Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757259Ab3FSQuo (ORCPT ); Wed, 19 Jun 2013 12:50:44 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:52103 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756817Ab3FSQum (ORCPT ); Wed, 19 Jun 2013 12:50:42 -0400 Message-ID: <1371660640.2409.44.camel@dabdike> Subject: Re: [PATCH -v2 0/4] EFI 1:1 mapping From: James Bottomley To: Borislav Petkov Cc: Matthew Garrett , Ingo Molnar , Linux EFI , Matt Fleming , X86 ML , LKML , Borislav Petkov Date: Wed, 19 Jun 2013 09:50:40 -0700 In-Reply-To: <20130619163804.GG28300@pd.tnic> References: <1371491416-11037-1-git-send-email-bp@alien8.de> <20130619125243.GD11209@gmail.com> <20130619130225.GA28311@pd.tnic> <20130619130434.GB24957@gmail.com> <20130619160804.GB27832@srcf.ucam.org> <20130619161827.GF28300@pd.tnic> <20130619162115.GA28119@srcf.ucam.org> <20130619163804.GG28300@pd.tnic> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.8.2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1373 Lines: 33 On Wed, 2013-06-19 at 18:38 +0200, Borislav Petkov wrote: > On Wed, Jun 19, 2013 at 05:21:15PM +0100, Matthew Garrett wrote: > > Yes, kexec needs a different solution. > > No need. If we say, "efi=use_11_map", the 1:1 map will be shoved down > SetVirtualAddressMap. Otherwise the high mappings. > > > Because firmware images don't always update all of the pointers, and > > so will crash if the 1:1 mappings aren't present. > > Ok, so it sounds like we want to *always* create both mappings but, > depending on what we want, to shove down SetVirtualAddressMap a > different set. And the 1:1 map will be the optional one which we give > SetVirtualAddressMap only when user wants it, i.e. when booting with > "efi=1:1_map". > > Makes sense? I think it will work. The only thing I'd worry about is aliasing. This scheme clearly won't work for any virtually indexed processor (so it's basically x86 only) but even on Physically Indexed, you do have to make sure the cache attributes of any given page are the same for all virtual address aliases. As long as the 1:1 mapping is writeback, I think this is satisfied. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/