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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 d3a59d1..50bba30 100644 (file)
--- a/palacios/src/palacios/vmm_v3dec.c
+++ b/palacios/src/palacios/vmm_v3dec.c
@@ -20,41 +20,37 @@
 #include <palacios/vmm_decoder.h>
 #include <palacios/vmm_instr_decoder.h>
 
-
-/* Disgusting mask hack...
-   I can't think right now, so we'll do it this way...
-*/
-static const ullong_t mask_1 = 0x00000000000000ffLL;
-static const ullong_t mask_2 = 0x000000000000ffffLL;
-static const ullong_t mask_4 = 0x00000000ffffffffLL;
-static const ullong_t mask_8 = 0xffffffffffffffffLL;
-
-
-#define MASK(val, length) ({                   \
-           ullong_t mask = 0x0LL;              \
-           switch (length) {                   \
-               case 1:                         \
-                   mask = mask_1;              \
-                   break;                      \
-               case 2:                         \
-                   mask = mask_2;              \
-                   break;                      \
-               case 4:                         \
-                   mask = mask_4;              \
-                   break;                      \
-               case 8:                         \
-                   mask = mask_8;              \
-                   break;                      \
-           }                                   \
-           val & mask;                         \
-       })
+#ifndef CONFIG_DEBUG_DECODER
+#undef PrintDebug
+#define PrintDebug(fmt, args...)
+#endif
+
+
+#define MASK(val, length) ({                                           \
+            uint64_t mask = 0x0LL;                                     \
+            switch (length) {                                          \
+               case 1:                                                 \
+                   mask = 0x00000000000000ffLL;                        \
+                    break;                                             \
+                case 2:                                                        \
+                    mask = 0x000000000000ffffLL;                       \
+                    break;                                             \
+                case 4:                                                        \
+                    mask = 0x00000000ffffffffLL;                       \
+                    break;                                             \
+                case 8:                                                        \
+                    mask = 0xffffffffffffffffLL;                       \
+                    break;                                             \
+            }                                                          \
+            val & mask;                                                        \
+        })
 
 static v3_op_type_t op_form_to_type(op_form_t form);
 static int parse_operands(struct guest_info * core, uint8_t * instr_ptr, struct x86_instr * instr, op_form_t form);
 
 
 int v3_disasm(struct guest_info * info, void *instr_ptr, addr_t * rip, int mark) {
-    return 0;
+    return -1;
 }
 
 
@@ -69,7 +65,7 @@ int v3_deinit_decoder(struct guest_info * core) {
 
 
 int v3_encode(struct guest_info * info, struct x86_instr * instr, uint8_t * instr_buf) {
-    return 0;
+    return -1;
 }
 
 
@@ -78,17 +74,36 @@ int v3_decode(struct guest_info * core, addr_t instr_ptr, struct x86_instr * ins
     int ret = 0;
     int length = 0;
 
+
+    V3_Print("Decoding Instruction at %p\n", (void *)instr_ptr);
+
     memset(instr, 0, sizeof(struct x86_instr));
 
     // scan for prefixes
     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;
+
+           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) {
        PrintError("Could not find instruction form (%x)\n", *(uint32_t *)(instr_ptr + length));
        return -1;
@@ -103,10 +118,10 @@ 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;
 }
@@ -116,11 +131,13 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
                          struct x86_instr * instr, op_form_t form) {
     // get operational mode of the guest for operand width
     uint8_t operand_width = get_operand_width(core, instr, form);
-    uint8_t addr_width = get_addr_width(core, instr, form);;
+    uint8_t addr_width = get_addr_width(core, instr);
     int ret = 0;
     uint8_t * instr_start = instr_ptr;
     
 
+    PrintDebug("\tOperand width=%d, Addr width=%d\n", operand_width, addr_width);
+
     switch (form) {
        case ADC_IMM2_8:
        case ADD_IMM2_8:
@@ -138,9 +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");
@@ -152,6 +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) {
@@ -163,6 +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;
@@ -185,9 +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");
@@ -199,7 +216,11 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            instr->src_operand.type = REG_OPERAND;
            instr->src_operand.size = operand_width;
 
-           decode_gpr(&(core->vm_regs), reg_code, &(instr->src_operand));
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
+
+           decode_gpr(core, reg_code, &(instr->src_operand));
 
            instr->num_operands = 2;
            break;
@@ -219,9 +240,33 @@ 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");
+               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_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");
@@ -232,7 +277,35 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
 
            instr->dst_operand.size = operand_width;
            instr->dst_operand.type = REG_OPERAND;
-           decode_gpr(&(core->vm_regs), reg_code, &(instr->dst_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;
 
@@ -245,9 +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");
@@ -258,7 +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;
 
@@ -277,22 +352,118 @@ static int parse_operands(struct guest_info * core, uint8_t * instr_ptr,
            }
 
            // Source: DS:(E)SI
-           // Source: ES:(E)DI
+           // Destination: ES:(E)DI
 
            instr->src_operand.type = MEM_OPERAND;
            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->src_operand.type = MEM_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;
+
+           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;
+           }
+               
+           instr_ptr += ret;
+
+           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;
+       }
+       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;
+           }
+
+           instr_ptr += ret;
+           
+           instr->src_operand.type = REG_OPERAND;
+           instr->src_operand.size = operand_width;
+           decode_cr(core, reg_code, &(instr->src_operand));
+
+           instr->src_operand.read = 1;
+           instr->dst_operand.write = 1;
+
+           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.operand = get_addr_linear(core, MASK(core->vm_regs.rdi, addr_width), &(core->segments.es));
+           instr->src_operand.type = REG_OPERAND;
+           instr->src_operand.operand = (addr_t)&(core->vm_regs.rax);
+
+           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;
 
            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: %d\n", form);
+           PrintError("Invalid Instruction form: %s\n", op_form_to_str(form));
            return -1;
     }
 
@@ -316,6 +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:
Public Palacios Development Repository for the V3VEE Project