KVM: x86 emulator: move all decoding process to function x86_decode_insn()

Split the decoding process into a new function x86_decode_insn().

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index d7026cb8fc70f26b60ae49648ab0aef52172c425..540589c5d427cf05ba2246472868f22fa09de2d2 100644 (file)
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -517,20 +517,16 @@ static int test_cc(unsigned int condition, unsigned int flags)
 }
 
 int
-x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
+x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 {
        struct decode_cache *c = &ctxt->decode;
        u8 sib, rex_prefix = 0;
        unsigned int i;
        int rc = 0;
-       unsigned long cr2 = ctxt->cr2;
        int mode = ctxt->mode;
        int index_reg = 0, base_reg = 0, scale, rip_relative = 0;
-       int no_wb = 0;
-       u64 msr_data;
 
        /* Shadow copy of register state. Committed on successful emulation. */
-       unsigned long _eflags = ctxt->eflags;
 
        memset(c, 0, sizeof(struct decode_cache));
        c->eip = ctxt->vcpu->rip;
@@ -622,8 +618,10 @@ done_prefixes:
                }
 
                /* Unrecognised? */
-               if (c->d == 0)
-                       goto cannot_emulate;
+               if (c->d == 0) {
+                       DPRINTF("Cannot emulate %02x\n", c->b);
+                       return -1;
+               }
        }
 
        /* ModRM and SIB bytes. */
@@ -776,7 +774,6 @@ done_prefixes:
                }
                if (c->ad_bytes != 8)
                        c->modrm_ea = (u32)c->modrm_ea;
-               cr2 = c->modrm_ea;
        modrm_done:
                ;
        }
@@ -838,13 +835,6 @@ done_prefixes:
                        break;
                }
                c->src.type = OP_MEM;
-               c->src.ptr = (unsigned long *)cr2;
-               c->src.val = 0;
-               if ((rc = ops->read_emulated((unsigned long)c->src.ptr,
-                                          &c->src.val,
-                                          c->src.bytes, ctxt->vcpu)) != 0)
-                       goto done;
-               c->src.orig_val = c->src.val;
                break;
        case SrcImm:
                c->src.type = OP_IMM;
@@ -877,7 +867,7 @@ done_prefixes:
        switch (c->d & DstMask) {
        case ImplicitOps:
                /* Special instructions do their own operand decoding. */
-               goto special_insn;
+               return 0;
        case DstReg:
                c->dst.type = OP_REG;
                if ((c->d & ByteOp)
@@ -905,14 +895,54 @@ done_prefixes:
                }
                break;
        case DstMem:
-               c->dst.type = OP_MEM;
-               c->dst.ptr = (unsigned long *)cr2;
-               c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               c->dst.val = 0;
                if ((c->d & ModRM) && c->modrm_mod == 3) {
                        c->dst.type = OP_REG;
                        break;
                }
+               c->dst.type = OP_MEM;
+               break;
+       }
+
+done:
+       return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
+}
+
+int
+x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
+{
+       unsigned long cr2 = ctxt->cr2;
+       int no_wb = 0;
+       u64 msr_data;
+       unsigned long _eflags = ctxt->eflags;
+       struct decode_cache *c = &ctxt->decode;
+       int rc;
+
+       rc = x86_decode_insn(ctxt, ops);
+       if (rc)
+               return rc;
+
+       if ((c->d & ModRM) && (c->modrm_mod != 3))
+               cr2 = c->modrm_ea;
+
+       if (c->src.type == OP_MEM) {
+               c->src.ptr = (unsigned long *)cr2;
+               c->src.val = 0;
+               if ((rc = ops->read_emulated((unsigned long)c->src.ptr,
+                                            &c->src.val,
+                                            c->src.bytes,
+                                            ctxt->vcpu)) != 0)
+                       goto done;
+               c->src.orig_val = c->src.val;
+       }
+
+       if ((c->d & DstMask) == ImplicitOps)
+               goto special_insn;
+
+
+       if (c->dst.type == OP_MEM) {
+               c->dst.ptr = (unsigned long *)cr2;
+               c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+               c->dst.val = 0;
                if (c->d & BitOp) {
                        unsigned long mask = ~(c->dst.bytes * 8 - 1);
 
@@ -925,7 +955,6 @@ done_prefixes:
                                           &c->dst.val,
                                          c->dst.bytes, ctxt->vcpu)) != 0))
                        goto done;
-               break;
        }
        c->dst.orig_val = c->dst.val;
 
@@ -983,7 +1012,7 @@ done_prefixes:
                emulate_2op_SrcV("cmp", c->src, c->dst, _eflags);
                break;
        case 0x63:              /* movsxd */
-               if (mode != X86EMUL_MODE_PROT64)
+               if (ctxt->mode != X86EMUL_MODE_PROT64)
                        goto cannot_emulate;
                c->dst.val = (s32) c->src.val;
                break;
@@ -1041,7 +1070,7 @@ done_prefixes:
                break;
        case 0x8f:              /* pop (sole member of Grp1a) */
                /* 64-bit mode: POP always pops a 64-bit operand. */
-               if (mode == X86EMUL_MODE_PROT64)
+               if (ctxt->mode == X86EMUL_MODE_PROT64)
                        c->dst.bytes = 8;
                if ((rc = ops->read_std(register_address(
                                                   ctxt->ss_base,
@@ -1152,7 +1181,7 @@ done_prefixes:
                        break;
                case 6: /* push */
                        /* 64-bit mode: PUSH always pushes a 64-bit operand. */
-                       if (mode == X86EMUL_MODE_PROT64) {
+                       if (ctxt->mode == X86EMUL_MODE_PROT64) {
                                c->dst.bytes = 8;
                                if ((rc = ops->read_std(
                                                 (unsigned long)c->dst.ptr,