmmcall */
        static_call(kvm_x86_patch_hypercall)(vcpu, instructions + 5);
 
        /* ret */
        instructions[8] = 0xc3;
 
        /* int3 to pad */
        memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
 
        for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
            *(u32 *)&instructions[1] = i;
            if (kvm_vcpu_write_guest(vcpu,
                         page_addr + (i * sizeof(instructions)),
                         instructions, sizeof(instructions)))
                return 1;
        }
    } else {
        /*
         * Note, truncation is a non-issue as 'lm' is guaranteed to be
         * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
         */
        hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
                     : kvm->arch.xen_hvm_config.blob_addr_32;
        u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
                  : kvm->arch.xen_hvm_config.blob_size_32;
        u8 *page;
        int ret;
 
        if (page_num >= blob_size)
            return 1;
 
        blob_addr += page_num * PAGE_SIZE;
 
        page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
        if (IS_ERR(page))
            return PTR_ERR(page);
 
        ret = kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE);
        kfree(page);
        if (ret)
            return 1;
    }
    return 0;
}
 
int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
{
    /* Only some feature flags need to be *enabled* by userspace */
    u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL |
        KVM_XEN_HVM_CONFIG_EVTCHN_SEND |
        KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE;
    u32 old_flags;
 
    if (xhc->flags & ~permitted_flags)
        return -EINVAL;
 
    /*
     * With hypercall interception the kernel generates its own
     * hypercall page so it must not be provided.
     */
    if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
        (xhc->blob_addr_32 || xhc->blob_addr_64 ||
         xhc->blob_size_32 || xhc->blob_size_64))
        return -EINVAL;
 
    mutex_lock(&kvm->arch.xen.xen_lock);
 
    if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
        static_branch_inc(&kvm_xen_enabled.key);
    else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
        static_branch_slow_dec_deferred(&kvm_xen_enabled);
 
    old_flags = kvm->arch.xen_hvm_config.flags;
    memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
 
    mutex_unlock(&kvm->arch.xen.xen_lock);
 
    if ((old_flags ^ xhc->flags) & KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE)
        kvm_make_all_cpus_request(kvm, KVM_REQ_CLOCK_UPDATE);
 
    return 0;
}
 
static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
{
    kvm_rax_write(vcpu, result);
    return kvm_skip_emulated_instruction(vcpu);
}
 
static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
{
    struct kvm_run *run = vcpu->run;
 
    if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
        return 1;
 
    return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
}
 
static inline int max_evtchn_port(struct kvm *kvm)
{
    if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
        return EVTCHN_2L_NR_CHANNELS;
    else
        return COMPAT_EVTCHN_2L_NR_CHANNELS;
}
 
static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
                   evtchn_port_t *ports)
{
    struct kvm *kvm = vcpu->kvm;
    struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
    unsigned long *pending_bits;
    unsigned long flags;
    bool ret = true;
    int idx, i;
 
    idx = srcu_read_lock(&kvm->srcu);
    read_lock_irqsave(&gpc->lock, flags);
    if (!kvm_gpc_check(gpc, PAGE_SIZE))
        goto out_rcu;
 
    ret = false;
    if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
        struct shared_info *shinfo = gpc->khva;
        pending_bits = (unsigned long *)&shinfo->evtchn_pending;
    } else {
        struct compat_shared_info *shinfo = gpc->khva;
        pending_bits = (unsigned long *)&shinfo->evtchn_pending;
    }
 
    for (i = 0; i < nr_ports; i++) {
        if (test_bit(ports[i], pending_bits)) {
            ret = true;
            break;
        }
    }
 
 out_rcu:
    read_unlock_irqrestore(&gpc->lock, flags);
    srcu_read_unlock(&kvm->srcu, idx);
 
    return ret;
}
 
static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
                 u64 param, u64 *r)
{
    struct sched_poll sched_poll;
    evtchn_port_t port, *ports;
    struct x86_exception e;
    int i;
 
    if (!lapic_in_kernel(vcpu) ||
        !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
        return false;
 
    if (IS_ENABLED(CONFIG_64BIT) && !longmode) {
        struct compat_sched_poll sp32;
 
        /* Sanity check that the compat struct definition is correct */
        BUILD_BUG_ON(sizeof(sp32) != 16);
 
        if (kvm_read_guest_virt(vcpu, param, &sp32, sizeof(sp32), &e)) {
            *r = -EFAULT;
            return true;
        }
 
