Archipelago » qemu

/*

 *  KQEMU support

 * 

 *  Copyright (c) 2005 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include "config.h"

#ifdef _WIN32

#include <windows.h>

#include <winioctl.h>

#else

#include <sys/types.h>

#include <sys/mman.h>

#include <sys/ioctl.h>

#endif

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <inttypes.h>

#include "cpu.h"

#include "exec-all.h"

#ifdef USE_KQEMU

#define DEBUG

//#define PROFILE

#include <unistd.h>

#include <fcntl.h>

#include "kqemu.h"

/* compatibility stuff */

#ifndef KQEMU_RET_SYSCALL

#define KQEMU_RET_SYSCALL   0x0300 /* syscall insn */

#endif

#ifndef KQEMU_MAX_RAM_PAGES_TO_UPDATE

#define KQEMU_MAX_RAM_PAGES_TO_UPDATE 512

#define KQEMU_RAM_PAGES_UPDATE_ALL (KQEMU_MAX_RAM_PAGES_TO_UPDATE + 1)

#endif

#ifndef KQEMU_MAX_MODIFIED_RAM_PAGES

#define KQEMU_MAX_MODIFIED_RAM_PAGES 512

#endif

#ifdef _WIN32

#define KQEMU_DEVICE "\\\\.\\kqemu"

#else

#define KQEMU_DEVICE "/dev/kqemu"

#endif

#ifdef _WIN32

#define KQEMU_INVALID_FD INVALID_HANDLE_VALUE

HANDLE kqemu_fd = KQEMU_INVALID_FD;

#define kqemu_closefd(x) CloseHandle(x)

#else

#define KQEMU_INVALID_FD -1

int kqemu_fd = KQEMU_INVALID_FD;

#define kqemu_closefd(x) close(x)

#endif

/* 0 = not allowed

   1 = user kqemu

   2 = kernel kqemu

*/

int kqemu_allowed = 1;

unsigned long *pages_to_flush;

unsigned int nb_pages_to_flush;

unsigned long *ram_pages_to_update;

unsigned int nb_ram_pages_to_update;

unsigned long *modified_ram_pages;

unsigned int nb_modified_ram_pages;

uint8_t *modified_ram_pages_table;

extern uint32_t **l1_phys_map;

#define cpuid(index, eax, ebx, ecx, edx) \

  asm volatile ("cpuid" \

                : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) \

                : "0" (index))

#ifdef __x86_64__

static int is_cpuid_supported(void)

{

    return 1;

}

#else

static int is_cpuid_supported(void)

{

    int v0, v1;

    asm volatile ("pushf\n"

                  "popl %0\n"

                  "movl %0, %1\n"

                  "xorl $0x00200000, %0\n"

                  "pushl %0\n"

                  "popf\n"

                  "pushf\n"

                  "popl %0\n"

                  : "=a" (v0), "=d" (v1)

                  :

                  : "cc");

    return (v0 != v1);

}

#endif

static void kqemu_update_cpuid(CPUState *env)

{

    int critical_features_mask, features;

    uint32_t eax, ebx, ecx, edx;

    /* the following features are kept identical on the host and

       target cpus because they are important for user code. Strictly

       speaking, only SSE really matters because the OS must support

       it if the user code uses it. */

    critical_features_mask = 

        CPUID_CMOV | CPUID_CX8 | 

        CPUID_FXSR | CPUID_MMX | CPUID_SSE | 

        CPUID_SSE2 | CPUID_SEP;

    if (!is_cpuid_supported()) {

        features = 0;

    } else {

        cpuid(1, eax, ebx, ecx, edx);

        features = edx;

    }

#ifdef __x86_64__

    /* NOTE: on x86_64 CPUs, SYSENTER is not supported in

       compatibility mode, so in order to have the best performances

       it is better not to use it */

    features &= ~CPUID_SEP;

#endif

    env->cpuid_features = (env->cpuid_features & ~critical_features_mask) |

        (features & critical_features_mask);

    /* XXX: we could update more of the target CPUID state so that the

       non accelerated code sees exactly the same CPU features as the

       accelerated code */

}

int kqemu_init(CPUState *env)

{

    struct kqemu_init init;

    int ret, version;

#ifdef _WIN32

    DWORD temp;

#endif

    if (!kqemu_allowed)

        return -1;

