Commit bcc4f2bc authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: MMU: mark page dirty in make_spte 



This simplifies set_spte, which we want to remove, and unifies code
between the shadow MMU and the TDP MMU.  The warning will be added
back later to make_spte as well.

There is a small disadvantage in the TDP MMU; it may unnecessarily mark
a page as dirty twice if two vCPUs end up mapping the same page twice.
However, this is a very small cost for a case that is already rare.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 68be1306

arch/x86/kvm/mmu/mmu.c

+0 −3
Original line number Diff line number Diff line
@@ -2688,9 +2688,6 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, 
	ret = make_spte(vcpu, pte_access, level, gfn, pfn, *sptep, speculative,

			can_unsync, host_writable, sp_ad_disabled(sp), &spte);



	if (spte & PT_WRITABLE_MASK)

		kvm_vcpu_mark_page_dirty(vcpu, gfn);



	if (*sptep == spte)

		ret |= SET_SPTE_SPURIOUS;

	else if (mmu_spte_update(sptep, spte))

arch/x86/kvm/mmu/spte.c

+3 −0
Original line number Diff line number Diff line
@@ -179,6 +179,9 @@ int make_spte(struct kvm_vcpu *vcpu, unsigned int pte_access, int level, 
		  "spte = 0x%llx, level = %d, rsvd bits = 0x%llx", spte, level,

		  get_rsvd_bits(&vcpu->arch.mmu->shadow_zero_check, spte, level));



	if (spte & PT_WRITABLE_MASK)

		kvm_vcpu_mark_page_dirty(vcpu, gfn);



	*new_spte = spte;

	return ret;

}

arch/x86/kvm/mmu/tdp_mmu.c

+1 −20
Original line number Diff line number Diff line
@@ -542,26 +542,7 @@ static inline bool tdp_mmu_map_set_spte_atomic(struct kvm_vcpu *vcpu, 
					       struct tdp_iter *iter,

					       u64 new_spte)

{

	struct kvm *kvm = vcpu->kvm;



	if (!tdp_mmu_set_spte_atomic_no_dirty_log(kvm, iter, new_spte))

		return false;



	/*

	 * Use kvm_vcpu_gfn_to_memslot() instead of going through

	 * handle_changed_spte_dirty_log() to leverage vcpu->last_used_slot.

	 */

	if (is_writable_pte(new_spte)) {

		struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, iter->gfn);



		if (slot && kvm_slot_dirty_track_enabled(slot)) {

			/* Enforced by kvm_mmu_hugepage_adjust. */

			WARN_ON_ONCE(iter->level > PG_LEVEL_4K);

			mark_page_dirty_in_slot(kvm, slot, iter->gfn);

		}

	}



	return true;

	return tdp_mmu_set_spte_atomic_no_dirty_log(vcpu->kvm, iter, new_spte);

}



static inline bool tdp_mmu_zap_spte_atomic(struct kvm *kvm,