        /*
         * This is a 32-bit pointer to an array of evtchn_port_t which
         * are uint32_t, so once it's converted no further compat
         * handling is needed.
         */
        sched_poll.ports = (void *)(unsigned long)(sp32.ports);
        sched_poll.nr_ports = sp32.nr_ports;
        sched_poll.timeout = sp32.timeout;
    } else {
        if (kvm_read_guest_virt(vcpu, param, &sched_poll,
                    sizeof(sched_poll), &e)) {
            *r = -EFAULT;
            return true;
        }
    }
 
    if (unlikely(sched_poll.nr_ports > 1)) {
        /* Xen (unofficially) limits number of pollers to 128 */
        if (sched_poll.nr_ports > 128) {
            *r = -EINVAL;
            return true;
        }
 
        ports = kmalloc_array(sched_poll.nr_ports,
                      sizeof(*ports), GFP_KERNEL);
        if (!ports) {
            *r = -ENOMEM;
            return true;
        }
    } else
        ports = &port;
 
    if (kvm_read_guest_virt(vcpu, (gva_t)sched_poll.ports, ports,
                sched_poll.nr_ports * sizeof(*ports), &e)) {
        *r = -EFAULT;
        return true;
    }
 
    for (i = 0; i < sched_poll.nr_ports; i++) {
        if (ports[i] >= max_evtchn_port(vcpu->kvm)) {
            *r = -EINVAL;
            goto out;
        }
    }
 
    if (sched_poll.nr_ports == 1)
        vcpu->arch.xen.poll_evtchn = port;
    else
        vcpu->arch.xen.poll_evtchn = -1;
 
    set_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
 
    if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
        vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
 
        if (sched_poll.timeout)
            mod_timer(&vcpu->arch.xen.poll_timer,
                  jiffies + nsecs_to_jiffies(sched_poll.timeout));
 
        kvm_vcpu_halt(vcpu);
 
        if (sched_poll.timeout)
            del_timer(&vcpu->arch.xen.poll_timer);
 
        vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
    }
 
    vcpu->arch.xen.poll_evtchn = 0;
    *r = 0;
out:
    /* Really, this is only needed in case of timeout */
    clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
 
    if (unlikely(sched_poll.nr_ports > 1))
        kfree(ports);
    return true;
}
 
static void cancel_evtchn_poll(struct timer_list *t)
{
    struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
 
    kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
    kvm_vcpu_kick(vcpu);
}
 
static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
                   int cmd, u64 param, u64 *r)
{
    switch (cmd) {
    case SCHEDOP_poll:
        if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
            return true;
        fallthrough;
    case SCHEDOP_yield:
        kvm_vcpu_on_spin(vcpu, true);
        *r = 0;
        return true;
    default:
        break;
    }
 
    return false;
}
 
struct compat_vcpu_set_singleshot_timer {
    uint64_t timeout_abs_ns;
    uint32_t flags;
} __attribute__((packed));
 
static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
                  int vcpu_id, u64 param, u64 *r)
{
    struct vcpu_set_singleshot_timer oneshot;
    struct x86_exception e;
    s64 delta;
 
    if (!kvm_xen_timer_enabled(vcpu))
        return false;
 
    switch (cmd) {
    case VCPUOP_set_singleshot_timer:
        if (vcpu->arch.xen.vcpu_id != vcpu_id) {
            *r = -EINVAL;
            return true;
        }
 
        /*
         * The only difference for 32-bit compat is the 4 bytes of
         * padding after the interesting part of the structure. So
         * for a faithful emulation of Xen we have to *try* to copy
         * the padding and return -EFAULT if we can't. Otherwise we
         * might as well just have copied the 12-byte 32-bit struct.
         */
        BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
                 offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
        BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
                 sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
        BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
                 offsetof(struct vcpu_set_singleshot_timer, flags));
        BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
                 sizeof_field(struct vcpu_set_singleshot_timer, flags));
 
        if (kvm_read_guest_virt(vcpu, param, &oneshot, longmode ? sizeof(oneshot) :
                    sizeof(struct compat_vcpu_set_singleshot_timer), &e)) {
            *r = -EFAULT;
            return true;
        }
 
