From patchwork Tue Jan 7 20:59:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 11321887 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7861A13A0 for ; Tue, 7 Jan 2020 21:25:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D583206F0 for ; Tue, 7 Jan 2020 21:25:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727826AbgAGVZE (ORCPT ); Tue, 7 Jan 2020 16:25:04 -0500 Received: from ale.deltatee.com ([207.54.116.67]:51280 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727257AbgAGVAQ (ORCPT ); Tue, 7 Jan 2020 16:00:16 -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 1iovxO-0007vy-Fh; Tue, 07 Jan 2020 14:00:09 -0700 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.92) (envelope-from ) id 1iovxJ-0001zP-94; Tue, 07 Jan 2020 14:00:01 -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, Dan Williams , Michal Hocko , David Hildenbrand , Andrew Morton Cc: Christoph Hellwig , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Eric Badger , Logan Gunthorpe , Jason Gunthorpe Date: Tue, 7 Jan 2020 13:59:59 -0700 Message-Id: <20200107205959.7575-9-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200107205959.7575-1-logang@deltatee.com> References: <20200107205959.7575-1-logang@deltatee.com> MIME-Version: 1.0 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, dan.j.williams@intel.com, akpm@linux-foundation.org, hch@lst.de, catalin.marinas@arm.com, benh@kernel.crashing.org, tglx@linutronix.de, david@redhat.com, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, mhocko@kernel.org, will@kernel.org, luto@kernel.org, peterz@infradead.org, ebadger@gigaio.com, logang@deltatee.com, jgg@ziepe.ca X-SA-Exim-Mail-From: gunthorp@deltatee.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on ale.deltatee.com X-Spam-Level: X-Spam-Status: No, score=-8.7 required=5.0 tests=ALL_TRUSTED,BAYES_00, GREYLIST_ISWHITE,MYRULES_NO_TEXT autolearn=ham autolearn_force=no version=3.4.2 Subject: [PATCH v2 8/8] 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-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@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 45ab4ef0643d..d36ff688b768 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: + modifiers.pgprot = pgprot_writecombine(modifiers.pgprot); need_devmap_managed = false; break; default: