Commit 7aac9dc6 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: x86/mmu: Fold mmu_spte_age() into kvm_rmap_age_gfn_range() 

Fold mmu_spte_age() into its sole caller now that aging and testing for
young SPTEs is handled in a common location, i.e. doesn't require more
helpers.

Opportunistically remove the use of mmu_spte_get_lockless(), as mmu_lock
is held (for write!), and marking SPTEs for access tracking outside of
mmu_lock is unsafe (at least, as written).  I.e. using the lockless
accessor is quite misleading.

No functional change intended.

Link: https://lore.kernel.org/r/20240809194335.1726916-16-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent c17f1500

arch/x86/kvm/mmu/mmu.c

+22 −28
Original line number Diff line number Diff line
@@ -614,32 +614,6 @@ static u64 mmu_spte_get_lockless(u64 *sptep) 
	return __get_spte_lockless(sptep);

}



/* Returns the Accessed status of the PTE and resets it at the same time. */

static bool mmu_spte_age(u64 *sptep)

{

	u64 spte = mmu_spte_get_lockless(sptep);



	if (!is_accessed_spte(spte))

		return false;



	if (spte_ad_enabled(spte)) {

		clear_bit((ffs(shadow_accessed_mask) - 1),

			  (unsigned long *)sptep);

	} else {

		/*

		 * Capture the dirty status of the page, so that it doesn't get

		 * lost when the SPTE is marked for access tracking.

		 */

		if (is_writable_pte(spte))

			kvm_set_pfn_dirty(spte_to_pfn(spte));



		spte = mark_spte_for_access_track(spte);

		mmu_spte_update_no_track(sptep, spte);

	}



	return true;

}



static inline bool is_tdp_mmu_active(struct kvm_vcpu *vcpu)

{

	return tdp_mmu_enabled && vcpu->arch.mmu->root_role.direct;
@@ -1641,10 +1615,30 @@ static bool kvm_rmap_age_gfn_range(struct kvm *kvm, 
	for_each_slot_rmap_range(range->slot, PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,

				 range->start, range->end - 1, &iterator) {

		for_each_rmap_spte(iterator.rmap, &iter, sptep) {

			if (test_only && is_accessed_spte(*sptep))

			u64 spte = *sptep;



			if (!is_accessed_spte(spte))

				continue;



			if (test_only)

				return true;



			young = mmu_spte_age(sptep);

			if (spte_ad_enabled(spte)) {

				clear_bit((ffs(shadow_accessed_mask) - 1),

					(unsigned long *)sptep);

			} else {

				/*

				 * Capture the dirty status of the page, so that

				 * it doesn't get lost when the SPTE is marked

				 * for access tracking.

				 */

				if (is_writable_pte(spte))

					kvm_set_pfn_dirty(spte_to_pfn(spte));



				spte = mark_spte_for_access_track(spte);

				mmu_spte_update_no_track(sptep, spte);

			}

			young = true;

		}

	}

	return young;