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    SubjectRe: [Patch v2 5/5] KVM: x86/mmu: Merge all handle_changed_pte* functions.
    On Fri, Feb 3, 2023 at 11:28 AM Vipin Sharma <vipinsh@google.com> wrote:
    >
    > __handle_changed_pte() and handle_changed_spte_acc_track() are always
    > used together. Merge these two functions and name the new function
    > handle_changed_pte(). Remove the existing handle_changed_pte() function
    > which just calls __handle_changed_pte and
    > handle_changed_spte_acc_track().
    >
    > This converges SPTEs change handling code to a single place.
    >
    > Signed-off-by: Vipin Sharma <vipinsh@google.com>

    Reviewed-by: Ben Gardon <bgardon@google.com>

    > ---
    > arch/x86/kvm/mmu/tdp_mmu.c | 42 +++++++++++---------------------------
    > 1 file changed, 12 insertions(+), 30 deletions(-)
    >
    > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
    > index afe0dcb1859e..9b0c81a28f97 100644
    > --- a/arch/x86/kvm/mmu/tdp_mmu.c
    > +++ b/arch/x86/kvm/mmu/tdp_mmu.c
    > @@ -334,17 +334,6 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
    > u64 old_spte, u64 new_spte, int level,
    > bool shared);
    >
    > -static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level)
    > -{
    > - if (!is_shadow_present_pte(old_spte) || !is_last_spte(old_spte, level))
    > - return;
    > -
    > - if (is_accessed_spte(old_spte) &&
    > - (!is_shadow_present_pte(new_spte) || !is_accessed_spte(new_spte) ||
    > - spte_to_pfn(old_spte) != spte_to_pfn(new_spte)))
    > - kvm_set_pfn_accessed(spte_to_pfn(old_spte));
    > -}
    > -
    > static void tdp_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
    > {
    > kvm_account_pgtable_pages((void *)sp->spt, +1);
    > @@ -487,7 +476,7 @@ static void handle_removed_pt(struct kvm *kvm, tdp_ptep_t pt, bool shared)
    > }
    >
    > /**
    > - * __handle_changed_spte - handle bookkeeping associated with an SPTE change
    > + * handle_changed_spte - handle bookkeeping associated with an SPTE change
    > * @kvm: kvm instance
    > * @as_id: the address space of the paging structure the SPTE was a part of
    > * @gfn: the base GFN that was mapped by the SPTE
    > @@ -501,9 +490,9 @@ static void handle_removed_pt(struct kvm *kvm, tdp_ptep_t pt, bool shared)
    > * Handle bookkeeping that might result from the modification of a SPTE.
    > * This function must be called for all TDP SPTE modifications.
    > */
    > -static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
    > - u64 old_spte, u64 new_spte, int level,
    > - bool shared)
    > +static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
    > + u64 old_spte, u64 new_spte, int level,
    > + bool shared)
    > {
    > bool was_present = is_shadow_present_pte(old_spte);
    > bool is_present = is_shadow_present_pte(new_spte);
    > @@ -587,15 +576,10 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
    > if (was_present && !was_leaf &&
    > (is_leaf || !is_present || WARN_ON_ONCE(pfn_changed)))
    > handle_removed_pt(kvm, spte_to_child_pt(old_spte, level), shared);
    > -}
    >
    > -static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
    > - u64 old_spte, u64 new_spte, int level,
    > - bool shared)
    > -{
    > - __handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level,
    > - shared);
    > - handle_changed_spte_acc_track(old_spte, new_spte, level);
    > + if (was_leaf && is_accessed_spte(old_spte) &&
    > + (!is_present || !is_accessed_spte(new_spte) || pfn_changed))
    > + kvm_set_pfn_accessed(spte_to_pfn(old_spte));
    > }
    >
    > /*
    > @@ -638,9 +622,8 @@ static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm,
    > if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte))
    > return -EBUSY;
    >
    > - __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
    > - new_spte, iter->level, true);
    > - handle_changed_spte_acc_track(iter->old_spte, new_spte, iter->level);
    > + handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
    > + new_spte, iter->level, true);
    >
    > return 0;
    > }
    > @@ -705,8 +688,7 @@ static u64 _tdp_mmu_set_spte(struct kvm *kvm, int as_id, tdp_ptep_t sptep,
    >
    > old_spte = kvm_tdp_mmu_write_spte(sptep, old_spte, new_spte, level);
    >
    > - __handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, false);
    > - handle_changed_spte_acc_track(old_spte, new_spte, level);
    > + handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, false);
    > return old_spte;
    > }
    >
    > @@ -1273,7 +1255,7 @@ static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter,
    > * Note, when changing a read-only SPTE, it's not strictly necessary to
    > * zero the SPTE before setting the new PFN, but doing so preserves the
    > * invariant that the PFN of a present * leaf SPTE can never change.
    > - * See __handle_changed_spte().
    > + * See handle_changed_spte().
    > */
    > tdp_mmu_set_spte(kvm, iter, 0);
    >
    > @@ -1298,7 +1280,7 @@ bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
    > /*
    > * No need to handle the remote TLB flush under RCU protection, the
    > * target SPTE _must_ be a leaf SPTE, i.e. cannot result in freeing a
    > - * shadow page. See the WARN on pfn_changed in __handle_changed_spte().
    > + * shadow page. See the WARN on pfn_changed in handle_changed_spte().
    > */
    > return kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn);
    > }
    > --
    > 2.39.1.519.gcb327c4b5f-goog
    >

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