Messages in this thread | | | Date | Sun, 29 Mar 2009 16:26:46 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH 4/7] kvm mmu: implement necessary data structures for second huge page accounting |
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Joerg Roedel wrote: > This patch adds the necessary data structures to take care of write > protections in place within a second huge page sized page. > > > +#ifdef KVM_PAGES_PER_LHPAGE > + if (npages && !new.hpage_info) { > + int hugepages = npages / KVM_PAGES_PER_LHPAGE; > + if (npages % KVM_PAGES_PER_LHPAGE) > + hugepages++; > + if (base_gfn % KVM_PAGES_PER_LHPAGE) > + hugepages++; >
Consider a slot with base_gfn == 1 and npages == 1. This will have hugepages == 2, which is wrong.
I think the right calculation is
((base_gfn + npages - 1) / N) - (base_gfn / N) + 1
i.e. index of last page, plus one so we can store it.
The small huge page calculation is off as well.
> + > + new.hpage_info = vmalloc(hugepages * sizeof(*new.hpage_info)); > + > + if (!new.hpage_info) > + goto out_free; > + > + memset(new.hpage_info, 0, hugepages * sizeof(*new.hpage_info)); > + > + if (base_gfn % KVM_PAGES_PER_LHPAGE) > + new.hpage_info[0].write_count = 1; > + if ((base_gfn+npages) % KVM_PAGES_PER_LHPAGE) > + new.hpage_info[hugepages-1].write_count = 1; > + } > +#endif > + >
-- error compiling committee.c: too many arguments to function
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