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Commit ce00053b authored by Peter Feiner's avatar Peter Feiner Committed by Paolo Bonzini
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x86: kvm: mmu: dead code thanks to access tracking 



The MMU always has hardware A bits or access tracking support, thus
it's unnecessary to handle the scenario where we have neither.

Signed-off-by: default avatarPeter Feiner <pfeiner@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8a53e7e5

arch/x86/kvm/mmu.c

+9 −21
Original line number Original line Diff line number Diff line
@@ -315,12 +315,21 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte) 
	return likely(kvm_gen == spte_gen);

	return likely(kvm_gen == spte_gen);

}

}





/*

 * Sets the shadow PTE masks used by the MMU.

 *

 * Assumptions:

 *  - Setting either @accessed_mask or @dirty_mask requires setting both

 *  - At least one of @accessed_mask or @acc_track_mask must be set

 */

void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,

void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,

		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,

		u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,

		u64 acc_track_mask)

		u64 acc_track_mask)

{

{

	if (acc_track_mask != 0)

	if (acc_track_mask != 0)

		acc_track_mask |= SPTE_SPECIAL_MASK;

		acc_track_mask |= SPTE_SPECIAL_MASK;

	BUG_ON(!dirty_mask != !accessed_mask);

	BUG_ON(!accessed_mask && !acc_track_mask);





	shadow_user_mask = user_mask;

	shadow_user_mask = user_mask;

	shadow_accessed_mask = accessed_mask;

	shadow_accessed_mask = accessed_mask;
@@ -1766,18 +1775,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, 
	u64 *sptep;

	u64 *sptep;

	struct rmap_iterator iter;

	struct rmap_iterator iter;





	/*

	 * If there's no access bit in the secondary pte set by the hardware and

	 * fast access tracking is also not enabled, it's up to gup-fast/gup to

	 * set the access bit in the primary pte or in the page structure.

	 */

	if (!shadow_accessed_mask && !shadow_acc_track_mask)

		goto out;



	for_each_rmap_spte(rmap_head, &iter, sptep)

	for_each_rmap_spte(rmap_head, &iter, sptep)

		if (is_accessed_spte(*sptep))

		if (is_accessed_spte(*sptep))

			return 1;

			return 1;

out:

	return 0;

	return 0;

}

}
@@ -1798,18 +1798,6 @@ static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) 




int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)

int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)

{

{

	/*

	 * In case of absence of EPT Access and Dirty Bits supports,

	 * emulate the accessed bit for EPT, by checking if this page has

	 * an EPT mapping, and clearing it if it does. On the next access,

	 * a new EPT mapping will be established.

	 * This has some overhead, but not as much as the cost of swapping

	 * out actively used pages or breaking up actively used hugepages.

	 */

	if (!shadow_accessed_mask && !shadow_acc_track_mask)

		return kvm_handle_hva_range(kvm, start, end, 0,

					    kvm_unmap_rmapp);



	return kvm_handle_hva_range(kvm, start, end, 0, kvm_age_rmapp);

	return kvm_handle_hva_range(kvm, start, end, 0, kvm_age_rmapp);

}

}