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>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0b70a36..4dce805 100644 (file)
--- 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);
        }