Commit 2362506f authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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: default avatarAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Tested-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-84-seanjc@google.com>
parent 66bc627e

arch/arm64/include/asm/kvm_pgtable.h

+1 −3
Original line number Diff line number Diff line
@@ -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

arch/arm64/kvm/hyp/pgtable.c

+2 −5
Original line number Diff line number Diff line
@@ -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 {

arch/arm64/kvm/mmu.c

+1 −5
Original line number Diff line number Diff line
@@ -1707,18 +1707,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, 
/* 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));

}



/**