On Sun, Feb 17, 2008 at 03:13:47PM +0200, Avi Kivity wrote: > Avi Kivity wrote: > >Marcelo Tosatti wrote: > >>Hypercall based pte updates are faster than faults, and also allow use > >>of the lazy MMU mode to batch operations. > >> > >>Don't report the feature if two dimensional paging is enabled. > >> > >>Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]> > >>+/* > >>+ * We only need to hook operations that are MMU writes. We hook > >>these so that > >>+ * we can use lazy MMU mode to batch these operations. We could > >>probably > >>+ * improve the performance of the host code if we used some of the > >>information > >>+ * here to simplify processing of batched writes. > >>+ */ > >> > > > >One option is, if the guest promises never to write to a page table > >directly, is to avoid write protecting guest page tables. I think the > >shadow code can handle it (since the gfn/spte relationship is > >maintained by shadow code, and doesn't require reading the guest page > >tables), but am not sure. > > > > In addition to reducing mmu work for write protection, this allows more > efficient use of large pages.
Yes, and gets rid of the remote TLB flushing. Issue is the paravirt_ops code in Linux does not cover all pte updates (bit updates, ptep_get_and_clear, etc). The plan is to get the basic infrastructure merged into KVM first (which is a significant improvement already) and then later have paravirt_ops cover all updates, disabling write protection. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
