// 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
 */

#include "x86.h"
#include "xen.h"
#include "hyperv.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 "trace.h"

DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);

static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
{
        gpa_t gpa = gfn_to_gpa(gfn);
        int wc_ofs, sec_hi_ofs;
        int ret = 0;
        int idx = srcu_read_lock(&kvm->srcu);

        if (kvm_is_error_hva(gfn_to_hva(kvm, gfn))) {
                ret = -EFAULT;
                goto out;
        }
        kvm->arch.xen.shinfo_gfn = gfn;

        /* 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);

        /* 32-bit location by default */
        wc_ofs = offsetof(struct compat_shared_info, wc);
        sec_hi_ofs = offsetof(struct compat_shared_info, arch.wc_sec_hi);

#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 (kvm->arch.xen.long_mode) {
                wc_ofs = offsetof(struct shared_info, wc);
                sec_hi_ofs = offsetof(struct shared_info, wc_sec_hi);
        }
#endif

        kvm_write_wall_clock(kvm, gpa + wc_ofs, sec_hi_ofs - wc_ofs);
        kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);

out:
        srcu_read_unlock(&kvm->srcu, idx);
        return ret;
}

static 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;
}

void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
{
        struct kvm_vcpu_xen *vx = &v->arch.xen;
        uint64_t state_entry_time;
        unsigned int offset;

        kvm_xen_update_runstate(v, state);

        if (!vx->runstate_set)
                return;

        BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);

        offset = offsetof(struct compat_vcpu_runstate_info, state_entry_time);
#ifdef CONFIG_X86_64
        /*
         * The only difference is alignment of uint64_t in 32-bit.
         * So the first field 'state' is accessed directly using
         * offsetof() (where its offset happens to be zero), while the
         * remaining fields which are all uint64_t, start at 'offset'
         * which we tweak here by adding 4.
         */
        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);

        if (v->kvm->arch.xen.long_mode)
                offset = offsetof(struct vcpu_runstate_info, state_entry_time);
#endif
        /*
         * First write the updated state_entry_time at the appropriate
         * location determined by 'offset'.
         */
        state_entry_time = vx->runstate_entry_time;
        state_entry_time |= XEN_RUNSTATE_UPDATE;

        BUILD_BUG_ON(sizeof(((struct vcpu_runstate_info *)0)->state_entry_time) !=
                     sizeof(state_entry_time));
        BUILD_BUG_ON(sizeof(((struct compat_vcpu_runstate_info *)0)->state_entry_time) !=
                     sizeof(state_entry_time));

        if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
                                          &state_entry_time, offset,
                                          sizeof(state_entry_time)))
                return;
        smp_wmb();

        /*
         * Next, write the new runstate. This is in the *same* place
         * for 32-bit and 64-bit guests, asserted here for paranoia.
         */
        BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
                     offsetof(struct compat_vcpu_runstate_info, state));
        BUILD_BUG_ON(sizeof(((struct vcpu_runstate_info *)0)->state) !=
                     sizeof(vx->current_runstate));
        BUILD_BUG_ON(sizeof(((struct compat_vcpu_runstate_info *)0)->state) !=
                     sizeof(vx->current_runstate));

        if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
                                          &vx->current_runstate,
                                          offsetof(struct vcpu_runstate_info, state),
                                          sizeof(vx->current_runstate)))
                return;

        /*
         * Write the actual runstate times immediately after the
         * runstate_entry_time.
         */
        BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
                     offsetof(struct vcpu_runstate_info, time) - sizeof(u64));
        BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
                     offsetof(struct compat_vcpu_runstate_info, time) - sizeof(u64));
        BUILD_BUG_ON(sizeof(((struct vcpu_runstate_info *)0)->time) !=
                     sizeof(((struct compat_vcpu_runstate_info *)0)->time));
        BUILD_BUG_ON(sizeof(((struct vcpu_runstate_info *)0)->time) !=
                     sizeof(vx->runstate_times));

        if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
                                          &vx->runstate_times[0],
                                          offset + sizeof(u64),
                                          sizeof(vx->runstate_times)))
                return;

        smp_wmb();

        /*
         * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's
         * runstate_entry_time field.
         */

        state_entry_time &= ~XEN_RUNSTATE_UPDATE;
        if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
                                          &state_entry_time, offset,
                                          sizeof(state_entry_time)))
                return;
}

int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
{
        int err;
        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.
         */
        struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
        struct kvm_memslots *slots = kvm_memslots(v->kvm);
        unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_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(((struct vcpu_info *)0)->evtchn_upcall_pending));
        BUILD_BUG_ON(sizeof(rc) !=
                     sizeof(((struct compat_vcpu_info *)0)->evtchn_upcall_pending));

