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Re: [PATCH 00/11] KVM: x86: track guest page access

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On 01/12/2015 16:02, Andrea Arcangeli wrote:
> > Applying your technique to non-leaf shadow pages actually makes this
> > series quite interesting. :)  Shadow paging is still in use for nested
> > EPT, so it's always a good idea to speed it up.
> 
> I don't have the full picture of how userfaultfd write tracking could
> also fit in the leaf/non-leaf shadow pagetable write tracking yet but
> it's good to think about it.

It's unrelated.

Xiao wrote this series for KVM-GT.  I'm suggesting that he uses
userfaultfd write tracking (or similar techniques---but anyway
implemented out of KVM) for KVM-GT.  The benefit is that KVM-GT is then
unrelated to KVM, similar to legacy KVM device assignment vs. VFIO.

However, he also applied this new API to shadow pagetable write
tracking.  He gets measurable (~2%) performance improvement.  We can
look separately at how to get a similar performance improvement, even if
KVM-GT will not use the new page tracking API.

Paolo
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[PATCH 00/11] KVM: x86: track guest page access Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 05/11] KVM: page track: introduce kvm_page_track_{add,remove}_page Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 07/11] KVM: page track: add notifier support Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 02/11] KVM: MMU: introduce kvm_mmu_gfn_{allow,disallow}_lpage Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 08/11] KVM: MMU: use page track for non-leaf shadow pages Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 10/11] KVM: MMU: clear write-flooding on the fast path of tracked page Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 01/11] KVM: MMU: rename has_wrprotected_page to mmu_gfn_lpage_is_disallowed Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  [PATCH 11/11] KVM: MMU: apply page track notifier Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-11-30 19:40 +0100
  Re: [PATCH 00/11] KVM: x86: track guest page access Paolo Bonzini <pbonzini@redhat.com> - 2015-12-01 11:20 +0100
    Re: [PATCH 00/11] KVM: x86: track guest page access Paolo Bonzini <pbonzini@redhat.com> - 2015-12-01 16:10 +0100
    Re: [PATCH 00/11] KVM: x86: track guest page access Andrea Arcangeli <aarcange@redhat.com> - 2015-12-01 16:10 +0100
    Re: [PATCH 00/11] KVM: x86: track guest page access Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-12-01 18:10 +0100
      Re: [PATCH 00/11] KVM: x86: track guest page access Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-12-05 18:10 +0100

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