Messages in this thread | | | Date | Wed, 21 Jul 2021 16:27:13 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH 1/2] kvm: mmu/x86: Remove redundant spte present check in mmu_set_spte |
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On Tue, Jul 20, 2021, Mingwei Zhang wrote: > Drop an unnecessary is_shadow_present_pte() check when updating the rmaps > after installing a non-MMIO SPTE. set_spte() is used only to create > shadow-present SPTEs, e.g. MMIO SPTEs are handled early on, mmu_set_spte() > runs with mmu_lock held for write, i.e. the SPTE can't be zapped between > writing the SPTE and updating the rmaps. > > Opportunistically combine the "new SPTE" logic for large pages and rmaps.
Heh, except you forgot to actually do this in the code.
> No functional change intended. > > Suggested-by: Ben Gardon <bgardon@google.com> > Signed-off-by: Mingwei Zhang <mizhang@google.com> > --- > arch/x86/kvm/mmu/mmu.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index b888385d1933..c45ddd2c964f 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -2693,12 +2693,10 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, > if (!was_rmapped && is_large_pte(*sptep)) > ++vcpu->kvm->stat.lpages; > > - if (is_shadow_present_pte(*sptep)) { > - if (!was_rmapped) { > - rmap_count = rmap_add(vcpu, sptep, gfn); > - if (rmap_count > RMAP_RECYCLE_THRESHOLD) > - rmap_recycle(vcpu, sptep, gfn); > - } > + if (!was_rmapped) {
As above, this should be:
if (!was_rmapped) { if (is_large_pte(*sptep)) ++vcpu->kvm->stat.lpages;
> + rmap_count = rmap_add(vcpu, sptep, gfn); > + if (rmap_count > RMAP_RECYCLE_THRESHOLD) > + rmap_recycle(vcpu, sptep, gfn); > } > > return ret; > -- > 2.32.0.402.g57bb445576-goog >
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