Re: [PATCH v2 0/3] nVMX: Emulated Page Modification Logging for Nested Virtualization

From: Paolo Bonzini
Date: Thu May 11 2017 - 01:02:29 EST




On 09/05/2017 18:03, Bandan Das wrote:
>> I tested this with api/dirty-log-perf, and nested PML is more than 3
>> times faster than pml=0. I want to do a few more tests because I don't
>> see any PML full exits in the L1 trace, but it seems to be a nice
>> improvement!
>
> Thanks for testing! Regarding the PML full exits, I did notice their
> absence. I induced it artifically in my testing with a lower index
> and it seemed to work fine.

Yes, tracing showed that it's because the guest's EXTERNAL_INTERRUPT
exits are too frequent.

Paolo