Commit e25c2332 authored by James Houghton's avatar James Houghton Committed by Sean Christopherson
Browse files

KVM: x86/mmu: Skip shadow MMU test_young if TDP MMU reports page as young 



Reorder the processing of the TDP MMU versus the shadow MMU when aging
SPTEs, and skip the shadow MMU entirely in the test-only case if the TDP
MMU reports that the page is young, i.e. completely avoid taking mmu_lock
if the TDP MMU SPTE is young.  Swap the order for the test-and-age helper
as well for consistency.

Signed-off-by: default avatarJames Houghton <jthoughton@google.com>
Acked-by: default avatarYu Zhao <yuzhao@google.com>
Link: https://lore.kernel.org/r/20250204004038.1680123-7-jthoughton@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent b146a9b3

arch/x86/kvm/mmu/mmu.c

+9 −9
Original line number Diff line number Diff line
@@ -1592,15 +1592,15 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) 
{

	bool young = false;



	if (tdp_mmu_enabled)

		young = kvm_tdp_mmu_age_gfn_range(kvm, range);



	if (kvm_memslots_have_rmaps(kvm)) {

		write_lock(&kvm->mmu_lock);

		young = kvm_rmap_age_gfn_range(kvm, range, false);

		young |= kvm_rmap_age_gfn_range(kvm, range, false);

		write_unlock(&kvm->mmu_lock);

	}



	if (tdp_mmu_enabled)

		young |= kvm_tdp_mmu_age_gfn_range(kvm, range);



	return young;

}
@@ -1608,15 +1608,15 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) 
{

	bool young = false;



	if (kvm_memslots_have_rmaps(kvm)) {

	if (tdp_mmu_enabled)

		young = kvm_tdp_mmu_test_age_gfn(kvm, range);



	if (!young && kvm_memslots_have_rmaps(kvm)) {

		write_lock(&kvm->mmu_lock);

		young = kvm_rmap_age_gfn_range(kvm, range, true);

		young |= kvm_rmap_age_gfn_range(kvm, range, true);

		write_unlock(&kvm->mmu_lock);

	}



	if (tdp_mmu_enabled)

		young |= kvm_tdp_mmu_test_age_gfn(kvm, range);



	return young;

}