Archipelago » qemu

/*

 *  i386 helpers (without register variable usage)

 * 

 *  Copyright (c) 2003 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 <stdarg.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <inttypes.h>

#include <signal.h>

#include <assert.h>

#include "cpu.h"

#include "exec-all.h"

//#define DEBUG_MMU

#ifdef USE_CODE_COPY

#include <asm/ldt.h>

#include <linux/unistd.h>

#include <linux/version.h>

int modify_ldt(int func, void *ptr, unsigned long bytecount)

{

        return syscall(__NR_modify_ldt, func, ptr, bytecount);

}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 66)

#define modify_ldt_ldt_s user_desc

#endif

#endif /* USE_CODE_COPY */

CPUX86State *cpu_x86_init(void)

{

    CPUX86State *env;

    static int inited;

    env = qemu_mallocz(sizeof(CPUX86State));

    if (!env)

        return NULL;

    cpu_exec_init(env);

    /* init various static tables */

    if (!inited) {

        inited = 1;

        optimize_flags_init();

    }

#ifdef USE_CODE_COPY

    /* testing code for code copy case */

    {

        struct modify_ldt_ldt_s ldt;

        ldt.entry_number = 1;

        ldt.base_addr = (unsigned long)env;

        ldt.limit = (sizeof(CPUState) + 0xfff) >> 12;

        ldt.seg_32bit = 1;

        ldt.contents = MODIFY_LDT_CONTENTS_DATA;

        ldt.read_exec_only = 0;

        ldt.limit_in_pages = 1;

        ldt.seg_not_present = 0;

        ldt.useable = 1;

        modify_ldt(1, &ldt, sizeof(ldt)); /* write ldt entry */

        asm volatile ("movl %0, %%fs" : : "r" ((1 << 3) | 7));

    }

#endif

    {

        int family, model, stepping;

#ifdef TARGET_X86_64

        env->cpuid_vendor1 = 0x68747541; /* "Auth" */

        env->cpuid_vendor2 = 0x69746e65; /* "enti" */

        env->cpuid_vendor3 = 0x444d4163; /* "cAMD" */

        family = 6;

        model = 2;

        stepping = 3;

#else

        env->cpuid_vendor1 = 0x756e6547; /* "Genu" */

        env->cpuid_vendor2 = 0x49656e69; /* "ineI" */

        env->cpuid_vendor3 = 0x6c65746e; /* "ntel" */

#if 0

        /* pentium 75-200 */

        family = 5;

        model = 2;

        stepping = 11;

#else

        /* pentium pro */

        family = 6;

        model = 3;

        stepping = 3;

#endif

#endif

        env->cpuid_level = 2;

        env->cpuid_version = (family << 8) | (model << 4) | stepping;

        env->cpuid_features = (CPUID_FP87 | CPUID_DE | CPUID_PSE |

                               CPUID_TSC | CPUID_MSR | CPUID_MCE |

                               CPUID_CX8 | CPUID_PGE | CPUID_CMOV |

                               CPUID_PAT);

        env->pat = 0x0007040600070406ULL;

        env->cpuid_ext_features = CPUID_EXT_SSE3;

        env->cpuid_features |= CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | CPUID_PAE | CPUID_SEP;

        env->cpuid_features |= CPUID_APIC;

        env->cpuid_xlevel = 0;

        {

            const char *model_id = "QEMU Virtual CPU version " QEMU_VERSION;

            int c, len, i;

            len = strlen(model_id);

            for(i = 0; i < 48; i++) {

                if (i >= len)

                    c = '\0';

                else

                    c = model_id[i];

                env->cpuid_model[i >> 2] |= c << (8 * (i & 3));

            }

        }

#ifdef TARGET_X86_64

        /* currently not enabled for std i386 because not fully tested */

        env->cpuid_ext2_features = (env->cpuid_features & 0x0183F3FF);

        env->cpuid_ext2_features |= CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX;

        env->cpuid_xlevel = 0x80000008;

