KVM: x86 emulator: during rep emulation decrement ECX only if emulation succeeded
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 3b32270..594574d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2411,13 +2411,13 @@
}
static void string_addr_inc(struct x86_emulate_ctxt *ctxt, unsigned long base,
- int reg, unsigned long **ptr)
+ int reg, struct operand *op)
{
struct decode_cache *c = &ctxt->decode;
int df = (ctxt->eflags & EFLG_DF) ? -1 : 1;
- register_address_increment(c, &c->regs[reg], df * c->src.bytes);
- *ptr = (unsigned long *)register_address(c, base, c->regs[reg]);
+ register_address_increment(c, &c->regs[reg], df * op->bytes);
+ op->ptr = (unsigned long *)register_address(c, base, c->regs[reg]);
}
int
@@ -2483,7 +2483,6 @@
goto done;
}
}
- register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
c->eip = ctxt->eip;
}
@@ -2936,11 +2935,13 @@
if ((c->d & SrcMask) == SrcSI)
string_addr_inc(ctxt, seg_override_base(ctxt, c), VCPU_REGS_RSI,
- &c->src.ptr);
+ &c->src);
if ((c->d & DstMask) == DstDI)
- string_addr_inc(ctxt, es_base(ctxt), VCPU_REGS_RDI,
- &c->dst.ptr);
+ string_addr_inc(ctxt, es_base(ctxt), VCPU_REGS_RDI, &c->dst);
+
+ if (c->rep_prefix && (c->d & String))
+ register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
/* Commit shadow register state. */
memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);