1 files changed, 495 insertions, 0 deletions

diff --git a/src/linux-user/vm86.c b/src/linux-user/vm86.c
new file mode 100644
index 0000000..22a4eb9
--- /dev/null
+++ b/src/linux-user/vm86.c
@@ -0,0 +1,495 @@
+/*
+ *  vm86 linux syscall support
+ *
+ *  Copyright (c) 2003 Fabrice Bellard
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "qemu.h"
+
+//#define DEBUG_VM86
+
+#ifdef DEBUG_VM86
+#  define LOG_VM86(...) qemu_log(__VA_ARGS__);
+#else
+#  define LOG_VM86(...) do { } while (0)
+#endif
+
+
+#define set_flags(X,new,mask) \
+((X) = ((X) & ~(mask)) | ((new) & (mask)))
+
+#define SAFE_MASK	(0xDD5)
+#define RETURN_MASK	(0xDFF)
+
+static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
+{
+    return (((uint8_t *)bitmap)[nr >> 3] >> (nr & 7)) & 1;
+}
+
+static inline void vm_putw(CPUX86State *env, uint32_t segptr,
+                           unsigned int reg16, unsigned int val)
+{
+    cpu_stw_data(env, segptr + (reg16 & 0xffff), val);
+}
+
+static inline void vm_putl(CPUX86State *env, uint32_t segptr,
+                           unsigned int reg16, unsigned int val)
+{
+    cpu_stl_data(env, segptr + (reg16 & 0xffff), val);
+}
+
+static inline unsigned int vm_getb(CPUX86State *env,
+                                   uint32_t segptr, unsigned int reg16)
+{
+    return cpu_ldub_data(env, segptr + (reg16 & 0xffff));
+}
+
+static inline unsigned int vm_getw(CPUX86State *env,
+                                   uint32_t segptr, unsigned int reg16)
+{
+    return cpu_lduw_data(env, segptr + (reg16 & 0xffff));
+}
+
+static inline unsigned int vm_getl(CPUX86State *env,
+                                   uint32_t segptr, unsigned int reg16)
+{
+    return cpu_ldl_data(env, segptr + (reg16 & 0xffff));
+}
+
+void save_v86_state(CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+    struct target_vm86plus_struct * target_v86;
+
+    if (!lock_user_struct(VERIFY_WRITE, target_v86, ts->target_v86, 0))
+        /* FIXME - should return an error */
+        return;
+    /* put the VM86 registers in the userspace register structure */
+    target_v86->regs.eax = tswap32(env->regs[R_EAX]);
+    target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
+    target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
+    target_v86->regs.edx = tswap32(env->regs[R_EDX]);
+    target_v86->regs.esi = tswap32(env->regs[R_ESI]);
+    target_v86->regs.edi = tswap32(env->regs[R_EDI]);
+    target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
+    target_v86->regs.esp = tswap32(env->regs[R_ESP]);
+    target_v86->regs.eip = tswap32(env->eip);
+    target_v86->regs.cs = tswap16(env->segs[R_CS].selector);
+    target_v86->regs.ss = tswap16(env->segs[R_SS].selector);
+    target_v86->regs.ds = tswap16(env->segs[R_DS].selector);
+    target_v86->regs.es = tswap16(env->segs[R_ES].selector);
+    target_v86->regs.fs = tswap16(env->segs[R_FS].selector);
+    target_v86->regs.gs = tswap16(env->segs[R_GS].selector);
+    set_flags(env->eflags, ts->v86flags, VIF_MASK | ts->v86mask);
+    target_v86->regs.eflags = tswap32(env->eflags);
+    unlock_user_struct(target_v86, ts->target_v86, 1);
+    LOG_VM86("save_v86_state: eflags=%08x cs:ip=%04x:%04x\n",
+             env->eflags, env->segs[R_CS].selector, env->eip);
+
+    /* restore 32 bit registers */
+    env->regs[R_EAX] = ts->vm86_saved_regs.eax;
+    env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
+    env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
+    env->regs[R_EDX] = ts->vm86_saved_regs.edx;
+    env->regs[R_ESI] = ts->vm86_saved_regs.esi;
+    env->regs[R_EDI] = ts->vm86_saved_regs.edi;
+    env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
+    env->regs[R_ESP] = ts->vm86_saved_regs.esp;
+    env->eflags = ts->vm86_saved_regs.eflags;
+    env->eip = ts->vm86_saved_regs.eip;
+
+    cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
+    cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
+    cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
+    cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
+    cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
+    cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
+}
+
+/* return from vm86 mode to 32 bit. The vm86() syscall will return
