KernelLand/Kernel/arch/x86/vm8086.c

   1 /*
   2  * Acess2 Kernel (x86)
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * vm8086.c
   6  * - Virtual 8086 Mode Monitor
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <vm8086.h>
  11 #include <modules.h>
  12 #include <hal_proc.h>
  13 #include <semaphore.h>
  14
  15 // === CONSTANTS ===
  16 #define TRACE_EMU       0
  17
  18 #define VM8086_USER_BASE        0x1000
  19
  20 #define VM8086_MAGIC_CS 0xFFFF
  21 #define VM8086_MAGIC_IP 0x0010
  22 #define VM8086_STACK_SEG        0x9F00
  23 #define VM8086_STACK_OFS        0x0AFE
  24 enum eVM8086_Opcodes
  25 {
  26         VM8086_OP_PUSHF   = 0x9C,
  27         VM8086_OP_POPF    = 0x9D,
  28         VM8086_OP_INT_I   = 0xCD,
  29         VM8086_OP_IRET    = 0xCF,
  30         VM8086_OP_IN_AD   = 0xEC,
  31         VM8086_OP_IN_ADX  = 0xED,
  32         VM8086_OP_OUT_AD  = 0xEE,
  33         VM8086_OP_OUT_ADX = 0xEF
  34 };
  35 #define VM8086_PAGES_PER_INST   4
  36
  37 #define VM8086_BLOCKSIZE        128
  38 #define VM8086_BLOCKCOUNT       ((0x9F000-0x10000)/VM8086_BLOCKSIZE)
  39
  40 // === TYPES ===
  41 struct sVM8086_InternalPages
  42 {
  43         Uint32  Bitmap; // 32 sections = 128 byte blocks
  44         char    *VirtBase;
  45         tPAddr  PhysAddr;
  46 };
  47 struct sVM8086_InternalData
  48 {
  49         struct sVM8086_InternalPages    AllocatedPages[VM8086_PAGES_PER_INST];
  50 };
  51
  52 // === PROTOTYPES ===
  53  int    VM8086_Install(char **Arguments);
  54 void    VM8086_GPF(tRegs *Regs);
  55 //tVM8086       *VM8086_Init(void);
  56
  57 // === GLOBALS ===
  58 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  59 tMutex  glVM8086_Process;
  60 tSemaphore      gVM8086_TaskComplete;
  61 tSemaphore      gVM8086_TasksToDo;
  62 tPID    gVM8086_WorkerPID;
  63 tTID    gVM8086_CallingThread;
  64 tVM8086 volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
  65 Uint32  gaVM8086_MemBitmap[VM8086_BLOCKCOUNT/32];
  66  int    gbVM8086_ShadowIF = 0;
  67
  68 // === FUNCTIONS ===
  69 int VM8086_Install(char **Arguments)
  70 {
  71         Semaphore_Init(&gVM8086_TasksToDo, 0, 10, "VM8086", "TasksToDo");
  72
  73         // Lock to avoid race conditions
  74         Mutex_Acquire( &glVM8086_Process );
  75
  76         // Create BIOS Call process
  77         tPID pid = Proc_Clone(CLONE_VM);
  78         LOG("pid = %i", pid);
  79         if(pid == -1)
  80         {
  81                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  82                 return MODULE_ERR_MISC;
  83         }
  84         if(pid == 0)
  85         {
  86                 Uint    * volatile stacksetup;  // Initialising Stack
  87                 Uint16  * volatile rmstack;     // Real Mode Stack
  88
  89                 LOG("Initialising worker");
  90
  91                 // Set Image Name
  92                 Threads_SetName("VM8086");
  93
  94                 // Map ROM Area
  95                 for(unsigned int i = 0xA0;i<0x100;i++) {
  96                         MM_RefPhys(i * 0x1000);
  97                         MM_Map( (void*)(i * 0x1000), i * 0x1000 );
  98                 }
  99                 MM_RefPhys(0);
 100                 MM_Map( (void*)0, 0 );  // IVT / BDA
 101                 if( MM_GetRefCount(0x00000) > 2 ) {
 102                         Log_Notice("VM8086", "Ok, who's touched the IVT? (%i)",
 103                                 MM_GetRefCount(0x00000));
 104                 }
 105                 MM_RefPhys(0x9F000);
 106                 MM_Map( (void*)0x9F000, 0x9F000 );      // Stack / EBDA
 107                 if( MM_GetRefCount(0x9F000) > 2 ) {
 108                         Log_Notice("VM8086", "And who's been playing with my EBDA? (%i)",
 109                                 MM_GetRefCount(0x9F000));
 110                 }
 111                 // System Stack / Stub
 112                 if( MM_Allocate( (void*)0x100000 ) == 0 ) {
 113                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
 114                         gVM8086_WorkerPID = 0;
 115                         Threads_Exit(0, 1);
 116                 }
 117
 118                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
 119                 *(Uint8*)(0x100001) = 0x07;     // POP ES
 120                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
 121                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
 122
 123                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
 124                 rmstack--;      *rmstack = 0xFFFF;      //CS
 125                 rmstack--;      *rmstack = 0x0010;      //IP
 126
