Messages in this thread | | | Subject | Re: [PATCH rebase/RFC 0/4] x86/kvm/nVMX: optimize MMU switch between L1 and L2 | From | Paolo Bonzini <> | Date | Tue, 31 Jul 2018 18:52:28 +0200 |
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On 31/07/2018 17:58, Vitaly Kuznetsov wrote: > Thank you for the rebase, > > it seems that with multi-root caching this series should just ignore CR3 > changes for both root_mmu and guest_mmu: we now have two separate > 'prev_roots' caches and these work well. However, we still can optimize > MMU re-initialization on L1->L2 and L2->L1 switches out using e.g. my > 'scache' idea (which can be orthogonal to page_role check on CR3).
Indeed, though if possible the scache should be based on the role to avoid duplicating code and data structures.
(Also I didn't quite have time to figure out _why_ without root_mmu/guest_mmu there is still contention, it's probably something trivial).
Paolo
> In my Hyper-V-on-KVM environment I'm seeing an additional 1000 CPU > cycles win for a nested vmexit. > > I'll pull things together and re-send the whole series.
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