Some points to consider: The injected MCE has _done_ the damages to guest workload. Recovering the guest poisoned memory doesn't help with the already happened guest workload memory corruption / loss / interruption due to injected MCEs. The hypervisor _must_ emulate poisons identified in guest physical address space (could be transported from the source VM), this is to prevent silent data corruption in the guest. With a paravirtual approach like this patch series, the hypervisor can clear some of the poisoned HVAs knowing for certain that the guest OS has isolated the poisoned page. I wonder how much value it provides to the guest if the guest and workload are _not_ in a pressing need for the extra KB/MB worth of memory. Thanks, -Jue
