From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752391AbbEGHwS (ORCPT ); Thu, 7 May 2015 03:52:18 -0400 Received: from mail.skyhub.de ([78.46.96.112]:51118 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750986AbbEGHwQ (ORCPT ); Thu, 7 May 2015 03:52:16 -0400 Date: Thu, 7 May 2015 09:52:10 +0200 From: Borislav Petkov To: Toshi Kani 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 Subject: Re: [PATCH v4 6/7] mtrr, x86: Clean up mtrr_type_lookup() Message-ID: <20150507075210.GA6859@pd.tnic> References: <1427234921-19737-1-git-send-email-toshi.kani@hp.com> <1427234921-19737-7-git-send-email-toshi.kani@hp.com> <20150506134127.GE22949@pd.tnic> <1430928030.23761.328.camel@misato.fc.hp.com> <20150506224931.GL22949@pd.tnic> <1430955730.23761.348.camel@misato.fc.hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1430955730.23761.348.camel@misato.fc.hp.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 06, 2015 at 05:42:10PM -0600, Toshi Kani wrote: > Well, creating mtrr_type_lookup_fixed() is one of the comments I had in > the previous code review. Anyway, let me make sure if I understand your > comment correctly. Do the following changes look right to you? > > 1) Change the caller responsible for the condition checks. > > if ((start < 0x100000) && > (mtrr_state.have_fixed) && > (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) > return mtrr_type_lookup_fixed(start, end); > > 2) Delete the checks with mtrr_state in mtrr_type_lookup_fixed() as they > are done by the caller. Keep the check with '(start >= 0x100000)' to > assure that the code handles the range [0xC0000 - 0xFFFFF] correctly. That is a good defensive measure. > static u8 mtrr_type_lookup_fixed(u64 start, u64 end) > { > int idx; > > if (start >= 0x100000) > return MTRR_TYPE_INVALID; > > - if (!(mtrr_state.have_fixed) || > - !(mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) > - return MTRR_TYPE_INVALID; Yeah, that's what I mean. Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id 2E1476B0038 for ; Thu, 7 May 2015 03:52:19 -0400 (EDT) Received: by wief7 with SMTP id f7so7296875wie.0 for ; Thu, 07 May 2015 00:52:17 -0700 (PDT) Received: from mail.skyhub.de (mail.skyhub.de. [2a01:4f8:120:8448::d00d]) by mx.google.com with ESMTP id cl2si1969131wjc.117.2015.05.07.00.52.15 for ; Thu, 07 May 2015 00:52:16 -0700 (PDT) Date: Thu, 7 May 2015 09:52:10 +0200 From: Borislav Petkov Subject: Re: [PATCH v4 6/7] mtrr, x86: Clean up mtrr_type_lookup() Message-ID: <20150507075210.GA6859@pd.tnic> References: <1427234921-19737-1-git-send-email-toshi.kani@hp.com> <1427234921-19737-7-git-send-email-toshi.kani@hp.com> <20150506134127.GE22949@pd.tnic> <1430928030.23761.328.camel@misato.fc.hp.com> <20150506224931.GL22949@pd.tnic> <1430955730.23761.348.camel@misato.fc.hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1430955730.23761.348.camel@misato.fc.hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: Toshi Kani 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 On Wed, May 06, 2015 at 05:42:10PM -0600, Toshi Kani wrote: > Well, creating mtrr_type_lookup_fixed() is one of the comments I had in > the previous code review. Anyway, let me make sure if I understand your > comment correctly. Do the following changes look right to you? > > 1) Change the caller responsible for the condition checks. > > if ((start < 0x100000) && > (mtrr_state.have_fixed) && > (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) > return mtrr_type_lookup_fixed(start, end); > > 2) Delete the checks with mtrr_state in mtrr_type_lookup_fixed() as they > are done by the caller. Keep the check with '(start >= 0x100000)' to > assure that the code handles the range [0xC0000 - 0xFFFFF] correctly. That is a good defensive measure. > static u8 mtrr_type_lookup_fixed(u64 start, u64 end) > { > int idx; > > if (start >= 0x100000) > return MTRR_TYPE_INVALID; > > - if (!(mtrr_state.have_fixed) || > - !(mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) > - return MTRR_TYPE_INVALID; Yeah, that's what I mean. Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org