On 07/31/2012 01:18 AM, Sunil wrote: > Hello List, > > I am a KVM newbie and studying KVM mmu code. > > On the existing guest, I am trying to track all guest writes by > marking page table entry as read-only in EPT entry [ I am using Intel > machine with vmx and ept support ]. Looks like EPT support re-uses > shadow page table(SPT) code and hence some of SPT routines. > > I was thinking of below possible approach. Use pte_list_walk() to > traverse through list of sptes and use mmu_spte_update() to flip the > PT_WRITABLE_MASK flag. But all SPTEs are not part of any single list; > but on separate lists (based on gfn, page level, memory_slot). So, > recording all the faulted guest GFN and then using above method work ? > There are two ways to write-protect all sptes: - use kvm_mmu_slot_remove_write_access() on all memslots - walk the shadow page cache to get the shadow pages in the highest level (level = 4 on EPT), then write-protect its entries. If you just want to do it for the specified gfn, you can use rmap_write_protect(). Just inquisitive, what is your purpose? :) -- 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
