Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758335AbcLRIpD (ORCPT ); Sun, 18 Dec 2016 03:45:03 -0500 Received: from mail-wj0-f195.google.com ([209.85.210.195]:36709 "EHLO mail-wj0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751532AbcLRIpC (ORCPT ); Sun, 18 Dec 2016 03:45:02 -0500 Date: Sun, 18 Dec 2016 09:44:57 +0100 From: Ingo Molnar To: Boris Ostrovsky Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, matt@codeblueprint.co.uk, Linus Torvalds , Andy Lutomirski , Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Denys Vlasenko , Brian Gerst Subject: Re: [PATCH] x86/head: Refactor 32-bit pgtable setup Message-ID: <20161218084457.GA19538@gmail.com> References: <1481215471-9639-1-git-send-email-boris.ostrovsky@oracle.com> <20161209043347.GB2595@gmail.com> <17b4298e-f073-d323-3a3f-1974ed3ec62f@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17b4298e-f073-d323-3a3f-1974ed3ec62f@oracle.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1752 Lines: 49 * Boris Ostrovsky wrote: > On 12/08/2016 11:33 PM, Ingo Molnar wrote: > > * Boris Ostrovsky wrote: > > > >> The new Xen PVH entry point requires page tables to be setup by the > >> kernel since it is entered with paging disabled. > >> > >> Pull the common code out of head_32.S so that mk_early_pgtbl_32 can be > >> invoked from both the new Xen entry point and the existing startup_32 > >> code. > >> > >> Convert resulting common code to C. > >> > >> Signed-off-by: Boris Ostrovsky > >> --- > >> This is replacement for https://lkml.org/lkml/2016/10/14/434, with > >> assembly code re-written in C as requested by Ingo. > >> > >> > >> arch/x86/include/asm/pgtable_32.h | 32 ++++++++++ > >> arch/x86/kernel/head32.c | 62 +++++++++++++++++++ > >> arch/x86/kernel/head_32.S | 122 +++----------------------------------- > >> 3 files changed, 101 insertions(+), 115 deletions(-) > > Whee, I love it! And the code is so much more readable! > > > > Did you have any particular robustness problems (difficult to resolve crashes) > > while developing it, or was it reasonably straightforward to do? > > There was nothing particularly difficult beyond understanding current > code. That, of course, is not to say that there were no crashes but > developing this on a guest gives you pretty good insight into why/where > you crashed. > > This was tested on bare-metal (in case you are wondering), but obviously > more testing is always good. Ok, cool! Would you like to carry this with your other Xen dependencies? If yes: Acked-by: Ingo Molnar If not then I can pick it up and get it to Linus in v4.10. Thanks, Ingo