        /* these features are needed for Win64 and aren't fully implemented */

        env->cpuid_features |= CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA;

        /* this feature is needed for Solaris and isn't fully implemented */

        env->cpuid_features |= CPUID_PSE36;

#endif

    }

    cpu_reset(env);

#ifdef USE_KQEMU

    kqemu_init(env);

#endif

    return env;

}

/* NOTE: must be called outside the CPU execute loop */

void cpu_reset(CPUX86State *env)

{

    int i;

    memset(env, 0, offsetof(CPUX86State, breakpoints));

    tlb_flush(env, 1);

    /* init to reset state */

#ifdef CONFIG_SOFTMMU

    env->hflags |= HF_SOFTMMU_MASK;

#endif

    cpu_x86_update_cr0(env, 0x60000010);

    env->a20_mask = 0xffffffff;

    env->smbase = 0x30000;

    env->idt.limit = 0xffff;

    env->gdt.limit = 0xffff;

    env->ldt.limit = 0xffff;

    env->ldt.flags = DESC_P_MASK;

    env->tr.limit = 0xffff;

    env->tr.flags = DESC_P_MASK;

    cpu_x86_load_seg_cache(env, R_CS, 0xf000, 0xffff0000, 0xffff, 0); 

    cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffff, 0);

    cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffff, 0);

    cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffff, 0);

    cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffff, 0);

    cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffff, 0);

    env->eip = 0xfff0;

    env->regs[R_EDX] = 0x600; /* indicate P6 processor */

    env->eflags = 0x2;

    /* FPU init */

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

        env->fptags[i] = 1;

    env->fpuc = 0x37f;

    env->mxcsr = 0x1f80;

}

void cpu_x86_close(CPUX86State *env)

{

    free(env);

}

/***********************************************************/

/* x86 debug */

static const char *cc_op_str[] = {

    "DYNAMIC",

    "EFLAGS",

    "MULB",

    "MULW",

    "MULL",

    "MULQ",

    "ADDB",

    "ADDW",

    "ADDL",

    "ADDQ",

    "ADCB",

    "ADCW",

    "ADCL",

    "ADCQ",

    "SUBB",

    "SUBW",

    "SUBL",

    "SUBQ",

    "SBBB",

    "SBBW",

    "SBBL",

    "SBBQ",

    "LOGICB",

    "LOGICW",

    "LOGICL",

    "LOGICQ",

    "INCB",

    "INCW",

    "INCL",

    "INCQ",

    "DECB",

    "DECW",

    "DECL",

    "DECQ",

    "SHLB",

    "SHLW",

    "SHLL",

    "SHLQ",

    "SARB",

    "SARW",

    "SARL",

    "SARQ",

};

void cpu_dump_state(CPUState *env, FILE *f, 

                    int (*cpu_fprintf)(FILE *f, const char *fmt, ...),

                    int flags)

{

    int eflags, i, nb;

    char cc_op_name[32];

    static const char *seg_name[6] = { "ES", "CS", "SS", "DS", "FS", "GS" };

    eflags = env->eflags;

#ifdef TARGET_X86_64

    if (env->hflags & HF_CS64_MASK) {

        cpu_fprintf(f, 

                    "RAX=%016" PRIx64 " RBX=%016" PRIx64 " RCX=%016" PRIx64 " RDX=%016" PRIx64 "\n"

                    "RSI=%016" PRIx64 " RDI=%016" PRIx64 " RBP=%016" PRIx64 " RSP=%016" PRIx64 "\n"

                    "R8 =%016" PRIx64 " R9 =%016" PRIx64 " R10=%016" PRIx64 " R11=%016" PRIx64 "\n"

                    "R12=%016" PRIx64 " R13=%016" PRIx64 " R14=%016" PRIx64 " R15=%016" PRIx64 "\n"

