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,
21 #define VM8086_PAGES_PER_INST 4
24 int Proc_Clone(Uint *Err, Uint Flags);
27 struct sVM8086_InternalData
30 Uint32 Bitmap; // 32 sections = 128 byte blocks
33 } AllocatedPages[VM8086_PAGES_PER_INST];
37 int VM8086_Install(char **Arguments);
38 void VM8086_GPF(tRegs *Regs);
39 tVM8086 *VM8086_Init(void);
42 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
43 tSpinlock glVM8086_Process;
44 tPID gVM8086_WorkerPID;
45 tTID gVM8086_CallingThread;
46 tVM8086 * volatile gpVM8086_State;
49 int VM8086_Install(char **Arguments)
53 // Create BIOS Call process
54 pid = Proc_Clone(NULL, CLONE_VM);
57 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
58 return MODULE_ERR_MISC;
62 Uint *stacksetup; // Initialising Stack
63 Uint16 *rmstack; // Real Mode Stack
67 Threads_SetName("VM8086");
70 for(i=0xA0;i<0x100;i++) {
71 MM_Map( i * 0x1000, i * 0x1000 );
72 MM_SetFlags( i * 0x1000, MM_PFLAG_RO, MM_PFLAG_RO ); // Set Read Only
74 MM_Map( 0, 0 ); // IVT / BDA
75 for(i=0x70;i<0x80;i++) {
76 MM_Map( i * 0x1000, i * 0x1000 ); MM_DerefPhys( i * 0x1000 );
78 MM_Map( 0x9F000, 0x9F000 ); // Stack / EBDA
79 MM_Allocate( 0x100000 ); // System Stack / Stub
81 *(Uint8*)(0x100000) = VM8086_OP_IRET;
82 *(Uint8*)(0x100001) = 0x07; // POP ES
83 *(Uint8*)(0x100002) = 0x1F; // POP DS
84 *(Uint8*)(0x100003) = 0xCB; // RET FAR
86 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
87 *rmstack-- = 0xFFFF; //CS
88 *rmstack-- = 0x0010; //IP
91 stacksetup = (Uint*)0x101000;
92 *--stacksetup = VM8086_STACK_SEG; // GS
93 *--stacksetup = VM8086_STACK_SEG; // FS
94 *--stacksetup = VM8086_STACK_SEG; // DS
95 *--stacksetup = VM8086_STACK_SEG; // ES
96 *--stacksetup = VM8086_STACK_SEG; // SS
97 *--stacksetup = VM8086_STACK_OFS-2; // SP
98 *--stacksetup = 0x20202; // FLAGS
99 *--stacksetup = 0xFFFF; // CS
100 *--stacksetup = 0x10; // IP
101 *--stacksetup = 0xAAAA; // AX
102 *--stacksetup = 0xCCCC; // CX
103 *--stacksetup = 0xDDDD; // DX
104 *--stacksetup = 0xBBBB; // BX
105 *--stacksetup = 0x5454; // SP
106 *--stacksetup = 0xB4B4; // BP
107 *--stacksetup = 0x5151; // SI
108 *--stacksetup = 0xD1D1; // DI
109 *--stacksetup = 0x20|3; // DS - Kernel
110 *--stacksetup = 0x20|3; // ES - Kernel
111 *--stacksetup = 0x20|3; // FS
112 *--stacksetup = 0x20|3; // GS
113 __asm__ __volatile__ (
114 "mov %%eax,%%esp;\n\t" // Set stack pointer
120 "iret;\n\t" : : "a" (stacksetup));
121 for(;;); // Shouldn't be reached
124 gVM8086_WorkerPID = pid;
125 Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
126 Threads_Yield(); // Yield to allow the child to initialise
128 return MODULE_ERR_OK;
131 void VM8086_GPF(tRegs *Regs)
135 //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
137 if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
138 && Threads_GetPID() == gVM8086_WorkerPID)
140 if( gpVM8086_State ) {
141 gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
142 gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
143 gpVM8086_State->BP = Regs->ebp;
144 gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
145 gpVM8086_State->DS = Regs->ds; gpVM8086_State->ES = Regs->es;
146 gpVM8086_State = NULL;
147 Threads_WakeTID(gVM8086_CallingThread);
150 //Log_Log("VM8086", "Waiting for something to do");
151 __asm__ __volatile__ ("sti");
152 // Wait for a new task
153 while(!gpVM8086_State) {
155 //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
158 //Log_Log("VM8086", "We have a task");
159 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
160 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
161 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
162 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
163 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
164 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
167 Regs->eip = 0x11; Regs->cs = 0xFFFF;
168 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
169 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
170 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
171 Regs->ebp = gpVM8086_State->BP;
172 Regs->ds = 0x23; Regs->es = 0x23;
173 Regs->fs = 0x23; Regs->gs = 0x23;
177 opcode = *(Uint8*)( KERNEL_BASE + (Regs->cs*16) + (Regs->eip) );
181 case VM8086_OP_PUSHF: //PUSHF
183 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
185 Log_Debug("VM8086", "Emulated PUSHF");
188 case VM8086_OP_POPF: //POPF
189 Regs->eflags &= 0xFFFF0002;
190 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD; // Changing IF is not allowed
193 Log_Debug("VM8086", "Emulated POPF");
197 case VM8086_OP_INT_I: //INT imm8
200 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
203 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
204 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
206 Regs->cs = *(Uint16*)(4*id + 2);
207 Regs->eip = *(Uint16*)(4*id);
209 Log_Debug("VM8086", "Emulated INT 0x%x", id);
215 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
216 Regs->cs = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
218 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
223 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
224 opcode, Regs->cs, Regs->eip);
225 // Force an end to the call
226 Regs->cs = VM8086_MAGIC_CS;
227 Regs->eip = VM8086_MAGIC_IP;
233 * \brief Create an instance of the VM8086 Emulator
235 tVM8086 *VM8086_Init(void)
238 ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
239 ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
243 void VM8086_Free(tVM8086 *State)
246 for( i = VM8086_PAGES_PER_INST; i --; )
247 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
251 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
257 Size = (Size + 127) & ~127;
260 if(Size > 4096) return NULL;
262 for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
264 if( State->Internal->AllocatedPages[i].VirtBase == 0 ) continue;
265 bmp = State->Internal->AllocatedPages[i].Bitmap;
268 // Scan the bitmap for a free block
269 for( j = 0; j < 32-nBlocks; j++ ) {
270 if( bmp & (1 << j) ) {
276 if(rem == 0) // Goodie, there's a gap
278 for( j = 0; j < nBlocks; j++ )
279 State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
280 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
282 return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
288 // No pages with free space?, allocate a new one
289 for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
291 if( State->Internal->AllocatedPages[i].VirtBase == 0 ) break;
293 // Darn, we can't allocate any more
294 if( i == VM8086_PAGES_PER_INST ) {
295 Log_Warning("VM8086", "Out of pages in %p", State);
299 State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
300 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
301 State->Internal->AllocatedPages[i].Bitmap = 0;
303 for( j = 0; j < nBlocks; j++ )
304 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
305 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
307 return (void*) State->Internal->AllocatedPages[i].VirtBase;
310 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
312 return (void*)( KERNEL_BASE + Segment*16 + Offset );
315 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
317 State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
318 State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
320 LOCK( &glVM8086_Process );
322 gpVM8086_State = State;
323 gVM8086_CallingThread = Threads_GetTID();
324 Threads_WakeTID( gVM8086_WorkerPID );
325 while( gpVM8086_State != NULL )
328 RELEASE( &glVM8086_Process );