Palacios Public Git Repository

To checkout Palacios execute

  git clone http://v3vee.org/palacios/palacios.web/palacios.git
This will give you the master branch. You probably want the devel branch or one of the release branches. To switch to the devel branch, simply execute
  cd palacios
  git checkout --track -b devel origin/devel
The other branches are similar.


Added RTC functionality (including interrupt injection) to nvram
[palacios.git] / palacios / src / palacios / vmm_ctrl_regs.c
index 931fc87..2fcd3b6 100644 (file)
@@ -7,83 +7,6 @@
 
 
 
-extern void SerialMemDump(unsigned char *start, int n);
-
-
-#if VMM_DEBUG
-void PrintCtrlRegs(struct guest_info *info)
-{
-  struct cr0_32 cr0 = *((struct cr0_32 *) &(info->ctrl_regs.cr0));
-  struct cr2_32 cr2 = *((struct cr2_32 *) &(info->ctrl_regs.cr2));
-  struct cr3_32 cr3 = *((struct cr3_32 *) &(info->ctrl_regs.cr3));
-  struct cr4_32 cr4 = *((struct cr4_32 *) &(info->ctrl_regs.cr4));
-  struct rflags rflags = *((struct rflags *) &(info->ctrl_regs.rflags));
-
-  PrintDebug("CR0:     pe    0x%x\n",cr0.pe);
-  PrintDebug("CR0:     mp    0x%x\n",cr0.mp);
-  PrintDebug("CR0:     em    0x%x\n",cr0.em);
-  PrintDebug("CR0:     ts    0x%x\n",cr0.ts);
-  PrintDebug("CR0:     et    0x%x\n",cr0.et);
-  PrintDebug("CR0:     ne    0x%x\n",cr0.ne);
-  PrintDebug("CR0:     rsvd1 0x%x\n",cr0.rsvd1);
-  PrintDebug("CR0:     wp    0x%x\n",cr0.wp);
-  PrintDebug("CR0:     rsvd2 0x%x\n",cr0.rsvd2);
-  PrintDebug("CR0:     am    0x%x\n",cr0.am);
-  PrintDebug("CR0:     rsvd3 0x%x\n",cr0.rsvd3);
-  PrintDebug("CR0:     nw    0x%x\n",cr0.nw);
-  PrintDebug("CR0:     cd    0x%x\n",cr0.cd);
-  PrintDebug("CR0:     pg    0x%x\n",cr0.pg);
-
-  PrintDebug("CR2:     pfadd 0x%x\n",cr2.pf_vaddr);
-
-  PrintDebug("CR3:     rsvd1 0x%x\n",cr3.rsvd1);
-  PrintDebug("CR3:     pwt   0x%x\n",cr3.pwt);
-  PrintDebug("CR3:     pcd   0x%x\n",cr3.pcd);
-  PrintDebug("CR3:     rsvd2 0x%x\n",cr3.rsvd2);
-  PrintDebug("CR3:     pdt   0x%x\n",cr3.pdt_base_addr);
-
-  PrintDebug("CR4:     vme   0x%x\n",cr4.vme);
-  PrintDebug("CR4:     pvi   0x%x\n",cr4.pvi);
-  PrintDebug("CR4:     tsd   0x%x\n",cr4.tsd);
-  PrintDebug("CR4:     de    0x%x\n",cr4.de);
-  PrintDebug("CR4:     pse   0x%x\n",cr4.pse);
-  PrintDebug("CR4:     pae   0x%x\n",cr4.pae);
-  PrintDebug("CR4:     mce   0x%x\n",cr4.mce);
-  PrintDebug("CR4:     pge   0x%x\n",cr4.pge);
-  PrintDebug("CR4:     pce   0x%x\n",cr4.pce);
-  PrintDebug("CR4:     osfx  0x%x\n",cr4.osf_xsr);
-  PrintDebug("CR4:     osx   0x%x\n",cr4.osx);
-  PrintDebug("CR4:     rsvd1 0x%x\n",cr4.rsvd1);
-
-  PrintDebug("RFLAGS:  cf    0x%x\n",rflags.cf);
-  PrintDebug("RFLAGS:  rsvd1 0x%x\n",rflags.rsvd1);
-  PrintDebug("RFLAGS:  pf    0x%x\n",rflags.pf);
-  PrintDebug("RFLAGS:  rsvd2 0x%x\n",rflags.rsvd2);
-  PrintDebug("RFLAGS:  af    0x%x\n",rflags.af);
-  PrintDebug("RFLAGS:  rsvd3 0x%x\n",rflags.rsvd3);
-  PrintDebug("RFLAGS:  zf    0x%x\n",rflags.zf);
-  PrintDebug("RFLAGS:  sf    0x%x\n",rflags.sf);
-  PrintDebug("RFLAGS:  tf    0x%x\n",rflags.tf);
-  PrintDebug("RFLAGS:  intr  0x%x\n",rflags.intr);
-  PrintDebug("RFLAGS:  df    0x%x\n",rflags.df);
-  PrintDebug("RFLAGS:  of    0x%x\n",rflags.of);
-  PrintDebug("RFLAGS:  iopl  0x%x\n",rflags.iopl);
-  PrintDebug("RFLAGS:  nt    0x%x\n",rflags.nt);
-  PrintDebug("RFLAGS:  rsvd4 0x%x\n",rflags.rsvd4);
-  PrintDebug("RFLAGS:  rf    0x%x\n",rflags.rf);
-  PrintDebug("RFLAGS:  vm    0x%x\n",rflags.vm);
-  PrintDebug("RFLAGS:  ac    0x%x\n",rflags.ac);
-  PrintDebug("RFLAGS:  vif   0x%x\n",rflags.vif);
-  PrintDebug("RFLAGS:  id    0x%x\n",rflags.id);
-  PrintDebug("RFLAGS:  rsvd5 0x%x\n",rflags.rsvd5);
-  PrintDebug("RFLAGS:  rsvd6 0x%x\n",rflags.rsvd6);
-
-}
-#else
-void PrintCtrlRegs(struct guest_info *info)
-{}
-#endif
-
 /* Segmentation is a problem here...
  *
  * When we get a memory operand, presumably we use the default segment (which is?) 
@@ -91,309 +14,120 @@ void PrintCtrlRegs(struct guest_info *info)
  */
 