                    "RIP=%016" PRIx64 " RFL=%08x [%c%c%c%c%c%c%c] CPL=%d II=%d A20=%d SMM=%d HLT=%d\n",

                    env->regs[R_EAX], 

                    env->regs[R_EBX], 

                    env->regs[R_ECX], 

                    env->regs[R_EDX], 

                    env->regs[R_ESI], 

                    env->regs[R_EDI], 

                    env->regs[R_EBP], 

                    env->regs[R_ESP], 

                    env->regs[8], 

                    env->regs[9], 

                    env->regs[10], 

                    env->regs[11], 

                    env->regs[12], 

                    env->regs[13], 

                    env->regs[14], 

                    env->regs[15], 

                    env->eip, eflags,

                    eflags & DF_MASK ? 'D' : '-',

                    eflags & CC_O ? 'O' : '-',

                    eflags & CC_S ? 'S' : '-',

                    eflags & CC_Z ? 'Z' : '-',

                    eflags & CC_A ? 'A' : '-',

                    eflags & CC_P ? 'P' : '-',

                    eflags & CC_C ? 'C' : '-',

                    env->hflags & HF_CPL_MASK, 

                    (env->hflags >> HF_INHIBIT_IRQ_SHIFT) & 1,

                    (env->a20_mask >> 20) & 1,

                    (env->hflags >> HF_SMM_SHIFT) & 1,

                    (env->hflags >> HF_HALTED_SHIFT) & 1);

    } else 

#endif

    {

        cpu_fprintf(f, "EAX=%08x EBX=%08x ECX=%08x EDX=%08x\n"

                    "ESI=%08x EDI=%08x EBP=%08x ESP=%08x\n"

                    "EIP=%08x EFL=%08x [%c%c%c%c%c%c%c] CPL=%d II=%d A20=%d SMM=%d HLT=%d\n",

                    (uint32_t)env->regs[R_EAX], 

                    (uint32_t)env->regs[R_EBX], 

                    (uint32_t)env->regs[R_ECX], 

                    (uint32_t)env->regs[R_EDX], 

                    (uint32_t)env->regs[R_ESI], 

                    (uint32_t)env->regs[R_EDI], 

                    (uint32_t)env->regs[R_EBP], 

                    (uint32_t)env->regs[R_ESP], 

                    (uint32_t)env->eip, eflags,

                    eflags & DF_MASK ? 'D' : '-',

                    eflags & CC_O ? 'O' : '-',

                    eflags & CC_S ? 'S' : '-',

                    eflags & CC_Z ? 'Z' : '-',

                    eflags & CC_A ? 'A' : '-',

                    eflags & CC_P ? 'P' : '-',

                    eflags & CC_C ? 'C' : '-',

                    env->hflags & HF_CPL_MASK, 

                    (env->hflags >> HF_INHIBIT_IRQ_SHIFT) & 1,

                    (env->a20_mask >> 20) & 1,

                    (env->hflags >> HF_SMM_SHIFT) & 1,

                    (env->hflags >> HF_HALTED_SHIFT) & 1);

    }

#ifdef TARGET_X86_64

    if (env->hflags & HF_LMA_MASK) {

        for(i = 0; i < 6; i++) {

            SegmentCache *sc = &env->segs[i];

            cpu_fprintf(f, "%s =%04x %016" PRIx64 " %08x %08x\n",

                        seg_name[i],

                        sc->selector,

                        sc->base,

                        sc->limit,

                        sc->flags);

        }

        cpu_fprintf(f, "LDT=%04x %016" PRIx64 " %08x %08x\n",

                    env->ldt.selector,

                    env->ldt.base,

                    env->ldt.limit,

                    env->ldt.flags);

        cpu_fprintf(f, "TR =%04x %016" PRIx64 " %08x %08x\n",

                    env->tr.selector,

                    env->tr.base,

                    env->tr.limit,

                    env->tr.flags);

        cpu_fprintf(f, "GDT=     %016" PRIx64 " %08x\n",

                    env->gdt.base, env->gdt.limit);

        cpu_fprintf(f, "IDT=     %016" PRIx64 " %08x\n",

                    env->idt.base, env->idt.limit);

        cpu_fprintf(f, "CR0=%08x CR2=%016" PRIx64 " CR3=%016" PRIx64 " CR4=%08x\n",

                    (uint32_t)env->cr[0], 

                    env->cr[2], 

                    env->cr[3], 

                    (uint32_t)env->cr[4]);

