sys/platform/pc32/i386/vm86.c

   1 /*-
   2  * Copyright (c) 1997 Jonathan Lemon
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/i386/i386/vm86.c,v 1.31.2.2 2001/10/05 06:18:55 peter Exp $
  27  * $DragonFly: src/sys/platform/pc32/i386/vm86.c,v 1.6 2003/07/06 21:23:48 dillon Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/proc.h>
  33 #include <sys/lock.h>
  34 #include <sys/malloc.h>
  35
  36 #include <vm/vm.h>
  37 #include <vm/pmap.h>
  38 #include <vm/vm_map.h>
  39 #include <vm/vm_page.h>
  40
  41 #include <sys/user.h>
  42
  43 #include <machine/md_var.h>
  44 #include <machine/pcb_ext.h>    /* pcb.h included via sys/user.h */
  45 #include <machine/psl.h>
  46 #include <machine/specialreg.h>
  47 #include <machine/sysarch.h>
  48
  49 extern int i386_extend_pcb      __P((struct proc *));
  50 extern int vm86pa;
  51 extern struct pcb *vm86pcb;
  52
  53 extern int vm86_bioscall(struct vm86frame *);
  54 extern void vm86_biosret(struct vm86frame *);
  55
  56 void vm86_prepcall(struct vm86frame);
  57
  58 struct system_map {
  59         int             type;
  60         vm_offset_t     start;
  61         vm_offset_t     end;
  62 };
  63
  64 #define HLT     0xf4
  65 #define CLI     0xfa
  66 #define STI     0xfb
  67 #define PUSHF   0x9c
  68 #define POPF    0x9d
  69 #define INTn    0xcd
  70 #define IRET    0xcf
  71 #define CALLm   0xff
  72 #define OPERAND_SIZE_PREFIX     0x66
  73 #define ADDRESS_SIZE_PREFIX     0x67
  74 #define PUSH_MASK       ~(PSL_VM | PSL_RF | PSL_I)
  75 #define POP_MASK        ~(PSL_VIP | PSL_VIF | PSL_VM | PSL_RF | PSL_IOPL)
  76
  77 static __inline caddr_t
  78 MAKE_ADDR(u_short sel, u_short off)
  79 {
  80         return ((caddr_t)((sel << 4) + off));
  81 }
  82
  83 static __inline void
  84 GET_VEC(u_int vec, u_short *sel, u_short *off)
  85 {
  86         *sel = vec >> 16;
  87         *off = vec & 0xffff;
  88 }
  89
  90 static __inline u_int
  91 MAKE_VEC(u_short sel, u_short off)
  92 {
  93         return ((sel << 16) | off);
  94 }
  95
  96 static __inline void
  97 PUSH(u_short x, struct vm86frame *vmf)
  98 {
  99         vmf->vmf_sp -= 2;
 100         susword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp), x);
 101 }
 102
 103 static __inline void
 104 PUSHL(u_int x, struct vm86frame *vmf)
 105 {
 106         vmf->vmf_sp -= 4;
 107         suword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp), x);
 108 }
 109
 110 static __inline u_short
 111 POP(struct vm86frame *vmf)
 112 {
 113         u_short x = fusword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp));
 114
 115         vmf->vmf_sp += 2;
 116         return (x);
 117 }
 118
 119 static __inline u_int
 120 POPL(struct vm86frame *vmf)
 121 {
 122         u_int x = fuword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp));
 123
 124         vmf->vmf_sp += 4;
 125         return (x);
 126 }
 127
 128 int
 129 vm86_emulate(vmf)
 130         struct vm86frame *vmf;
 131 {
 132         struct vm86_kernel *vm86;
 133         caddr_t addr;
 134         u_char i_byte;
 135         u_int temp_flags;
 136         int inc_ip = 1;
 137         int retcode = 0;
 138
 139         /*
 140          * pcb_ext contains the address of the extension area, or zero if
 141          * the extension is not present.  (This check should not be needed,
 142          * as we can't enter vm86 mode until we set up an extension area)
 143          */
 144         if (curthread->td_pcb->pcb_ext == 0)
 145                 return (SIGBUS);
 146         vm86 = &curthread->td_pcb->pcb_ext->ext_vm86;
 147
 148         if (vmf->vmf_eflags & PSL_T)
 149                 retcode = SIGTRAP;
 150
 151         addr = MAKE_ADDR(vmf->vmf_cs, vmf->vmf_ip);
 152         i_byte = fubyte(addr);
 153         if (i_byte == ADDRESS_SIZE_PREFIX) {
 154                 i_byte = fubyte(++addr);