 127                 // Setup Stack
 128                 stacksetup = (Uint*)0x101000;
 129                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 130                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 131                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 132                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 133                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 134                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 135                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 136                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 137                 stacksetup--;   *stacksetup = 0x10;     // IP
 138                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 139                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 140                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 141                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 142                 stacksetup--;   *stacksetup = 0x5454;   // SP
 143                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 144                 stacksetup--;   *stacksetup = 0x5151;   // SI
 145                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 146                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 147                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 148                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 149                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 150                 LOG("stacksetup = %p, entering vm8086");
 151                 __asm__ __volatile__ (
 152                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 153                 "pop %%gs;\n\t"
 154                 "pop %%fs;\n\t"
 155                 "pop %%es;\n\t"
 156                 "pop %%ds;\n\t"
 157                 "popa;\n\t"
 158                 "iret;\n\t" : : "a" (stacksetup));
 159                 for(;;);        // Shouldn't be reached
 160         }
 161
 162         gVM8086_WorkerPID = pid;
 163
 164         // It's released when the GPF fires
 165         LOG("Waiting for worker %i to start", gVM8086_WorkerPID);
 166         Mutex_Acquire( &glVM8086_Process );
 167         Mutex_Release( &glVM8086_Process );
 168
 169         // Worker killed itself
 170         if( gVM8086_WorkerPID != pid ) {
 171                 return MODULE_ERR_MISC;
 172         }
 173
 174         return MODULE_ERR_OK;
 175 }
 176
 177 void VM8086_GPF(tRegs *Regs)
 178 {
 179         Uint8   opcode;
 180         Uint16  newcs, newip;
 181
 182 //      Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 183
 184         LOG("VM8086 GPF at %04x:%04x", Regs->cs, Regs->eip);
 185
 186         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 187         && Threads_GetPID() == gVM8086_WorkerPID)
 188         {
 189                 if( gpVM8086_State == (void*)-1 ) {
 190                         Log_Log("VM8086", "Worker thread ready and waiting");
 191                         gpVM8086_State = NULL;
 192                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 193                 }
 194 //              Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 195 //                      gpVM8086_State, gVM8086_CallingThread);
 196                 if( gpVM8086_State )
 197                 {
 198                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 199                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 200                         gpVM8086_State->BP = Regs->ebp;
 201                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 202                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 203
 204                         LOG("gpVM8086_State = %p", gpVM8086_State);
 205                         LOG("gpVM8086_State->Internal = %p", gpVM8086_State->Internal);
 206                         for( Uint i = 0; i < VM8086_PAGES_PER_INST; i ++ )
 207                         {
 208                                 if( !gpVM8086_State->Internal->AllocatedPages[i].VirtBase )
 209                                         continue ;
 210                                 MM_Deallocate( (tPage*)VM8086_USER_BASE + i );
 211                         }
 212
 213                         gpVM8086_State = NULL;
 214
 215                         // Wake the caller
 216                         Semaphore_Signal(&gVM8086_TaskComplete, 1);
 217                 }
 218
 219                 //Log_Log("VM8086", "Waiting for something to do");
 220                 __asm__ __volatile__ ("sti");
