On Wed, 13 Mar 2013 13:06:23 +0800 Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> wrote: > On 03/12/2013 04:44 PM, Takuya Yoshikawa wrote: > > This will be used not to zap unrelated mmu pages when creating/moving > > a memory slot later. > > How about save all mmio spte into a mmio-rmap? The problem is that other mmu code would need to care about the pointers stored in the new rmap list: when mmu_shrink zaps shadow pages for example. Maybe worth thinking about, but I want to have a simple, back-portable patch for distributors, as a first step: note that creating a memory slot can happen many times for some guest configurations since QEMU is doing strange things for re-mapping some regions IIRC. > > The good things are: > - instead walking all shadow page, we can only walk the rmap Traversing the active list does not take such a long time compared to other things to do for zapping pages: us, not ms order. But I'm now preparing for an additional work to avoid "goto restart" after deleting entries. That will at least help us not to traverse more than once. > - Comparing to zap a shadow page, it does not need to flush TLB after > zapping mmio sptes If we check each spte in the sp, we can achieve the similar goal: similar to the old remove_write_access() code. I implemented such code but have not seen a clear improvement yet. Pros and cons will be there. Thanks, Takuya -- 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
