Messages in this thread | | | From | Mingwei Zhang <> | Date | Thu, 29 Jul 2021 12:01:00 -0700 | Subject | Re: [PATCH v2 2/3] KVM: x86/mmu: Avoid collision with !PRESENT SPTEs in TDP MMU lpage stats |
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oh, definitely. Sorry for the confusion.
On Thu, Jul 29, 2021 at 11:34 AM Sean Christopherson <seanjc@google.com> wrote: > > On Mon, Jul 26, 2021, Mingwei Zhang wrote: > > Factor in whether or not the old/new SPTEs are shadow-present when > > adjusting the large page stats in the TDP MMU. A modified MMIO SPTE can > > toggle the page size bit, as bit 7 is used to store the MMIO generation, > > i.e. is_large_pte() can get a false positive when called on a MMIO SPTE. > > Ditto for nuking SPTEs with REMOVED_SPTE, which sets bit 7 in its magic > > value. > > > > Opportunistically move the logic below the check to verify at least one > > of the old/new SPTEs is shadow present. > > > > Use is/was_leaf even though is/was_present would suffice. The code > > generation is roughly equivalent since all flags need to be computed > > prior to the code in question, and using the *_leaf flags will minimize > > the diff in a future enhancement to account all pages, i.e. will change > > the check to "is_leaf != was_leaf". > > > > Suggested-by: Sean Christopherson <seanjc@google.com> > > There's no hard rule for when to use Suggested-by vs. giving Author credit, but > in this case, since you took the patch and changelog verbatim[*] (sans the missing > tags below), it's more polite to take the full patch (with me as Author in > this case) and add your SOB since you're posting the patch. > > Fixes: 1699f65c8b65 ("kvm/x86: Fix 'lpages' kvm stat for TDM MMU") > Cc: stable@vger.kernel.org > > [*] https://lkml.kernel.org/r/YPho0ME5pSjqRSoc@google.com > > > Signed-off-by: Mingwei Zhang <mizhang@google.com>
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