KVM: x86 emulator: covert SETCC to fastop

This is a bit of a special case since we don't have the usual
byte/word/long/quad switch; instead we switch on the condition code embedded
in the instruction.

Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi.kivity@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 29 insertions, 31 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a94b1d76f799..e13138dd073e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -499,6 +499,28 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt)
         ON64(FOP3E(op##q, rax, rbx, cl)) \
         FOP_END
 
+/* Special case for SETcc - 1 instruction per cc */
+#define FOP_SETCC(op) ".align 4; " #op " %al; ret \n\t"
+
+FOP_START(setcc)
+FOP_SETCC(seto)
+FOP_SETCC(setno)
+FOP_SETCC(setc)
+FOP_SETCC(setnc)
+FOP_SETCC(setz)
+FOP_SETCC(setnz)
+FOP_SETCC(setbe)
+FOP_SETCC(setnbe)
+FOP_SETCC(sets)
+FOP_SETCC(setns)
+FOP_SETCC(setp)
+FOP_SETCC(setnp)
+FOP_SETCC(setl)
+FOP_SETCC(setnl)
+FOP_SETCC(setle)
+FOP_SETCC(setnle)
+FOP_END;
+
 #define __emulate_1op_rax_rdx(ctxt, _op, _suffix, _ex)                  \
         do {                                                            \
                 unsigned long _tmp;                                     \
@@ -939,39 +961,15 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
         return rc;
 }
 
-static int test_cc(unsigned int condition, unsigned int flags)
+static u8 test_cc(unsigned int condition, unsigned long flags)
 {
-        int rc = 0;
+        u8 rc;
+        void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
 
-        switch ((condition & 15) >> 1) {
-        case 0: /* o */
-                rc |= (flags & EFLG_OF);
-                break;
-        case 1: /* b/c/nae */
-                rc |= (flags & EFLG_CF);
-                break;
-        case 2: /* z/e */
-                rc |= (flags & EFLG_ZF);
-                break;
-        case 3: /* be/na */
-                rc |= (flags & (EFLG_CF|EFLG_ZF));
-                break;
-        case 4: /* s */
-                rc |= (flags & EFLG_SF);
-                break;
-        case 5: /* p/pe */
-                rc |= (flags & EFLG_PF);
-                break;
-        case 7: /* le/ng */
-                rc |= (flags & EFLG_ZF);
-                /* fall through */
-        case 6: /* l/nge */
-                rc |= (!(flags & EFLG_SF) != !(flags & EFLG_OF));
-                break;
-        }
-
-        /* Odd condition identifiers (lsb == 1) have inverted sense. */
-        return (!!rc ^ (condition & 1));
+        flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
+        asm("pushq %[flags]; popf; call *%[fastop]"
+            : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
+        return rc;
 }
 
 static void fetch_register_operand(struct operand *op)