 155                 inc_ip++;
 156         }
 157
 158         if (vm86->vm86_has_vme) {
 159                 switch (i_byte) {
 160                 case OPERAND_SIZE_PREFIX:
 161                         i_byte = fubyte(++addr);
 162                         inc_ip++;
 163                         switch (i_byte) {
 164                         case PUSHF:
 165                                 if (vmf->vmf_eflags & PSL_VIF)
 166                                         PUSHL((vmf->vmf_eflags & PUSH_MASK)
 167                                             | PSL_IOPL | PSL_I, vmf);
 168                                 else
 169                                         PUSHL((vmf->vmf_eflags & PUSH_MASK)
 170                                             | PSL_IOPL, vmf);
 171                                 vmf->vmf_ip += inc_ip;
 172                                 return (0);
 173
 174                         case POPF:
 175                                 temp_flags = POPL(vmf) & POP_MASK;
 176                                 vmf->vmf_eflags = (vmf->vmf_eflags & ~POP_MASK)
 177                                     | temp_flags | PSL_VM | PSL_I;
 178                                 vmf->vmf_ip += inc_ip;
 179                                 if (temp_flags & PSL_I) {
 180                                         vmf->vmf_eflags |= PSL_VIF;
 181                                         if (vmf->vmf_eflags & PSL_VIP)
 182                                                 break;
 183                                 } else {
 184                                         vmf->vmf_eflags &= ~PSL_VIF;
 185                                 }
 186                                 return (0);
 187                         }
 188                         break;
 189
 190                 /* VME faults here if VIP is set, but does not set VIF. */
 191                 case STI:
 192                         vmf->vmf_eflags |= PSL_VIF;
 193                         vmf->vmf_ip += inc_ip;
 194                         if ((vmf->vmf_eflags & PSL_VIP) == 0) {
 195                                 uprintf("fatal sti\n");
 196                                 return (SIGKILL);
 197                         }
 198                         break;
 199
 200                 /* VME if no redirection support */
 201                 case INTn:
 202                         break;
 203
 204                 /* VME if trying to set PSL_TF, or PSL_I when VIP is set */
 205                 case POPF:
 206                         temp_flags = POP(vmf) & POP_MASK;
 207                         vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
 208                             | temp_flags | PSL_VM | PSL_I;
 209                         vmf->vmf_ip += inc_ip;
 210                         if (temp_flags & PSL_I) {
 211                                 vmf->vmf_eflags |= PSL_VIF;
 212                                 if (vmf->vmf_eflags & PSL_VIP)
 213                                         break;
 214                         } else {
 215                                 vmf->vmf_eflags &= ~PSL_VIF;
 216                         }
 217                         return (retcode);
 218
 219                 /* VME if trying to set PSL_TF, or PSL_I when VIP is set */
 220                 case IRET:
 221                         vmf->vmf_ip = POP(vmf);
 222                         vmf->vmf_cs = POP(vmf);
 223                         temp_flags = POP(vmf) & POP_MASK;
 224                         vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
 225                             | temp_flags | PSL_VM | PSL_I;
 226                         if (temp_flags & PSL_I) {
 227                                 vmf->vmf_eflags |= PSL_VIF;
 228                                 if (vmf->vmf_eflags & PSL_VIP)
 229                                         break;
