From patchwork Wed Nov 17 21:54:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 12625511 X-Patchwork-Delegate: bhelgaas@google.com 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8C81C3525A for ; Wed, 17 Nov 2021 21:54:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B626861265 for ; Wed, 17 Nov 2021 21:54:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241030AbhKQV5n (ORCPT ); Wed, 17 Nov 2021 16:57:43 -0500 Received: from ale.deltatee.com ([204.191.154.188]:58842 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240916AbhKQV52 (ORCPT ); Wed, 17 Nov 2021 16:57:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:MIME-Version:References:In-Reply-To: Message-Id:Date:Cc:To:From:content-disposition; bh=aR9/NOunbjx2VrbBvqvaOV6WJfKqIrvKUy098YHBKIs=; b=lWKQx+YOxtX4F9UOqlW7UFAwyw 9pKxueuIcLcyyJiQRJ5QeyMRtWaN7EYrGXbYDh6toF6bVWayKR7AZitKrP7zwU1jk1lyKmuiZVMqs kbHXQzE5rDsVFKf1Km2CY9x08gk9TX3XSG3wG5uF2BVS1rR3S7k6O17NEjKj0EKBaOmASWD93QNn1 lPeJNv5mXFIBqZ8OnMiZNfxBs09ttmczPeraV1sj0jL1mQgMVDTjSPvWXDYICJ1s8W2ZyCZxlz4bc RVVAEz0Px2vMSL05BmRI619hUNGgWjlBJdyFckOY1GsmvCsbMj6heCEWlCTeCJoybVwLtb8RH2uRJ YEB1XA1Q==; Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mnSso-000Zo3-OW; Wed, 17 Nov 2021 14:54:24 -0700 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.94.2) (envelope-from ) id 1mnSsk-0000zl-BK; Wed, 17 Nov 2021 14:54:18 -0700 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org Cc: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?utf-8?q?Christian_K=C3=B6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni , Logan Gunthorpe Date: Wed, 17 Nov 2021 14:54:02 -0700 Message-Id: <20211117215410.3695-16-logang@deltatee.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211117215410.3695-1-logang@deltatee.com> References: <20211117215410.3695-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, sbates@raithlin.com, hch@lst.de, jgg@ziepe.ca, christian.koenig@amd.com, jhubbard@nvidia.com, ddutile@redhat.com, willy@infradead.org, daniel.vetter@ffwll.ch, jason@jlekstrand.net, dave.hansen@linux.intel.com, helgaas@kernel.org, dan.j.williams@intel.com, andrzej.jakowski@intel.com, dave.b.minturn@intel.com, jianxin.xiong@intel.com, ira.weiny@intel.com, robin.murphy@arm.com, martin.oliveira@eideticom.com, ckulkarnilinux@gmail.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v4 15/23] mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Callers that expect PCI P2PDMA pages can now set FOLL_PCI_P2PDMA to allow obtaining P2PDMA pages. If a caller does not set this flag and tries to map P2PDMA pages it will fail. This is implemented by checking failing if PCI p2pdma pages are found when FOLL_PCI_P2PDMA is set. This is only done if pte_devmap() is set. FOLL_PCI_P2PDMA cannot be set if FOLL_LONGTERM is set. Signed-off-by: Logan Gunthorpe --- include/linux/mm.h | 1 + mm/gup.c | 22 +++++++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index a7e4a9e7d807..65cb27cebbab 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2971,6 +2971,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */ #define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */ #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ +#define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ /* * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each diff --git a/mm/gup.c b/mm/gup.c index 2c51e9748a6a..c31461c3d256 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -527,6 +527,12 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, page = pte_page(pte); else goto no_page; + + if (unlikely(!(flags & FOLL_PCI_P2PDMA) && + is_pci_p2pdma_page(page))) { + page = ERR_PTR(-EREMOTEIO); + goto out; + } } else if (unlikely(!page)) { if (flags & FOLL_DUMP) { /* Avoid special (like zero) pages in core dumps */ @@ -980,6 +986,9 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma)) return -EOPNOTSUPP; + if ((gup_flags & FOLL_LONGTERM) && (gup_flags & FOLL_PCI_P2PDMA)) + return -EOPNOTSUPP; + if (vma_is_secretmem(vma)) return -EFAULT; @@ -2297,6 +2306,10 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); + if (unlikely(pte_devmap(pte) && !(flags & FOLL_PCI_P2PDMA) && + is_pci_p2pdma_page(page))) + goto pte_unmap; + head = try_grab_compound_head(page, 1, flags); if (!head) goto pte_unmap; @@ -2374,6 +2387,12 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, undo_dev_pagemap(nr, nr_start, flags, pages); break; } + + if (!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)) { + undo_dev_pagemap(nr, nr_start, flags, pages); + break; + } + SetPageReferenced(page); pages[*nr] = page; if (unlikely(!try_grab_page(page, flags))) { @@ -2842,7 +2861,8 @@ static int internal_get_user_pages_fast(unsigned long start, if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | FOLL_FORCE | FOLL_PIN | FOLL_GET | - FOLL_FAST_ONLY | FOLL_NOFAULT))) + FOLL_FAST_ONLY | FOLL_NOFAULT | + FOLL_PCI_P2PDMA))) return -EINVAL; if (gup_flags & FOLL_PIN)