KVM: x86 emulator: fix RCX access during rep emulation

During rep emulation access length to RCX depends on current address
mode.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0b70a364f0f4..4dce80560d26 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1852,7 +1852,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 
         if (c->rep_prefix && (c->d & String)) {
                 /* All REP prefixes have the same first termination condition */
-                if (c->regs[VCPU_REGS_RCX] == 0) {
+                if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
                         kvm_rip_write(ctxt->vcpu, c->eip);
                         goto done;
                 }
@@ -1876,7 +1876,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
                                 goto done;
                         }
                 }
-                c->regs[VCPU_REGS_RCX]--;
+                register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
                 c->eip = kvm_rip_read(ctxt->vcpu);
         }