        /* A delta <= 0 results in an immediate callback, which is what we want */
        delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
        kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
        *r = 0;
        return true;
 
    case VCPUOP_stop_singleshot_timer:
        if (vcpu->arch.xen.vcpu_id != vcpu_id) {
            *r = -EINVAL;
            return true;
        }
        kvm_xen_stop_timer(vcpu);
        *r = 0;
        return true;
    }
 
    return false;
}
 
static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
                       u64 *r)
{
    if (!kvm_xen_timer_enabled(vcpu))
        return false;
 
    if (timeout) {
        uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
        int64_t delta = timeout - guest_now;
 
        /* Xen has a 'Linux workaround' in do_set_timer_op() which
         * checks for negative absolute timeout values (caused by
         * integer overflow), and for values about 13 days in the
         * future (2^50ns) which would be caused by jiffies
         * overflow. For those cases, it sets the timeout 100ms in
         * the future (not *too* soon, since if a guest really did
         * set a long timeout on purpose we don't want to keep
         * churning CPU time by waking it up).
         */
        if (unlikely((int64_t)timeout < 0 ||
                 (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
            delta = 100 * NSEC_PER_MSEC;
            timeout = guest_now + delta;
        }
 
        kvm_xen_start_timer(vcpu, timeout, delta);
    } else {
        kvm_xen_stop_timer(vcpu);
    }
 
    *r = 0;
    return true;
}
 
int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
{
    bool longmode;
    u64 input, params[6], r = -ENOSYS;
    bool handled = false;
    u8 cpl;
 
    input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
 
    /* Hyper-V hypercalls get bit 31 set in EAX */
    if ((input & 0x80000000) &&
        kvm_hv_hypercall_enabled(vcpu))
        return kvm_hv_hypercall(vcpu);
 
    longmode = is_64_bit_hypercall(vcpu);
    if (!longmode) {
        params[0] = (u32)kvm_rbx_read(vcpu);
        params[1] = (u32)kvm_rcx_read(vcpu);
        params[2] = (u32)kvm_rdx_read(vcpu);
        params[3] = (u32)kvm_rsi_read(vcpu);
        params[4] = (u32)kvm_rdi_read(vcpu);
        params[5] = (u32)kvm_rbp_read(vcpu);
    }
#ifdef CONFIG_X86_64
    else {
        params[0] = (u64)kvm_rdi_read(vcpu);
        params[1] = (u64)kvm_rsi_read(vcpu);
        params[2] = (u64)kvm_rdx_read(vcpu);
        params[3] = (u64)kvm_r10_read(vcpu);
        params[4] = (u64)kvm_r8_read(vcpu);
        params[5] = (u64)kvm_r9_read(vcpu);
    }
#endif
    cpl = static_call(kvm_x86_get_cpl)(vcpu);
    trace_kvm_xen_hypercall(cpl, input, params[0], params[1], params[2],
                params[3], params[4], params[5]);
 
    /*
     * Only allow hypercall acceleration for CPL0. The rare hypercalls that
     * are permitted in guest userspace can be handled by the VMM.
     */
    if (unlikely(cpl > 0))
        goto handle_in_userspace;
 
    switch (input) {
    case __HYPERVISOR_xen_version:
        if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
            r = vcpu->kvm->arch.xen.xen_version;
            handled = true;
        }
        break;
    case __HYPERVISOR_event_channel_op:
        if (params[0] == EVTCHNOP_send)
            handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
        break;
    case __HYPERVISOR_sched_op:
        handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
                         params[1], &r);
        break;
    case __HYPERVISOR_vcpu_op:
        handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
                        params[2], &r);
        break;
    case __HYPERVISOR_set_timer_op: {
        u64 timeout = params[0];
        /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
        if (!longmode)
            timeout |= params[1] << 32;
        handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
        break;
    }
    default:
        break;
    }
 
    if (handled)
        return kvm_xen_hypercall_set_result(vcpu, r);
 
handle_in_userspace:
    vcpu->run->exit_reason = KVM_EXIT_XEN;
    vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
    vcpu->run->xen.u.hcall.longmode = longmode;
    vcpu->run->xen.u.hcall.cpl = cpl;
    vcpu->run->xen.u.hcall.input = input;
    vcpu->run->xen.u.hcall.params[0] = params[0];
    vcpu->run->xen.u.hcall.params[1] = params[1];
    vcpu->run->xen.u.hcall.params[2] = params[2];
    vcpu->run->xen.u.hcall.params[3] = params[3];
    vcpu->run->xen.u.hcall.params[4] = params[4];
    vcpu->run->xen.u.hcall.params[5] = params[5];
    vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
    vcpu->arch.complete_userspace_io =
        kvm_xen_hypercall_complete_userspace;
 
    return 0;
}
 
static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
{
    int poll_evtchn = vcpu->arch.xen.poll_evtchn;
 
    if ((poll_evtchn == port || poll_evtchn == -1) &&
        test_and_clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask)) {
        kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
        kvm_vcpu_kick(vcpu);
    }
}
 