 
-int handle_cr0_write(struct guest_info * info) {
-  char instr[15];
-  
-  
-  switch (info->cpu_mode) { 
-  case REAL: 
-    {
-      int index = 0;
-      int ret;
-      
-      PrintDebug("Real Mode write to CR0 at linear guest pa 0x%x\n",get_addr_linear(info,info->rip,&(info->segments.cs)));
+#ifndef DEBUG_CTRL_REGS
+#undef PrintDebug
+#define PrintDebug(fmt, args...)
+#endif
 
-      // The real rip address is actually a combination of the rip + CS base 
-      ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
-      if (ret != 15) {
-       // I think we should inject a GPF into the guest
-       PrintDebug("Could not read instruction (ret=%d)\n", ret);
-       return -1;
-      }
 
-      while (is_prefix_byte(instr[index])) {
-       index++; 
-      }
 
-      if ((instr[index] == cr_access_byte) && 
-         (instr[index + 1] == lmsw_byte) && 
-         (MODRM_REG(instr[index + 2]) == lmsw_reg_byte)) {
-       addr_t first_operand;
-       addr_t second_operand;
-       struct cr0_real *real_cr0;
-       struct cr0_real *new_cr0;
-       operand_type_t addr_type;
-       char new_cr0_val = 0;
-       // LMSW
-       // decode mod/RM
-       index += 2;
-       real_cr0 = (struct cr0_real*)&(info->ctrl_regs.cr0);
-
-       addr_type = decode_operands16(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG16);
 
 
-       if (addr_type == REG_OPERAND) {
-         new_cr0 = (struct cr0_real *)first_operand;
-       } else if (addr_type == MEM_OPERAND) {
-         addr_t host_addr;
 
-         if (guest_pa_to_host_va(info, first_operand + (info->segments.ds.base << 4), &host_addr) == -1) {
-           // gpf the guest
-           return -1;
-         }
 
-         new_cr0 = (struct cr0_real *)host_addr;
-       } else {
-         PrintDebug("Memory operand in real mode write to CR0 is UNIMPLEMENTED\n");
-         // error... don't know what to do
-         return -1;
-       }
-                
-       if ((new_cr0->pe == 1) && (real_cr0->pe == 0)) {
-         info->cpu_mode = PROTECTED;
-       } else if ((new_cr0->pe == 0) && (real_cr0->pe == 1)) {
-         info->cpu_mode = REAL;
-       }
-      
-       new_cr0_val = *(char*)(new_cr0) & 0x0f;
+int handle_cr0_write(struct guest_info * info) {
+  char instr[15];
+  int ret;
+  struct x86_instr dec_instr;
 
+  if (info->mem_mode == PHYSICAL_MEM) { 
+    ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
+  } else { 
+    ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
+  }
 