 230                         } else {
 231                                 vmf->vmf_eflags &= ~PSL_VIF;
 232                         }
 233                         return (retcode);
 234
 235                 }
 236                 return (SIGBUS);
 237         }
 238
 239         switch (i_byte) {
 240         case OPERAND_SIZE_PREFIX:
 241                 i_byte = fubyte(++addr);
 242                 inc_ip++;
 243                 switch (i_byte) {
 244                 case PUSHF:
 245                         if (vm86->vm86_eflags & PSL_VIF)
 246                                 PUSHL((vmf->vmf_flags & PUSH_MASK)
 247                                     | PSL_IOPL | PSL_I, vmf);
 248                         else
 249                                 PUSHL((vmf->vmf_flags & PUSH_MASK)
 250                                     | PSL_IOPL, vmf);
 251                         vmf->vmf_ip += inc_ip;
 252                         return (retcode);
 253
 254                 case POPF:
 255                         temp_flags = POPL(vmf) & POP_MASK;
 256                         vmf->vmf_eflags = (vmf->vmf_eflags & ~POP_MASK)
 257                             | temp_flags | PSL_VM | PSL_I;
 258                         vmf->vmf_ip += inc_ip;
 259                         if (temp_flags & PSL_I) {
 260                                 vm86->vm86_eflags |= PSL_VIF;
 261                                 if (vm86->vm86_eflags & PSL_VIP)
 262                                         break;
 263                         } else {
 264                                 vm86->vm86_eflags &= ~PSL_VIF;
 265                         }
 266                         return (retcode);
 267                 }
 268                 return (SIGBUS);
 269
 270         case CLI:
 271                 vm86->vm86_eflags &= ~PSL_VIF;
 272                 vmf->vmf_ip += inc_ip;
 273                 return (retcode);
 274
 275         case STI:
 276                 /* if there is a pending interrupt, go to the emulator */
 277                 vm86->vm86_eflags |= PSL_VIF;
 278                 vmf->vmf_ip += inc_ip;
 279                 if (vm86->vm86_eflags & PSL_VIP)
 280                         break;
 281                 return (retcode);
 282
 283         case PUSHF:
 284                 if (vm86->vm86_eflags & PSL_VIF)
 285                         PUSH((vmf->vmf_flags & PUSH_MASK)
 286                             | PSL_IOPL | PSL_I, vmf);
 287                 else
 288                         PUSH((vmf->vmf_flags & PUSH_MASK) | PSL_IOPL, vmf);
 289                 vmf->vmf_ip += inc_ip;
 290                 return (retcode);
 291
 292         case INTn:
 293                 i_byte = fubyte(addr + 1);
 294                 if ((vm86->vm86_intmap[i_byte >> 3] & (1 << (i_byte & 7))) != 0)
 295                         break;
 296                 if (vm86->vm86_eflags & PSL_VIF)
 297                         PUSH((vmf->vmf_flags & PUSH_MASK)
 298                             | PSL_IOPL | PSL_I, vmf);
 299                 else
 300                         PUSH((vmf->vmf_flags & PUSH_MASK) | PSL_IOPL, vmf);
 301                 PUSH(vmf->vmf_cs, vmf);
 302                 PUSH(vmf->vmf_ip + inc_ip + 1, vmf);    /* increment IP */
 303                 GET_VEC(fuword((caddr_t)(i_byte * 4)),
 304                      &vmf->vmf_cs, &vmf->vmf_ip);
 305                 vmf->vmf_flags &= ~PSL_T;
 306                 vm86->vm86_eflags &= ~PSL_VIF;
 307                 return (retcode);
 308
 309         case IRET:
 310                 vmf->vmf_ip = POP(vmf);
 311                 vmf->vmf_cs = POP(vmf);
 312                 temp_flags = POP(vmf) & POP_MASK;
 313                 vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
 314                     | temp_flags | PSL_VM | PSL_I;
 315                 if (temp_flags & PSL_I) {
 316                         vm86->vm86_eflags |= PSL_VIF;
 317                         if (vm86->vm86_eflags & PSL_VIP)
 318                                 break;
 319                 } else {
 320                         vm86->vm86_eflags &= ~PSL_VIF;
 321                 }
 322                 return (retcode);
 323
 324         case POPF:
 325                 temp_flags = POP(vmf) & POP_MASK;
 326                 vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
 327                     | temp_flags | PSL_VM | PSL_I;
 328                 vmf->vmf_ip += inc_ip;
 329                 if (temp_flags & PSL_I) {
 330                         vm86->vm86_eflags |= PSL_VIF;
 331                         if (vm86->vm86_eflags & PSL_VIP)
 332                                 break;
 333                 } else {
 334                         vm86->vm86_eflags &= ~PSL_VIF;
 335                 }
 336                 return (retcode);
 337         }
 338         return (SIGBUS);
 339 }
 340
 341 #define PGTABLE_SIZE    ((1024 + 64) * 1024 / PAGE_SIZE)
 342 #define INTMAP_SIZE     32
 343 #define IOMAP_SIZE      ctob(IOPAGES)
 344 #define TSS_SIZE \
 345         (sizeof(struct pcb_ext) - sizeof(struct segment_descriptor) + \
 346          INTMAP_SIZE + IOMAP_SIZE + 1)
 347
 348 struct vm86_layout {
 349         pt_entry_t      vml_pgtbl[PGTABLE_SIZE];
 350         struct  pcb vml_pcb;
 351         struct  pcb_ext vml_ext;
 352         char    vml_intmap[INTMAP_SIZE];
 353         char    vml_iomap[IOMAP_SIZE];
 354         char    vml_iomap_trailer;
 355 };
 356
 357 void
 358 vm86_initialize(void)
 359 {
 360         int i;
 361         u_int *addr;
 362         struct vm86_layout *vml = (struct vm86_layout *)vm86paddr;
 363         struct pcb *pcb;
 364         struct pcb_ext *ext;
 365         struct soft_segment_descriptor ssd = {
 366                 0,                      /* segment base address (overwritten) */
 367                 0,                      /* length (overwritten) */
 368                 SDT_SYS386TSS,          /* segment type */
 369                 0,                      /* priority level */
 370                 1,                      /* descriptor present */
 371                 0, 0,
 372                 0,                      /* default 16 size */
 373                 0                       /* granularity */
 374         };
 375
 376         /*
 377          * this should be a compile time error, but cpp doesn't grok sizeof().
 378          */
 379         if (sizeof(struct vm86_layout) > ctob(3))
 380                 panic("struct vm86_layout exceeds space allocated in locore.s");
 381
 382         /*
 383          * Below is the memory layout that we use for the vm86 region.
 384          *
 385          * +--------+
 386          * |        |
 387          * |        |
 388          * | page 0 |
 389          * |        | +--------+
 390          * |        | | stack  |
 391          * +--------+ +--------+ <--------- vm86paddr
 392          * |        | |Page Tbl| 1M + 64K = 272 entries = 1088 bytes
 393          * |        | +--------+
 394          * |        | |  PCB   | size: ~240 bytes
 395          * | page 1 | |PCB Ext | size: ~140 bytes (includes TSS)
 396          * |        | +--------+
 397          * |        | |int map |
 398          * |        | +--------+
 399          * +--------+ |        |
 400          * | page 2 | |  I/O   |
 401          * +--------+ | bitmap |
 402          * | page 3 | |        |
 403          * |        | +--------+
 404          * +--------+
 405          */
 406
 407         /*
 408          * A rudimentary PCB must be installed, in order to get to the
 409          * PCB extension area.  We use the PCB area as a scratchpad for
 410          * data storage, the layout of which is shown below.
 411          *
 412          * pcb_esi      = new PTD entry 0
 413          * pcb_ebp      = pointer to frame on vm86 stack
 414          * pcb_esp      =    stack frame pointer at time of switch
 415          * pcb_ebx      = va of vm86 page table
 416          * pcb_eip      =    argument pointer to initial call
 417          * pcb_spare[0] =    saved TSS descriptor, word 0
 418          * pcb_space[1] =    saved TSS descriptor, word 1
 419          */
 420 #define new_ptd         pcb_esi
 421 #define vm86_frame      pcb_ebp
 422 #define pgtable_va      pcb_ebx
 423
 424         pcb = &vml->vml_pcb;
 425         ext = &vml->vml_ext;
 426
 427         bzero(pcb, sizeof(struct pcb));
 428         pcb->new_ptd = vm86pa | PG_V | PG_RW | PG_U;
 429         pcb->vm86_frame = vm86paddr - sizeof(struct vm86frame);
 430         pcb->pgtable_va = vm86paddr;
 431         pcb->pcb_ext = ext;
 432
 433         bzero(ext, sizeof(struct pcb_ext));
 434         ext->ext_tss.tss_esp0 = vm86paddr;
 435         ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
 436         ext->ext_tss.tss_ioopt =
 437                 ((u_int)vml->vml_iomap - (u_int)&ext->ext_tss) << 16;
 438         ext->ext_iomap = vml->vml_iomap;
 439         ext->ext_vm86.vm86_intmap = vml->vml_intmap;
 440
 441         if (cpu_feature & CPUID_VME)
 442                 ext->ext_vm86.vm86_has_vme = (rcr4() & CR4_VME ? 1 : 0);
 443
 444         addr = (u_int *)ext->ext_vm86.vm86_intmap;
 445         for (i = 0; i < (INTMAP_SIZE + IOMAP_SIZE) / sizeof(u_int); i++)
 446                 *addr++ = 0;
 447         vml->vml_iomap_trailer = 0xff;
 448
 449         ssd.ssd_base = (u_int)&ext->ext_tss;
 450         ssd.ssd_limit = TSS_SIZE - 1;
 451         ssdtosd(&ssd, &ext->ext_tssd);
 452
 453         vm86pcb = pcb;
 454
 455 #if 0
 456         /*
 457          * use whatever is leftover of the vm86 page layout as a
 458          * message buffer so we can capture early output.
 459          */
 460         msgbufinit((vm_offset_t)vm86paddr + sizeof(struct vm86_layout),
 461             ctob(3) - sizeof(struct vm86_layout));
 462 #endif
 463 }
 464
 465 vm_offset_t
 466 vm86_getpage(struct vm86context *vmc, int pagenum)
 467 {
 468         int i;
 469
 470         for (i = 0; i < vmc->npages; i++)
 471                 if (vmc->pmap[i].pte_num == pagenum)
 472                         return (vmc->pmap[i].kva);
 473         return (0);
 474 }
 475
 476 vm_offset_t
 477 vm86_addpage(struct vm86context *vmc, int pagenum, vm_offset_t kva)
 478 {
 479         int i, flags = 0;
 480
 481         for (i = 0; i < vmc->npages; i++)
 482                 if (vmc->pmap[i].pte_num == pagenum)
 483                         goto bad;
 484
 485         if (vmc->npages == VM86_PMAPSIZE)
 486                 goto bad;                       /* XXX grow map? */
 487
 488         if (kva == 0) {
 489                 kva = (vm_offset_t)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
 490                 flags = VMAP_MALLOC;
 491         }
 492
 493         i = vmc->npages++;
 494         vmc->pmap[i].flags = flags;
 495         vmc->pmap[i].kva = kva;
 496         vmc->pmap[i].pte_num = pagenum;
 497         return (kva);
 498 bad:
 499         panic("vm86_addpage: not enough room, or overlap");
 500 }
 501
 502 static void
 503 vm86_initflags(struct vm86frame *vmf)
 504 {
 505         int eflags = vmf->vmf_eflags;
 506         struct vm86_kernel *vm86 = &curthread->td_pcb->pcb_ext->ext_vm86;
 507
 508         if (vm86->vm86_has_vme) {
 509                 eflags = (vmf->vmf_eflags & ~VME_USERCHANGE) |
 510                     (eflags & VME_USERCHANGE) | PSL_VM;
 511         } else {
 512                 vm86->vm86_eflags = eflags;     /* save VIF, VIP */
 513                 eflags = (vmf->vmf_eflags & ~VM_USERCHANGE) |
 514                     (eflags & VM_USERCHANGE) | PSL_VM;
 515         }
 516         vmf->vmf_eflags = eflags | PSL_VM;
 517 }
 518
 519 /*
 520  * called from vm86_bioscall, while in vm86 address space, to finalize setup.
 521  */
 522 void
 523 vm86_prepcall(struct vm86frame vmf)
 524 {
 525         uintptr_t addr[] = { 0xA00, 0x1000 };   /* code, stack */
 526         u_char intcall[] = {
 527                 CLI, INTn, 0x00, STI, HLT
 528         };
 529
 530         if ((vmf.vmf_trapno & PAGE_MASK) <= 0xff) {
 531                 /* interrupt call requested */
 532                 intcall[2] = (u_char)(vmf.vmf_trapno & 0xff);
 533                 memcpy((void *)addr[0], (void *)intcall, sizeof(intcall));
 534                 vmf.vmf_ip = addr[0];
 535                 vmf.vmf_cs = 0;
 536         }
 537         vmf.vmf_sp = addr[1] - 2;              /* keep aligned */
 538         vmf.kernel_fs = vmf.kernel_es = vmf.kernel_ds = 0;
 539         vmf.vmf_ss = 0;
 540         vmf.vmf_eflags = PSL_VIF | PSL_VM | PSL_USER;
 541         vm86_initflags(&vmf);
 542 }
 543
 544 /*
 545  * vm86 trap handler; determines whether routine succeeded or not.
 546  * Called while in vm86 space, returns to calling process.
 547  *
 548  * A MP lock ref is held on entry from trap() and must be released prior
 549  * to returning to the VM86 call.
 550  */
 551 void
 552 vm86_trap(struct vm86frame *vmf)
 553 {
 554         caddr_t addr;
 555
 556         /* "should not happen" */
 557         if ((vmf->vmf_eflags & PSL_VM) == 0)
 558                 panic("vm86_trap called, but not in vm86 mode");
 559
 560         addr = MAKE_ADDR(vmf->vmf_cs, vmf->vmf_ip);
 561         if (*(u_char *)addr == HLT)
 562                 vmf->vmf_trapno = vmf->vmf_eflags & PSL_C;
 563         else
 564                 vmf->vmf_trapno = vmf->vmf_trapno << 16;
 565
 566         rel_mplock();
 567         vm86_biosret(vmf);
 568 }
 569
 570 int
 571 vm86_intcall(int intnum, struct vm86frame *vmf)
 572 {
 573         if (intnum < 0 || intnum > 0xff)
 574                 return (EINVAL);
 575
 576         ASSERT_MP_LOCK_HELD();
 577
 578         vmf->vmf_trapno = intnum;
 579         return (vm86_bioscall(vmf));
 580 }
 581
 582 /*
 583  * struct vm86context contains the page table to use when making
 584  * vm86 calls.  If intnum is a valid interrupt number (0-255), then
 585  * the "interrupt trampoline" will be used, otherwise we use the
 586  * caller's cs:ip routine.
 587  */
 588 int
 589 vm86_datacall(intnum, vmf, vmc)
 590         int intnum;
 591         struct vm86frame *vmf;
 592         struct vm86context *vmc;
 593 {
 594         pt_entry_t pte = (pt_entry_t)vm86paddr;
 595         u_int page;
 596         int i, entry, retval;
 597
 598         ASSERT_MP_LOCK_HELD();
 599
 600         for (i = 0; i < vmc->npages; i++) {
 601                 page = vtophys(vmc->pmap[i].kva & PG_FRAME);
 602                 entry = vmc->pmap[i].pte_num;
 603                 vmc->pmap[i].old_pte = pte[entry];
 604                 pte[entry] = page | PG_V | PG_RW | PG_U;
 605         }
 606
 607         vmf->vmf_trapno = intnum;
 608         retval = vm86_bioscall(vmf);
 609
 610         for (i = 0; i < vmc->npages; i++) {
 611                 entry = vmc->pmap[i].pte_num;
 612                 pte[entry] = vmc->pmap[i].old_pte;
 613         }
 614
 615         return (retval);
 616 }
 617
 618 vm_offset_t
 619 vm86_getaddr(vmc, sel, off)
 620         struct vm86context *vmc;
 621         u_short sel;
 622         u_short off;
 623 {
 624         int i, page;
 625         vm_offset_t addr;
 626
 627         addr = (vm_offset_t)MAKE_ADDR(sel, off);
 628         page = addr >> PAGE_SHIFT;
 629         for (i = 0; i < vmc->npages; i++)
 630                 if (page == vmc->pmap[i].pte_num)
 631                         return (vmc->pmap[i].kva + (addr & PAGE_MASK));
 632         return (0);
 633 }
 634
 635 int
 636 vm86_getptr(vmc, kva, sel, off)
 637         struct vm86context *vmc;
 638         vm_offset_t kva;
 639         u_short *sel;
 640         u_short *off;
 641 {
 642         int i;
 643
 644         for (i = 0; i < vmc->npages; i++)
 645                 if (kva >= vmc->pmap[i].kva &&
 646                     kva < vmc->pmap[i].kva + PAGE_SIZE) {
 647                         *off = kva - vmc->pmap[i].kva;
 648                         *sel = vmc->pmap[i].pte_num << 8;
 649                         return (1);
 650                 }
 651         return (0);
 652         panic("vm86_getptr: address not found");
 653 }
 654
 655 int
 656 vm86_sysarch(struct proc *p, char *args)
 657 {
 658         int error = 0;
 659         struct i386_vm86_args ua;
 660         struct vm86_kernel *vm86;
 661
 662         if ((error = copyin(args, &ua, sizeof(struct i386_vm86_args))) != 0)
 663                 return (error);
 664
 665         if (p->p_thread->td_pcb->pcb_ext == 0)
 666                 if ((error = i386_extend_pcb(p)) != 0)
 667                         return (error);
 668         vm86 = &p->p_thread->td_pcb->pcb_ext->ext_vm86;
 669
 670         switch (ua.sub_op) {
 671         case VM86_INIT: {
 672                 struct vm86_init_args sa;
 673
 674                 if ((error = copyin(ua.sub_args, &sa, sizeof(sa))) != 0)
 675                         return (error);
 676                 if (cpu_feature & CPUID_VME)
 677                         vm86->vm86_has_vme = (rcr4() & CR4_VME ? 1 : 0);
 678                 else
 679                         vm86->vm86_has_vme = 0;
 680                 vm86->vm86_inited = 1;
 681                 vm86->vm86_debug = sa.debug;
 682                 bcopy(&sa.int_map, vm86->vm86_intmap, 32);
 683                 }
 684                 break;
 685
 686 #if 0
 687         case VM86_SET_VME: {
 688                 struct vm86_vme_args sa;
 689
 690                 if ((cpu_feature & CPUID_VME) == 0)
 691                         return (ENODEV);
 692
 693                 if (error = copyin(ua.sub_args, &sa, sizeof(sa)))
 694                         return (error);
 695                 if (sa.state)
 696                         load_cr4(rcr4() | CR4_VME);
 697                 else
 698                         load_cr4(rcr4() & ~CR4_VME);
 699                 }
 700                 break;
 701 #endif
 702
 703         case VM86_GET_VME: {
 704                 struct vm86_vme_args sa;
 705
 706                 sa.state = (rcr4() & CR4_VME ? 1 : 0);
 707                 error = copyout(&sa, ua.sub_args, sizeof(sa));
 708                 }
 709                 break;
 710
 711         case VM86_INTCALL: {
 712                 struct vm86_intcall_args sa;
 713
 714                 if ((error = suser_cred(p->p_ucred, 0)))
 715                         return (error);
 716                 if ((error = copyin(ua.sub_args, &sa, sizeof(sa))))
 717                         return (error);
 718                 if ((error = vm86_intcall(sa.intnum, &sa.vmf)))
 719                         return (error);
 720                 error = copyout(&sa, ua.sub_args, sizeof(sa));
 721                 }
 722                 break;
 723
 724         default:
 725                 error = EINVAL;
 726         }
 727         return (error);
 728 }