diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 16c037e7db7d..282d28cb9931 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4117,7 +4117,10 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
 	case OpMem8:
 		ctxt->memop.bytes = 1;
 		if (ctxt->memop.type == OP_REG) {
-			ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm, 1);
+			int highbyte_regs = ctxt->rex_prefix == 0;
+
+			ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm,
+					       highbyte_regs);
 			fetch_register_operand(&ctxt->memop);
 		}
 		goto mem_common;