In reply to sri205:
It’s not really clear from your post what you are trying to accomplish.
Is the CPU being replaced by a UVM VIP? Is the CPU or IP protocol compliant by not waiting for a response or not supporting non-posted transactions.
If an IP block or verification component isn’t protocol compliant, then you have bigger issues that you need to address. If there are parts of the protocol that are optional and not supported, then your verification IP should allow for this.
Why is modifying the driver/monitor not an option? As a verification engineer, your job is to create the VIP necessary for your job. If it is third party VIP, then you need to work with your provider to determine how to handle any non-compliance issues.