#ifdef _WIN32

    kqemu_fd = CreateFile(KQEMU_DEVICE, GENERIC_WRITE | GENERIC_READ,

                          FILE_SHARE_READ | FILE_SHARE_WRITE,

                          NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,

                          NULL);

#else

    kqemu_fd = open(KQEMU_DEVICE, O_RDWR);

#endif

    if (kqemu_fd == KQEMU_INVALID_FD) {

        fprintf(stderr, "Could not open '%s' - QEMU acceleration layer not activated\n", KQEMU_DEVICE);

        return -1;

    }

    version = 0;

#ifdef _WIN32

    DeviceIoControl(kqemu_fd, KQEMU_GET_VERSION, NULL, 0,

                    &version, sizeof(version), &temp, NULL);

#else

    ioctl(kqemu_fd, KQEMU_GET_VERSION, &version);

#endif

    if (version != KQEMU_VERSION) {

        fprintf(stderr, "Version mismatch between kqemu module and qemu (%08x %08x) - disabling kqemu use\n",

                version, KQEMU_VERSION);

        goto fail;

    }

    pages_to_flush = qemu_vmalloc(KQEMU_MAX_PAGES_TO_FLUSH * 

                                  sizeof(unsigned long));

    if (!pages_to_flush)

        goto fail;

    ram_pages_to_update = qemu_vmalloc(KQEMU_MAX_RAM_PAGES_TO_UPDATE * 

                                       sizeof(unsigned long));

    if (!ram_pages_to_update)

        goto fail;

    modified_ram_pages = qemu_vmalloc(KQEMU_MAX_MODIFIED_RAM_PAGES * 

                                      sizeof(unsigned long));

    if (!modified_ram_pages)

        goto fail;

    modified_ram_pages_table = qemu_mallocz(phys_ram_size >> TARGET_PAGE_BITS);

    if (!modified_ram_pages_table)

        goto fail;

    init.ram_base = phys_ram_base;

    init.ram_size = phys_ram_size;

    init.ram_dirty = phys_ram_dirty;

    init.phys_to_ram_map = l1_phys_map;

    init.pages_to_flush = pages_to_flush;

#if KQEMU_VERSION >= 0x010200

    init.ram_pages_to_update = ram_pages_to_update;

#endif

#if KQEMU_VERSION >= 0x010300

    init.modified_ram_pages = modified_ram_pages;

#endif

#ifdef _WIN32

    ret = DeviceIoControl(kqemu_fd, KQEMU_INIT, &init, sizeof(init),

                          NULL, 0, &temp, NULL) == TRUE ? 0 : -1;

#else

    ret = ioctl(kqemu_fd, KQEMU_INIT, &init);

#endif

    if (ret < 0) {

        fprintf(stderr, "Error %d while initializing QEMU acceleration layer - disabling it for now\n", ret);

    fail:

        kqemu_closefd(kqemu_fd);

        kqemu_fd = KQEMU_INVALID_FD;

        return -1;

    }

    kqemu_update_cpuid(env);

    env->kqemu_enabled = kqemu_allowed;

    nb_pages_to_flush = 0;

    nb_ram_pages_to_update = 0;

    return 0;

}

void kqemu_flush_page(CPUState *env, target_ulong addr)

{

#if defined(DEBUG)

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "kqemu_flush_page: addr=" TARGET_FMT_lx "\n", addr);

    }

#endif

    if (nb_pages_to_flush >= KQEMU_MAX_PAGES_TO_FLUSH)

        nb_pages_to_flush = KQEMU_FLUSH_ALL;

    else

        pages_to_flush[nb_pages_to_flush++] = addr;

}

void kqemu_flush(CPUState *env, int global)

{

#ifdef DEBUG

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "kqemu_flush:\n");

    }

#endif

    nb_pages_to_flush = KQEMU_FLUSH_ALL;

}

void kqemu_set_notdirty(CPUState *env, ram_addr_t ram_addr)

{

#ifdef DEBUG

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "kqemu_set_notdirty: addr=%08lx\n", ram_addr);

