3 * - By John Hodge (thePowersGang)
10 #define VM8086_MAGIC_CS 0xFFFF
11 #define VM8086_MAGIC_IP 0x0010
12 #define VM8086_STACK_SEG 0x9F00
13 #define VM8086_STACK_OFS 0x0AFE
16 VM8086_OP_PUSHF = 0x9C,
17 VM8086_OP_POPF = 0x9D,
18 VM8086_OP_INT_I = 0xCD,
19 VM8086_OP_IRET = 0xCF,
20 VM8086_OP_IN_AD = 0xEC,
21 VM8086_OP_IN_ADX= 0xED
23 #define VM8086_PAGES_PER_INST 4
26 int Proc_Clone(Uint *Err, Uint Flags);
29 struct sVM8086_InternalData
32 Uint32 Bitmap; // 32 sections = 128 byte blocks
35 } AllocatedPages[VM8086_PAGES_PER_INST];
39 int VM8086_Install(char **Arguments);
40 void VM8086_GPF(tRegs *Regs);
41 tVM8086 *VM8086_Init(void);
44 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
45 tSpinlock glVM8086_Process;
46 tPID gVM8086_WorkerPID;
47 tTID gVM8086_CallingThread;
48 tVM8086 * volatile gpVM8086_State;
51 int VM8086_Install(char **Arguments)
55 // Create BIOS Call process
56 pid = Proc_Clone(NULL, CLONE_VM);
59 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
60 return MODULE_ERR_MISC;
64 Uint *stacksetup; // Initialising Stack
65 Uint16 *rmstack; // Real Mode Stack
69 Threads_SetName("VM8086");
72 for(i=0xA0;i<0x100;i++) {
73 MM_Map( i * 0x1000, i * 0x1000 );
74 //MM_SetFlags( i * 0x1000, MM_PFLAG_RO, MM_PFLAG_RO ); // Set Read Only
76 MM_Map( 0, 0 ); // IVT / BDA
77 for(i=0x70;i<0x80;i++) {
78 MM_Map( i * 0x1000, i * 0x1000 ); MM_DerefPhys( i * 0x1000 );
80 MM_Map( 0x9F000, 0x9F000 ); // Stack / EBDA
81 MM_Allocate( 0x100000 ); // System Stack / Stub
83 *(Uint8*)(0x100000) = VM8086_OP_IRET;
84 *(Uint8*)(0x100001) = 0x07; // POP ES
85 *(Uint8*)(0x100002) = 0x1F; // POP DS
86 *(Uint8*)(0x100003) = 0xCB; // RET FAR
88 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
89 *rmstack-- = 0xFFFF; //CS
90 *rmstack-- = 0x0010; //IP
93 stacksetup = (Uint*)0x101000;
94 *--stacksetup = VM8086_STACK_SEG; // GS
95 *--stacksetup = VM8086_STACK_SEG; // FS
96 *--stacksetup = VM8086_STACK_SEG; // DS
97 *--stacksetup = VM8086_STACK_SEG; // ES
98 *--stacksetup = VM8086_STACK_SEG; // SS
99 *--stacksetup = VM8086_STACK_OFS-2; // SP
100 *--stacksetup = 0x20202; // FLAGS
101 *--stacksetup = 0xFFFF; // CS
102 *--stacksetup = 0x10; // IP
103 *--stacksetup = 0xAAAA; // AX
104 *--stacksetup = 0xCCCC; // CX
105 *--stacksetup = 0xDDDD; // DX
106 *--stacksetup = 0xBBBB; // BX
107 *--stacksetup = 0x5454; // SP
108 *--stacksetup = 0xB4B4; // BP
109 *--stacksetup = 0x5151; // SI
110 *--stacksetup = 0xD1D1; // DI
111 *--stacksetup = 0x20|3; // DS - Kernel
112 *--stacksetup = 0x20|3; // ES - Kernel
113 *--stacksetup = 0x20|3; // FS
114 *--stacksetup = 0x20|3; // GS
115 __asm__ __volatile__ (
116 "mov %%eax,%%esp;\n\t" // Set stack pointer
122 "iret;\n\t" : : "a" (stacksetup));
123 for(;;); // Shouldn't be reached
126 gVM8086_WorkerPID = pid;
127 Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
128 Threads_Yield(); // Yield to allow the child to initialise
130 return MODULE_ERR_OK;
133 void VM8086_GPF(tRegs *Regs)
137 //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
139 if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
140 && Threads_GetPID() == gVM8086_WorkerPID)
142 if( gpVM8086_State ) {
143 gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
144 gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
145 gpVM8086_State->BP = Regs->ebp;
146 gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
147 gpVM8086_State->DS = Regs->ds; gpVM8086_State->ES = Regs->es;
148 gpVM8086_State = NULL;
149 Threads_WakeTID(gVM8086_CallingThread);
152 //Log_Log("VM8086", "Waiting for something to do");
153 __asm__ __volatile__ ("sti");
154 // Wait for a new task
155 while(!gpVM8086_State) {
157 //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
160 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
161 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
162 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
163 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
164 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
165 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
166 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
169 Regs->eip = 0x11; Regs->cs = 0xFFFF;
170 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
171 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
172 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
