Re: [PATCH 2/6] KVM MMU: fix kvm_mmu_zap_page() and its calling path

Marcelo Tosatti
2010-04-12T17:10:37Z

On Mon, Apr 12, 2010 at 04:01:09PM +0800, Xiao Guangrong wrote:
> - calculate zapped page number properly in mmu_zap_unsync_children()
> - calculate freeed page number properly kvm_mmu_change_mmu_pages()
> - restart list walking if have children page zapped
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
> arch/x86/kvm/mmu.c | 7 ++++---
> 1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index a23ca75..8f4f781 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1483,8 +1483,8 @@ 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);
> }

Don't see why this is needed? The for_each_sp loop uses pvec.nr.

> @@ -1540,7 +1540,7 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
>
> 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->arch.n_free_mmu_pages = 0;

Oops.

> @@ -1589,7 +1589,8 @@ 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;

Oops 2.