From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932807AbbESOGe (ORCPT ); Tue, 19 May 2015 10:06:34 -0400 Received: from g4t3425.houston.hp.com ([15.201.208.53]:47862 "EHLO g4t3425.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932468AbbESOGc (ORCPT ); Tue, 19 May 2015 10:06:32 -0400 Message-ID: <1432043228.25898.0.camel@misato.fc.hp.com> Subject: Re: [PATCH v5 6/6] mtrr, mm, x86: Enhance MTRR checks for KVA huge page mapping From: Toshi Kani To: Borislav Petkov Cc: akpm@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, Elliott@hp.com, pebolle@tiscali.nl, mcgrof@suse.com Date: Tue, 19 May 2015 07:47:08 -0600 In-Reply-To: <20150519132307.GG4641@pd.tnic> References: <1431714237-880-7-git-send-email-toshi.kani@hp.com> <20150518133348.GA23618@pd.tnic> <1431969759.19889.5.camel@misato.fc.hp.com> <20150518190150.GC23618@pd.tnic> <1431977519.20569.15.camel@misato.fc.hp.com> <20150518200114.GE23618@pd.tnic> <1431980468.21019.11.camel@misato.fc.hp.com> <20150518205123.GI23618@pd.tnic> <1431985994.21526.12.camel@misato.fc.hp.com> <20150519114437.GF4641@pd.tnic> <20150519132307.GG4641@pd.tnic> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) 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 On Tue, 2015-05-19 at 15:23 +0200, Borislav Petkov wrote: > On Tue, May 19, 2015 at 01:44:37PM +0200, Borislav Petkov wrote: > > > Try with a smaller page size. > > > > > > The callers, pud_set_huge() and pmd_set_huge(), check if the given range > > > is safe with MTRRs for creating a huge page mapping. If not, they fail > > > the request, which leads their callers, ioremap_pud_range() and > > > ioremap_pmd_range(), to retry with a smaller page size, i.e. 1GB -> 2MB > > > -> 4KB. 4KB may not have overlap with MTRRs (hence no checking is > > > necessary), which will succeed as before. > > Scratch that, I think I have it now. And I even have a good feeling > about it :-) Looks good. Thanks for the update! -Toshi