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  cd palacios
  git checkout --track -b devel origin/devel
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additions for syscall hijacking
[palacios.git] / palacios / src / palacios / vmm_v3dec.c
diff --git a/palacios/src/palacios/vmm_v3dec.c b/palacios/src/palacios/vmm_v3dec.c
index 7dd716e..50bba30 100644 (file)
--- a/palacios/src/palacios/vmm_v3dec.c
+++ b/palacios/src/palacios/vmm_v3dec.c
@@ -20,9 +20,14 @@
 #include <palacios/vmm_decoder.h>
 #include <palacios/vmm_instr_decoder.h>
 
+#ifndef CONFIG_DEBUG_DECODER
+#undef PrintDebug
+#define PrintDebug(fmt, args...)
+#endif
+
 
 #define MASK(val, length) ({                                           \
-            ullong_t mask = 0x0LL;                                     \
+            uint64_t mask = 0x0LL;                                     \
             switch (length) {                                          \
                case 1:                                                 \
                    mask = 0x00000000000000ffLL;                        \
@@ -78,12 +83,25 @@ int v3_decode(struct guest_info * core, addr_t instr_ptr, struct x86_instr * ins
     length = v3_get_prefixes((uint8_t *)instr_ptr, &(instr->prefixes));
 
 
-    // check for REX prefix
+    // REX prefix
+    if (v3_get_vm_cpu_mode(core) == LONG) {
+       uint8_t prefix = *(uint8_t *)(instr_ptr + length);
 
+       if ((prefix & 0xf0) == 0x40) {
+           instr->prefixes.rex = 1;
 
-    form = op_code_to_form((uint8_t *)(instr_ptr + length), &length);
+           instr->prefixes.rex_rm = (prefix & 0x01);
+           instr->prefixes.rex_sib_idx = ((prefix & 0x02) >> 1);
+           instr->prefixes.rex_reg = ((prefix & 0x04) >> 2);
+           instr->prefixes.rex_op_size = ((prefix & 0x08) >> 3);
+
+           length += 1;
+       }
+    }
 
 
+    form = op_code_to_form((uint8_t *)(instr_ptr + length), &length);
+
     V3_Print("\t decoded as (%s)\n", op_form_to_str(form));
 
     if (form == INVALID_INSTR) {
@@ -100,11 +118,9 @@ int v3_decode(struct guest_info * core, addr_t instr_ptr, struct x86_instr * ins
        return -1;
     }
     length += ret;
-    
 
     instr->instr_length += length;
 
-
     v3_print_instr(instr);
 
     return 0;
@@ -139,9 +155,7 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
        case MOV_IMM2:{
            uint8_t reg_code = 0;
 
-           instr->dst_operand.size = operand_width;
-
-           ret = decode_rm_operand(core, instr_ptr, instr, &(instr->dst_operand), &reg_code);
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->dst_operand), &reg_code);
 
            if (ret == -1) {
                PrintError("Error decoding operand\n");
@@ -153,6 +167,7 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            instr->src_operand.type = IMM_OPERAND;
            instr->src_operand.size = operand_width;
 
+
            if (operand_width == 1) {
                instr->src_operand.operand = *(uint8_t *)instr_ptr;
            } else if (operand_width == 2) {
@@ -164,6 +179,9 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
                return -1;
            }
 
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
            instr_ptr += operand_width;
 
            instr->num_operands = 2;
@@ -186,9 +204,7 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
        case MOV_2MEM: {
            uint8_t reg_code = 0;
 
-           instr->dst_operand.size = operand_width;
-
-           ret = decode_rm_operand(core, instr_ptr, instr, &(instr->dst_operand), &reg_code);
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->dst_operand), &reg_code);
 
            if (ret == -1) {
                PrintError("Error decoding operand\n");
@@ -200,6 +216,10 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            instr->src_operand.type = REG_OPERAND;
            instr->src_operand.size = operand_width;
 
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
+
            decode_gpr(core, reg_code, &(instr->src_operand));
 
            instr->num_operands = 2;
@@ -220,9 +240,8 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
        case XOR_MEM2:
        case MOV_MEM2: {
            uint8_t reg_code = 0;
-           instr->src_operand.size = operand_width;
 
