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

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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: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-08-09 12:43:27 -07:00
parent c17f150000
commit 7aac9dc680
1 changed files with 22 additions and 28 deletions
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50
arch/x86/kvm/mmu/mmu.c
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@ -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;