?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Fix typo in comment, by Andreas Faerber.
[qemu/dscho.git] / linux-user / vm86.c
blobb28eea60d49d47dcd98368aa68859b592a3f7e0c
1 /*
2 * vm86 linux syscall support
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20 #include <stdlib.h>
21 #include <stdio.h>
22 #include <stdarg.h>
23 #include <string.h>
24 #include <errno.h>
25 #include <unistd.h>
26
27 #include "qemu.h"
28
29 //#define DEBUG_VM86
30
31 #define set_flags(X,new,mask) \
32 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
33
34 #define SAFE_MASK (0xDD5)
35 #define RETURN_MASK (0xDFF)
36
37 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
38 {
39 return (((uint8_t *)bitmap)[nr >> 3] >> (nr & 7)) & 1;
40 }
41
42 static inline void vm_putw(uint8_t *segptr, unsigned int reg16, unsigned int val)
43 {
44 stw(segptr + (reg16 & 0xffff), val);
45 }
46
47 static inline void vm_putl(uint8_t *segptr, unsigned int reg16, unsigned int val)
48 {
49 stl(segptr + (reg16 & 0xffff), val);
50 }
51
52 static inline unsigned int vm_getw(uint8_t *segptr, unsigned int reg16)
53 {
54 return lduw(segptr + (reg16 & 0xffff));
55 }
56
57 static inline unsigned int vm_getl(uint8_t *segptr, unsigned int reg16)
58 {
59 return ldl(segptr + (reg16 & 0xffff));
60 }
61
62 void save_v86_state(CPUX86State *env)
63 {
64 TaskState *ts = env->opaque;
65 struct target_vm86plus_struct * target_v86;
66
67 lock_user_struct(target_v86, ts->target_v86, 0);
68 /* put the VM86 registers in the userspace register structure */
69 target_v86->regs.eax = tswap32(env->regs[R_EAX]);
70 target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
71 target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
72 target_v86->regs.edx = tswap32(env->regs[R_EDX]);
73 target_v86->regs.esi = tswap32(env->regs[R_ESI]);
74 target_v86->regs.edi = tswap32(env->regs[R_EDI]);
75 target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
76 target_v86->regs.esp = tswap32(env->regs[R_ESP]);
77 target_v86->regs.eip = tswap32(env->eip);
78 target_v86->regs.cs = tswap16(env->segs[R_CS].selector);
79 target_v86->regs.ss = tswap16(env->segs[R_SS].selector);
80 target_v86->regs.ds = tswap16(env->segs[R_DS].selector);
81 target_v86->regs.es = tswap16(env->segs[R_ES].selector);
82 target_v86->regs.fs = tswap16(env->segs[R_FS].selector);
83 target_v86->regs.gs = tswap16(env->segs[R_GS].selector);
84 set_flags(env->eflags, ts->v86flags, VIF_MASK | ts->v86mask);
85 target_v86->regs.eflags = tswap32(env->eflags);
86 unlock_user_struct(target_v86, ts->target_v86, 1);
87 #ifdef DEBUG_VM86
88 fprintf(logfile, "save_v86_state: eflags=%08x cs:ip=%04x:%04x\n",
89 env->eflags, env->segs[R_CS].selector, env->eip);
90 #endif
91
92 /* restore 32 bit registers */
93 env->regs[R_EAX] = ts->vm86_saved_regs.eax;
94 env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
95 env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
96 env->regs[R_EDX] = ts->vm86_saved_regs.edx;
97 env->regs[R_ESI] = ts->vm86_saved_regs.esi;
98 env->regs[R_EDI] = ts->vm86_saved_regs.edi;
99 env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
100 env->regs[R_ESP] = ts->vm86_saved_regs.esp;
101 env->eflags = ts->vm86_saved_regs.eflags;
102 env->eip = ts->vm86_saved_regs.eip;
103
104 cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
105 cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
106 cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
107 cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
108 cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
109 cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
110 }
111
112 /* return from vm86 mode to 32 bit. The vm86() syscall will return
113 'retval' */
114 static inline void return_to_32bit(CPUX86State *env, int retval)
115 {
116 #ifdef DEBUG_VM86