    } else

#endif

    {

        for(i = 0; i < 6; i++) {

            SegmentCache *sc = &env->segs[i];

            cpu_fprintf(f, "%s =%04x %08x %08x %08x\n",

                        seg_name[i],

                        sc->selector,

                        (uint32_t)sc->base,

                        sc->limit,

                        sc->flags);

        }

        cpu_fprintf(f, "LDT=%04x %08x %08x %08x\n",

                    env->ldt.selector,

                    (uint32_t)env->ldt.base,

                    env->ldt.limit,

                    env->ldt.flags);

        cpu_fprintf(f, "TR =%04x %08x %08x %08x\n",

                    env->tr.selector,

                    (uint32_t)env->tr.base,

                    env->tr.limit,

                    env->tr.flags);

        cpu_fprintf(f, "GDT=     %08x %08x\n",

                    (uint32_t)env->gdt.base, env->gdt.limit);

        cpu_fprintf(f, "IDT=     %08x %08x\n",

                    (uint32_t)env->idt.base, env->idt.limit);

        cpu_fprintf(f, "CR0=%08x CR2=%08x CR3=%08x CR4=%08x\n",

                    (uint32_t)env->cr[0], 

                    (uint32_t)env->cr[2], 

                    (uint32_t)env->cr[3], 

                    (uint32_t)env->cr[4]);

    }

    if (flags & X86_DUMP_CCOP) {

        if ((unsigned)env->cc_op < CC_OP_NB)

            snprintf(cc_op_name, sizeof(cc_op_name), "%s", cc_op_str[env->cc_op]);

        else

            snprintf(cc_op_name, sizeof(cc_op_name), "[%d]", env->cc_op);

#ifdef TARGET_X86_64

        if (env->hflags & HF_CS64_MASK) {

            cpu_fprintf(f, "CCS=%016" PRIx64 " CCD=%016" PRIx64 " CCO=%-8s\n",

                        env->cc_src, env->cc_dst, 

                        cc_op_name);

        } else 

#endif

        {

            cpu_fprintf(f, "CCS=%08x CCD=%08x CCO=%-8s\n",

                        (uint32_t)env->cc_src, (uint32_t)env->cc_dst, 

                        cc_op_name);

        }

    }

    if (flags & X86_DUMP_FPU) {

        int fptag;

        fptag = 0;

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

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

        }

        cpu_fprintf(f, "FCW=%04x FSW=%04x [ST=%d] FTW=%02x MXCSR=%08x\n",

                    env->fpuc,

                    (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11,

                    env->fpstt,

                    fptag,

                    env->mxcsr);

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

#if defined(USE_X86LDOUBLE)

            union {

                long double d;

                struct {

                    uint64_t lower;

                    uint16_t upper;

                } l;

            } tmp;

            tmp.d = env->fpregs[i].d;

            cpu_fprintf(f, "FPR%d=%016" PRIx64 " %04x",

                        i, tmp.l.lower, tmp.l.upper);

#else

            cpu_fprintf(f, "FPR%d=%016" PRIx64,

                        i, env->fpregs[i].mmx.q);

#endif

            if ((i & 1) == 1)

                cpu_fprintf(f, "\n");

            else

                cpu_fprintf(f, " ");

        }

        if (env->hflags & HF_CS64_MASK) 

            nb = 16;

        else

            nb = 8;

