From: Vipin Sharma <vipinsh@xxxxxxxxxx> Use the constant-after-module-load kvm_ad_enabled() to check if SPTEs in the TDP MMU need to be write-protected when clearing accessed/dirty status instead of manually checking every SPTE. The per-SPTE A/D enabling is specific to nested EPT MMUs, i.e. when KVM is using EPT A/D bits but L1 is not, and so cannot happen in the TDP MMU (which is non-nested only). Keep the original code as sanity checks buried under MMU_WARN_ON(). MMU_WARN_ON() is more or less useless at the moment, but there are plans to change that. Link: https://lore.kernel.org/all/Yz4Qi7cn7TWTWQjj@xxxxxxxxxx Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx> [sean: split to separate patch, apply to dirty path, write changelog] Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- arch/x86/kvm/mmu/tdp_mmu.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 7c25dbf32ecc..5a5642650c3e 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1621,7 +1621,10 @@ static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, if (!is_shadow_present_pte(iter.old_spte)) continue; - if (spte_ad_need_write_protect(iter.old_spte)) { + MMU_WARN_ON(kvm_ad_enabled() && + spte_ad_need_write_protect(iter.old_spte)); + + if (!kvm_ad_enabled()) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK; else @@ -1685,13 +1688,16 @@ static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root, if (!mask) break; + MMU_WARN_ON(kvm_ad_enabled() && + spte_ad_need_write_protect(iter.old_spte)); + if (iter.level > PG_LEVEL_4K || !(mask & (1UL << (iter.gfn - gfn)))) continue; mask &= ~(1UL << (iter.gfn - gfn)); - if (wrprot || spte_ad_need_write_protect(iter.old_spte)) { + if (wrprot || !kvm_ad_enabled()) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK; else -- 2.40.0.rc2.332.ga46443480c-goog
