On Mon, Jul 26, 2021, Ben Gardon wrote:
> On Mon, Jul 26, 2021 at 10:54 AM Mingwei Zhang <mizhang@xxxxxxxxxx> wrote:
> > diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> > index 83e6c6965f1e..ad5638815311 100644
> > --- a/arch/x86/kvm/mmu.h
> > +++ b/arch/x86/kvm/mmu.h
> > @@ -240,4 +240,6 @@ static inline bool kvm_memslots_have_rmaps(struct kvm *kvm)
> > return smp_load_acquire(&kvm->arch.memslots_have_rmaps);
> > }
> >
> > +void kvm_update_page_stats(struct kvm *kvm, int level, int count);
> > +
> > #endif
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index 442cc554ebd6..7e0fc760739b 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -588,16 +588,22 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
> > return flush;
> > }
> >
> > +void kvm_update_page_stats(struct kvm *kvm, int level, int count)
> > +{
> > + atomic64_add(count, &kvm->stat.page_stats.pages[level - 1]);
> > +}
This can be static inline in the header. Ignoring prolog+RET, it's four instructions,
and two of those are sign extending input params.
> > +
> > /*
> > * Rules for using mmu_spte_clear_track_bits:
> > * It sets the sptep from present to nonpresent, and track the
> > * state bits, it is used to clear the last level sptep.
> > * Returns non-zero if the PTE was previously valid.
> > */
> > -static int mmu_spte_clear_track_bits(u64 *sptep)
> > +static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
> > {
> > kvm_pfn_t pfn;
> > u64 old_spte = *sptep;
> > + int level = sptep_to_sp(sptep)->role.level;
> >
> > if (!spte_has_volatile_bits(old_spte))
> > __update_clear_spte_fast(sptep, 0ull);
> > @@ -607,6 +613,9 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
> > if (!is_shadow_present_pte(old_spte))
> > return 0;
> >
> > + if (is_last_spte(old_spte, level))
>
> You can drop this check since it's part of the contract for calling
> this function.
Ah, nice! I overlooked that.
