Messages in this thread | | | Date | Tue, 3 Jul 2012 17:30:53 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH 3/3] KVM: MMU: track the refcount when unmap the page |
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On Tue, Jul 03, 2012 at 02:32:14PM +0800, Xiao Guangrong wrote: > It will trigger a WARN_ON if the page has been freed but it is still > used in mmu, it can help us to detect mm bug early > > Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> > --- > arch/x86/kvm/mmu.c | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index cac3408..af7e076 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -527,6 +527,14 @@ static int mmu_spte_clear_track_bits(u64 *sptep) > return 0; > > pfn = spte_to_pfn(old_spte); > + > + /* > + * KVM does not hold the refcount of the page used by > + * kvm mmu, before reclaiming the page, we should > + * unmap it from mmu first. > + */ > + WARN_ON(!page_count(pfn_to_page(pfn))); > +
Except for mmio pfns.
Applied patch 1 and 2 to master, thanks.
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