    }

#endif

    /* we only track transitions to dirty state */

    if (phys_ram_dirty[ram_addr >> TARGET_PAGE_BITS] != 0xff)

        return;

    if (nb_ram_pages_to_update >= KQEMU_MAX_RAM_PAGES_TO_UPDATE)

        nb_ram_pages_to_update = KQEMU_RAM_PAGES_UPDATE_ALL;

    else

        ram_pages_to_update[nb_ram_pages_to_update++] = ram_addr;

}

static void kqemu_reset_modified_ram_pages(void)

{

    int i;

    unsigned long page_index;

    for(i = 0; i < nb_modified_ram_pages; i++) {

        page_index = modified_ram_pages[i] >> TARGET_PAGE_BITS;

        modified_ram_pages_table[page_index] = 0;

    }

    nb_modified_ram_pages = 0;

}

void kqemu_modify_page(CPUState *env, ram_addr_t ram_addr)

{

    unsigned long page_index;

    int ret;

#ifdef _WIN32

    DWORD temp;

#endif

    page_index = ram_addr >> TARGET_PAGE_BITS;

    if (!modified_ram_pages_table[page_index]) {

#if 0

        printf("%d: modify_page=%08lx\n", nb_modified_ram_pages, ram_addr);

#endif

        modified_ram_pages_table[page_index] = 1;

        modified_ram_pages[nb_modified_ram_pages++] = ram_addr;

        if (nb_modified_ram_pages >= KQEMU_MAX_MODIFIED_RAM_PAGES) {

            /* flush */

#ifdef _WIN32

            ret = DeviceIoControl(kqemu_fd, KQEMU_MODIFY_RAM_PAGES, 

                                  &nb_modified_ram_pages, 

                                  sizeof(nb_modified_ram_pages),

                                  NULL, 0, &temp, NULL);

#else

            ret = ioctl(kqemu_fd, KQEMU_MODIFY_RAM_PAGES, 

                        &nb_modified_ram_pages);

#endif

            kqemu_reset_modified_ram_pages();

        }

    }

}

struct fpstate {

    uint16_t fpuc;

    uint16_t dummy1;

    uint16_t fpus;

    uint16_t dummy2;

    uint16_t fptag;

    uint16_t dummy3;

    uint32_t fpip;

    uint32_t fpcs;

    uint32_t fpoo;

    uint32_t fpos;

    uint8_t fpregs1[8 * 10];

};

struct fpxstate {

    uint16_t fpuc;

    uint16_t fpus;

    uint16_t fptag;

    uint16_t fop;

    uint32_t fpuip;

    uint16_t cs_sel;

    uint16_t dummy0;

    uint32_t fpudp;

    uint16_t ds_sel;

    uint16_t dummy1;

    uint32_t mxcsr;

    uint32_t mxcsr_mask;

    uint8_t fpregs1[8 * 16];

    uint8_t xmm_regs[16 * 16];

    uint8_t dummy2[96];

};

static struct fpxstate fpx1 __attribute__((aligned(16)));

static void restore_native_fp_frstor(CPUState *env)

{

    int fptag, i, j;

    struct fpstate fp1, *fp = &fp1;

    fp->fpuc = env->fpuc;

    fp->fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;

    fptag = 0;

    for (i=7; i>=0; i--) {

        fptag <<= 2;

        if (env->fptags[i]) {

            fptag |= 3;

        } else {

            /* the FPU automatically computes it */

        }

    }

    fp->fptag = fptag;

    j = env->fpstt;

    for(i = 0;i < 8; i++) {

        memcpy(&fp->fpregs1[i * 10], &env->fpregs[j].d, 10);

        j = (j + 1) & 7;

    }

    asm volatile ("frstor %0" : "=m" (*fp));

}

static void save_native_fp_fsave(CPUState *env)

{

    int fptag, i, j;

    uint16_t fpuc;

    struct fpstate fp1, *fp = &fp1;

    asm volatile ("fsave %0" : : "m" (*fp));

    env->fpuc = fp->fpuc;

    env->fpstt = (fp->fpus >> 11) & 7;

    env->fpus = fp->fpus & ~0x3800;

    fptag = fp->fptag;

    for(i = 0;i < 8; i++) {

        env->fptags[i] = ((fptag & 3) == 3);

        fptag >>= 2;

    }

    j = env->fpstt;

    for(i = 0;i < 8; i++) {

        memcpy(&env->fpregs[j].d, &fp->fpregs1[i * 10], 10);

        j = (j + 1) & 7;