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

            cpu_fprintf(f, "XMM%02d=%08x%08x%08x%08x",

                        i, 

                        env->xmm_regs[i].XMM_L(3),

                        env->xmm_regs[i].XMM_L(2),

                        env->xmm_regs[i].XMM_L(1),

                        env->xmm_regs[i].XMM_L(0));

            if ((i & 1) == 1)

                cpu_fprintf(f, "\n");

            else

                cpu_fprintf(f, " ");

        }

    }

}

/***********************************************************/

/* x86 mmu */

/* XXX: add PGE support */

void cpu_x86_set_a20(CPUX86State *env, int a20_state)

{

    a20_state = (a20_state != 0);

    if (a20_state != ((env->a20_mask >> 20) & 1)) {

#if defined(DEBUG_MMU)

        printf("A20 update: a20=%d\n", a20_state);

#endif

        /* if the cpu is currently executing code, we must unlink it and

           all the potentially executing TB */

        cpu_interrupt(env, CPU_INTERRUPT_EXITTB);

        /* when a20 is changed, all the MMU mappings are invalid, so

           we must flush everything */

        tlb_flush(env, 1);

        env->a20_mask = 0xffefffff | (a20_state << 20);

    }

}

void cpu_x86_update_cr0(CPUX86State *env, uint32_t new_cr0)

{

    int pe_state;

#if defined(DEBUG_MMU)

    printf("CR0 update: CR0=0x%08x\n", new_cr0);

#endif

    if ((new_cr0 & (CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK)) !=

        (env->cr[0] & (CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK))) {

        tlb_flush(env, 1);

    }

#ifdef TARGET_X86_64

    if (!(env->cr[0] & CR0_PG_MASK) && (new_cr0 & CR0_PG_MASK) &&

        (env->efer & MSR_EFER_LME)) {

        /* enter in long mode */

        /* XXX: generate an exception */

        if (!(env->cr[4] & CR4_PAE_MASK))

            return;

        env->efer |= MSR_EFER_LMA;

        env->hflags |= HF_LMA_MASK;

    } else if ((env->cr[0] & CR0_PG_MASK) && !(new_cr0 & CR0_PG_MASK) &&

               (env->efer & MSR_EFER_LMA)) {

        /* exit long mode */

        env->efer &= ~MSR_EFER_LMA;

        env->hflags &= ~(HF_LMA_MASK | HF_CS64_MASK);

        env->eip &= 0xffffffff;

    }

#endif

    env->cr[0] = new_cr0 | CR0_ET_MASK;

    /* update PE flag in hidden flags */

    pe_state = (env->cr[0] & CR0_PE_MASK);

    env->hflags = (env->hflags & ~HF_PE_MASK) | (pe_state << HF_PE_SHIFT);

    /* ensure that ADDSEG is always set in real mode */

    env->hflags |= ((pe_state ^ 1) << HF_ADDSEG_SHIFT);

    /* update FPU flags */

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

        ((new_cr0 << (HF_MP_SHIFT - 1)) & (HF_MP_MASK | HF_EM_MASK | HF_TS_MASK));

}

/* XXX: in legacy PAE mode, generate a GPF if reserved bits are set in

   the PDPT */

void cpu_x86_update_cr3(CPUX86State *env, target_ulong new_cr3)

{

    env->cr[3] = new_cr3;

    if (env->cr[0] & CR0_PG_MASK) {

#if defined(DEBUG_MMU)

        printf("CR3 update: CR3=" TARGET_FMT_lx "\n", new_cr3);

#endif

        tlb_flush(env, 0);

    }

}

void cpu_x86_update_cr4(CPUX86State *env, uint32_t new_cr4)

{

#if defined(DEBUG_MMU)

    printf("CR4 update: CR4=%08x\n", (uint32_t)env->cr[4]);

#endif

    if ((new_cr4 & (CR4_PGE_MASK | CR4_PAE_MASK | CR4_PSE_MASK)) !=

        (env->cr[4] & (CR4_PGE_MASK | CR4_PAE_MASK | CR4_PSE_MASK))) {

        tlb_flush(env, 1);