+   'retval' */
+static inline void return_to_32bit(CPUX86State *env, int retval)
+{
+    LOG_VM86("return_to_32bit: ret=0x%x\n", retval);
+    save_v86_state(env);
+    env->regs[R_EAX] = retval;
+}
+
+static inline int set_IF(CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+
+    ts->v86flags |= VIF_MASK;
+    if (ts->v86flags & VIP_MASK) {
+        return_to_32bit(env, TARGET_VM86_STI);
+        return 1;
+    }
+    return 0;
+}
+
+static inline void clear_IF(CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+
+    ts->v86flags &= ~VIF_MASK;
+}
+
+static inline void clear_TF(CPUX86State *env)
+{
+    env->eflags &= ~TF_MASK;
+}
+
+static inline void clear_AC(CPUX86State *env)
+{
+    env->eflags &= ~AC_MASK;
+}
+
+static inline int set_vflags_long(unsigned long eflags, CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+
+    set_flags(ts->v86flags, eflags, ts->v86mask);
+    set_flags(env->eflags, eflags, SAFE_MASK);
+    if (eflags & IF_MASK)
+        return set_IF(env);
+    else
+        clear_IF(env);
+    return 0;
+}
+
+static inline int set_vflags_short(unsigned short flags, CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+
+    set_flags(ts->v86flags, flags, ts->v86mask & 0xffff);
+    set_flags(env->eflags, flags, SAFE_MASK);
+    if (flags & IF_MASK)
+        return set_IF(env);
+    else
+        clear_IF(env);
+    return 0;
+}
+
+static inline unsigned int get_vflags(CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+    unsigned int flags;
+
+    flags = env->eflags & RETURN_MASK;
+    if (ts->v86flags & VIF_MASK)
+        flags |= IF_MASK;
+    flags |= IOPL_MASK;
+    return flags | (ts->v86flags & ts->v86mask);
+}
+
+#define ADD16(reg, val) reg = (reg & ~0xffff) | ((reg + (val)) & 0xffff)
+
+/* handle VM86 interrupt (NOTE: the CPU core currently does not
+   support TSS interrupt revectoring, so this code is always executed) */
+static void do_int(CPUX86State *env, int intno)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+    uint32_t int_addr, segoffs, ssp;
+    unsigned int sp;
+
+    if (env->segs[R_CS].selector == TARGET_BIOSSEG)
+        goto cannot_handle;
+    if (is_revectored(intno, &ts->vm86plus.int_revectored))
+        goto cannot_handle;
+    if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
+                                       &ts->vm86plus.int21_revectored))
+        goto cannot_handle;
+    int_addr = (intno << 2);
+    segoffs = cpu_ldl_data(env, int_addr);
+    if ((segoffs >> 16) == TARGET_BIOSSEG)
+        goto cannot_handle;
+    LOG_VM86("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
+             intno, segoffs >> 16, segoffs & 0xffff);
+    /* save old state */
+    ssp = env->segs[R_SS].selector << 4;
+    sp = env->regs[R_ESP] & 0xffff;
+    vm_putw(env, ssp, sp - 2, get_vflags(env));
+    vm_putw(env, ssp, sp - 4, env->segs[R_CS].selector);
+    vm_putw(env, ssp, sp - 6, env->eip);
+    ADD16(env->regs[R_ESP], -6);
+    /* goto interrupt handler */
+    env->eip = segoffs & 0xffff;
+    cpu_x86_load_seg(env, R_CS, segoffs >> 16);
+    clear_TF(env);
+    clear_IF(env);
+    clear_AC(env);
+    return;
+ cannot_handle:
+    LOG_VM86("VM86: return to 32 bits int 0x%x\n", intno);
+    return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
+}
+
+void handle_vm86_trap(CPUX86State *env, int trapno)
+{
+    if (trapno == 1 || trapno == 3) {
+        return_to_32bit(env, TARGET_VM86_TRAP + (trapno << 8));
+    } else {
+        do_int(env, trapno);
+    }
+}
+
+#define CHECK_IF_IN_TRAP() \
+      if ((ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) && \
+          (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_TFpendig)) \
+		newflags |= TF_MASK
+
+#define VM86_FAULT_RETURN \
+        if ((ts->vm86plus.vm86plus.flags & TARGET_force_return_for_pic) && \
+            (ts->v86flags & (IF_MASK | VIF_MASK))) \
+            return_to_32bit(env, TARGET_VM86_PICRETURN); \
+        return
+
+void handle_vm86_fault(CPUX86State *env)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+    uint32_t csp, ssp;
+    unsigned int ip, sp, newflags, newip, newcs, opcode, intno;
+    int data32, pref_done;
+
+    csp = env->segs[R_CS].selector << 4;