    }

    /* we must restore the default rounding state */

    fpuc = 0x037f | (env->fpuc & (3 << 10));

    asm volatile("fldcw %0" : : "m" (fpuc));

}

static void restore_native_fp_fxrstor(CPUState *env)

{

    struct fpxstate *fp = &fpx1;

    int i, j, fptag;

    fp->fpuc = env->fpuc;

    fp->fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;

    fptag = 0;

    for(i = 0; i < 8; i++)

        fptag |= (env->fptags[i] << i);

    fp->fptag = fptag ^ 0xff;

    j = env->fpstt;

    for(i = 0;i < 8; i++) {

        memcpy(&fp->fpregs1[i * 16], &env->fpregs[j].d, 10);

        j = (j + 1) & 7;

    }

    if (env->cpuid_features & CPUID_SSE) {

        fp->mxcsr = env->mxcsr;

        /* XXX: check if DAZ is not available */

        fp->mxcsr_mask = 0xffff;

        memcpy(fp->xmm_regs, env->xmm_regs, CPU_NB_REGS * 16);

    }

    asm volatile ("fxrstor %0" : "=m" (*fp));

}

static void save_native_fp_fxsave(CPUState *env)

{

    struct fpxstate *fp = &fpx1;

    int fptag, i, j;

    uint16_t fpuc;

    asm volatile ("fxsave %0" : : "m" (*fp));

    env->fpuc = fp->fpuc;

    env->fpstt = (fp->fpus >> 11) & 7;

    env->fpus = fp->fpus & ~0x3800;

    fptag = fp->fptag ^ 0xff;

    for(i = 0;i < 8; i++) {

        env->fptags[i] = (fptag >> i) & 1;

    }

    j = env->fpstt;

    for(i = 0;i < 8; i++) {

        memcpy(&env->fpregs[j].d, &fp->fpregs1[i * 16], 10);

        j = (j + 1) & 7;

    }

    if (env->cpuid_features & CPUID_SSE) {

        env->mxcsr = fp->mxcsr;

        memcpy(env->xmm_regs, fp->xmm_regs, CPU_NB_REGS * 16);

    }

    /* we must restore the default rounding state */

    asm volatile ("fninit");

    fpuc = 0x037f | (env->fpuc & (3 << 10));

    asm volatile("fldcw %0" : : "m" (fpuc));

}

static int do_syscall(CPUState *env,

                      struct kqemu_cpu_state *kenv)

{

    int selector;

    selector = (env->star >> 32) & 0xffff;

#ifdef __x86_64__

    if (env->hflags & HF_LMA_MASK) {

        env->regs[R_ECX] = kenv->next_eip;

        env->regs[11] = env->eflags;

        cpu_x86_set_cpl(env, 0);

        cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc, 

                               0, 0xffffffff, 

                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |

                               DESC_S_MASK |

                               DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK | DESC_L_MASK);

        cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc, 

                               0, 0xffffffff,

                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |

                               DESC_S_MASK |

                               DESC_W_MASK | DESC_A_MASK);

        env->eflags &= ~env->fmask;

        if (env->hflags & HF_CS64_MASK)

            env->eip = env->lstar;

        else

            env->eip = env->cstar;

    } else 

#endif

    {

        env->regs[R_ECX] = (uint32_t)kenv->next_eip;

        cpu_x86_set_cpl(env, 0);

        cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc, 

                           0, 0xffffffff, 

                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |

                               DESC_S_MASK |

                               DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK);

        cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc, 

                               0, 0xffffffff,

                               DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |

                               DESC_S_MASK |

                               DESC_W_MASK | DESC_A_MASK);

        env->eflags &= ~(IF_MASK | RF_MASK | VM_MASK);

        env->eip = (uint32_t)env->star;

    }

    return 2;

}

#ifdef CONFIG_PROFILER

#define PC_REC_SIZE 1

#define PC_REC_HASH_BITS 16

#define PC_REC_HASH_SIZE (1 << PC_REC_HASH_BITS)

typedef struct PCRecord {

    unsigned long pc;

    int64_t count;

    struct PCRecord *next;

} PCRecord;

static PCRecord *pc_rec_hash[PC_REC_HASH_SIZE];

static int nb_pc_records;

static void kqemu_record_pc(unsigned long pc)

{

    unsigned long h;

