From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83395C00454 for ; Mon, 9 Dec 2019 19:14:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EB7A206D3 for ; Mon, 9 Dec 2019 19:14:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726953AbfLITOH (ORCPT ); Mon, 9 Dec 2019 14:14:07 -0500 Received: from ale.deltatee.com ([207.54.116.67]:56032 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726365AbfLITOF (ORCPT ); Mon, 9 Dec 2019 14:14:05 -0500 Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ieOTk-00025q-NL; Mon, 09 Dec 2019 12:13:57 -0700 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.92) (envelope-from ) id 1ieOTd-0001Mv-Me; Mon, 09 Dec 2019 12:13:49 -0700 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig , Dan Williams , Andrew Morton Cc: Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Logan Gunthorpe , Jason Gunthorpe Date: Mon, 9 Dec 2019 12:13:46 -0700 Message-Id: <20191209191346.5197-7-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191209191346.5197-1-logang@deltatee.com> References: <20191209191346.5197-1-logang@deltatee.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, hch@lst.de, dan.j.williams@intel.com, akpm@linux-foundation.org, catalin.marinas@arm.com, benh@kernel.crashing.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, will@kernel.org, luto@kernel.org, peterz@infradead.org, logang@deltatee.com, jgg@ziepe.ca X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH 6/6] mm/memremap: Set caching mode for PCI P2PDMA memory to WC X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PCI BAR IO memory should never be mapped as WB, however prior to this the PAT bits were set WB and it was typically overridden by MTRR registers set by the firmware. Set PCI P2PDMA memory to be WC (writecombining) as the only current user (the NVMe CMB) was originally mapped WC before the P2PDMA code replaced the mapping with devm_memremap_pages(). Future use-cases may need to generalize this by adding flags to select the caching type, as some P2PDMA cases will not want WC. However, those use-cases are not upstream yet and this can be changed when they arrive. Cc: Dan Williams Cc: Christoph Hellwig Cc: Jason Gunthorpe Signed-off-by: Logan Gunthorpe --- mm/memremap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memremap.c b/mm/memremap.c index 4edcca074e15..ced32593e4a7 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -187,7 +187,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) } break; case MEMORY_DEVICE_DEVDAX: + need_devmap_managed = false; + break; case MEMORY_DEVICE_PCI_P2PDMA: + pgprot = pgprot_writecombine(pgprot); need_devmap_managed = false; break; default: -- 2.20.1