/*
 * The return value from this function is propagated to kvm_set_irq() API,
 * so it returns:
 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 *  = 0   Interrupt was coalesced (previous irq is still pending)
 *  > 0   Number of CPUs interrupt was delivered to
 *
 * It is also called directly from kvm_arch_set_irq_inatomic(), where the
 * only check on its return value is a comparison with -EWOULDBLOCK'.
 */
int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
{
    struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
    struct kvm_vcpu *vcpu;
    unsigned long *pending_bits, *mask_bits;
    unsigned long flags;
    int port_word_bit;
    bool kick_vcpu = false;
    int vcpu_idx, idx, rc;
 
    vcpu_idx = READ_ONCE(xe->vcpu_idx);
    if (vcpu_idx >= 0)
        vcpu = kvm_get_vcpu(kvm, vcpu_idx);
    else {
        vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
        if (!vcpu)
            return -EINVAL;
        WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx);
    }
 
    if (!vcpu->arch.xen.vcpu_info_cache.active)
        return -EINVAL;
 
    if (xe->port >= max_evtchn_port(kvm))
        return -EINVAL;
 
    rc = -EWOULDBLOCK;
 
    idx = srcu_read_lock(&kvm->srcu);
 
    read_lock_irqsave(&gpc->lock, flags);
    if (!kvm_gpc_check(gpc, PAGE_SIZE))
        goto out_rcu;
 
    if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
        struct shared_info *shinfo = gpc->khva;
        pending_bits = (unsigned long *)&shinfo->evtchn_pending;
        mask_bits = (unsigned long *)&shinfo->evtchn_mask;
        port_word_bit = xe->port / 64;
    } else {
        struct compat_shared_info *shinfo = gpc->khva;
        pending_bits = (unsigned long *)&shinfo->evtchn_pending;
        mask_bits = (unsigned long *)&shinfo->evtchn_mask;
        port_word_bit = xe->port / 32;
    }
 
    /*
     * If this port wasn't already set, and if it isn't masked, then
     * we try to set the corresponding bit in the in-kernel shadow of
     * evtchn_pending_sel for the target vCPU. And if *that* wasn't
     * already set, then we kick the vCPU in question to write to the
     * *real* evtchn_pending_sel in its own guest vcpu_info struct.
     */
    if (test_and_set_bit(xe->port, pending_bits)) {
        rc = 0; /* It was already raised */
    } else if (test_bit(xe->port, mask_bits)) {
        rc = -ENOTCONN; /* Masked */
        kvm_xen_check_poller(vcpu, xe->port);
    } else {
        rc = 1; /* Delivered to the bitmap in shared_info. */
        /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
        read_unlock_irqrestore(&gpc->lock, flags);
        gpc = &vcpu->arch.xen.vcpu_info_cache;
 
        read_lock_irqsave(&gpc->lock, flags);
        if (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
            /*
             * Could not access the vcpu_info. Set the bit in-kernel
             * and prod the vCPU to deliver it for itself.
             */
            if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
                kick_vcpu = true;
            goto out_rcu;
        }
 
        if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
            struct vcpu_info *vcpu_info = gpc->khva;
            if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
                WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
                kick_vcpu = true;
            }
        } else {
            struct compat_vcpu_info *vcpu_info = gpc->khva;
            if (!test_and_set_bit(port_word_bit,
                          (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
                WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
                kick_vcpu = true;
            }
        }
 