-       if (info->shdw_pg_mode == SHADOW_PAGING) {
-         struct cr0_real * shadow_cr0 = (struct cr0_real*)&(info->shdw_pg_state.guest_cr0);
-
-         PrintDebug("Old CR0=%x, Old Shadow CR0=%x\n", *real_cr0, *shadow_cr0);        
-         /* struct cr0_real is only 4 bits wide, 
-          * so we can overwrite the real_cr0 without worrying about the shadow fields
-          */
-         *(char*)real_cr0 &= 0xf0;
-         *(char*)real_cr0 |= new_cr0_val;
-       
-         *(char*)shadow_cr0 &= 0xf0;
-         *(char*)shadow_cr0 |= new_cr0_val;
+  if (ret != 15) {
+    // I think we should inject a GPF into the guest
+    PrintError("Could not read instruction (ret=%d)\n", ret);
+    return -1;
+  }
 
-         PrintDebug("New CR0=%x, New Shadow CR0=%x\n", *real_cr0, *shadow_cr0);        
-       } else {
-         PrintDebug("Old CR0=%x\n", *real_cr0);        
-         // for now we just pass through....
-         *(char*)real_cr0 &= 0xf0;
-         *(char*)real_cr0 |= new_cr0_val;
+  if (v3_decode(info, (addr_t)instr, &dec_instr) == -1) {
+    PrintError("Could not decode instruction\n");
+    return -1;
+  }
 
-         PrintDebug("New CR0=%x\n", *real_cr0);        
-       }
 
+  if (opcode_cmp(V3_OPCODE_LMSW, (const uchar_t *)(dec_instr.opcode)) == 0) {
+    struct cr0_real *real_cr0  = (struct cr0_real*)&(info->ctrl_regs.cr0);
+    struct cr0_real *new_cr0 = (struct cr0_real *)(dec_instr.first_operand.operand);   
+    uchar_t new_cr0_val;
 
-       info->rip += index;
+    PrintDebug("LMSW\n");
 
-      } else if ((instr[index] == cr_access_byte) && 
-                (instr[index + 1] == clts_byte)) {
-       // CLTS
-       PrintDebug("CLTS unhandled in CR0 write\n");
-       return -1;
+    new_cr0_val = (*(char*)(new_cr0)) & 0x0f;
+    
+    PrintDebug("OperandVal = %x\n", new_cr0_val);
 
-      } else if ((instr[index] == cr_access_byte) && 
-                (instr[index + 1] = mov_to_cr_byte)) {
-       addr_t first_operand;
-       addr_t second_operand;
-       struct cr0_32 *real_cr0;
-       struct cr0_32 *new_cr0;
-       operand_type_t addr_type;
-     
+    PrintDebug("Old CR0=%x\n", *real_cr0);     
+    *(uchar_t*)real_cr0 &= 0xf0;
+    *(uchar_t*)real_cr0 |= new_cr0_val;
+    PrintDebug("New CR0=%x\n", *real_cr0);     
       
-       index += 2;
-       real_cr0 = (struct cr0_32*)&(info->ctrl_regs.cr0);
-
-       addr_type = decode_operands16(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32);
-
-       if (addr_type != REG_OPERAND) {
-         PrintDebug("Moving to CR0 from non-register operand in CR0 write\n");
-         /* Mov to CR0 Can only be a 32 bit register */
-         // FIX ME
-         return -1;
-       }
-
-       new_cr0 = (struct cr0_32 *)first_operand;
 
-       if (new_cr0->pe == 1) {
-         PrintDebug("Entering Protected Mode\n");
-         info->cpu_mode = PROTECTED;
-       }
-
-       if (new_cr0->pe == 0) { 
-         PrintDebug("Entering Real Mode\n");
-         info->cpu_mode = REAL;
-       }
-         
-
-       if (new_cr0->pg == 1) {
-         PrintDebug("Paging is already turned on in switch to protected mode in CR0 write\n");
-
-         // GPF the guest??
-         return -1;
-       }
-
-       if (info->shdw_pg_mode == SHADOW_PAGING) {
-         struct cr0_32 * shadow_cr0 = (struct cr0_32 *)&(info->shdw_pg_state.guest_cr0);
-       
-         PrintDebug("Old CR0=%x, Old Shadow CR0=%x\n", *real_cr0, *shadow_cr0);        
-         *real_cr0 = *new_cr0;
-         real_cr0->pg = 1;
-
-         *shadow_cr0 = *new_cr0;
-
-         PrintDebug("New CR0=%x, New Shadow CR0=%x\n", *real_cr0, *shadow_cr0);        
-       } else {
-         PrintDebug("Old CR0=%x\n", *real_cr0);        
-         *real_cr0 = *new_cr0;
-         PrintDebug("New CR0=%x\n", *real_cr0);        
-       }
-
-       info->rip += index;
-
-      } else {
-       PrintDebug("Unsupported Instruction\n");
-       // unsupported instruction, UD the guest
-       return -1;
-      }
+    if (info->shdw_pg_mode == SHADOW_PAGING) {
+      struct cr0_real * shadow_cr0 = (struct cr0_real*)&(info->shdw_pg_state.guest_cr0);
+      
+      PrintDebug(" Old Shadow CR0=%x\n", *shadow_cr0); 
+      *(uchar_t*)shadow_cr0 &= 0xf0;
+      *(uchar_t*)shadow_cr0 |= new_cr0_val;
+      PrintDebug("New Shadow CR0=%x\n", *shadow_cr0);  
+    }
+  } else if (opcode_cmp(V3_OPCODE_MOV2CR, (const uchar_t *)(dec_instr.opcode)) == 0) {
+    PrintDebug("MOV2CR0\n");
 
