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: 12625637 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 8D20CC433EF for ; Wed, 17 Nov 2021 22:04:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4132E610C8 for ; Wed, 17 Nov 2021 22:04:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4132E610C8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D15DD6B0093; Wed, 17 Nov 2021 16:54:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 049F86B0096; Wed, 17 Nov 2021 16:54:44 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A7F036B0087; Wed, 17 Nov 2021 16:54:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0145.hostedemail.com [216.40.44.145]) by kanga.kvack.org (Postfix) with ESMTP id 296E06B007B for ; Wed, 17 Nov 2021 16:54:43 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id CE79D1831A9E8 for ; Wed, 17 Nov 2021 21:54:32 +0000 (UTC) X-FDA: 78819776994.05.F6175E4 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by imf03.hostedemail.com (Postfix) with ESMTP id 36FFF30019C3 for ; Wed, 17 Nov 2021 21:54:30 +0000 (UTC) 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=; 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dkim=pass header.d=deltatee.com header.s=20200525 header.b=lWKQx+YO; dmarc=pass (policy=none) header.from=deltatee.com; spf=pass (imf03.hostedemail.com: domain of gunthorp@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=gunthorp@deltatee.com X-HE-Tag: 1637186070-720122 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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)