On 06/06/2013 12:36 PM, Borislav Petkov wrote: > On Thu, Jun 06, 2013 at 12:28:20PM -0700, H. Peter Anvin wrote: >> Or we could materialize mappings for this specific PGD. However, >> adding a read of %cr3 in __do_page_fault sounds expensive. > > Yes, I think we want to make sure all mappings are there when we do an > EFI runtime call so that we never #PF while it executes. > > Matt mentioned on IRC that the it could be that his EFI runtime is > referencing EFI_RESERVED area which we don't map. However, we need to > confirm/disprove that first, as it is currently only a hunch. If it is true, then maybe a #PF handler which materializes mappings on demand might be the right thing to do. Again, it would be interesting to stop a WinX VM in the process of doing an EFI call and see exactly what it has set up in its page tables. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