    }

    /* SSE handling */

    if (!(env->cpuid_features & CPUID_SSE))

        new_cr4 &= ~CR4_OSFXSR_MASK;

    if (new_cr4 & CR4_OSFXSR_MASK)

        env->hflags |= HF_OSFXSR_MASK;

    else

        env->hflags &= ~HF_OSFXSR_MASK;

    env->cr[4] = new_cr4;

}

/* XXX: also flush 4MB pages */

void cpu_x86_flush_tlb(CPUX86State *env, target_ulong addr)

{

    tlb_flush_page(env, addr);

}

#if defined(CONFIG_USER_ONLY) 

int cpu_x86_handle_mmu_fault(CPUX86State *env, target_ulong addr, 

                             int is_write, int is_user, int is_softmmu)

{

    /* user mode only emulation */

    is_write &= 1;

    env->cr[2] = addr;

    env->error_code = (is_write << PG_ERROR_W_BIT);

    env->error_code |= PG_ERROR_U_MASK;

    env->exception_index = EXCP0E_PAGE;

    return 1;

}

target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr)

{

    return addr;

}

#else

#define PHYS_ADDR_MASK 0xfffff000

/* return value:

   -1 = cannot handle fault 

   0  = nothing more to do 

   1  = generate PF fault

   2  = soft MMU activation required for this block

*/

int cpu_x86_handle_mmu_fault(CPUX86State *env, target_ulong addr, 

                             int is_write1, int is_user, int is_softmmu)

{

    uint64_t ptep, pte;

    uint32_t pdpe_addr, pde_addr, pte_addr;

    int error_code, is_dirty, prot, page_size, ret, is_write;

    unsigned long paddr, page_offset;

    target_ulong vaddr, virt_addr;

#if defined(DEBUG_MMU)

    printf("MMU fault: addr=" TARGET_FMT_lx " w=%d u=%d eip=" TARGET_FMT_lx "\n", 

           addr, is_write1, is_user, env->eip);

#endif

    is_write = is_write1 & 1;

    if (!(env->cr[0] & CR0_PG_MASK)) {

        pte = addr;

        virt_addr = addr & TARGET_PAGE_MASK;

        prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;

        page_size = 4096;

        goto do_mapping;

    }

    if (env->cr[4] & CR4_PAE_MASK) {

        uint64_t pde, pdpe;

        /* XXX: we only use 32 bit physical addresses */

#ifdef TARGET_X86_64

        if (env->hflags & HF_LMA_MASK) {

            uint32_t pml4e_addr;

            uint64_t pml4e;

            int32_t sext;

            /* test virtual address sign extension */

            sext = (int64_t)addr >> 47;

            if (sext != 0 && sext != -1) {

                env->error_code = 0;

                env->exception_index = EXCP0D_GPF;

                return 1;

            }

            pml4e_addr = ((env->cr[3] & ~0xfff) + (((addr >> 39) & 0x1ff) << 3)) & 

                env->a20_mask;

            pml4e = ldq_phys(pml4e_addr);

            if (!(pml4e & PG_PRESENT_MASK)) {

                error_code = 0;

                goto do_fault;

            }

            if (!(env->efer & MSR_EFER_NXE) && (pml4e & PG_NX_MASK)) {

                error_code = PG_ERROR_RSVD_MASK;

                goto do_fault;

            }

            if (!(pml4e & PG_ACCESSED_MASK)) {

                pml4e |= PG_ACCESSED_MASK;

                stl_phys_notdirty(pml4e_addr, pml4e);

            }

            ptep = pml4e ^ PG_NX_MASK;

            pdpe_addr = ((pml4e & PHYS_ADDR_MASK) + (((addr >> 30) & 0x1ff) << 3)) & 

                env->a20_mask;

            pdpe = ldq_phys(pdpe_addr);

            if (!(pdpe & PG_PRESENT_MASK)) {

                error_code = 0;

                goto do_fault;