-    } 
-    break;
-  case PROTECTED: 
-    {
+    if (info->cpu_mode == LONG) {
+      // 64 bit registers
+    } else {
+      // 32 bit registers
+       struct cr0_32 *real_cr0 = (struct cr0_32*)&(info->ctrl_regs.cr0);
+       struct cr0_32 *new_cr0= (struct cr0_32 *)(dec_instr.second_operand.operand);
 
-      int index = 0;
-      int ret;
+       PrintDebug("OperandVal = %x, length=%d\n", *new_cr0, dec_instr.first_operand.size);
 
-      PrintDebug("Protected %s Mode write to CR0 at guest %s linear rip 0x%x\n", 
-                info->mem_mode == VIRTUAL_MEM ? "Paged" : "",
-                info->mem_mode == VIRTUAL_MEM ? "virtual" : "",
-                get_addr_linear(info, info->rip, &(info->segments.cs)));
 
-      // OK, now we will read the instruction
-      // The only difference between PROTECTED and PROTECTED_PG is whether we read
-      // from guest_pa or guest_va
-      if (info->mem_mode == PHYSICAL_MEM) { 
-       // The real rip address is actually a combination of the rip + CS base 
-       ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
-      } else { 
-       ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
-      }
+       PrintDebug("Old CR0=%x\n", *real_cr0);
+       *real_cr0 = *new_cr0;
        
 
-      if (ret != 15) {
-       // I think we should inject a GPF into the guest
-       PrintDebug("Could not read instruction (ret=%d)\n", ret);
-       return -1;
-      }
-
-      while (is_prefix_byte(instr[index])) {
-       index++; 
-      }
-
-      struct cr0_32 * shadow_cr0 = (struct cr0_32 *)&(info->shdw_pg_state.guest_cr0);
-
-      struct cr0_32 * real_cr0 = (struct cr0_32*)&(info->ctrl_regs.cr0);
-
-      if ((instr[index] == cr_access_byte) && 
-         (instr[index + 1] == mov_to_cr_byte)) {
-
-       // MOV to CR0
-    
-       addr_t first_operand;
-       addr_t second_operand;
-       struct cr0_32 *new_cr0;
-       operand_type_t addr_type;
-
-       index += 2;
-
-       addr_type = decode_operands32(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32);
-
-       if (addr_type != REG_OPERAND) {
-         PrintDebug("Non-register operand in write to CR0\n");
-         return -1;
-       }
-
-       new_cr0 = (struct cr0_32 *)first_operand;
-
-
-
-       if (info->shdw_pg_mode == SHADOW_PAGING) {
-         struct cr0_32 * shadow_cr0 = (struct cr0_32 *)&(info->shdw_pg_state.guest_cr0);
-
-         if (new_cr0->pg == 1){
-           // This should be new_cr0->pg && !(old_cr->pg), right?
-           // and then a case for turning paging off?
-
-           struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.shadow_cr3);
-
-           info->mem_mode = VIRTUAL_MEM;
+       if (info->shdw_pg_mode == SHADOW_PAGING) {
+         struct cr0_32 * shadow_cr0 = (struct cr0_32 *)&(info->shdw_pg_state.guest_cr0);
          
-           *shadow_cr0 = *new_cr0;
-           *real_cr0 = *new_cr0;
-
-           //
-           // Activate Shadow Paging
-           //
-           PrintDebug("Turning on paging in the guest\n");
-
-           info->ctrl_regs.cr3 = *(addr_t*)shadow_cr3;
+         PrintDebug("Old Shadow CR0=%x\n", *shadow_cr0);       
          