173 Regs->ebp = gpVM8086_State->BP;
174 Regs->ds = 0x23; Regs->es = 0x23;
175 Regs->fs = 0x23; Regs->gs = 0x23;
179 opcode = *(Uint8*)( KERNEL_BASE + (Regs->cs*16) + (Regs->eip) );
183 case VM8086_OP_PUSHF: //PUSHF
185 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
187 Log_Debug("VM8086", "Emulated PUSHF");
190 case VM8086_OP_POPF: //POPF
191 Regs->eflags &= 0xFFFF0002;
192 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD; // Changing IF is not allowed
195 Log_Debug("VM8086", "Emulated POPF");
199 case VM8086_OP_INT_I: //INT imm8
202 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
205 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
206 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
208 Regs->cs = *(Uint16*)(4*id + 2);
209 Regs->eip = *(Uint16*)(4*id);
211 Log_Debug("VM8086", "Emulated INT 0x%x", id);
216 case VM8086_OP_IRET: //IRET
217 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
218 Regs->cs = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
220 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
225 case VM8086_OP_IN_AD: //IN AL, DX
226 Regs->eax &= 0xFFFFFF00;
227 Regs->eax |= inb(Regs->edx&0xFFFF);
229 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
232 case VM8086_OP_IN_ADX: //IN AX, DX
233 Regs->eax &= 0xFFFF0000;
234 Regs->eax |= inw(Regs->edx&0xFFFF);
236 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
240 case 0xEE: //OUT DX, AL
241 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
243 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
246 case 0xEF: //OUT DX, AX
247 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
249 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
253 // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
260 Log_Warning("VM8086", "Code at %04x:%04x attempted to use an operand override, ignored",
261 Regs->cs, Regs->eip);
265 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
266 opcode, Regs->cs, Regs->eip);
267 // Force an end to the call
268 Regs->cs = VM8086_MAGIC_CS;
269 Regs->eip = VM8086_MAGIC_IP;
275 * \brief Create an instance of the VM8086 Emulator
277 tVM8086 *VM8086_Init(void)
280 ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
281 ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
285 void VM8086_Free(tVM8086 *State)
288 for( i = VM8086_PAGES_PER_INST; i --; )
289 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
293 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
299 Size = (Size + 127) & ~127;
302 if(Size > 4096) return NULL;
304 for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
306 if( State->Internal->AllocatedPages[i].VirtBase == 0 ) continue;
307 bmp = State->Internal->AllocatedPages[i].Bitmap;
310 // Scan the bitmap for a free block
311 for( j = 0; j < 32-nBlocks; j++ ) {
312 if( bmp & (1 << j) ) {
318 if(rem == 0) // Goodie, there's a gap
320 for( j = 0; j < nBlocks; j++ )
321 State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
322 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
324 return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
330 // No pages with free space?, allocate a new one
331 for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
333 if( State->Internal->AllocatedPages[i].VirtBase == 0 ) break;
335 // Darn, we can't allocate any more
336 if( i == VM8086_PAGES_PER_INST ) {
337 Log_Warning("VM8086", "Out of pages in %p", State);
341 State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
342 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
343 State->Internal->AllocatedPages[i].Bitmap = 0;
345 for( j = 0; j < nBlocks; j++ )
346 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
347 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
349 return (void*) State->Internal->AllocatedPages[i].VirtBase;
352 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
354 return (void*)( KERNEL_BASE + Segment*16 + Offset );
357 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
359 State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
360 State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
362 LOCK( &glVM8086_Process );
364 gpVM8086_State = State;
365 gVM8086_CallingThread = Threads_GetTID();
366 Threads_WakeTID( gVM8086_WorkerPID );
367 while( gpVM8086_State != NULL )
370 RELEASE( &glVM8086_Process );