+    ip = env->eip & 0xffff;
+
+    ssp = env->segs[R_SS].selector << 4;
+    sp = env->regs[R_ESP] & 0xffff;
+
+    LOG_VM86("VM86 exception %04x:%08x\n",
+             env->segs[R_CS].selector, env->eip);
+
+    data32 = 0;
+    pref_done = 0;
+    do {
+        opcode = vm_getb(env, csp, ip);
+        ADD16(ip, 1);
+        switch (opcode) {
+        case 0x66:      /* 32-bit data */     data32=1; break;
+        case 0x67:      /* 32-bit address */  break;
+        case 0x2e:      /* CS */              break;
+        case 0x3e:      /* DS */              break;
+        case 0x26:      /* ES */              break;
+        case 0x36:      /* SS */              break;
+        case 0x65:      /* GS */              break;
+        case 0x64:      /* FS */              break;
+        case 0xf2:      /* repnz */	      break;
+        case 0xf3:      /* rep */             break;
+        default: pref_done = 1;
+        }
+    } while (!pref_done);
+
+    /* VM86 mode */
+    switch(opcode) {
+    case 0x9c: /* pushf */
+        if (data32) {
+            vm_putl(env, ssp, sp - 4, get_vflags(env));
+            ADD16(env->regs[R_ESP], -4);
+        } else {
+            vm_putw(env, ssp, sp - 2, get_vflags(env));
+            ADD16(env->regs[R_ESP], -2);
+        }
+        env->eip = ip;
+        VM86_FAULT_RETURN;
+
+    case 0x9d: /* popf */
+        if (data32) {
+            newflags = vm_getl(env, ssp, sp);
+            ADD16(env->regs[R_ESP], 4);
+        } else {
+            newflags = vm_getw(env, ssp, sp);
+            ADD16(env->regs[R_ESP], 2);
+        }
+        env->eip = ip;
+        CHECK_IF_IN_TRAP();
+        if (data32) {
+            if (set_vflags_long(newflags, env))
+                return;
+        } else {
+            if (set_vflags_short(newflags, env))
+                return;
+        }
+        VM86_FAULT_RETURN;
+
+    case 0xcd: /* int */
+        intno = vm_getb(env, csp, ip);
+        ADD16(ip, 1);
+        env->eip = ip;
+        if (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) {
+            if ( (ts->vm86plus.vm86plus.vm86dbg_intxxtab[intno >> 3] >>
+                  (intno &7)) & 1) {
+                return_to_32bit(env, TARGET_VM86_INTx + (intno << 8));
+                return;
+            }
+        }
+        do_int(env, intno);
+        break;
+
+    case 0xcf: /* iret */
+        if (data32) {
+            newip = vm_getl(env, ssp, sp) & 0xffff;
+            newcs = vm_getl(env, ssp, sp + 4) & 0xffff;
+            newflags = vm_getl(env, ssp, sp + 8);
+            ADD16(env->regs[R_ESP], 12);
+        } else {
+            newip = vm_getw(env, ssp, sp);
+            newcs = vm_getw(env, ssp, sp + 2);
+            newflags = vm_getw(env, ssp, sp + 4);
+            ADD16(env->regs[R_ESP], 6);
+        }
+        env->eip = newip;
+        cpu_x86_load_seg(env, R_CS, newcs);
+        CHECK_IF_IN_TRAP();
+        if (data32) {
+            if (set_vflags_long(newflags, env))
+                return;
+        } else {
+            if (set_vflags_short(newflags, env))
+                return;
+        }
+        VM86_FAULT_RETURN;
+
+    case 0xfa: /* cli */
+        env->eip = ip;
+        clear_IF(env);
+        VM86_FAULT_RETURN;
+
+    case 0xfb: /* sti */
+        env->eip = ip;
+        if (set_IF(env))
+            return;
+        VM86_FAULT_RETURN;
+
+    default:
+        /* real VM86 GPF exception */
+        return_to_32bit(env, TARGET_VM86_UNKNOWN);
+        break;
+    }
+}
+
+int do_vm86(CPUX86State *env, long subfunction, abi_ulong vm86_addr)
+{
+    CPUState *cs = CPU(x86_env_get_cpu(env));
+    TaskState *ts = cs->opaque;
+    struct target_vm86plus_struct * target_v86;
+    int ret;
+
+    switch (subfunction) {
+    case TARGET_VM86_REQUEST_IRQ:
+    case TARGET_VM86_FREE_IRQ:
+    case TARGET_VM86_GET_IRQ_BITS:
+    case TARGET_VM86_GET_AND_RESET_IRQ:
+        gemu_log("qemu: unsupported vm86 subfunction (%ld)\n", subfunction);
+        ret = -TARGET_EINVAL;
+        goto out;
+    case TARGET_VM86_PLUS_INSTALL_CHECK:
+        /* NOTE: on old vm86 stuff this will return the error
+           from verify_area(), because the subfunction is
+           interpreted as (invalid) address to vm86_struct.