-
-         } else if (new_cr0->pe == 0) {
-           info->cpu_mode = REAL;
-
-           *shadow_cr0 = *new_cr0;
-           *real_cr0 = *new_cr0;
+         real_cr0->et = 1;
+         
+         *shadow_cr0 = *new_cr0;
+         shadow_cr0->et = 1;
+         
+         if (get_mem_mode(info) == VIRTUAL_MEM) {
+           struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.shadow_cr3);
+           
+           info->ctrl_regs.cr3 = *(addr_t*)shadow_cr3;
+         } else  {
+           info->ctrl_regs.cr3 = *(addr_t*)&(info->direct_map_pt);
            real_cr0->pg = 1;
          }
-
-
-       } else {
-         *real_cr0 = *new_cr0;
-       }
-
-       info->rip += index;
-
-      } else if ((instr[index] == 0x0f) &&
-                (instr[index + 1] == 0x06)) { 
-       // CLTS instruction
-       PrintDebug("CLTS instruction - clearing TS flag of real and shadow CR0\n");
-       shadow_cr0->ts = 0;
-       real_cr0->ts = 0;
-       
-       index+=2;
-       
-       info->rip+=index;
-
-      } else {
-       PrintDebug("Unkown instruction: \n");
-       SerialMemDump(instr,15);
-       return -1;
-      }
+         
+         PrintDebug("New Shadow CR0=%x\n",*shadow_cr0);
+       }
+       PrintDebug("New CR0=%x\n", *real_cr0);
     }
-    break;
-    
-  case PROTECTED_PAE:
-    PrintDebug("Protected PAE Mode write to CR0 is UNIMPLEMENTED\n");
-    return -1;
 
-  case LONG:
-    PrintDebug("Protected Long Mode write to CR0 is UNIMPLEMENTED\n");
-    return -1;
+  } else if (opcode_cmp(V3_OPCODE_CLTS, (const uchar_t *)(dec_instr.opcode)) == 0) {
+    // CLTS
+    struct cr0_32 *real_cr0 = (struct cr0_32*)&(info->ctrl_regs.cr0);
+       
+    real_cr0->ts = 0;
 
-  default: 
-    {
-      PrintDebug("Unknown Mode write to CR0 (info->cpu_mode=0x%x\n)",info->cpu_mode);
-      return -1;
+    if (info->shdw_pg_mode == SHADOW_PAGING) {
+      struct cr0_32 * shadow_cr0 = (struct cr0_32 *)&(info->shdw_pg_state.guest_cr0);
+      shadow_cr0->ts = 0;
     }
-    break;
-
   }
 
+  info->rip += dec_instr.instr_length;
+
   return 0;
 }
 
@@ -410,6 +144,7 @@ int handle_cr0_read(struct guest_info * info) {
       int ret;
 
       PrintDebug("Real Mode read from CR0 at linear guest pa 0x%x\n",get_addr_linear(info,info->rip,&(info->segments.cs)));
+      //PrintV3Segments(info);
 
       // The real rip address is actually a combination of the rip + CS base 
       ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
@@ -421,9 +156,28 @@ int handle_cr0_read(struct guest_info * info) {
 
 
       while (is_prefix_byte(instr[index])) {
+       switch(instr[index]) {
+       case PREFIX_CS_OVERRIDE:
+       case PREFIX_SS_OVERRIDE:
+       case PREFIX_DS_OVERRIDE:
+       case PREFIX_ES_OVERRIDE:
+       case PREFIX_FS_OVERRIDE:
+       case PREFIX_GS_OVERRIDE:
+         PrintDebug("Segment Override!!\n");
+         return -1;
+         break;
+       default:
+         break;
+       }
        index++; 
       }
 
+      /*
+       while (is_prefix_byte(instr[index])) {
+       index++; 
+       }
+      */
+
       if ((instr[index] == cr_access_byte) && 
          (instr[index + 1] == smsw_byte) && 
          (MODRM_REG(instr[index + 2]) == smsw_reg_byte)) {
@@ -497,6 +251,8 @@ int handle_cr0_read(struct guest_info * info) {
          *virt_cr0 = *real_cr0;
        }
 
+       PrintDebug("Returning CR0: %x\n", *virt_cr0);
+
        info->rip += index;
 
       } else {
@@ -529,6 +285,12 @@ int handle_cr0_read(struct guest_info * info) {
        ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
       }
 
+
+      /*
+       PrintDebug("Instr (15 bytes) at %x:\n", instr);
+       PrintTraceMemDump((char*)instr, 15);
+      */
+
       if (ret != 15) {
        // I think we should inject a GPF into the guest
        PrintDebug("Could not read Protected %s mode instruction (ret=%d)\n", 
@@ -536,11 +298,31 @@ int handle_cr0_read(struct guest_info * info) {
        return -1;
       }
 
+
       while (is_prefix_byte(instr[index])) {
+       switch(instr[index]) {
+       case PREFIX_CS_OVERRIDE:
+       case PREFIX_SS_OVERRIDE:
+       case PREFIX_DS_OVERRIDE:
+       case PREFIX_ES_OVERRIDE:
+       case PREFIX_FS_OVERRIDE:
+       case PREFIX_GS_OVERRIDE:
+         PrintDebug("Segment Override!!\n");
+         return -1;
+         break;
+       default:
+         break;
+       }
        index++; 
       }
 
