From patchwork Tue Mar 23 00:49:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 12156509 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBDFFC433E0 for ; Tue, 23 Mar 2021 00:50:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6EBB26196C for ; Tue, 23 Mar 2021 00:50:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EBB26196C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D215E6B0136; Mon, 22 Mar 2021 20:49:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C5F896B0137; Mon, 22 Mar 2021 20:49:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C4AF6B0139; Mon, 22 Mar 2021 20:49:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0021.hostedemail.com [216.40.44.21]) by kanga.kvack.org (Postfix) with ESMTP id 62F816B0137 for ; Mon, 22 Mar 2021 20:49:48 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 2A9C218035453 for ; Tue, 23 Mar 2021 00:49:48 +0000 (UTC) X-FDA: 77949306456.05.822FEF9 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf20.hostedemail.com (Postfix) with ESMTP id 2AB71E7 for ; Tue, 23 Mar 2021 00:49:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616460587; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AiO26VDrmUg6vB+7BT5Jj5YPPTcAM0VGHQAxP1RtUns=; b=WGvD8H8hhqbaZSFJnIxUpXur3+sdcp4POjBfbPG7IK2UU1sU4BijklJXZ5hdZ6vf18gtZm HhH0TWfgT6Cx7YQVjD1TAkcMQ3327w+sFmTO8X9GF1ZVWS2ANz07D+Nr9LedKICMvErfxT +eD7fMu6tNFHxScAUXxqbyN0vaaZHdE= Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-172--pX-GioUOI2NEbZe4GkZgA-1; Mon, 22 Mar 2021 20:49:43 -0400 X-MC-Unique: -pX-GioUOI2NEbZe4GkZgA-1 Received: by mail-qt1-f197.google.com with SMTP id m8so392879qtp.14 for ; Mon, 22 Mar 2021 17:49:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=AiO26VDrmUg6vB+7BT5Jj5YPPTcAM0VGHQAxP1RtUns=; b=Dqo1siJvd2usyPuGZOHub3oYy7yDCHzruhJ/IjciTGIw2xSjesaRk8xMe/LbFRoaui tt/FWwQ6vvWuZlzlAL4UG7VhSUxRfNgVBlQa/JJ0pT+ODRnbWhLJmlUAb0LwUhwK7rLn acIx0uvBrIQzBl7Wk7xwvS9j8uHrTXXlDDQTLzObAj7a5lnVhULHZz6ZWZpiL9y7ycDw zhdibqZ9yKsGpzCnqO0TCW7w+IkS8Xda4jdmCJsbGisNBKZm6IgsMtS0vCv87JCBEXKA LlPPPkq/rsUaMg/5UMVwzTxtb4keqzvU+XfOSzBjjuFGhnODfj8CMkYaPmUObTDvgvpR QoSw== X-Gm-Message-State: AOAM530M6wdNTIumwnK6yvkmFyZY1aAYnBS93uNXM5dbG8DZaByaNHt1 oUFlk5XyW1SU2Px05WjzCj5bhpdIy4GMIcfP50qX7PcNpGDdqX5n0mupEPlW4wZcUl3gce3d1kn 7wJl9LZjKzFY= X-Received: by 2002:a05:620a:244f:: with SMTP id h15mr2827100qkn.235.1616460582825; Mon, 22 Mar 2021 17:49:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzWIpDXhwdNCAyIRtAVCaaAMdmYrNrenAgax2tWD83MS43YI42hO1l+4DhwqPJ+NaQThw1Wgg== X-Received: by 2002:a05:620a:244f:: with SMTP id h15mr2827076qkn.235.1616460582571; Mon, 22 Mar 2021 17:49:42 -0700 (PDT) Received: from localhost.localdomain (bras-base-toroon474qw-grc-82-174-91-135-175.dsl.bell.ca. [174.91.135.175]) by smtp.gmail.com with ESMTPSA id n6sm5031793qtx.22.2021.03.22.17.49.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Mar 2021 17:49:41 -0700 (PDT) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: "Kirill A . Shutemov" , Jerome Glisse , Mike Kravetz , Matthew Wilcox , Andrew Morton , Axel Rasmussen , Hugh Dickins , peterx@redhat.com, Nadav Amit , Andrea Arcangeli , Mike Rapoport Subject: [PATCH 16/23] hugetlb/userfaultfd: Take care of UFFDIO_COPY_MODE_WP Date: Mon, 22 Mar 2021 20:49:05 -0400 Message-Id: <20210323004912.35132-17-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210323004912.35132-1-peterx@redhat.com> References: <20210323004912.35132-1-peterx@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2AB71E7 X-Stat-Signature: pc7q89ioeh1ywk7m8uy43okpzn3hcdec Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf20; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=170.10.133.