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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99071C00140 for ; Wed, 10 Aug 2022 21:44:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229487AbiHJVoe (ORCPT ); Wed, 10 Aug 2022 17:44:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231508AbiHJVod (ORCPT ); Wed, 10 Aug 2022 17:44:33 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F07678BEC for ; Wed, 10 Aug 2022 14:44:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C8DE0B81EA8 for ; Wed, 10 Aug 2022 21:44:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 83DF1C433C1; Wed, 10 Aug 2022 21:44:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1660167868; bh=qcOin+u8MWbmUNLMeHFmWURyLpPLwJTStB0N5R47ccc=; h=Date:To:From:Subject:From; b=qLAcwoBU7KdFqUNHrpwpfJCpke3a3/EPZwycncybwt/v12NKVuwxd3Z+ucySBLnWw R5r0StO+8bsTbpyLPg3jSztApLci9mitMrcNNtifz0mASZQNEzsogcnSuePVLDDSKp iJtE75uHLuqpCoWyT2IQc9KtsC750A96gMrdOAX8= Date: Wed, 10 Aug 2022 14:44:27 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, hch@lst.de, felix.kuehling@amd.com, david@redhat.com, apopple@nvidia.com, alex.sierra@amd.com, alex.williamson@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-re-allow-pinning-of-zero-pfns-again.patch added to mm-hotfixes-unstable branch Message-Id: <20220810214428.83DF1C433C1@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: re-allow pinning of zero pfns (again) has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-re-allow-pinning-of-zero-pfns-again.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-re-allow-pinning-of-zero-pfns-again.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Alex Williamson Subject: mm: re-allow pinning of zero pfns (again) Date: Wed, 10 Aug 2022 10:53:59 -0600 The below referenced commit makes the same error as 1c563432588d ("mm: fix is_pinnable_page against a cma page"), re-interpreting the logic to exclude pinning of the zero page, which breaks device assignment with vfio. To avoid further subtle mistakes, split the logic into discrete tests. Link: https://lkml.kernel.org/r/166015037385.760108.16881097713975517242.stgit@omen Link: https://lore.kernel.org/all/165490039431.944052.12458624139225785964.stgit@omen Fixes: f25cbb7a95a2 ("mm: add zone device coherent type memory support") Signed-off-by: Alex Williamson Suggested-by: Matthew Wilcox Suggested-by: Felix Kuehling Cc: Alex Sierra Cc: Christoph Hellwig Cc: Alistair Popple Cc: David Hildenbrand Signed-off-by: Andrew Morton --- include/linux/mm.h | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/include/linux/mm.h~mm-re-allow-pinning-of-zero-pfns-again +++ a/include/linux/mm.h @@ -1544,9 +1544,20 @@ static inline bool is_longterm_pinnable_ if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE) return false; #endif - return !(is_device_coherent_page(page) || - is_zone_movable_page(page) || - is_zero_pfn(page_to_pfn(page))); + /* + * The zero page might reside in a movable zone, however it may not + * be migrated and can therefore be pinned. The vfio subsystem pins + * user mappings including the zero page for IOMMU translation. + */ + if (is_zero_pfn(page_to_pfn(page))) + return true; + + /* Coherent device memory must always allow eviction. */ + if (is_device_coherent_page(page)) + return false; + + /* Otherwise, non-movable zone pages can be pinned. */ + return !is_zone_movable_page(page); } #else static inline bool is_longterm_pinnable_page(struct page *page) _ Patches currently in -mm which might be from alex.williamson@redhat.com are mm-re-allow-pinning-of-zero-pfns-again.patch