 
+      /*
+       while (is_prefix_byte(instr[index])) {
+       index++; 
+       }
+      */
+
       if ((instr[index] == cr_access_byte) &&
          (instr[index+1] == mov_from_cr_byte)) {
        
@@ -573,6 +355,9 @@ int handle_cr0_read(struct guest_info * info) {
        } else {
          *virt_cr0 = *real_cr0;
        }
+
+         PrintDebug("real CR0: %x\n", *(uint_t*)real_cr0);
+         PrintDebug("returned CR0: %x\n", *(uint_t*)virt_cr0);
       
        info->rip += index;
 
@@ -608,7 +393,131 @@ int handle_cr0_read(struct guest_info * info) {
 
 
 int handle_cr3_write(struct guest_info * info) {
-  if (info->cpu_mode == PROTECTED) {
+  if (info->cpu_mode == REAL) {
+    // WHAT THE HELL DOES THIS EVEN MEAN?????
+
+    int index = 0;
+    int ret;
+    char instr[15];
+
+    PrintDebug("Real Mode Write to CR3.\n");
+    // We need to read the instruction, which is at CS:IP, but that 
+    // linear address is guest physical without PG and guest virtual with PG
+
+    ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
+
+    if (ret != 15) {
+      PrintDebug("Could not read instruction (ret=%d)\n", ret);
+      return -1;
+    }
+
+    while (is_prefix_byte(instr[index])) {
+      switch(instr[index]) {
+      case PREFIX_CS_OVERRIDE:
+      case PREFIX_SS_OVERRIDE:
+      case PREFIX_DS_OVERRIDE:
+      case PREFIX_ES_OVERRIDE:
+      case PREFIX_FS_OVERRIDE:
+      case PREFIX_GS_OVERRIDE:
+       PrintDebug("Segment Override!!\n");
+       return -1;
+       break;
+      default:
+       break;
+      }
+      index++; 
+    }
+    
+
+    if ((instr[index] == cr_access_byte) && 
+       (instr[index + 1] == mov_to_cr_byte)) {
+
+      addr_t first_operand;
+      addr_t second_operand;
+      struct cr3_32 * new_cr3;
+      //      struct cr3_32 * real_cr3;
+      operand_type_t addr_type;
+
+      index += 2;
+
+      addr_type = decode_operands16(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32);
+
+      if (addr_type != REG_OPERAND) {
+       /* Mov to CR3 can only be a 32 bit register */
+       return -1;
+      }
+
+      new_cr3 = (struct cr3_32 *)first_operand;
+
+      if (info->shdw_pg_mode == SHADOW_PAGING) {
+       int flushed=0;
+       addr_t shadow_pt;
+       struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.shadow_cr3);
+       struct cr3_32 * guest_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.guest_cr3);
+
+       /*
+
+         if (CR3_TO_PDE32(*(uint_t*)shadow_cr3) != 0) {
+           PrintDebug("Shadow Page Table\n");
+           PrintDebugPageTables((pde32_t *)CR3_TO_PDE32(*(uint_t*)shadow_cr3));
+         }
+       */
+
+       /* Delete the current Page Tables */
+       if (!CR3_32_SAME_BASE(new_cr3,guest_cr3)) { 
+         PrintDebug("New CR3 is different - flushing shadow page table\n");
+         delete_page_tables_pde32((pde32_t *)CR3_TO_PDE32(*(uint_t*)shadow_cr3));
+         flushed=1;
+       } else {
+         PrintDebug("New CR3 (0x%x) has same base as previous CR3 (0x%x) - reusing shadow page table\n", *((uint_t*)new_cr3), *((uint_t*)guest_cr3));
+       }
+
+       PrintDebug("Old Shadow CR3=%x; Old Guest CR3=%x\n", 
+                  *(uint_t*)shadow_cr3, *(uint_t*)guest_cr3);
+
+
+       *guest_cr3 = *new_cr3;
+
+
+       if (flushed) { 
+         // Something like this
+         shadow_pt =  create_new_shadow_pt32(info);
+         //shadow_pt = setup_shadow_pt32(info, CR3_TO_PDE32(*(addr_t *)new_cr3));
+       } else {
+         shadow_pt = shadow_cr3->pdt_base_addr<<12;
+       }
+
+       /* Copy Various flags */
+       *shadow_cr3 = *new_cr3;
+
+       /*
+       {
+         addr_t tmp_addr;
+         guest_pa_to_host_va(info, ((*(uint_t*)guest_cr3) & 0xfffff000), &tmp_addr);
+         PrintDebug("Guest PD\n");
+         PrintPD32((pde32_t *)tmp_addr);
+
+       }
+       */
+
+       
+       shadow_cr3->pdt_base_addr = PD32_BASE_ADDR(shadow_pt);
+
+       PrintDebug("New Shadow CR3=%x; New Guest CR3=%x\n", 
+                  *(uint_t*)shadow_cr3, *(uint_t*)guest_cr3);
+
+      }
+      info->rip += index;
+
+    } else {
+      PrintDebug("Unknown Instruction\n");
+      PrintTraceMemDump(instr,15);
+      return -1;
+    }
+
+
+
+  } else if (info->cpu_mode == PROTECTED) {
     int index = 0;
     int ret;
     char instr[15];
@@ -622,10 +531,10 @@ int handle_cr3_write(struct guest_info * info) {
     // linear address is guest physical without PG and guest virtual with PG
     if (info->mem_mode == PHYSICAL_MEM) { 
       // The real rip address is actually a combination of the rip + CS base 
-      PrintDebug("Writing Guest CR3 Write (Physical Address)\n");
+      //PrintDebug("Writing Guest CR3 Write (Physical Address)\n");
       ret = read_guest_pa_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
     } else { 
-      PrintDebug("Writing Guest CR3 Write (Virtual Address)\n");
+      //PrintDebug("Writing Guest CR3 Write (Virtual Address)\n");
       // The real rip address is actually a combination of the rip + CS base 
       ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
     }
@@ -634,10 +543,29 @@ int handle_cr3_write(struct guest_info * info) {
       PrintDebug("Could not read instruction (ret=%d)\n", ret);
       return -1;
     }
-    
+
     while (is_prefix_byte(instr[index])) {
-      index++;
+      switch(instr[index]) {
+      case PREFIX_CS_OVERRIDE:
+      case PREFIX_SS_OVERRIDE:
+      case PREFIX_DS_OVERRIDE:
+      case PREFIX_ES_OVERRIDE:
+      case PREFIX_FS_OVERRIDE:
+      case PREFIX_GS_OVERRIDE:
+       PrintDebug("Segment Override!!\n");
+       return -1;
+       break;
+      default:
+       break;
+      }
+      index++; 
     }
+    
+    /*    
+         while (is_prefix_byte(instr[index])) {
+         index++;
+         }
+    */
 
