Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH rebase/RFC 0/4] x86/kvm/nVMX: optimize MMU switch between L1 and L2 | Date | Tue, 31 Jul 2018 17:58:54 +0200 |
| |
Paolo Bonzini <pbonzini@redhat.com> writes:
> This is a rebased version of Vitaly's RFC series. This isn't > quite ready for application as I haven't yet thought through > the interactions between the root_mmu/guest_mmu split and > the multi-root caching. > > Speaking of the multi-root caching, it is a bit of a duplicate work > with Vitaly's last three patches that avoided reinitialization if > the parameters and CR3 matched, so the series got smaller too. >
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).
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.
-- Vitaly
| |