hvf: correctly handle REX prefix in relation to legacy prefixes

In real x86 processors, the REX prefix must come after legacy prefixes.
REX before legacy is ignored.  Update the HVF emulation code to properly
handle this.  Fix some spelling errors in constants.  Fix some decoder
table initialization issues found by Coverity.

Signed-off-by: Cameron Esfahani <dirty@apple.com>
Message-Id: <eff30ded8307471936bec5d84c3b6efbc95e3211.1574625592.git.dirty@apple.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 46 insertions, 38 deletions

diff --git a/target/i386/hvf/x86_decode.c b/target/i386/hvf/x86_decode.c
index 822fa18..77c3466 100644
--- a/target/i386/hvf/x86_decode.c
+++ b/target/i386/hvf/x86_decode.c
@@ -122,7 +122,8 @@ static void decode_rax(CPUX86State *env, struct x86_decode *decode,
 {
     op->type = X86_VAR_REG;
     op->reg = R_EAX;
-    op->ptr = get_reg_ref(env, op->reg, decode->rex.rex, 0,
+    /* Since reg is always AX, REX prefix has no impact. */
+    op->ptr = get_reg_ref(env, op->reg, false, 0,
                           decode->operand_size);
 }
 
@@ -1687,40 +1688,37 @@ calc_addr:
     }
 }
 
-target_ulong get_reg_ref(CPUX86State *env, int reg, int rex, int is_extended,
-                         int size)
+target_ulong get_reg_ref(CPUX86State *env, int reg, int rex_present,
+                         int is_extended, int size)
 {
     target_ulong ptr = 0;
-    int which = 0;
 
     if (is_extended) {
         reg |= R_R8;
     }
 
-
     switch (size) {
     case 1:
-        if (is_extended || reg < 4 || rex) {
-            which = 1;
+        if (is_extended || reg < 4 || rex_present) {
             ptr = (target_ulong)&RL(env, reg);
         } else {
-            which = 2;
             ptr = (target_ulong)&RH(env, reg - 4);
         }
         break;
     default:
-        which = 3;
         ptr = (target_ulong)&RRX(env, reg);
         break;
     }
     return ptr;
 }
 
-target_ulong get_reg_val(CPUX86State *env, int reg, int rex, int is_extended,
-                         int size)
+target_ulong get_reg_val(CPUX86State *env, int reg, int rex_present,
+                         int is_extended, int size)
 {
     target_ulong val = 0;
-    memcpy(&val, (void *)get_reg_ref(env, reg, rex, is_extended, size), size);
+    memcpy(&val,
+           (void *)get_reg_ref(env, reg, rex_present, is_extended, size),
+           size);
     return val;
 }
 
@@ -1853,28 +1851,38 @@ void calc_modrm_operand(CPUX86State *env, struct x86_decode *decode,
 static void decode_prefix(CPUX86State *env, struct x86_decode *decode)
 {
     while (1) {
+        /*
+         * REX prefix must come after legacy prefixes.
+         * REX before legacy is ignored.
+         * Clear rex to simulate this.
+         */
         uint8_t byte = decode_byte(env, decode);
         switch (byte) {
         case PREFIX_LOCK:
             decode->lock = byte;
+            decode->rex.rex = 0;
             break;
         case PREFIX_REPN:
         case PREFIX_REP:
             decode->rep = byte;
+            decode->rex.rex = 0;
             break;
-        case PREFIX_CS_SEG_OVEERIDE:
-        case PREFIX_SS_SEG_OVEERIDE:
-        case PREFIX_DS_SEG_OVEERIDE:
-        case PREFIX_ES_SEG_OVEERIDE:
-        case PREFIX_FS_SEG_OVEERIDE:
-        case PREFIX_GS_SEG_OVEERIDE:
+        case PREFIX_CS_SEG_OVERRIDE:
+        case PREFIX_SS_SEG_OVERRIDE:
+        case PREFIX_DS_SEG_OVERRIDE:
+        case PREFIX_ES_SEG_OVERRIDE:
+        case PREFIX_FS_SEG_OVERRIDE:
+        case PREFIX_GS_SEG_OVERRIDE:
             decode->segment_override = byte;
+            decode->rex.rex = 0;
             break;
         case PREFIX_OP_SIZE_OVERRIDE:
             decode->op_size_override = byte;
+            decode->rex.rex = 0;
             break;
         case PREFIX_ADDR_SIZE_OVERRIDE:
             decode->addr_size_override = byte;
+            decode->rex.rex = 0;
             break;
         case PREFIX_REX ... (PREFIX_REX + 0xf):
             if (x86_is_long_mode(env_cpu(env))) {
@@ -2111,14 +2119,14 @@ void init_decoder()
 {
     int i;
     