+           So the installation check works.
+            */
+        ret = 0;
+        goto out;
+    }
+
+    /* save current CPU regs */
+    ts->vm86_saved_regs.eax = 0; /* default vm86 syscall return code */
+    ts->vm86_saved_regs.ebx = env->regs[R_EBX];
+    ts->vm86_saved_regs.ecx = env->regs[R_ECX];
+    ts->vm86_saved_regs.edx = env->regs[R_EDX];
+    ts->vm86_saved_regs.esi = env->regs[R_ESI];
+    ts->vm86_saved_regs.edi = env->regs[R_EDI];
+    ts->vm86_saved_regs.ebp = env->regs[R_EBP];
+    ts->vm86_saved_regs.esp = env->regs[R_ESP];
+    ts->vm86_saved_regs.eflags = env->eflags;
+    ts->vm86_saved_regs.eip  = env->eip;
+    ts->vm86_saved_regs.cs = env->segs[R_CS].selector;
+    ts->vm86_saved_regs.ss = env->segs[R_SS].selector;
+    ts->vm86_saved_regs.ds = env->segs[R_DS].selector;
+    ts->vm86_saved_regs.es = env->segs[R_ES].selector;
+    ts->vm86_saved_regs.fs = env->segs[R_FS].selector;
+    ts->vm86_saved_regs.gs = env->segs[R_GS].selector;
+
+    ts->target_v86 = vm86_addr;
+    if (!lock_user_struct(VERIFY_READ, target_v86, vm86_addr, 1))
+        return -TARGET_EFAULT;
+    /* build vm86 CPU state */
+    ts->v86flags = tswap32(target_v86->regs.eflags);
+    env->eflags = (env->eflags & ~SAFE_MASK) |
+        (tswap32(target_v86->regs.eflags) & SAFE_MASK) | VM_MASK;
+
+    ts->vm86plus.cpu_type = tswapal(target_v86->cpu_type);
+    switch (ts->vm86plus.cpu_type) {
+    case TARGET_CPU_286:
+        ts->v86mask = 0;
+        break;
+    case TARGET_CPU_386:
+        ts->v86mask = NT_MASK | IOPL_MASK;
+        break;
+    case TARGET_CPU_486:
+        ts->v86mask = AC_MASK | NT_MASK | IOPL_MASK;
+        break;
+    default:
+        ts->v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
+        break;
+    }
+
+    env->regs[R_EBX] = tswap32(target_v86->regs.ebx);
+    env->regs[R_ECX] = tswap32(target_v86->regs.ecx);
+    env->regs[R_EDX] = tswap32(target_v86->regs.edx);
+    env->regs[R_ESI] = tswap32(target_v86->regs.esi);
+    env->regs[R_EDI] = tswap32(target_v86->regs.edi);
+    env->regs[R_EBP] = tswap32(target_v86->regs.ebp);
+    env->regs[R_ESP] = tswap32(target_v86->regs.esp);
+    env->eip = tswap32(target_v86->regs.eip);
+    cpu_x86_load_seg(env, R_CS, tswap16(target_v86->regs.cs));
+    cpu_x86_load_seg(env, R_SS, tswap16(target_v86->regs.ss));
+    cpu_x86_load_seg(env, R_DS, tswap16(target_v86->regs.ds));
+    cpu_x86_load_seg(env, R_ES, tswap16(target_v86->regs.es));
+    cpu_x86_load_seg(env, R_FS, tswap16(target_v86->regs.fs));
+    cpu_x86_load_seg(env, R_GS, tswap16(target_v86->regs.gs));
+    ret = tswap32(target_v86->regs.eax); /* eax will be restored at
+                                            the end of the syscall */
+    memcpy(&ts->vm86plus.int_revectored,
+           &target_v86->int_revectored, 32);
+    memcpy(&ts->vm86plus.int21_revectored,
+           &target_v86->int21_revectored, 32);
+    ts->vm86plus.vm86plus.flags = tswapal(target_v86->vm86plus.flags);
+    memcpy(&ts->vm86plus.vm86plus.vm86dbg_intxxtab,
+           target_v86->vm86plus.vm86dbg_intxxtab, 32);
+    unlock_user_struct(target_v86, vm86_addr, 0);
+
+    LOG_VM86("do_vm86: cs:ip=%04x:%04x\n",
+             env->segs[R_CS].selector, env->eip);
+    /* now the virtual CPU is ready for vm86 execution ! */
+ out:
+    return ret;
+}