Messages in this thread | | | Date | Tue, 29 Jan 2013 19:53:45 -0200 | From | Marcelo Tosatti <> | Subject | Re: [PATCH v2 03/12] KVM: MMU: simplify mmu_set_spte |
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On Tue, Jan 29, 2013 at 10:55:24AM +0800, Xiao Guangrong wrote: > On 01/29/2013 08:21 AM, Marcelo Tosatti wrote: > > On Wed, Jan 23, 2013 at 06:05:29PM +0800, Xiao Guangrong wrote: > >> In order to detecting spte remapping, we can simply check whether the > >> spte has already been pointing to the pfn even if the spte is not the > >> last spte, for middle spte is pointing to the kernel pfn which can not > >> be mapped to userspace > > > > This check is detecting spte overwrite, when a large spte is replaced by > > pointer to spte table. > > > > Can't see why check for different pfn is safe: only 'int level' can > > differ, and pfn be equivalent, for example. > > The 'u64 *sptep' must on the "int level" we want to set, that means: > page_header(__pa(sptep)).role.level == "int level".
Right, then stick a comment there noting which cases that condition handles. Keep the current comment and add more.
> We discussed this before :), the discussion can be found at: > http://marc.info/?l=kvm&m=135345057329427&w=2.
Note http://marc.info/?l=kvm&m=135345059929436&w=2, please take into account in the future.
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