117 fprintf(logfile, "return_to_32bit: ret=0x%x\n", retval);
118 #endif
119 save_v86_state(env);
120 env->regs[R_EAX] = retval;
121 }
122
123 static inline int set_IF(CPUX86State *env)
124 {
125 TaskState *ts = env->opaque;
126
127 ts->v86flags |= VIF_MASK;
128 if (ts->v86flags & VIP_MASK) {
129 return_to_32bit(env, TARGET_VM86_STI);
130 return 1;
131 }
132 return 0;
133 }
134
135 static inline void clear_IF(CPUX86State *env)
136 {
137 TaskState *ts = env->opaque;
138
139 ts->v86flags &= ~VIF_MASK;
140 }
141
142 static inline void clear_TF(CPUX86State *env)
143 {
144 env->eflags &= ~TF_MASK;
145 }
146
147 static inline void clear_AC(CPUX86State *env)
148 {
149 env->eflags &= ~AC_MASK;
150 }
151
152 static inline int set_vflags_long(unsigned long eflags, CPUX86State *env)
153 {
154 TaskState *ts = env->opaque;
155
156 set_flags(ts->v86flags, eflags, ts->v86mask);
157 set_flags(env->eflags, eflags, SAFE_MASK);
158 if (eflags & IF_MASK)
159 return set_IF(env);
160 else
161 clear_IF(env);
162 return 0;
163 }
164
165 static inline int set_vflags_short(unsigned short flags, CPUX86State *env)
166 {
167 TaskState *ts = env->opaque;
168
169 set_flags(ts->v86flags, flags, ts->v86mask & 0xffff);
170 set_flags(env->eflags, flags, SAFE_MASK);
171 if (flags & IF_MASK)
172 return set_IF(env);
173 else
174 clear_IF(env);
175 return 0;
176 }
177
178 static inline unsigned int get_vflags(CPUX86State *env)
179 {
180 TaskState *ts = env->opaque;
181 unsigned int flags;
182
183 flags = env->eflags & RETURN_MASK;
184 if (ts->v86flags & VIF_MASK)
185 flags |= IF_MASK;
186 flags |= IOPL_MASK;
187 return flags | (ts->v86flags & ts->v86mask);
188 }
189
190 #define ADD16(reg, val) reg = (reg & ~0xffff) | ((reg + (val)) & 0xffff)
191
192 /* handle VM86 interrupt (NOTE: the CPU core currently does not
193 support TSS interrupt revectoring, so this code is always executed) */
194 static void do_int(CPUX86State *env, int intno)
195 {
196 TaskState *ts = env->opaque;
197 uint32_t *int_ptr, segoffs;
198 uint8_t *ssp;
199 unsigned int sp;
200
201 if (env->segs[R_CS].selector == TARGET_BIOSSEG)
202 goto cannot_handle;
203 if (is_revectored(intno, &ts->vm86plus.int_revectored))
204 goto cannot_handle;
205 if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
206 &ts->vm86plus.int21_revectored))
207 goto cannot_handle;
208 int_ptr = (uint32_t *)(intno << 2);
209 segoffs = tswap32(*int_ptr);
210 if ((segoffs >> 16) == TARGET_BIOSSEG)
211 goto cannot_handle;
212 #if defined(DEBUG_VM86)
213 fprintf(logfile, "VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
214 intno, segoffs >> 16, segoffs & 0xffff);
215 #endif
216 /* save old state */
217 ssp = (uint8_t *)(env->segs[R_SS].selector << 4);
218 sp = env->regs[R_ESP] & 0xffff;
219 vm_putw(ssp, sp - 2, get_vflags(env));
220 vm_putw(ssp, sp - 4, env->segs[R_CS].selector);
221 vm_putw(ssp, sp - 6, env->eip);
222 ADD16(env->regs[R_ESP], -6);
223 /* goto interrupt handler */
224 env->eip = segoffs & 0xffff;
225 cpu_x86_load_seg(env, R_CS, segoffs >> 16);
226 clear_TF(env);
227 clear_IF(env);
228 clear_AC(env);
229 return;
230 cannot_handle:
231 #if defined(DEBUG_VM86)
232 fprintf(logfile, "VM86: return to 32 bits int 0x%x\n", intno);
233 #endif
234 return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
235 }
236
237 void handle_vm86_trap(CPUX86State *env, int trapno)
238 {
239 if (trapno == 1 || trapno == 3) {
240 return_to_32bit(env, TARGET_VM86_TRAP + (trapno << 8));
241 } else {
242 do_int(env, trapno);
243 }
244 }
245
246 #define CHECK_IF_IN_TRAP() \
247 if ((ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) && \
248 (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_TFpendig)) \
249 newflags |= TF_MASK
250
251 #define VM86_FAULT_RETURN \
252 if ((ts->vm86plus.vm86plus.flags & TARGET_force_return_for_pic) && \