-    for (i = 0; i < ARRAY_SIZE(_decode_tbl2); i++) {
-        memcpy(_decode_tbl1, &invl_inst, sizeof(invl_inst));
+    for (i = 0; i < ARRAY_SIZE(_decode_tbl1); i++) {
+        memcpy(&_decode_tbl1[i], &invl_inst, sizeof(invl_inst));
     }
     for (i = 0; i < ARRAY_SIZE(_decode_tbl2); i++) {
-        memcpy(_decode_tbl2, &invl_inst, sizeof(invl_inst));
+        memcpy(&_decode_tbl2[i], &invl_inst, sizeof(invl_inst));
     }
     for (i = 0; i < ARRAY_SIZE(_decode_tbl3); i++) {
-        memcpy(_decode_tbl3, &invl_inst, sizeof(invl_inst_x87));
+        memcpy(&_decode_tbl3[i], &invl_inst_x87, sizeof(invl_inst_x87));
     
     }
     for (i = 0; i < ARRAY_SIZE(_1op_inst); i++) {
@@ -2167,22 +2175,22 @@ target_ulong decode_linear_addr(CPUX86State *env, struct x86_decode *decode,
                                target_ulong addr, X86Seg seg)
 {
     switch (decode->segment_override) {
-    case PREFIX_CS_SEG_OVEERIDE:
+    case PREFIX_CS_SEG_OVERRIDE:
         seg = R_CS;
         break;
-    case PREFIX_SS_SEG_OVEERIDE:
+    case PREFIX_SS_SEG_OVERRIDE:
         seg = R_SS;
         break;
-    case PREFIX_DS_SEG_OVEERIDE:
+    case PREFIX_DS_SEG_OVERRIDE:
         seg = R_DS;
         break;
-    case PREFIX_ES_SEG_OVEERIDE:
+    case PREFIX_ES_SEG_OVERRIDE:
         seg = R_ES;
         break;
-    case PREFIX_FS_SEG_OVEERIDE:
+    case PREFIX_FS_SEG_OVERRIDE:
         seg = R_FS;
         break;
-    case PREFIX_GS_SEG_OVEERIDE:
+    case PREFIX_GS_SEG_OVERRIDE:
         seg = R_GS;
         break;
     default:
diff --git a/target/i386/hvf/x86_decode.h b/target/i386/hvf/x86_decode.h
index bc574a7..ef79601 100644
--- a/target/i386/hvf/x86_decode.h
+++ b/target/i386/hvf/x86_decode.h
@@ -27,12 +27,12 @@ typedef enum x86_prefix {
     PREFIX_REPN =                  0xf2,
     PREFIX_REP =                   0xf3,
     /* group 2 */
-    PREFIX_CS_SEG_OVEERIDE =       0x2e,
-    PREFIX_SS_SEG_OVEERIDE =       0x36,
-    PREFIX_DS_SEG_OVEERIDE =       0x3e,
-    PREFIX_ES_SEG_OVEERIDE =       0x26,
-    PREFIX_FS_SEG_OVEERIDE =       0x64,
-    PREFIX_GS_SEG_OVEERIDE =       0x65,
+    PREFIX_CS_SEG_OVERRIDE =       0x2e,
+    PREFIX_SS_SEG_OVERRIDE =       0x36,
+    PREFIX_DS_SEG_OVERRIDE =       0x3e,
+    PREFIX_ES_SEG_OVERRIDE =       0x26,
+    PREFIX_FS_SEG_OVERRIDE =       0x64,
+    PREFIX_GS_SEG_OVERRIDE =       0x65,
     /* group 3 */
     PREFIX_OP_SIZE_OVERRIDE =      0x66,
     /* group 4 */
@@ -303,10 +303,10 @@ uint64_t sign(uint64_t val, int size);
 
 uint32_t decode_instruction(CPUX86State *env, struct x86_decode *decode);
 
-target_ulong get_reg_ref(CPUX86State *env, int reg, int rex, int is_extended,
-                         int size);
-target_ulong get_reg_val(CPUX86State *env, int reg, int rex, int is_extended,
-                         int size);
+target_ulong get_reg_ref(CPUX86State *env, int reg, int rex_present,
+                         int is_extended, int size);
+target_ulong get_reg_val(CPUX86State *env, int reg, int rex_present,
+                         int is_extended, int size);
 void calc_modrm_operand(CPUX86State *env, struct x86_decode *decode,
                         struct x86_decode_op *op);
 target_ulong decode_linear_addr(CPUX86State *env, struct x86_decode *decode,