        /* For the per-vCPU lapic vector, deliver it as MSI. */
        if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
            kvm_xen_inject_vcpu_vector(vcpu);
            kick_vcpu = false;
        }
    }
 
 out_rcu:
    read_unlock_irqrestore(&gpc->lock, flags);
    srcu_read_unlock(&kvm->srcu, idx);
 
    if (kick_vcpu) {
        kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
        kvm_vcpu_kick(vcpu);
    }
 
    return rc;
}
 
static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
{
    bool mm_borrowed = false;
    int rc;
 
    rc = kvm_xen_set_evtchn_fast(xe, kvm);
    if (rc != -EWOULDBLOCK)
        return rc;
 
    if (current->mm != kvm->mm) {
        /*
         * If not on a thread which already belongs to this KVM,
         * we'd better be in the irqfd workqueue.
         */
        if (WARN_ON_ONCE(current->mm))
            return -EINVAL;
 
        kthread_use_mm(kvm->mm);
        mm_borrowed = true;
    }
 
    mutex_lock(&kvm->arch.xen.xen_lock);
 
    /*
     * It is theoretically possible for the page to be unmapped
     * and the MMU notifier to invalidate the shared_info before
     * we even get to use it. In that case, this looks like an
     * infinite loop. It was tempting to do it via the userspace
     * HVA instead... but that just *hides* the fact that it's
     * an infinite loop, because if a fault occurs and it waits
     * for the page to come back, it can *still* immediately
     * fault and have to wait again, repeatedly.
     *
     * Conversely, the page could also have been reinstated by
     * another thread before we even obtain the mutex above, so
     * check again *first* before remapping it.
     */
    do {
        struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
        int idx;
 
        rc = kvm_xen_set_evtchn_fast(xe, kvm);
        if (rc != -EWOULDBLOCK)
            break;
 
        idx = srcu_read_lock(&kvm->srcu);
        rc = kvm_gpc_refresh(gpc, PAGE_SIZE);
        srcu_read_unlock(&kvm->srcu, idx);
    } while(!rc);
 
    mutex_unlock(&kvm->arch.xen.xen_lock);
 
    if (mm_borrowed)
        kthread_unuse_mm(kvm->mm);
 
    return rc;
}
 
/* This is the version called from kvm_set_irq() as the .set function */
static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
             int irq_source_id, int level, bool line_status)
{
    if (!level)
        return -EINVAL;
 
    return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
}
 
/*
 * Set up an event channel interrupt from the KVM IRQ routing table.
 * Used for e.g. PIRQ from passed through physical devices.
 */
int kvm_xen_setup_evtchn(struct kvm *kvm,
             struct kvm_kernel_irq_routing_entry *e,
             const struct kvm_irq_routing_entry *ue)
 
{
    struct kvm_vcpu *vcpu;
 
    if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
        return -EINVAL;
 
    /* We only support 2 level event channels for now */
    if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
        return -EINVAL;
 
    /*
     * Xen gives us interesting mappings from vCPU index to APIC ID,
     * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
     * to find it. Do that once at setup time, instead of every time.
     * But beware that on live update / live migration, the routing
     * table might be reinstated before the vCPU threads have finished
     * recreating their vCPUs.
     */
    vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
    if (vcpu)
        e->xen_evtchn.vcpu_idx = vcpu->vcpu_idx;
    else
        e->xen_evtchn.vcpu_idx = -1;
 
    e->xen_evtchn.port = ue->u.xen_evtchn.port;
    e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
    e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
    e->set = evtchn_set_fn;
 
    return 0;
}
 
/*
 * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
 */
int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
{
    struct kvm_xen_evtchn e;
    int ret;
 
    if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
        return -EINVAL;
 
    /* We only support 2 level event channels for now */
    if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
        return -EINVAL;
 
    e.port = uxe->port;
    e.vcpu_id = uxe->vcpu;
    e.vcpu_idx = -1;
    e.priority = uxe->priority;
 
    ret = kvm_xen_set_evtchn(&e, kvm);
 
    /*
     * None of that 'return 1 if it actually got delivered' nonsense.
     * We don't care if it was masked (-ENOTCONN) either.
     */
    if (ret > 0 || ret == -ENOTCONN)
        ret = 0;
 
    return ret;
}
 
/*
 * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
 */
struct evtchnfd {
    u32 send_port;
    u32 type;
    union {
        struct kvm_xen_evtchn port;
        struct {
            u32 port; /* zero */
            struct eventfd_ctx *ctx;
        } eventfd;
    } deliver;
};
 
