On Tue, Feb 25, 2014 at 11:30:37AM +0800, Xiao Guangrong wrote: > On 02/25/2014 12:59 AM, Marcelo Tosatti wrote: > > > > Read-only large sptes can be created due to read-only faults as > > follows: > > > > - QEMU pagetable entry that maps guest memory is read-only > > due to COW. > > - Guest read faults such memory, COW is not broken, because > > it is a read-only fault. > > - Enable dirty logging, large spte not nuked because it is read-only. > > - Write-fault on such memory causes guest to loop endlessly > > (which must go down to level 1 because dirty logging is enabled). > > Hi Marcelo, > > It surprised me that the large-readonly mapping was not dropped > by mmu-notifer as this is write fault on readonly mapping in Qemu. > Hmm... i missed something? You mean COW was not broken by gup? (that is the problem, so a read-only large spte is created). Don't see why mmu-notifier should invalidate the spte? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
