KVM: MMU: collapse TLB flushes when zap all pages (f34d251d) · Commits · 戴 / test

arch/x86/kvm/mmu.c

+30 −3

Original line number	Diff line number	Diff line
		@@ -1654,6 +1654,16 @@ static int kvm_mmu_prepare_zap_page(struct kvm kvm, struct kvm_mmu_page sp,
		static void kvm_mmu_commit_zap_page(struct kvm *kvm,
		struct list_head *invalid_list);

		/*
		* NOTE: we should pay more attention on the zapped-obsolete page
		* (is_obsolete_sp(sp) && sp->role.invalid) when you do hash list walk
		* since it has been deleted from active_mmu_pages but still can be found
		* at hast list.
		*
		* for_each_gfn_indirect_valid_sp has skipped that kind of page and
		* kvm_mmu_get_page(), the only user of for_each_gfn_sp(), has skipped
		* all the obsolete pages.
		*/
		#define for_each_gfn_sp(_kvm, _sp, _gfn) \
		hlist_for_each_entry(_sp, \
		&(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \
		@@ -4224,11 +4234,13 @@ restart:
		if (sp->role.invalid)
		continue;

		/*
		* Need not flush tlb since we only zap the sp with invalid
		* generation number.
		*/
		if (batch >= BATCH_ZAP_PAGES &&
		(need_resched() \|\| spin_needbreak(&kvm->mmu_lock))) {
		cond_resched_lock(&kvm->mmu_lock)) {
		batch = 0;
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
		cond_resched_lock(&kvm->mmu_lock);
		goto restart;
		}

		@@ -4239,6 +4251,10 @@ restart:
		goto restart;
		}

		/*
		* Should flush tlb before free page tables since lockless-walking
		* may use the pages.
		*/
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
		}

		@@ -4257,6 +4273,17 @@ void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm)
		trace_kvm_mmu_invalidate_zap_all_pages(kvm);
		kvm->arch.mmu_valid_gen++;

		/*
		* Notify all vcpus to reload its shadow page table
		* and flush TLB. Then all vcpus will switch to new
		* shadow page table with the new mmu_valid_gen.
		*
		* Note: we should do this under the protection of
		* mmu-lock, otherwise, vcpu would purge shadow page
		* but miss tlb flush.
		*/
		kvm_reload_remote_mmus(kvm);

		kvm_zap_obsolete_pages(kvm);
		spin_unlock(&kvm->mmu_lock);
		}

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