            }

            if (!(env->efer & MSR_EFER_NXE) && (pdpe & PG_NX_MASK)) {

                error_code = PG_ERROR_RSVD_MASK;

                goto do_fault;

            }

            ptep &= pdpe ^ PG_NX_MASK;

            if (!(pdpe & PG_ACCESSED_MASK)) {

                pdpe |= PG_ACCESSED_MASK;

                stl_phys_notdirty(pdpe_addr, pdpe);

            }

        } else

#endif

        {

            /* XXX: load them when cr3 is loaded ? */

            pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 27) & 0x18)) & 

                env->a20_mask;

            pdpe = ldq_phys(pdpe_addr);

            if (!(pdpe & PG_PRESENT_MASK)) {

                error_code = 0;

                goto do_fault;

            }

            ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK;

        }

        pde_addr = ((pdpe & PHYS_ADDR_MASK) + (((addr >> 21) & 0x1ff) << 3)) &

            env->a20_mask;

        pde = ldq_phys(pde_addr);

        if (!(pde & PG_PRESENT_MASK)) {

            error_code = 0;

            goto do_fault;

        }

        if (!(env->efer & MSR_EFER_NXE) && (pde & PG_NX_MASK)) {

            error_code = PG_ERROR_RSVD_MASK;

            goto do_fault;

        }

        ptep &= pde ^ PG_NX_MASK;

        if (pde & PG_PSE_MASK) {

            /* 2 MB page */

            page_size = 2048 * 1024;

            ptep ^= PG_NX_MASK;

            if ((ptep & PG_NX_MASK) && is_write1 == 2)

                goto do_fault_protect;

            if (is_user) {

                if (!(ptep & PG_USER_MASK))

                    goto do_fault_protect;

                if (is_write && !(ptep & PG_RW_MASK))

                    goto do_fault_protect;

            } else {

                if ((env->cr[0] & CR0_WP_MASK) && 

                    is_write && !(ptep & PG_RW_MASK)) 

                    goto do_fault_protect;

            }

            is_dirty = is_write && !(pde & PG_DIRTY_MASK);

            if (!(pde & PG_ACCESSED_MASK) || is_dirty) {

                pde |= PG_ACCESSED_MASK;

                if (is_dirty)

                    pde |= PG_DIRTY_MASK;

                stl_phys_notdirty(pde_addr, pde);

            }

            /* align to page_size */

            pte = pde & ((PHYS_ADDR_MASK & ~(page_size - 1)) | 0xfff); 

            virt_addr = addr & ~(page_size - 1);

        } else {

            /* 4 KB page */

            if (!(pde & PG_ACCESSED_MASK)) {

                pde |= PG_ACCESSED_MASK;

                stl_phys_notdirty(pde_addr, pde);

            }

            pte_addr = ((pde & PHYS_ADDR_MASK) + (((addr >> 12) & 0x1ff) << 3)) &

                env->a20_mask;

            pte = ldq_phys(pte_addr);

            if (!(pte & PG_PRESENT_MASK)) {

                error_code = 0;

                goto do_fault;

            }

            if (!(env->efer & MSR_EFER_NXE) && (pte & PG_NX_MASK)) {

                error_code = PG_ERROR_RSVD_MASK;

                goto do_fault;

            }

            /* combine pde and pte nx, user and rw protections */

            ptep &= pte ^ PG_NX_MASK;

            ptep ^= PG_NX_MASK;

            if ((ptep & PG_NX_MASK) && is_write1 == 2)

                goto do_fault_protect; 

            if (is_user) {

                if (!(ptep & PG_USER_MASK))

                    goto do_fault_protect;

                if (is_write && !(ptep & PG_RW_MASK))

                    goto do_fault_protect;

            } else {

                if ((env->cr[0] & CR0_WP_MASK) &&

                    is_write && !(ptep & PG_RW_MASK)) 

                    goto do_fault_protect;