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616460586-713205 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: Firstly, pass the wp_copy variable into hugetlb_mcopy_atomic_pte() thoughout the stack. Then, apply the UFFD_WP bit if UFFDIO_COPY_MODE_WP is with UFFDIO_COPY. Introduce huge_pte_mkuffd_wp() for it. Note that similar to how we've handled shmem, we'd better keep setting the dirty bit even if UFFDIO_COPY_MODE_WP is provided, so that the core mm will know this page contains valid data and never drop it. Signed-off-by: Peter Xu --- include/asm-generic/hugetlb.h | 5 +++++ include/linux/hugetlb.h | 6 ++++-- mm/hugetlb.c | 22 +++++++++++++++++----- mm/userfaultfd.c | 12 ++++++++---- 4 files changed, 34 insertions(+), 11 deletions(-) diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h index 8e1e6244a89d..548212eccbd6 100644 --- a/include/asm-generic/hugetlb.h +++ b/include/asm-generic/hugetlb.h @@ -27,6 +27,11 @@ static inline pte_t huge_pte_mkdirty(pte_t pte) return pte_mkdirty(pte); } +static inline pte_t huge_pte_mkuffd_wp(pte_t pte) +{ + return pte_mkuffd_wp(pte); +} + static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot) { return pte_modify(pte, newprot); diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index a7f7d5f328dc..ef8d2b8427b1 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -141,7 +141,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte, unsigned long dst_addr, unsigned long src_addr, enum mcopy_atomic_mode mode, - struct page **pagep); + struct page **pagep, + bool wp_copy); #endif /* CONFIG_USERFAULTFD */ bool hugetlb_reserve_pages(struct inode *inode, long from, long to, struct vm_area_struct *vma, @@ -321,7 +322,8 @@ static inline int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, unsigned long dst_addr, unsigned long src_addr, enum mcopy_atomic_mode mode, - struct page **pagep) + struct page **pagep, + bool wp_copy) { BUG(); return 0; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index def2c7ddf3ae..f0e55b341ebd 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4725,7 +4725,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, unsigned long dst_addr, unsigned long src_addr, enum mcopy_atomic_mode mode, - struct page **pagep) + struct page **pagep, + bool wp_copy) { bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE); struct address_space *mapping; @@ -4822,17 +4823,28 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); } - /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */ - if (is_continue && !vm_shared) + /* + * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY + * with wp flag set, don't set pte write bit. + */ + if (wp_copy || (is_continue && !vm_shared)) writable = 0; else writable = dst_vma->vm_flags & VM_WRITE; _dst_pte = make_huge_pte(dst_vma, page, writable); - if (writable) - _dst_pte = huge_pte_mkdirty(_dst_pte); + /* + * Always mark UFFDIO_COPY page dirty; note that this may not be + * extremely important for hugetlbfs for now since swapping is not + * supported, but we should still be clear in that this page cannot be + * thrown away at will, even if write bit not set. + */ + _dst_pte = huge_pte_mkdirty(_dst_pte); _dst_pte = pte_mkyoung(_dst_pte); + if (wp_copy) + _dst_pte = huge_pte_mkuffd_wp(_dst_pte); + set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte, diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 0963e0d9ed20..78471ae3d25c 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -207,7 +207,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, unsigned long dst_start, unsigned long src_start, unsigned long len, - enum mcopy_atomic_mode mode) + enum mcopy_atomic_mode mode, + bool wp_copy) { int vm_alloc_shared = dst_vma->vm_flags & VM_SHARED; int vm_shared = dst_vma->vm_flags & VM_SHARED; @@ -304,7 +305,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, } err = hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, - dst_addr, src_addr, mode, &page); + dst_addr, src_addr, mode, &page, + wp_copy); mutex_unlock(&hugetlb_fault_mutex_table[hash]); i_mmap_unlock_read(mapping); @@ -406,7 +408,8 @@ extern ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, unsigned long dst_start, unsigned long src_start, unsigned long len, - enum mcopy_atomic_mode mode); + enum mcopy_atomic_mode mode, + bool wp_copy); #endif /* CONFIG_HUGETLB_PAGE */ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, @@ -527,7 +530,8 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, */ if (is_vm_hugetlb_page(dst_vma)) return __mcopy_atomic_hugetlb(dst_mm, dst_vma, dst_start, - src_start, len, mcopy_mode); + src_start, len, mcopy_mode, + wp_copy); if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) goto out_unlock;