-           ret = decode_rm_operand(core, instr_ptr, instr, &(instr->src_operand), &reg_code);
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->src_operand), &reg_code);
 
            if (ret == -1) {
                PrintError("Error decoding operand\n");
@@ -235,6 +254,59 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            instr->dst_operand.type = REG_OPERAND;
            decode_gpr(core, reg_code, &(instr->dst_operand));
 
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
+           instr->num_operands = 2;
+
+           break;
+       }
+       case MOVSX_8:
+       case MOVZX_8: {
+           uint8_t reg_code = 0;
+
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->src_operand), &reg_code);
+           instr->src_operand.size = 1;
+
+           if (ret == -1) {
+               PrintError("Error decoding operand\n");
+               return -1;
+           }
+
+           instr_ptr += ret;
+
+           instr->dst_operand.size = operand_width;
+           instr->dst_operand.type = REG_OPERAND;
+           decode_gpr(core, reg_code, &(instr->dst_operand));
+
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
+           instr->num_operands = 2;
+
+           break;
+       }
+       case MOVSX:
+       case MOVZX: {
+           uint8_t reg_code = 0;
+
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->src_operand), &reg_code);
+           instr->src_operand.size = 2;
+
+           if (ret == -1) {
+               PrintError("Error decoding operand\n");
+               return -1;
+           }
+
+           instr_ptr += ret;
+
+           instr->dst_operand.size = operand_width;
+           instr->dst_operand.type = REG_OPERAND;
+           decode_gpr(core, reg_code, &(instr->dst_operand));
+
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
            instr->num_operands = 2;
 
            break;
@@ -246,9 +318,8 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
        case SUB_IMM2SX_8:
        case XOR_IMM2SX_8: {
            uint8_t reg_code = 0;
-           instr->src_operand.size = operand_width;
 
-           ret = decode_rm_operand(core, instr_ptr, instr, &(instr->src_operand), &reg_code);
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->dst_operand), &reg_code);
 
            if (ret == -1) {
                PrintError("Error decoding operand\n");
@@ -259,7 +330,10 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
 
            instr->src_operand.type = IMM_OPERAND;
            instr->src_operand.size = operand_width;
-           instr->src_operand.operand = *(sint8_t *)instr_ptr;  // sign extend.
+           instr->src_operand.operand = (addr_t)MASK((sint64_t)*(sint8_t *)instr_ptr, operand_width);  // sign extend.
+
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
 
            instr_ptr += 1;
 
@@ -284,104 +358,109 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            instr->src_operand.size = operand_width;
            instr->src_operand.operand = get_addr_linear(core,  MASK(core->vm_regs.rsi, addr_width), &(core->segments.ds));
 
+
            instr->dst_operand.type = MEM_OPERAND;
            instr->dst_operand.size = operand_width;
            instr->dst_operand.operand = get_addr_linear(core, MASK(core->vm_regs.rdi, addr_width), &(core->segments.es));
 
-           instr->num_operands = 2;
-
-           break;
 
-           case MOV_2CR: {
-               uint8_t reg_code = 0;
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
 
-               instr->src_operand.size = operand_width;
+           instr->num_operands = 2;
 
-               ret = decode_rm_operand(core, instr_ptr, instr, &(instr->src_operand),
-                                       &reg_code);
+           break;
+       }
+       case MOV_2CR: {
+           uint8_t reg_code = 0;
+           
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->src_operand),
+                                   &reg_code);
 
-               if (ret == -1) {
-                   PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
-                   return -1;
-               }
+           if (ret == -1) {
+               PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
+               return -1;
+           }
                
-               instr_ptr += ret;
+           instr_ptr += ret;
 
-               instr->dst_operand.type = REG_OPERAND;
-               instr->dst_operand.size = operand_width;
-               decode_cr(core, reg_code, &(instr->dst_operand));
+           instr->dst_operand.type = REG_OPERAND;
+           instr->dst_operand.size = operand_width;
+           decode_cr(core, reg_code, &(instr->dst_operand));
+           
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
 