    PCRecord **pr, *r;

    h = pc / PC_REC_SIZE;

    h = h ^ (h >> PC_REC_HASH_BITS);

    h &= (PC_REC_HASH_SIZE - 1);

    pr = &pc_rec_hash[h];

    for(;;) {

        r = *pr;

        if (r == NULL)

            break;

        if (r->pc == pc) {

            r->count++;

            return;

        }

        pr = &r->next;

    }

    r = malloc(sizeof(PCRecord));

    r->count = 1;

    r->pc = pc;

    r->next = NULL;

    *pr = r;

    nb_pc_records++;

}

static int pc_rec_cmp(const void *p1, const void *p2)

{

    PCRecord *r1 = *(PCRecord **)p1;

    PCRecord *r2 = *(PCRecord **)p2;

    if (r1->count < r2->count)

        return 1;

    else if (r1->count == r2->count)

        return 0;

    else

        return -1;

}

static void kqemu_record_flush(void)

{

    PCRecord *r, *r_next;

    int h;

    for(h = 0; h < PC_REC_HASH_SIZE; h++) {

        for(r = pc_rec_hash[h]; r != NULL; r = r_next) {

            r_next = r->next;

            free(r);

        }

        pc_rec_hash[h] = NULL;

    }

    nb_pc_records = 0;

}

void kqemu_record_dump(void)

{

    PCRecord **pr, *r;

    int i, h;

    FILE *f;

    int64_t total, sum;

    pr = malloc(sizeof(PCRecord *) * nb_pc_records);

    i = 0;

    total = 0;

    for(h = 0; h < PC_REC_HASH_SIZE; h++) {

        for(r = pc_rec_hash[h]; r != NULL; r = r->next) {

            pr[i++] = r;

            total += r->count;

        }

    }

    qsort(pr, nb_pc_records, sizeof(PCRecord *), pc_rec_cmp);

    f = fopen("/tmp/kqemu.stats", "w");

    if (!f) {

        perror("/tmp/kqemu.stats");

        exit(1);

    }

    fprintf(f, "total: %" PRId64 "\n", total);

    sum = 0;

    for(i = 0; i < nb_pc_records; i++) {

        r = pr[i];

        sum += r->count;

        fprintf(f, "%08lx: %" PRId64 " %0.2f%% %0.2f%%\n", 

                r->pc, 

                r->count, 

                (double)r->count / (double)total * 100.0,

                (double)sum / (double)total * 100.0);

    }

    fclose(f);

    free(pr);

    kqemu_record_flush();

}

#endif

int kqemu_cpu_exec(CPUState *env)

{

    struct kqemu_cpu_state kcpu_state, *kenv = &kcpu_state;

    int ret, cpl, i;

#ifdef CONFIG_PROFILER

    int64_t ti;

#endif

#ifdef _WIN32

    DWORD temp;

#endif

#ifdef CONFIG_PROFILER

    ti = profile_getclock();

#endif

#ifdef DEBUG

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "kqemu: cpu_exec: enter\n");

        cpu_dump_state(env, logfile, fprintf, 0);

    }

#endif

    memcpy(kenv->regs, env->regs, sizeof(kenv->regs));

    kenv->eip = env->eip;

    kenv->eflags = env->eflags;

    memcpy(&kenv->segs, &env->segs, sizeof(env->segs));

    memcpy(&kenv->ldt, &env->ldt, sizeof(env->ldt));

    memcpy(&kenv->tr, &env->tr, sizeof(env->tr));

    memcpy(&kenv->gdt, &env->gdt, sizeof(env->gdt));

    memcpy(&kenv->idt, &env->idt, sizeof(env->idt));

    kenv->cr0 = env->cr[0];

    kenv->cr2 = env->cr[2];

    kenv->cr3 = env->cr[3];

    kenv->cr4 = env->cr[4];

    kenv->a20_mask = env->a20_mask;

#if KQEMU_VERSION >= 0x010100

    kenv->efer = env->efer;

#endif

#if KQEMU_VERSION >= 0x010300

    kenv->tsc_offset = 0;

    kenv->star = env->star;

    kenv->sysenter_cs = env->sysenter_cs;

    kenv->sysenter_esp = env->sysenter_esp;

    kenv->sysenter_eip = env->sysenter_eip;

