1 files changed, 30 insertions, 3 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index fe9d6f10e7a9..674c0442ac89 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -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);
 }