253 (ts->v86flags & (IF_MASK | VIF_MASK))) \
254 return_to_32bit(env, TARGET_VM86_PICRETURN); \
255 return
256
257 void handle_vm86_fault(CPUX86State *env)
258 {
259 TaskState *ts = env->opaque;
260 uint8_t *csp, *pc, *ssp;
261 unsigned int ip, sp, newflags, newip, newcs, opcode, intno;
262 int data32, pref_done;
263
264 csp = (uint8_t *)(env->segs[R_CS].selector << 4);
265 ip = env->eip & 0xffff;
266 pc = csp + ip;
267
268 ssp = (uint8_t *)(env->segs[R_SS].selector << 4);
269 sp = env->regs[R_ESP] & 0xffff;
270
271 #if defined(DEBUG_VM86)
272 fprintf(logfile, "VM86 exception %04x:%08x %02x %02x\n",
273 env->segs[R_CS].selector, env->eip, pc[0], pc[1]);
274 #endif
275
276 data32 = 0;
277 pref_done = 0;
278 do {
279 opcode = csp[ip];
280 ADD16(ip, 1);
281 switch (opcode) {
282 case 0x66: /* 32-bit data */ data32=1; break;
283 case 0x67: /* 32-bit address */ break;
284 case 0x2e: /* CS */ break;
285 case 0x3e: /* DS */ break;
286 case 0x26: /* ES */ break;
287 case 0x36: /* SS */ break;
288 case 0x65: /* GS */ break;
289 case 0x64: /* FS */ break;
290 case 0xf2: /* repnz */ break;
291 case 0xf3: /* rep */ break;
292 default: pref_done = 1;
293 }
294 } while (!pref_done);
295
296 /* VM86 mode */
297 switch(opcode) {
298 case 0x9c: /* pushf */
299 if (data32) {
300 vm_putl(ssp, sp - 4, get_vflags(env));
301 ADD16(env->regs[R_ESP], -4);
302 } else {
303 vm_putw(ssp, sp - 2, get_vflags(env));
304 ADD16(env->regs[R_ESP], -2);
305 }
306 env->eip = ip;
307 VM86_FAULT_RETURN;
308
309 case 0x9d: /* popf */
310 if (data32) {
311 newflags = vm_getl(ssp, sp);
312 ADD16(env->regs[R_ESP], 4);
313 } else {
314 newflags = vm_getw(ssp, sp);
315 ADD16(env->regs[R_ESP], 2);
316 }
317 env->eip = ip;
318 CHECK_IF_IN_TRAP();
319 if (data32) {
320 if (set_vflags_long(newflags, env))
321 return;
322 } else {
323 if (set_vflags_short(newflags, env))
324 return;
325 }
326 VM86_FAULT_RETURN;
327
328 case 0xcd: /* int */
329 intno = csp[ip];
330 ADD16(ip, 1);
331 env->eip = ip;
332 if (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) {
333 if ( (ts->vm86plus.vm86plus.vm86dbg_intxxtab[intno >> 3] >>
334 (intno &7)) & 1) {
335 return_to_32bit(env, TARGET_VM86_INTx + (intno << 8));
336 return;
337 }
338 }
339 do_int(env, intno);
340 break;
341
342 case 0xcf: /* iret */
343 if (data32) {
344 newip = vm_getl(ssp, sp) & 0xffff;
345 newcs = vm_getl(ssp, sp + 4) & 0xffff;
346 newflags = vm_getl(ssp, sp + 8);
347 ADD16(env->regs[R_ESP], 12);
348 } else {
349 newip = vm_getw(ssp, sp);
350 newcs = vm_getw(ssp, sp + 2);
351 newflags = vm_getw(ssp, sp + 4);
352 ADD16(env->regs[R_ESP], 6);
353 }
354 env->eip = newip;
355 cpu_x86_load_seg(env, R_CS, newcs);
356 CHECK_IF_IN_TRAP();
357 if (data32) {
358 if (set_vflags_long(newflags, env))
359 return;
360 } else {
361 if (set_vflags_short(newflags, env))
362 return;
363 }
364 VM86_FAULT_RETURN;
365
366 case 0xfa: /* cli */
367 env->eip = ip;
368 clear_IF(env);
369 VM86_FAULT_RETURN;
370
371 case 0xfb: /* sti */
372 env->eip = ip;
373 if (set_IF(env))
374 return;
375 VM86_FAULT_RETURN;
376
377 default:
378 /* real VM86 GPF exception */
379 return_to_32bit(env, TARGET_VM86_UNKNOWN);
380 break;
381 }
382 }
383
384 int do_vm86(CPUX86State *env, long subfunction, target_ulong vm86_addr)
385 {
386 TaskState *ts = env->opaque;
387 struct target_vm86plus_struct * target_v86;
388 int ret;
389
390 switch (subfunction) {
391 case TARGET_VM86_REQUEST_IRQ:
392 case TARGET_VM86_FREE_IRQ:
393 case TARGET_VM86_GET_IRQ_BITS:
394 case TARGET_VM86_GET_AND_RESET_IRQ:
395 gemu_log("qemu: unsupported vm86 subfunction (%ld)\n", subfunction);
396 ret = -EINVAL;
397 goto out;
398 case TARGET_VM86_PLUS_INSTALL_CHECK:
399 /* NOTE: on old vm86 stuff this will return the error
400 from verify_area(), because the subfunction is
401 interpreted as (invalid) address to vm86_struct.
