/* * 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(uint32_t segptr, unsigned int reg16, unsigned int val) { stw(segptr + (reg16 & 0xffff), val); } static inline void vm_putl(uint32_t segptr, unsigned int reg16, unsigned int val) { stl(segptr + (reg16 & 0xffff), val); } static inline unsigned int vm_getb(uint32_t segptr, unsigned int reg16) { return ldub(segptr + (reg16 & 0xffff)); } static inline unsigned int vm_getw(uint32_t segptr, unsigned int reg16) { return lduw(segptr + (reg16 & 0xffff)); } static inline unsigned int vm_getl(uint32_t segptr, unsigned int reg16) { return ldl(segptr + (reg16 & 0xffff)); } void save_v86_state(CPUX86State *env) { TaskState *ts = env->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) { TaskState *ts = env->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) { TaskState *ts = env->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) { TaskState *ts = env->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) { TaskState *ts = env->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) { TaskState *ts = env->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) { TaskState *ts = env->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 = ldl(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(ssp, sp - 2, get_vflags(env)); vm_putw(ssp, sp - 4, env->segs[R_CS].selector); vm_putw(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) { TaskState *ts = env->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(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(ssp, sp - 4, get_vflags(env)); ADD16(env->regs[R_ESP], -4); } else { vm_putw(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(ssp, sp); ADD16(env->regs[R_ESP], 4); } else { newflags = vm_getw(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(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(ssp, sp) & 0xffff; newcs = vm_getl(ssp, sp + 4) & 0xffff; newflags = vm_getl(ssp, sp + 8); ADD16(env->regs[R_ESP], 12); } else { newip = vm_getw(ssp, sp); newcs = vm_getw(ssp, sp + 2); newflags = vm_getw(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) { TaskState *ts = env->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 = tswapl(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 = tswapl(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; }