        /*
         * For efficiency, this mirrors the checks for using the valid
         * cache in kvm_read_guest_offset_cached(), but just uses
         * __get_user() instead. And falls back to the slow path.
         */
        if (likely(slots->generation == ghc->generation &&
                   !kvm_is_error_hva(ghc->hva) && ghc->memslot)) {
                /* Fast path */
                pagefault_disable();
                err = __get_user(rc, (u8 __user *)ghc->hva + offset);
                pagefault_enable();
                if (!err)
                        return rc;
        }

        /* Slow path */

        /*
         * 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;

        kvm_read_guest_offset_cached(v->kvm, ghc, &rc, offset,
                                     sizeof(rc));

        return rc;
}

int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
        int r = -ENOENT;

        mutex_lock(&kvm->lock);

        switch (data->type) {
        case KVM_XEN_ATTR_TYPE_LONG_MODE:
                if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
                        r = -EINVAL;
                } else {
                        kvm->arch.xen.long_mode = !!data->u.long_mode;
                        r = 0;
                }
                break;

        case KVM_XEN_ATTR_TYPE_SHARED_INFO:
                if (data->u.shared_info.gfn == GPA_INVALID) {
                        kvm->arch.xen.shinfo_gfn = GPA_INVALID;
                        r = 0;
                        break;
                }
                r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
                break;


        case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
                if (data->u.vector && data->u.vector < 0x10)
                        r = -EINVAL;
                else {
                        kvm->arch.xen.upcall_vector = data->u.vector;
                        r = 0;
                }
                break;

        default:
                break;
        }

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

int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
{
        int r = -ENOENT;

        mutex_lock(&kvm->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:
                data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_gfn);
                r = 0;
                break;

        case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
                data->u.vector = kvm->arch.xen.upcall_vector;
                r = 0;
                break;

        default:
                break;
        }

        mutex_unlock(&kvm->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->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 == GPA_INVALID) {
                        vcpu->arch.xen.vcpu_info_set = false;
                        r = 0;
                        break;
                }

                r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
                                              &vcpu->arch.xen.vcpu_info_cache,
                                              data->u.gpa,
                                              sizeof(struct vcpu_info));
                if (!r) {
                        vcpu->arch.xen.vcpu_info_set = true;
                        kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                }
                break;

        case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
                if (data->u.gpa == GPA_INVALID) {
                        vcpu->arch.xen.vcpu_time_info_set = false;
                        r = 0;
                        break;
                }

                r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
                                              &vcpu->arch.xen.vcpu_time_info_cache,
                                              data->u.gpa,
                                              sizeof(struct pvclock_vcpu_time_info));
                if (!r) {
                        vcpu->arch.xen.vcpu_time_info_set = true;
                        kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                }
                break;

        case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
                if (!sched_info_on()) {
                        r = -EOPNOTSUPP;
                        break;
                }
                if (data->u.gpa == GPA_INVALID) {
                        vcpu->arch.xen.runstate_set = false;
                        r = 0;
                        break;
                }

                r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
                                              &vcpu->arch.xen.runstate_cache,
                                              data->u.gpa,
                                              sizeof(struct vcpu_runstate_info));
                if (!r) {
                        vcpu->arch.xen.runstate_set = true;
                }
                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);
                r = 0;
                break;

        default:
                break;
        }

        srcu_read_unlock(&vcpu->kvm->srcu, idx);
        mutex_unlock(&vcpu->kvm->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->lock);

        switch (data->type) {
        case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
                if (vcpu->arch.xen.vcpu_info_set)
                        data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
                else
                        data->u.gpa = GPA_INVALID;
                r = 0;
                break;

        case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
                if (vcpu->arch.xen.vcpu_time_info_set)
                        data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
                else
                        data->u.gpa = GPA_INVALID;
                r = 0;
                break;

        case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
                if (!sched_info_on()) {
                        r = -EOPNOTSUPP;
                        break;
                }
                if (vcpu->arch.xen.runstate_set) {
                        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;

        default:
                break;
        }

        mutex_unlock(&vcpu->kvm->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 */
                kvm_x86_ops.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;

                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);

                if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
                        kfree(page);
                        return 1;
                }
        }
        return 0;
}

int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
{
        if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL)
                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->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);

        memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));

        mutex_unlock(&kvm->lock);
        return 0;
}

void kvm_xen_init_vm(struct kvm *kvm)
{
        kvm->arch.xen.shinfo_gfn = GPA_INVALID;
}

void kvm_xen_destroy_vm(struct kvm *kvm)
{
        if (kvm->arch.xen_hvm_config.msr)
                static_branch_slow_dec_deferred(&kvm_xen_enabled);
}

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);
}

int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
{
        bool longmode;
        u64 input, params[6];

        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_mode(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
        trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
                                params[3], params[4], params[5]);

        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 = kvm_x86_ops.get_cpl(vcpu);
        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;
}