KVM: arm64: Don't mark "struct page" accessed when making SPTE young

Don't mark pages/folios as accessed in the primary MMU when making a SPTE
young in KVM's secondary MMU, as doing so relies on
kvm_pfn_to_refcounted_page(), and generally speaking is unnecessary and
wasteful.  KVM participates in page aging via mmu_notifiers, so there's no
need to push "accessed" updates to the primary MMU.

Dropping use of kvm_set_pfn_accessed() also paves the way for removing
kvm_pfn_to_refcounted_page() and all its users.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-84-seanjc@google.com>

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 03f4c3d7839c2cc234f94121571d46498b618a4b..aab04097b5054a8a48a237d8e79971f57034c7e1 100644 (file)
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -674,10 +674,8 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
  *
  * If there is a valid, leaf page-table entry used to translate @addr, then
  * set the access flag in that entry.
- *
- * Return: The old page-table entry prior to setting the flag, 0 on failure.
  */
-kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr);
+void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr);
 
 /**
  * kvm_pgtable_stage2_test_clear_young() - Test and optionally clear the access

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index b11bcebac908a7f2927170360d0690d8e56adaeb..40bd559665404d0b971314888dd0842179813d1c 100644 (file)
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1245,19 +1245,16 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
                                        NULL, NULL, 0);
 }
 
-kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
+void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
 {
-       kvm_pte_t pte = 0;
        int ret;
 
        ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
-                                      &pte, NULL,
+                                      NULL, NULL,
                                       KVM_PGTABLE_WALK_HANDLE_FAULT |
                                       KVM_PGTABLE_WALK_SHARED);
        if (!ret)
                dsb(ishst);
-
-       return pte;
 }
 
 struct stage2_age_data {

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 75795fb67d1dc3c41f128ff0b36ebbbe6642e04a..a71fe6f6bd90f258378ca40a527e7bee736f591c 100644 (file)
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1707,18 +1707,14 @@ out_unlock:
 /* Resolve the access fault by making the page young again. */
 static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
 {
-       kvm_pte_t pte;
        struct kvm_s2_mmu *mmu;
 
        trace_kvm_access_fault(fault_ipa);
 
        read_lock(&vcpu->kvm->mmu_lock);
        mmu = vcpu->arch.hw_mmu;
-       pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
+       kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
        read_unlock(&vcpu->kvm->mmu_lock);
-
-       if (kvm_pte_valid(pte))
-               kvm_set_pfn_accessed(kvm_pte_to_pfn(pte));
 }
 
 /**