KVM: x86 emulator: move string instruction completion check into separate function

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 42d42ca..3dcbc1d 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2933,6 +2933,28 @@ done:
        return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
 }
 
+static bool string_insn_completed(struct x86_emulate_ctxt *ctxt)
+{
+       struct decode_cache *c = &ctxt->decode;
+
+       /* The second termination condition only applies for REPE
+        * and REPNE. Test if the repeat string operation prefix is
+        * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
+        * corresponding termination condition according to:
+        *      - if REPE/REPZ and ZF = 0 then done
+        *      - if REPNE/REPNZ and ZF = 1 then done
+        */
+       if (((c->b == 0xa6) || (c->b == 0xa7) ||
+            (c->b == 0xae) || (c->b == 0xaf))
+           && (((c->rep_prefix == REPE_PREFIX) &&
+                ((ctxt->eflags & EFLG_ZF) == 0))
+               || ((c->rep_prefix == REPNE_PREFIX) &&
+                   ((ctxt->eflags & EFLG_ZF) == EFLG_ZF))))
+               return true;
+
+       return false;
+}
+
 int
 x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
 {
@@ -3423,19 +3445,8 @@ writeback:
        if (c->rep_prefix && (c->d & String)) {
                struct read_cache *r = &ctxt->decode.io_read;
                register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
-               /* The second termination condition only applies for REPE
-                * and REPNE. Test if the repeat string operation prefix is
-                * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
-                * corresponding termination condition according to:
-                *      - if REPE/REPZ and ZF = 0 then done
-                *      - if REPNE/REPNZ and ZF = 1 then done
-                */
-               if (((c->b == 0xa6) || (c->b == 0xa7) ||
-                    (c->b == 0xae) || (c->b == 0xaf))
-                   && (((c->rep_prefix == REPE_PREFIX) &&
-                        ((ctxt->eflags & EFLG_ZF) == 0))
-                       || ((c->rep_prefix == REPNE_PREFIX) &&
-                           ((ctxt->eflags & EFLG_ZF) == EFLG_ZF))))
+
+               if (string_insn_completed(ctxt))
                        ctxt->restart = false;
                /*
                 * Re-enter guest when pio read ahead buffer is empty or,