     if ((instr[index] == cr_access_byte) && 
        (instr[index + 1] == mov_to_cr_byte)) {
@@ -660,18 +588,27 @@ int handle_cr3_write(struct guest_info * info) {
       new_cr3 = (struct cr3_32 *)first_operand;
 
       if (info->shdw_pg_mode == SHADOW_PAGING) {
+       int flushed=0;
        addr_t shadow_pt;
        struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.shadow_cr3);
        struct cr3_32 * guest_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.guest_cr3);
 
 
+       /*
          if (CR3_TO_PDE32(*(uint_t*)shadow_cr3) != 0) {
            PrintDebug("Shadow Page Table\n");
            PrintDebugPageTables((pde32_t *)CR3_TO_PDE32(*(uint_t*)shadow_cr3));
          }
+       */
 
        /* Delete the current Page Tables */
-       delete_page_tables_pde32((pde32_t *)CR3_TO_PDE32(*(uint_t*)shadow_cr3));
+       if (!CR3_32_SAME_BASE(guest_cr3,new_cr3)) { 
+         PrintDebug("New CR3 is different - flushing shadow page table\n");
+         delete_page_tables_pde32((pde32_t *)CR3_TO_PDE32(*(uint_t*)shadow_cr3));
+         flushed=1;
+       } else {
+         PrintDebug("New CR3 (0x%x) has same base as previous CR3 (0x%x) - reusing shadow page table\n",*((uint_t*)new_cr3), *((uint_t*)guest_cr3));
+       }
 
        PrintDebug("Old Shadow CR3=%x; Old Guest CR3=%x\n", 
                   *(uint_t*)shadow_cr3, *(uint_t*)guest_cr3);
@@ -679,15 +616,19 @@ int handle_cr3_write(struct guest_info * info) {
 
        *guest_cr3 = *new_cr3;
 
+       if (flushed) { 
+         // Something like this
+         shadow_pt =  create_new_shadow_pt32(info);
+         //shadow_pt = setup_shadow_pt32(info, CR3_TO_PDE32(*(addr_t *)new_cr3));
+       } else {
+         shadow_pt =shadow_cr3->pdt_base_addr << 12;
+       }
 
 
-       // Something like this
-       shadow_pt =  create_new_shadow_pt32(info);
-       //shadow_pt = setup_shadow_pt32(info, CR3_TO_PDE32(*(addr_t *)new_cr3));
-
        /* Copy Various flags */
        *shadow_cr3 = *new_cr3;
 