402 So the installation check works.
403 */
404 ret = 0;
405 goto out;
406 }
407
408 /* save current CPU regs */
409 ts->vm86_saved_regs.eax = 0; /* default vm86 syscall return code */
410 ts->vm86_saved_regs.ebx = env->regs[R_EBX];
411 ts->vm86_saved_regs.ecx = env->regs[R_ECX];
412 ts->vm86_saved_regs.edx = env->regs[R_EDX];
413 ts->vm86_saved_regs.esi = env->regs[R_ESI];
414 ts->vm86_saved_regs.edi = env->regs[R_EDI];
415 ts->vm86_saved_regs.ebp = env->regs[R_EBP];
416 ts->vm86_saved_regs.esp = env->regs[R_ESP];
417 ts->vm86_saved_regs.eflags = env->eflags;
418 ts->vm86_saved_regs.eip = env->eip;
419 ts->vm86_saved_regs.cs = env->segs[R_CS].selector;
420 ts->vm86_saved_regs.ss = env->segs[R_SS].selector;
421 ts->vm86_saved_regs.ds = env->segs[R_DS].selector;
422 ts->vm86_saved_regs.es = env->segs[R_ES].selector;
423 ts->vm86_saved_regs.fs = env->segs[R_FS].selector;
424 ts->vm86_saved_regs.gs = env->segs[R_GS].selector;
425
426 ts->target_v86 = vm86_addr;
427 lock_user_struct(target_v86, vm86_addr, 1);
428 /* build vm86 CPU state */
429 ts->v86flags = tswap32(target_v86->regs.eflags);
430 env->eflags = (env->eflags & ~SAFE_MASK) |
431 (tswap32(target_v86->regs.eflags) & SAFE_MASK) | VM_MASK;
432
433 ts->vm86plus.cpu_type = tswapl(target_v86->cpu_type);
434 switch (ts->vm86plus.cpu_type) {
435 case TARGET_CPU_286:
436 ts->v86mask = 0;
437 break;
438 case TARGET_CPU_386:
439 ts->v86mask = NT_MASK | IOPL_MASK;
440 break;
441 case TARGET_CPU_486:
442 ts->v86mask = AC_MASK | NT_MASK | IOPL_MASK;
443 break;
444 default:
445 ts->v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
446 break;
447 }
448
449 env->regs[R_EBX] = tswap32(target_v86->regs.ebx);
450 env->regs[R_ECX] = tswap32(target_v86->regs.ecx);
451 env->regs[R_EDX] = tswap32(target_v86->regs.edx);
452 env->regs[R_ESI] = tswap32(target_v86->regs.esi);
453 env->regs[R_EDI] = tswap32(target_v86->regs.edi);
454 env->regs[R_EBP] = tswap32(target_v86->regs.ebp);
455 env->regs[R_ESP] = tswap32(target_v86->regs.esp);
456 env->eip = tswap32(target_v86->regs.eip);
457 cpu_x86_load_seg(env, R_CS, tswap16(target_v86->regs.cs));
458 cpu_x86_load_seg(env, R_SS, tswap16(target_v86->regs.ss));
459 cpu_x86_load_seg(env, R_DS, tswap16(target_v86->regs.ds));
460 cpu_x86_load_seg(env, R_ES, tswap16(target_v86->regs.es));
461 cpu_x86_load_seg(env, R_FS, tswap16(target_v86->regs.fs));
462 cpu_x86_load_seg(env, R_GS, tswap16(target_v86->regs.gs));
463 ret = tswap32(target_v86->regs.eax); /* eax will be restored at
464 the end of the syscall */
465 memcpy(&ts->vm86plus.int_revectored,
466 &target_v86->int_revectored, 32);
467 memcpy(&ts->vm86plus.int21_revectored,
468 &target_v86->int21_revectored, 32);
469 ts->vm86plus.vm86plus.flags = tswapl(target_v86->vm86plus.flags);
470 memcpy(&ts->vm86plus.vm86plus.vm86dbg_intxxtab,
471 target_v86->vm86plus.vm86dbg_intxxtab, 32);
472 unlock_user_struct(target_v86, vm86_addr, 0);
473
474 #ifdef DEBUG_VM86
475 fprintf(logfile, "do_vm86: cs:ip=%04x:%04x\n",
476 env->segs[R_CS].selector, env->eip);
477 #endif
478 /* now the virtual CPU is ready for vm86 execution ! */
479 out:
480 return ret;
481 }
482
Random branches for QEmu