KVM: x86 emulator: consolidate group handling

Move all groups into a single field and handle them in a single place.  This
saves bits when we add more group types (3 bits -> 7 groups types).

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 40 insertions, 40 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c1d9116cf3ac..7466abae84bf 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -73,11 +73,12 @@
 #define MemAbs      (1<<11)      /* Memory operand is absolute displacement */
 #define String      (1<<12)     /* String instruction (rep capable) */
 #define Stack       (1<<13)     /* Stack instruction (push/pop) */
+#define GroupMask   (7<<14)     /* Opcode uses one of the group mechanisms */
 #define Group       (1<<14)     /* Bits 3:5 of modrm byte extend opcode */
-#define GroupDual   (1<<15)     /* Alternate decoding of mod == 3 */
-#define Prefix      (1<<16)     /* Instruction varies with 66/f2/f3 prefix */
+#define GroupDual   (2<<14)     /* Alternate decoding of mod == 3 */
+#define Prefix      (3<<14)     /* Instruction varies with 66/f2/f3 prefix */
+#define RMExt       (4<<14)     /* Opcode extension in ModRM r/m if mod == 3 */
 #define Sse         (1<<17)     /* SSE Vector instruction */
-#define RMExt       (1<<18)     /* Opcode extension in ModRM r/m if mod == 3 */
 /* Misc flags */
 #define Prot        (1<<21) /* instruction generates #UD if not in prot-mode */
 #define VendorSpecific (1<<22) /* Vendor specific instruction */
@@ -2969,7 +2970,7 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
 #define N    D(0)
 #define EXT(_f, _e) { .flags = ((_f) | RMExt), .u.group = (_e) }
 #define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }
-#define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }
+#define GD(_f, _g) { .flags = ((_f) | GroupDual), .u.gdual = (_g) }
 #define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
 #define II(_f, _e, _i) \
         { .flags = (_f), .u.execute = (_e), .intercept = x86_intercept_##_i }
@@ -3337,9 +3338,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
         struct decode_cache *c = &ctxt->decode;
         int rc = X86EMUL_CONTINUE;
         int mode = ctxt->mode;
-        int def_op_bytes, def_ad_bytes, dual, goffset, simd_prefix;
+        int def_op_bytes, def_ad_bytes, goffset, simd_prefix;
         bool op_prefix = false;
-        struct opcode opcode, *g_mod012, *g_mod3;
+        struct opcode opcode;
         struct operand memop = { .type = OP_NONE };
 
         c->eip = ctxt->eip;
@@ -3433,44 +3434,43 @@ done_prefixes:
         }
         c->d = opcode.flags;
 
-        if (c->d & Group) {
-                dual = c->d & GroupDual;
-                c->modrm = insn_fetch(u8, 1, c->eip);
-                --c->eip;
-
-                if (c->d & GroupDual) {
-                        g_mod012 = opcode.u.gdual->mod012;
-                        g_mod3 = opcode.u.gdual->mod3;
-                } else
-                        g_mod012 = g_mod3 = opcode.u.group;
-
-                c->d &= ~(Group | GroupDual);
-
-                goffset = (c->modrm >> 3) & 7;
-
-                if ((c->modrm >> 6) == 3)
-                        opcode = g_mod3[goffset];
-                else
-                        opcode = g_mod012[goffset];
-
-                if (opcode.flags & RMExt) {
+        while (c->d & GroupMask) {
+                switch (c->d & GroupMask) {
+                case Group:
+                        c->modrm = insn_fetch(u8, 1, c->eip);
+                        --c->eip;
+                        goffset = (c->modrm >> 3) & 7;
+                        opcode = opcode.u.group[goffset];
+                        break;
+                case GroupDual:
+                        c->modrm = insn_fetch(u8, 1, c->eip);
+                        --c->eip;
+                        goffset = (c->modrm >> 3) & 7;
+                        if ((c->modrm >> 6) == 3)
+                                opcode = opcode.u.gdual->mod3[goffset];
+                        else
+                                opcode = opcode.u.gdual->mod012[goffset];
+                        break;
+                case RMExt:
                         goffset = c->modrm & 7;
                         opcode = opcode.u.group[goffset];
-                }
-
-                c->d |= opcode.flags;
-        }
-
-        if (c->d & Prefix) {
-                if (c->rep_prefix && op_prefix)
+                        break;
+                case Prefix:
+                        if (c->rep_prefix && op_prefix)
+                                return X86EMUL_UNHANDLEABLE;
+                        simd_prefix = op_prefix ? 0x66 : c->rep_prefix;
+                        switch (simd_prefix) {
+                        case 0x00: opcode = opcode.u.gprefix->pfx_no; break;
+                        case 0x66: opcode = opcode.u.gprefix->pfx_66; break;
+                        case 0xf2: opcode = opcode.u.gprefix->pfx_f2; break;
+                        case 0xf3: opcode = opcode.u.gprefix->pfx_f3; break;
+                        }
+                        break;
+                default:
                         return X86EMUL_UNHANDLEABLE;
-                simd_prefix = op_prefix ? 0x66 : c->rep_prefix;
-                switch (simd_prefix) {
-                case 0x00: opcode = opcode.u.gprefix->pfx_no; break;
-                case 0x66: opcode = opcode.u.gprefix->pfx_66; break;
-                case 0xf2: opcode = opcode.u.gprefix->pfx_f2; break;
-                case 0xf3: opcode = opcode.u.gprefix->pfx_f3; break;
                 }
+
+                c->d &= ~GroupMask;
                 c->d |= opcode.flags;
         }