KVM: x86 emulator: allow storing emulator execution function in decode tables

Instead of looking up the opcode twice (once for decode flags, once for
the big execution switch) look up both flags and function in the decode tables.

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

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 9ddfa5ed22891d2be7303c53676d031268efb354..0f901c16cf1c03ce969529b1759fcc070c809723 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -190,6 +190,7 @@ struct decode_cache {
        bool has_seg_override;
        u8 seg_override;
        unsigned int d;
+       int (*execute)(struct x86_emulate_ctxt *ctxt);
        unsigned long regs[NR_VCPU_REGS];
        unsigned long eip;
        /* modrm */

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 3689f34a303a583ed2b3a02284df6aa133bbecb3..799e895fb08e72dbd333c717d50e95c96e08dd68 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -106,6 +106,7 @@
 struct opcode {
        u32 flags;
        union {
+               int (*execute)(struct x86_emulate_ctxt *ctxt);
                struct opcode *group;
                struct group_dual *gdual;
        } u;
@@ -120,6 +121,7 @@ struct group_dual {
 #define N    D(0)
 #define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }
 #define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }
+#define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
 
 static struct opcode group1[] = {
        X7(D(Lock)), N
@@ -349,6 +351,7 @@ static struct opcode twobyte_table[256] = {
 #undef N
 #undef G
 #undef GD
+#undef I
 
 /* EFLAGS bit definitions. */
 #define EFLG_ID (1<<21)
@@ -1070,6 +1073,8 @@ done_prefixes:
                c->d |= opcode.flags;
        }
 
+       c->execute = opcode.u.execute;
+
        /* Unrecognised? */
        if (c->d == 0 || (c->d & Undefined)) {
                DPRINTF("Cannot emulate %02x\n", c->b);
@@ -2705,6 +2710,13 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
 
 special_insn:
 
+       if (c->execute) {
+               rc = c->execute(ctxt);
+               if (rc != X86EMUL_CONTINUE)
+                       goto done;
+               goto writeback;
+       }
+
        if (c->twobyte)
                goto twobyte_insn;