From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:44566 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbfLIUnu (ORCPT ); Mon, 9 Dec 2019 15:43:50 -0500 Date: Mon, 9 Dec 2019 21:43:45 +0100 From: Christoph Hellwig Subject: Re: [PATCH 0/6] Allow setting caching mode in arch_add_memory() for P2PDMA Message-ID: <20191209204345.GA29265@lst.de> References: <20191209191346.5197-1-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191209191346.5197-1-logang@deltatee.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Logan Gunthorpe Cc: 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 , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andy Lutomirski , Peter Zijlstra On Mon, Dec 09, 2019 at 12:13:40PM -0700, Logan Gunthorpe wrote: > This changes is pretty routine for most of the arches: x86_64, s390, arm64 > and powerpc simply need to thread the pgprot through to where the page tables > are setup. x86_32 unfortunately sets up the page tables at boot so > must use _set_memory_prot() to change their caching mode. ia64 and sh > don't appear to have an easy way to change the page tables so, for now > at least, we just return -EINVAL on such mappings and thus they will > not support P2PDMA memory until the work for this is done. ia64 and sh don't support ZONE_DEVICE mappings anyway as far as I know. This generally looks fine to me.