 221                 Semaphore_Wait(&gVM8086_TasksToDo, 1);
 222
 223                 for( Uint i = 0; i < VM8086_PAGES_PER_INST; i ++ )
 224                 {
 225                         if( !gpVM8086_State->Internal->AllocatedPages[i].VirtBase )
 226                                 continue ;
 227                         MM_RefPhys( gpVM8086_State->Internal->AllocatedPages[i].PhysAddr );
 228                         MM_Map( (tPage*)VM8086_USER_BASE + i, gpVM8086_State->Internal->AllocatedPages[i].PhysAddr );
 229                 }
 230
 231
 232                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 233                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 234                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 235                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 236                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 237                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 238                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 239
 240                 // Set Registers
 241                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 242                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 243                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 244                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 245                 Regs->ebp = gpVM8086_State->BP;
 246                 Regs->ds = 0x23;        Regs->es = 0x23;
 247                 Regs->fs = 0x23;        Regs->gs = 0x23;
 248                 return ;
 249         }
 250
 251         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 252         Regs->eip ++;
 253         switch(opcode)
 254         {
 255         case VM8086_OP_PUSHF:   //PUSHF
 256                 Regs->esp -= 2;
 257                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 258                 if( gbVM8086_ShadowIF )
 259                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) |= 0x200;
 260                 else
 261                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) &= ~0x200;
 262                 #if TRACE_EMU
 263                 Log_Debug("VM8086", "%04x:%04x Emulated PUSHF (value 0x%x)",
 264                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 265                 #endif
 266                 break;
 267         case VM8086_OP_POPF:    //POPF
 268                 // Changing IF is not allowed
 269                 Regs->eflags &= 0xFFFF0202;
 270                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );
 271                 gbVM8086_ShadowIF = !!(*(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0x200);
 272                 Regs->esp += 2;
 273                 #if TRACE_EMU
 274                 Log_Debug("VM8086", "%04x:%04x Emulated POPF (new value 0x%x)",
 275                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 276                 #endif
 277                 break;
 278
 279         case VM8086_OP_INT_I:   //INT imm8
 280                 {
 281                  int    id;
 282                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 283                 Regs->eip ++;
 284
 285                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags;
 286                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 287                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 288
 289                 newcs = *(Uint16*)(4*id + 2);
 290                 newip = *(Uint16*)(4*id);
 291                 #if TRACE_EMU
 292                 Log_Debug("VM8086", "%04x:%04x Emulated INT 0x%x (%04x:%04x) - AX=%04x,BX=%04x",
 293                         Regs->cs, Regs->eip-2, id, newcs, newip, Regs->eax, Regs->ebx);
 294                 #endif
 295                 Regs->cs = newcs;
 296                 Regs->eip = newip;
 297                 }
 298                 break;
 299
 300         case VM8086_OP_IRET:    //IRET
 301                 newip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 302                 newcs = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 303                 #if TRACE_EMU
 304                 Log_Debug("VM8086", "%04x:%04x IRET to %04x:%04x",
 305                         Regs->cs, Regs->eip-1, newcs, newip);
 306                 #endif
 307                 Regs->cs = newcs;
 308                 Regs->eip = newip;
 309                 break;
 310
 311
 312         case VM8086_OP_IN_AD:   //IN AL, DX
 313                 Regs->eax &= 0xFFFFFF00;
 314                 Regs->eax |= inb(Regs->edx&0xFFFF);
 315                 #if TRACE_EMU
 316                 Log_Debug("VM8086", "%04x:%04x Emulated IN AL, DX (Port 0x%x [Val 0x%02x])",
 317                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 318                 #endif
 319                 break;
 320         case VM8086_OP_IN_ADX:  //IN AX, DX
 321                 Regs->eax &= 0xFFFF0000;
 322                 Regs->eax |= inw(Regs->edx&0xFFFF);
 323                 #if TRACE_EMU
 324                 Log_Debug("VM8086", "%04x:%04x Emulated IN AX, DX (Port 0x%x [Val 0x%04x])",
 325                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 326                 #endif
 327                 break;
 328
 329         case VM8086_OP_OUT_AD:  //OUT DX, AL
 330                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 331                 #if TRACE_EMU
 332                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AL (*0x%04x = 0x%02x)",
 333                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 334                 #endif
 335                 break;
 336         case VM8086_OP_OUT_ADX: //OUT DX, AX
 337                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 338                 #if TRACE_EMU
 339                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AX (*0x%04x = 0x%04x)",
 340                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 341                 #endif
 342                 break;
 343
 344         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 345         case 0xFA:      //CLI
 346                 #if TRACE_EMU
 347                 Log_Debug("VM8086", "%04x:%04x Ignored CLI",
 348                         Regs->cs, Regs->eip);
 349                 #endif
 350                 gbVM8086_ShadowIF = 0;
 351                 break;
 352         case 0xFB:      //STI
 353                 #if TRACE_EMU
 354                 Log_Debug("VM8086", "%04x:%04x Ignored STI",
 355                         Regs->cs, Regs->eip);
 356                 #endif
 357                 gbVM8086_ShadowIF = 1;
 358                 break;
 359
 360         case 0x66:
 361                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 362                 Regs->eip ++;
 363                 switch( opcode )
 364                 {
 365                 case VM8086_OP_IN_ADX:  //IN AX, DX
 366                         Regs->eax = ind(Regs->edx&0xFFFF);
 367                         #if TRACE_EMU
 368                         Log_Debug("VM8086", "%04x:%04x Emulated IN EAX, DX (Port 0x%x [Val 0x%08x])",
 369                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 370                         #endif
 371                         break;
 372                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 373                         outd(Regs->edx&0xFFFF, Regs->eax);
 374                         #if TRACE_EMU
 375                         Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, EAX (*0x%04x = 0x%08x)",
 376                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 377                         #endif
 378                         break;
 379                 default:
 380                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 381                                 Regs->cs, Regs->eip-2,
 382                                 opcode
 383                                 );
 384                         // Force an end to the call
 385                         Regs->cs = VM8086_MAGIC_CS;
 386                         Regs->eip = VM8086_MAGIC_IP;
 387                         break;
 388                 }
 389                 break;
 390
 391         case 0x0F:
 392                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 393                 Log_Error("VM8086", "Error - Unknown opcode 0F %02x caused a GPF at %04x:%04x",
 394                         opcode, Regs->cs, Regs->eip);
 395                 // Force an end to the call
 396                 Regs->cs = VM8086_MAGIC_CS;
 397                 Regs->eip = VM8086_MAGIC_IP;
 398                 break;
 399
 400         default:
 401                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 402                         opcode, Regs->cs, Regs->eip-1);
 403                 // Force an end to the call
 404                 Regs->cs = VM8086_MAGIC_CS;
 405                 Regs->eip = VM8086_MAGIC_IP;
 406                 break;
 407         }
 408 }
 409
 410 /**
 411  * \brief Create an instance of the VM8086 Emulator
 412  */
 413 tVM8086 *VM8086_Init(void)
 414 {
 415         tVM8086 *ret;
 416         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 417         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 418         return ret;
 419 }
 420
 421 void VM8086_Free(tVM8086 *State)
 422 {
 423         // TODO: Make sure the state isn't in use currently
 424         for( Uint i = VM8086_PAGES_PER_INST; i --; )
 425                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 426         free(State);
 427 }
 428
 429 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 430 {
 431         struct sVM8086_InternalPages    *pages = State->Internal->AllocatedPages;
 432          int    i, j, base = 0;
 433          int    nBlocks, rem;
 434
 435         Size = (Size + 127) & ~127;
 436         nBlocks = Size / 128;
 437
 438         if(Size > 4096) return NULL;
 439
 440         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 441         {
 442                 if( pages[i].VirtBase == 0 )    continue;
 443
 444                 //Log_Debug("VM8086", "pages[%i].Bitmap = 0b%b", i, pages[i].Bitmap);
 445
 446                 rem = nBlocks;
 447                 base = 0;
 448                 // Scan the bitmap for a free block
 449                 // - 32 blocks per page == 128 bytes per block == 8 segments
 450                 for( j = 0; j < 32; j++ )
 451                 {
 452                         if( pages[i].Bitmap & (1 << j) )
 453                         {
 454                                 base = j+1;
 455                                 rem = nBlocks;
 456                         }
 457
 458                         rem --;
 459                         if(rem == 0)    // Goodie, there's a gap
 460                         {
 461                                 for( j = 0; j < nBlocks; j++ )
 462                                         pages[i].Bitmap |= 1 << (base + j);
 463                                 *Segment = (VM8086_USER_BASE + i * 0x1000) / 16 + base * 8;
 464                                 *Offset = 0;
 465                                 LOG("Allocated at #%i,%04x", i, base*8*16);
 466                                 LOG(" - %x:%x", *Segment, *Offset);
 467                                 return pages[i].VirtBase + base * 8 * 16;
 468                         }
 469                 }
 470         }
 471
 472         // No pages with free space?, allocate a new one
 473         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 474         {
 475                 if( pages[i].VirtBase == 0 )    break;
 476         }
 477         // Darn, we can't allocate any more
 478         if( i == VM8086_PAGES_PER_INST ) {
 479                 Log_Warning("VM8086", "Out of pages in %p", State);
 480                 return NULL;
 481         }
 482
 483         pages[i].VirtBase = MM_AllocDMA(1, -1, &pages[i].PhysAddr);
 484         if( pages[i].VirtBase == 0 ) {
 485                 Log_Warning("VM8086", "Unable to allocate data page");
 486                 return NULL;
 487         }
 488         pages[i].Bitmap = 0;
 489         LOG("AllocatedPages[%i].VirtBase = %p", i, pages[i].VirtBase);
 490         LOG("AllocatedPages[%i].PhysAddr = %P", i, pages[i].PhysAddr);
 491
 492         for( j = 0; j < nBlocks; j++ )
 493                 pages[i].Bitmap |= 1 << j;
 494         LOG("AllocatedPages[%i].Bitmap = 0b%b", i, pages[i].Bitmap);
 495         *Segment = (VM8086_USER_BASE + i * 0x1000) / 16;
 496         *Offset = 0;
 497         LOG(" - %04x:%04x", *Segment, *Offset);
 498         return pages[i].VirtBase;
 499 }
 500
 501 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 502 {
 503         Uint32  addr = Segment * 16 + Offset;
 504
 505         if( VM8086_USER_BASE <= addr && addr < VM8086_USER_BASE + VM8086_PAGES_PER_INST*0x1000 )
 506         {
 507                 int pg = (addr - VM8086_USER_BASE) / 0x1000;
 508                 if( State->Internal->AllocatedPages[pg].VirtBase == 0)
 509                         return NULL;
 510                 else
 511                         return State->Internal->AllocatedPages[pg].VirtBase + (addr & 0xFFF);
 512         }
 513         else
 514         {
 515                 return (void*)( KERNEL_BASE + addr );
 516         }
 517 }
 518
 519 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 520 {
 521         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 522         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 523
 524 //      Log_Debug("VM8086", "Software interrupt %i to %04x:%04x", Interrupt, State->CS, State->IP);
 525
 526         Mutex_Acquire( &glVM8086_Process );
 527
 528         gpVM8086_State = State;
 529         gVM8086_CallingThread = Threads_GetTID();
 530         Semaphore_Signal(&gVM8086_TasksToDo, 1);
 531
 532         Semaphore_Wait(&gVM8086_TaskComplete, 1);
 533
 534         Mutex_Release( &glVM8086_Process );
 535 }