#ifdef __x86_64__

    kenv->lstar = env->lstar;

    kenv->cstar = env->cstar;

    kenv->fmask = env->fmask;

    kenv->kernelgsbase = env->kernelgsbase;

#endif

#endif

    if (env->dr[7] & 0xff) {

        kenv->dr7 = env->dr[7];

        kenv->dr0 = env->dr[0];

        kenv->dr1 = env->dr[1];

        kenv->dr2 = env->dr[2];

        kenv->dr3 = env->dr[3];

    } else {

        kenv->dr7 = 0;

    }

    kenv->dr6 = env->dr[6];

    cpl = (env->hflags & HF_CPL_MASK);

    kenv->cpl = cpl;

    kenv->nb_pages_to_flush = nb_pages_to_flush;

#if KQEMU_VERSION >= 0x010200

    kenv->user_only = (env->kqemu_enabled == 1);

    kenv->nb_ram_pages_to_update = nb_ram_pages_to_update;

#endif

    nb_ram_pages_to_update = 0;

#if KQEMU_VERSION >= 0x010300

    kenv->nb_modified_ram_pages = nb_modified_ram_pages;

#endif

    kqemu_reset_modified_ram_pages();

    if (env->cpuid_features & CPUID_FXSR)

        restore_native_fp_fxrstor(env);

    else

        restore_native_fp_frstor(env);

#ifdef _WIN32

    if (DeviceIoControl(kqemu_fd, KQEMU_EXEC,

                        kenv, sizeof(struct kqemu_cpu_state),

                        kenv, sizeof(struct kqemu_cpu_state),

                        &temp, NULL)) {

        ret = kenv->retval;

    } else {

        ret = -1;

    }

#else

#if KQEMU_VERSION >= 0x010100

    ioctl(kqemu_fd, KQEMU_EXEC, kenv);

    ret = kenv->retval;

#else

    ret = ioctl(kqemu_fd, KQEMU_EXEC, kenv);

#endif

#endif

    if (env->cpuid_features & CPUID_FXSR)

        save_native_fp_fxsave(env);

    else

        save_native_fp_fsave(env);

    memcpy(env->regs, kenv->regs, sizeof(env->regs));

    env->eip = kenv->eip;

    env->eflags = kenv->eflags;

    memcpy(env->segs, kenv->segs, sizeof(env->segs));

    cpu_x86_set_cpl(env, kenv->cpl);

    memcpy(&env->ldt, &kenv->ldt, sizeof(env->ldt));

#if 0

    /* no need to restore that */

    memcpy(env->tr, kenv->tr, sizeof(env->tr));

    memcpy(env->gdt, kenv->gdt, sizeof(env->gdt));

    memcpy(env->idt, kenv->idt, sizeof(env->idt));

    env->a20_mask = kenv->a20_mask;

#endif

    env->cr[0] = kenv->cr0;

    env->cr[4] = kenv->cr4;

    env->cr[3] = kenv->cr3;

    env->cr[2] = kenv->cr2;

    env->dr[6] = kenv->dr6;

#if KQEMU_VERSION >= 0x010300

#ifdef __x86_64__

    env->kernelgsbase = kenv->kernelgsbase;

#endif

#endif

    /* flush pages as indicated by kqemu */

    if (kenv->nb_pages_to_flush >= KQEMU_FLUSH_ALL) {

        tlb_flush(env, 1);

    } else {

        for(i = 0; i < kenv->nb_pages_to_flush; i++) {

            tlb_flush_page(env, pages_to_flush[i]);

        }

    }

    nb_pages_to_flush = 0;

#ifdef CONFIG_PROFILER

    kqemu_time += profile_getclock() - ti;

    kqemu_exec_count++;

#endif

#if KQEMU_VERSION >= 0x010200

    if (kenv->nb_ram_pages_to_update > 0) {

        cpu_tlb_update_dirty(env);

    }

#endif

#if KQEMU_VERSION >= 0x010300

    if (kenv->nb_modified_ram_pages > 0) {

        for(i = 0; i < kenv->nb_modified_ram_pages; i++) {

            unsigned long addr;

            addr = modified_ram_pages[i];

            tb_invalidate_phys_page_range(addr, addr + TARGET_PAGE_SIZE, 0);

        }

    }

#endif

    /* restore the hidden flags */

    {

        unsigned int new_hflags;

