forked from Minki/linux
x86: kvm: mmu: dead code thanks to access tracking
The MMU always has hardware A bits or access tracking support, thus it's unnecessary to handle the scenario where we have neither. Signed-off-by: Peter Feiner <pfeiner@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -315,12 +315,21 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
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return likely(kvm_gen == spte_gen);
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}
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/*
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* Sets the shadow PTE masks used by the MMU.
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*
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* Assumptions:
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* - Setting either @accessed_mask or @dirty_mask requires setting both
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* - At least one of @accessed_mask or @acc_track_mask must be set
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*/
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void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
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u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
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u64 acc_track_mask)
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{
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if (acc_track_mask != 0)
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acc_track_mask |= SPTE_SPECIAL_MASK;
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BUG_ON(!dirty_mask != !accessed_mask);
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BUG_ON(!accessed_mask && !acc_track_mask);
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shadow_user_mask = user_mask;
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shadow_accessed_mask = accessed_mask;
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@ -1766,18 +1775,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
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u64 *sptep;
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struct rmap_iterator iter;
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/*
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* If there's no access bit in the secondary pte set by the hardware and
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* fast access tracking is also not enabled, it's up to gup-fast/gup to
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* set the access bit in the primary pte or in the page structure.
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*/
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if (!shadow_accessed_mask && !shadow_acc_track_mask)
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goto out;
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for_each_rmap_spte(rmap_head, &iter, sptep)
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if (is_accessed_spte(*sptep))
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return 1;
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out:
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return 0;
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}
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@ -1798,18 +1798,6 @@ static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
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int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
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{
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/*
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* In case of absence of EPT Access and Dirty Bits supports,
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* emulate the accessed bit for EPT, by checking if this page has
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* an EPT mapping, and clearing it if it does. On the next access,
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* a new EPT mapping will be established.
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* This has some overhead, but not as much as the cost of swapping
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* out actively used pages or breaking up actively used hugepages.
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*/
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if (!shadow_accessed_mask && !shadow_acc_track_mask)
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return kvm_handle_hva_range(kvm, start, end, 0,
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kvm_unmap_rmapp);
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return kvm_handle_hva_range(kvm, start, end, 0, kvm_age_rmapp);
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}
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