-               instr->num_operands = 2;
-               break;
+           instr->num_operands = 2;
+           break;
+       }
+       case MOV_CR2: {
+           uint8_t reg_code = 0;
+           
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->dst_operand),
+                                   &reg_code);
+           
+           if (ret == -1) {
+               PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
+               return -1;
            }
-           case MOV_CR2: {
-               uint8_t reg_code = 0;
-
-               instr->dst_operand.size = operand_width;
-
-               ret = decode_rm_operand(core, instr_ptr, instr, &(instr->dst_operand),
-                                       &reg_code);
-
-               if (ret == -1) {
-                   PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
-                   return -1;
-               }
-
-               instr_ptr += ret;
-               
-               instr->src_operand.type = REG_OPERAND;
-               instr->src_operand.size = operand_width;
-               decode_cr(core, reg_code, &(instr->src_operand));
 
-               instr->num_operands = 2;
-               break;
-           }
-           case STOS:
-           case STOS_8: {
-               instr->is_str_op = 1;
-               
-               if (instr->prefixes.rep == 1) {
-                   instr->str_op_length = MASK(core->vm_regs.rcx, operand_width);
-               } else {
-                   instr->str_op_length = 1;
-               }
-               
-               instr->src_operand.size = operand_width;
-               instr->src_operand.type = REG_OPERAND;
-               instr->src_operand.operand = (addr_t)&(core->vm_regs.rax);
+           instr_ptr += ret;
+           
+           instr->src_operand.type = REG_OPERAND;
+           instr->src_operand.size = operand_width;
+           decode_cr(core, reg_code, &(instr->src_operand));
 
-               instr->dst_operand.type = MEM_OPERAND;
-               instr->dst_operand.size = operand_width;
-               instr->dst_operand.operand = get_addr_linear(core, MASK(core->vm_regs.rdi, addr_width), &(core->segments.es));
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
 
-               instr->num_operands = 2;
+           instr->num_operands = 2;
+           break;
+       }
+       case STOS:
+       case STOS_8: {
+           instr->is_str_op = 1;
 
-               break;
+           if (instr->prefixes.rep == 1) {
+               instr->str_op_length = MASK(core->vm_regs.rcx, operand_width);
+           } else {
+               instr->str_op_length = 1;
            }
-           case INVLPG: {
-               uint8_t reg_code = 0;
 
-               // We use the dst operand here to maintain bug-for-bug compatibility with XED
-
-               instr->dst_operand.size = operand_width;
-
-               ret = decode_rm_operand(core, instr_ptr, instr, &(instr->dst_operand), &reg_code);
+           instr->src_operand.size = operand_width;
+           instr->src_operand.type = REG_OPERAND;
+           instr->src_operand.operand = (addr_t)&(core->vm_regs.rax);
 
-               if (ret == -1) {
-                   PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
-                   return -1;
-               }
+           instr->dst_operand.type = MEM_OPERAND;
+           instr->dst_operand.size = operand_width;
+           instr->dst_operand.operand = get_addr_linear(core, MASK(core->vm_regs.rdi, addr_width), &(core->segments.es));
 
-               instr_ptr += ret;
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
 
-               instr->num_operands = 1;
-               break;
-           }
-           case CLTS: {
-               // no operands. 
-               break;
+           instr->num_operands = 2;
 
+           break;
+       }
+       case INVLPG: {
+           uint8_t reg_code = 0;
+           
+           ret = decode_rm_operand(core, instr_ptr, form, instr, &(instr->dst_operand), &reg_code);
+           
+           if (ret == -1) {
+               PrintError("Error decoding operand for (%s)\n", op_form_to_str(form));
+               return -1;
            }
+           
+           instr_ptr += ret;
+           
+           instr->num_operands = 1;
+           break;
+       }
+       case CLTS: {
+           // no operands. 
+           break;
+           
        }
        default:
            PrintError("Invalid Instruction form: %s\n", op_form_to_str(form));
@@ -408,6 +487,10 @@ static v3_op_type_t op_form_to_type(op_form_t form) {
        case MOV_2CR:
            return V3_OP_MOV2CR;
 
+    // KCH: for syscall interposition
+    case INT:
+        return V3_OP_INT;
+
 
        case MOV_MEM2_8:
        case MOV_MEM2:
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