#ifdef TARGET_X86_64

        if ((env->hflags & HF_LMA_MASK) && 

            (env->segs[R_CS].flags & DESC_L_MASK)) {

            /* long mode */

            new_hflags = HF_CS32_MASK | HF_SS32_MASK | HF_CS64_MASK;

        } else

#endif

        {

            /* legacy / compatibility case */

            new_hflags = (env->segs[R_CS].flags & DESC_B_MASK)

                >> (DESC_B_SHIFT - HF_CS32_SHIFT);

            new_hflags |= (env->segs[R_SS].flags & DESC_B_MASK)

                >> (DESC_B_SHIFT - HF_SS32_SHIFT);

            if (!(env->cr[0] & CR0_PE_MASK) || 

                   (env->eflags & VM_MASK) ||

                   !(env->hflags & HF_CS32_MASK)) {

                /* XXX: try to avoid this test. The problem comes from the

                   fact that is real mode or vm86 mode we only modify the

                   'base' and 'selector' fields of the segment cache to go

                   faster. A solution may be to force addseg to one in

                   translate-i386.c. */

                new_hflags |= HF_ADDSEG_MASK;

            } else {

                new_hflags |= ((env->segs[R_DS].base | 

                                env->segs[R_ES].base |

                                env->segs[R_SS].base) != 0) << 

                    HF_ADDSEG_SHIFT;

            }

        }

        env->hflags = (env->hflags & 

           ~(HF_CS32_MASK | HF_SS32_MASK | HF_CS64_MASK | HF_ADDSEG_MASK)) |

            new_hflags;

    }

    /* update FPU flags */

    env->hflags = (env->hflags & ~(HF_MP_MASK | HF_EM_MASK | HF_TS_MASK)) |

        ((env->cr[0] << (HF_MP_SHIFT - 1)) & (HF_MP_MASK | HF_EM_MASK | HF_TS_MASK));

    if (env->cr[4] & CR4_OSFXSR_MASK)

        env->hflags |= HF_OSFXSR_MASK;

    else

        env->hflags &= ~HF_OSFXSR_MASK;

#ifdef DEBUG

    if (loglevel & CPU_LOG_INT) {

        fprintf(logfile, "kqemu: kqemu_cpu_exec: ret=0x%x\n", ret);

    }

#endif

    if (ret == KQEMU_RET_SYSCALL) {

        /* syscall instruction */

        return do_syscall(env, kenv);

    } else 

    if ((ret & 0xff00) == KQEMU_RET_INT) {

        env->exception_index = ret & 0xff;

        env->error_code = 0;

        env->exception_is_int = 1;

        env->exception_next_eip = kenv->next_eip;

#ifdef CONFIG_PROFILER

        kqemu_ret_int_count++;

#endif

#ifdef DEBUG

        if (loglevel & CPU_LOG_INT) {

            fprintf(logfile, "kqemu: interrupt v=%02x:\n", 

                    env->exception_index);

            cpu_dump_state(env, logfile, fprintf, 0);

        }

#endif

        return 1;

    } else if ((ret & 0xff00) == KQEMU_RET_EXCEPTION) {

        env->exception_index = ret & 0xff;

        env->error_code = kenv->error_code;

        env->exception_is_int = 0;

        env->exception_next_eip = 0;

#ifdef CONFIG_PROFILER

        kqemu_ret_excp_count++;

#endif

#ifdef DEBUG

        if (loglevel & CPU_LOG_INT) {

            fprintf(logfile, "kqemu: exception v=%02x e=%04x:\n",

                    env->exception_index, env->error_code);

            cpu_dump_state(env, logfile, fprintf, 0);

        }

#endif

        return 1;

    } else if (ret == KQEMU_RET_INTR) {

#ifdef CONFIG_PROFILER

        kqemu_ret_intr_count++;

#endif

#ifdef DEBUG

        if (loglevel & CPU_LOG_INT) {

            cpu_dump_state(env, logfile, fprintf, 0);

        }

#endif

        return 0;

    } else if (ret == KQEMU_RET_SOFTMMU) { 

#ifdef CONFIG_PROFILER

        {

            unsigned long pc = env->eip + env->segs[R_CS].base;

            kqemu_record_pc(pc);

        }

#endif

#ifdef DEBUG