/*
 * Update target vCPU or priority for a registered sending channel.
 */
static int kvm_xen_eventfd_update(struct kvm *kvm,
                  struct kvm_xen_hvm_attr *data)
{
    u32 port = data->u.evtchn.send_port;
    struct evtchnfd *evtchnfd;
    int ret;
 
    /* Protect writes to evtchnfd as well as the idr lookup.  */
    mutex_lock(&kvm->arch.xen.xen_lock);
    evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
 
    ret = -ENOENT;
    if (!evtchnfd)
        goto out_unlock;
 
    /* For an UPDATE, nothing may change except the priority/vcpu */
    ret = -EINVAL;
    if (evtchnfd->type != data->u.evtchn.type)
        goto out_unlock;
 
    /*
     * Port cannot change, and if it's zero that was an eventfd
     * which can't be changed either.
     */
    if (!evtchnfd->deliver.port.port ||
        evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
        goto out_unlock;
 
    /* We only support 2 level event channels for now */
    if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
        goto out_unlock;
 
    evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
    if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
        evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
        evtchnfd->deliver.port.vcpu_idx = -1;
    }
    ret = 0;
out_unlock:
    mutex_unlock(&kvm->arch.xen.xen_lock);
    return ret;
}
 
/*
 * Configure the target (eventfd or local port delivery) for sending on
 * a given event channel.
 */
static int kvm_xen_eventfd_assign(struct kvm *kvm,
                  struct kvm_xen_hvm_attr *data)
{
    u32 port = data->u.evtchn.send_port;
    struct eventfd_ctx *eventfd = NULL;
    struct evtchnfd *evtchnfd;
    int ret = -EINVAL;
 
    evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
    if (!evtchnfd)
        return -ENOMEM;
 
    switch(data->u.evtchn.type) {
    case EVTCHNSTAT_ipi:
        /* IPI  must map back to the same port# */
        if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
            goto out_noeventfd; /* -EINVAL */
        break;
 
    case EVTCHNSTAT_interdomain:
        if (data->u.evtchn.deliver.port.port) {
            if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
                goto out_noeventfd; /* -EINVAL */
        } else {
            eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
            if (IS_ERR(eventfd)) {
                ret = PTR_ERR(eventfd);
                goto out_noeventfd;
            }
        }
        break;
 
    case EVTCHNSTAT_virq:
    case EVTCHNSTAT_closed:
    case EVTCHNSTAT_unbound:
    case EVTCHNSTAT_pirq:
    default: /* Unknown event channel type */
        goto out; /* -EINVAL */
    }
 
    evtchnfd->send_port = data->u.evtchn.send_port;
    evtchnfd->type = data->u.evtchn.type;
    if (eventfd) {
        evtchnfd->deliver.eventfd.ctx = eventfd;
    } else {
        /* We only support 2 level event channels for now */
        if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
            goto out; /* -EINVAL; */
 
        evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
        evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
        evtchnfd->deliver.port.vcpu_idx = -1;
        evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
    }
 
    mutex_lock(&kvm->arch.xen.xen_lock);
    ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
            GFP_KERNEL);
    mutex_unlock(&kvm->arch.xen.xen_lock);
    if (ret >= 0)
        return 0;
 
    if (ret == -ENOSPC)
        ret = -EEXIST;
out:
    if (eventfd)
        eventfd_ctx_put(eventfd);
out_noeventfd:
    kfree(evtchnfd);
    return ret;
}
 
static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
{
    struct evtchnfd *evtchnfd;
 
    mutex_lock(&kvm->arch.xen.xen_lock);
    evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
    mutex_unlock(&kvm->arch.xen.xen_lock);
 
    if (!evtchnfd)
        return -ENOENT;
 
    synchronize_srcu(&kvm->srcu);
    if (!evtchnfd->deliver.port.port)
        eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
    kfree(evtchnfd);
    return 0;
}
 
static int kvm_xen_eventfd_reset(struct kvm *kvm)
{
    struct evtchnfd *evtchnfd, **all_evtchnfds;
    int i;
    int n = 0;
 
    mutex_lock(&kvm->arch.xen.xen_lock);
 
    /*
     * Because synchronize_srcu() cannot be called inside the
     * critical section, first collect all the evtchnfd objects
     * in an array as they are removed from evtchn_ports.
     */
    idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i)
        n++;
 
    all_evtchnfds = kmalloc_array(n, sizeof(struct evtchnfd *), GFP_KERNEL);
    if (!all_evtchnfds) {
        mutex_unlock(&kvm->arch.xen.xen_lock);
        return -ENOMEM;
    }
 
    n = 0;
    idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
        all_evtchnfds[n++] = evtchnfd;
        idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
    }
    mutex_unlock(&kvm->arch.xen.xen_lock);
 
    synchronize_srcu(&kvm->srcu);
 
    while (n--) {
        evtchnfd = all_evtchnfds[n];
        if (!evtchnfd->deliver.port.port)
            eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
        kfree(evtchnfd);
    }
    kfree(all_evtchnfds);
 
    return 0;
}
 
static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
    u32 port = data->u.evtchn.send_port;
 
    if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
        return kvm_xen_eventfd_reset(kvm);
 
    if (!port || port >= max_evtchn_port(kvm))
        return -EINVAL;
 
    if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
        return kvm_xen_eventfd_deassign(kvm, port);
    if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
        return kvm_xen_eventfd_update(kvm, data);
    if (data->u.evtchn.flags)
        return -EINVAL;
 
    return kvm_xen_eventfd_assign(kvm, data);
}
 
static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
{
    struct evtchnfd *evtchnfd;
    struct evtchn_send send;
    struct x86_exception e;
 
    /* Sanity check: this structure is the same for 32-bit and 64-bit */
    BUILD_BUG_ON(sizeof(send) != 4);
    if (kvm_read_guest_virt(vcpu, param, &send, sizeof(send), &e)) {
        *r = -EFAULT;
        return true;
    }
 
    /*
     * evtchnfd is protected by kvm->srcu; the idr lookup instead
     * is protected by RCU.
     */
    rcu_read_lock();
    evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
    rcu_read_unlock();
    if (!evtchnfd)
        return false;
 
    if (evtchnfd->deliver.port.port) {
        int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
        if (ret < 0 && ret != -ENOTCONN)
            return false;
    } else {
        eventfd_signal(evtchnfd->deliver.eventfd.ctx);
    }
 
    *r = 0;
    return true;
}
 
void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
{
    vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
    vcpu->arch.xen.poll_evtchn = 0;
 
    timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
 
    kvm_gpc_init(&vcpu->arch.xen.runstate_cache, vcpu->kvm, NULL,
             KVM_HOST_USES_PFN);
    kvm_gpc_init(&vcpu->arch.xen.runstate2_cache, vcpu->kvm, NULL,
             KVM_HOST_USES_PFN);
    kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache, vcpu->kvm, NULL,
             KVM_HOST_USES_PFN);
    kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache, vcpu->kvm, NULL,
             KVM_HOST_USES_PFN);
}
 
void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
{
    if (kvm_xen_timer_enabled(vcpu))
        kvm_xen_stop_timer(vcpu);
 
    kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
    kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
    kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
    kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
 
    del_timer_sync(&vcpu->arch.xen.poll_timer);
}
 
void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu)
{
    struct kvm_cpuid_entry2 *entry;
    u32 function;
 
    if (!vcpu->arch.xen.cpuid.base)
        return;
 
    function = vcpu->arch.xen.cpuid.base | XEN_CPUID_LEAF(3);
    if (function > vcpu->arch.xen.cpuid.limit)
        return;
 
    entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
    if (entry) {
        entry->ecx = vcpu->arch.hv_clock.tsc_to_system_mul;
        entry->edx = vcpu->arch.hv_clock.tsc_shift;
    }
 
    entry = kvm_find_cpuid_entry_index(vcpu, function, 2);
    if (entry)
        entry->eax = vcpu->arch.hw_tsc_khz;
}
 
void kvm_xen_init_vm(struct kvm *kvm)
{
    mutex_init(&kvm->arch.xen.xen_lock);
    idr_init(&kvm->arch.xen.evtchn_ports);
    kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm, NULL, KVM_HOST_USES_PFN);
}
 
void kvm_xen_destroy_vm(struct kvm *kvm)
{
    struct evtchnfd *evtchnfd;
    int i;
 
    kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
 
    idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
        if (!evtchnfd->deliver.port.port)
            eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
        kfree(evtchnfd);
    }
    idr_destroy(&kvm->arch.xen.evtchn_ports);
 
    if (kvm->arch.xen_hvm_config.msr)
        static_branch_slow_dec_deferred(&kvm_xen_enabled);
}