+       /*
        {
          addr_t tmp_addr;
          guest_pa_to_host_va(info, ((*(uint_t*)guest_cr3) & 0xfffff000), &tmp_addr);
@@ -695,7 +636,7 @@ int handle_cr3_write(struct guest_info * info) {
          PrintPD32((pde32_t *)tmp_addr);
 
        }
-       
+       */
 
        
        shadow_cr3->pdt_base_addr = PD32_BASE_ADDR(shadow_pt);
@@ -715,7 +656,7 @@ int handle_cr3_write(struct guest_info * info) {
 
     } else {
       PrintDebug("Unknown Instruction\n");
-      SerialMemDump(instr,15);
+      PrintTraceMemDump(instr,15);
       return -1;
     }
   } else {
@@ -730,7 +671,80 @@ int handle_cr3_write(struct guest_info * info) {
 
 
 int handle_cr3_read(struct guest_info * info) {
-  if (info->cpu_mode == PROTECTED ) {
+
+  if (info->cpu_mode == REAL) {
+    char instr[15];
+    int ret;
+    int index = 0;
+    addr_t linear_addr = 0;
+
+    linear_addr = get_addr_linear(info, info->rip, &(info->segments.cs));
+
+    
+    //PrintDebug("RIP Linear: %x\n", linear_addr);
+    //PrintV3Segments(info);
+    
+    ret = read_guest_pa_memory(info, linear_addr, 15, instr);
+
+    if (ret != 15) {
+      PrintDebug("Could not read instruction (ret=%d)\n", ret);
+      return -1;
+    }
+    
+    while (is_prefix_byte(instr[index])) {
+      switch(instr[index]) {
+      case PREFIX_CS_OVERRIDE:
+      case PREFIX_SS_OVERRIDE:
+      case PREFIX_DS_OVERRIDE:
+      case PREFIX_ES_OVERRIDE:
+      case PREFIX_FS_OVERRIDE:
+      case PREFIX_GS_OVERRIDE:
+       PrintDebug("Segment Override!!\n");
+       return -1;
+       break;
+      default:
+       break;
+      }
+      index++; 
+    }
+
+
+    if ((instr[index] == cr_access_byte) && 
+       (instr[index + 1] == mov_from_cr_byte)) {
+      addr_t first_operand;
+      addr_t second_operand;
+      struct cr3_32 * virt_cr3;
+      struct cr3_32 * real_cr3 = (struct cr3_32 *)&(info->ctrl_regs.cr3);
+      operand_type_t addr_type;
+
+      index += 2;
+
+      addr_type = decode_operands16(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32);
+
+      if (addr_type != REG_OPERAND) {
+       /* Mov to CR3 can only be a 32 bit register */
+       return -1;
+      }
+
+      virt_cr3 = (struct cr3_32 *)first_operand;
+
+      if (info->shdw_pg_mode == SHADOW_PAGING) {
+       *virt_cr3 = *(struct cr3_32 *)&(info->shdw_pg_state.guest_cr3);
+      } else {
+       *virt_cr3 = *real_cr3;
+      }
+      
+      info->rip += index;
+    } else {
+      PrintDebug("Unknown Instruction\n");
+      PrintTraceMemDump(instr,15);
+      return -1;
+    }
+
+
+    return 0;
+  } else if (info->cpu_mode == PROTECTED) {
+
     int index = 0;
     int ret;
     char instr[15];
@@ -752,9 +766,28 @@ int handle_cr3_read(struct guest_info * info) {
     }
     
     while (is_prefix_byte(instr[index])) {
-      index++;
+      switch(instr[index]) {
+      case PREFIX_CS_OVERRIDE:
+      case PREFIX_SS_OVERRIDE:
+      case PREFIX_DS_OVERRIDE:
+      case PREFIX_ES_OVERRIDE:
+      case PREFIX_FS_OVERRIDE:
+      case PREFIX_GS_OVERRIDE:
+       PrintDebug("Segment Override!!\n");
+       return -1;
+       break;
+      default:
+       break;
+      }
+      index++; 
     }
 
+    /*
+      while (is_prefix_byte(instr[index])) {
+      index++;
+      }
+    */
+
     if ((instr[index] == cr_access_byte) && 
        (instr[index + 1] == mov_from_cr_byte)) {
       addr_t first_operand;
@@ -783,12 +816,12 @@ int handle_cr3_read(struct guest_info * info) {
       info->rip += index;
     } else {
       PrintDebug("Unknown Instruction\n");
-      SerialMemDump(instr,15);
+      PrintTraceMemDump(instr,15);
       return -1;
     }
   } else {
     PrintDebug("Invalid operating Mode (0x%x), control registers follow\n", info->cpu_mode);
-    PrintCtrlRegs(info);
+    PrintV3CtrlRegs(info);
     return -1;
   }