            }

            is_dirty = is_write && !(pte & PG_DIRTY_MASK);

            if (!(pte & PG_ACCESSED_MASK) || is_dirty) {

                pte |= PG_ACCESSED_MASK;

                if (is_dirty)

                    pte |= PG_DIRTY_MASK;

                stl_phys_notdirty(pte_addr, pte);

            }

            page_size = 4096;

            virt_addr = addr & ~0xfff;

            pte = pte & (PHYS_ADDR_MASK | 0xfff);

        }

    } else {

        uint32_t pde;

        /* page directory entry */

        pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & 0xffc)) & 

            env->a20_mask;

        pde = ldl_phys(pde_addr);

        if (!(pde & PG_PRESENT_MASK)) {

            error_code = 0;

            goto do_fault;

        }

        /* if PSE bit is set, then we use a 4MB page */

        if ((pde & PG_PSE_MASK) && (env->cr[4] & CR4_PSE_MASK)) {

            page_size = 4096 * 1024;

            if (is_user) {

                if (!(pde & PG_USER_MASK))

                    goto do_fault_protect;

                if (is_write && !(pde & PG_RW_MASK))

                    goto do_fault_protect;

            } else {

                if ((env->cr[0] & CR0_WP_MASK) && 

                    is_write && !(pde & PG_RW_MASK)) 

                    goto do_fault_protect;

            }

            is_dirty = is_write && !(pde & PG_DIRTY_MASK);

            if (!(pde & PG_ACCESSED_MASK) || is_dirty) {

                pde |= PG_ACCESSED_MASK;

                if (is_dirty)

                    pde |= PG_DIRTY_MASK;

                stl_phys_notdirty(pde_addr, pde);

            }

            pte = pde & ~( (page_size - 1) & ~0xfff); /* align to page_size */

            ptep = pte;

            virt_addr = addr & ~(page_size - 1);

        } else {

            if (!(pde & PG_ACCESSED_MASK)) {

                pde |= PG_ACCESSED_MASK;

                stl_phys_notdirty(pde_addr, pde);

            }

            /* page directory entry */

            pte_addr = ((pde & ~0xfff) + ((addr >> 10) & 0xffc)) & 

                env->a20_mask;

            pte = ldl_phys(pte_addr);

            if (!(pte & PG_PRESENT_MASK)) {

                error_code = 0;

                goto do_fault;

            }

            /* combine pde and pte user and rw protections */

            ptep = pte & pde;

            if (is_user) {

                if (!(ptep & PG_USER_MASK))

                    goto do_fault_protect;

                if (is_write && !(ptep & PG_RW_MASK))

                    goto do_fault_protect;

            } else {

                if ((env->cr[0] & CR0_WP_MASK) &&

                    is_write && !(ptep & PG_RW_MASK)) 

                    goto do_fault_protect;

            }

            is_dirty = is_write && !(pte & PG_DIRTY_MASK);

            if (!(pte & PG_ACCESSED_MASK) || is_dirty) {

                pte |= PG_ACCESSED_MASK;

                if (is_dirty)

                    pte |= PG_DIRTY_MASK;

                stl_phys_notdirty(pte_addr, pte);

            }

            page_size = 4096;

            virt_addr = addr & ~0xfff;

        }

    }

    /* the page can be put in the TLB */

    prot = PAGE_READ;

    if (!(ptep & PG_NX_MASK))

        prot |= PAGE_EXEC;

    if (pte & PG_DIRTY_MASK) {

        /* only set write access if already dirty... otherwise wait

           for dirty access */

        if (is_user) {

            if (ptep & PG_RW_MASK)

                prot |= PAGE_WRITE;

        } else {

            if (!(env->cr[0] & CR0_WP_MASK) ||

                (ptep & PG_RW_MASK))

                prot |= PAGE_WRITE;

        }

    }

 do_mapping:

    pte = pte & env->a20_mask;