KVM: MMU: fix kvm_mmu_zap_page() and its calling path

This patch fix:

- calculate zapped page number properly in mmu_zap_unsync_children()
- calculate freeed page number properly kvm_mmu_change_mmu_pages()
- if zapped children page it shoud restart hlist walking

KVM-Stable-Tag.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 48aeee8eefb0e52d2cfbf870eaec5630f788376d..19a8906bcaa2c5301dddf55821078248a85e23a7 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1490,8 +1490,8 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
                for_each_sp(pages, sp, parents, i) {
                        kvm_mmu_zap_page(kvm, sp);
                        mmu_pages_clear_parents(&parents);
+                       zapped++;
                }
-               zapped += pages.nr;
                kvm_mmu_pages_init(parent, &parents, &pages);
        }
 
@@ -1542,14 +1542,16 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
         */
 
        if (used_pages > kvm_nr_mmu_pages) {
-               while (used_pages > kvm_nr_mmu_pages) {
+               while (used_pages > kvm_nr_mmu_pages &&
+                       !list_empty(&kvm->arch.active_mmu_pages)) {
                        struct kvm_mmu_page *page;
 
                        page = container_of(kvm->arch.active_mmu_pages.prev,
                                            struct kvm_mmu_page, link);
-                       kvm_mmu_zap_page(kvm, page);
+                       used_pages -= kvm_mmu_zap_page(kvm, page);
                        used_pages--;
                }
+               kvm_nr_mmu_pages = used_pages;
                kvm->arch.n_free_mmu_pages = 0;
        }
        else
@@ -1596,7 +1598,8 @@ static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
                    && !sp->role.invalid) {
                        pgprintk("%s: zap %lx %x\n",
                                 __func__, gfn, sp->role.word);
-                       kvm_mmu_zap_page(kvm, sp);
+                       if (kvm_mmu_zap_page(kvm, sp))
+                               nn = bucket->first;
                }
        }
 }