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 4BD82C433EF for ; Fri, 13 May 2022 19:21:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380334AbiEMTVc (ORCPT ); Fri, 13 May 2022 15:21:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383788AbiEMTVF (ORCPT ); Fri, 13 May 2022 15:21:05 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCB02266D for ; Fri, 13 May 2022 12:21:03 -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 81985B8313A for ; Fri, 13 May 2022 19:21:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28DCEC34100; Fri, 13 May 2022 19:21:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1652469662; bh=nx/fPMYQ/y7UXm4/jj78rHzsd6UgKkAHDQgRXBDYJH4=; h=Date:To:From:Subject:From; b=DZk2DnkqIlwxpqFTec5XCWwPg40k3u+NxCojYNDxoy6snsyYBNj4JqXs62mRXzMvw scAsWAINMTxQ1wIb0e/+d5y03Dd7c7etMc674FhkVoolM1oem1QBtqm3l6Oj22f3TM 5rvVAvmWnK7DplumWCSxKMU8BTe5yN4JZX/T/TbQ= Date: Fri, 13 May 2022 12:21:01 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, rppt@linux.vnet.ibm.com, nadav.amit@gmail.com, mike.kravetz@oracle.com, kirill@shutemov.name, jglisse@redhat.com, hughd@google.com, david@redhat.com, axelrasmussen@google.com, apopple@nvidia.com, aarcange@redhat.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-hugetlb-take-care-of-uffdio_copy_mode_wp.patch removed from -mm tree Message-Id: <20220513192102.28DCEC34100@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/hugetlb: take care of UFFDIO_COPY_MODE_WP has been removed from the -mm tree. Its filename was mm-hugetlb-take-care-of-uffdio_copy_mode_wp.patch This patch was dropped because it was merged into the mm-stable branch\nof git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Peter Xu Subject: mm/hugetlb: take care of UFFDIO_COPY_MODE_WP Pass the wp_copy variable into hugetlb_mcopy_atomic_pte() thoughout the stack. Apply the UFFD_WP bit if UFFDIO_COPY_MODE_WP is with UFFDIO_COPY. Hugetlb pages are only managed by hugetlbfs, so we're safe even without setting dirty bit in the huge pte if the page is installed as read-only. However we'd better still keep the dirty bit set for a read-only UFFDIO_COPY pte (when UFFDIO_COPY_MODE_WP bit is set), not only to match what we do with shmem, but also because the page does contain dirty data that the kernel just copied from the userspace. Link: https://lkml.kernel.org/r/20220405014904.14643-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Alistair Popple Cc: Andrea Arcangeli Cc: Axel Rasmussen Cc: David Hildenbrand Cc: Hugh Dickins Cc: Jerome Glisse Cc: "Kirill A . Shutemov" Cc: Matthew Wilcox Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 6 ++++-- mm/hugetlb.c | 29 +++++++++++++++++++++++------ mm/userfaultfd.c | 14 +++++++++----- 3 files changed, 36 insertions(+), 13 deletions(-) --- a/include/linux/hugetlb.h~mm-hugetlb-take-care-of-uffdio_copy_mode_wp +++ a/include/linux/hugetlb.h @@ -160,7 +160,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_s 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, @@ -356,7 +357,8 @@ static inline int hugetlb_mcopy_atomic_p 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; --- a/mm/hugetlb.c~mm-hugetlb-take-care-of-uffdio_copy_mode_wp +++ a/mm/hugetlb.c @@ -5821,7 +5821,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_s 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 hstate *h = hstate_vma(dst_vma); @@ -5951,7 +5952,12 @@ int hugetlb_mcopy_atomic_pte(struct mm_s goto out_release_unlock; ret = -EEXIST; - if (!huge_pte_none(huge_ptep_get(dst_pte))) + /* + * We allow to overwrite a pte marker: consider when both MISSING|WP + * registered, we firstly wr-protect a none pte which has no page cache + * page backing it, then access the page. + */ + if (!huge_pte_none_mostly(huge_ptep_get(dst_pte))) goto out_release_unlock; if (vm_shared) { @@ -5961,17 +5967,28 @@ int hugetlb_mcopy_atomic_pte(struct mm_s 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, --- a/mm/userfaultfd.c~mm-hugetlb-take-care-of-uffdio_copy_mode_wp +++ a/mm/userfaultfd.c @@ -305,7 +305,8 @@ static __always_inline ssize_t __mcopy_a 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_shared = dst_vma->vm_flags & VM_SHARED; ssize_t err; @@ -393,7 +394,7 @@ retry: } if (mode != MCOPY_ATOMIC_CONTINUE && - !huge_pte_none(huge_ptep_get(dst_pte))) { + !huge_pte_none_mostly(huge_ptep_get(dst_pte))) { err = -EEXIST; mutex_unlock(&hugetlb_fault_mutex_table[hash]); i_mmap_unlock_read(mapping); @@ -401,7 +402,8 @@ retry: } 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); @@ -456,7 +458,8 @@ extern ssize_t __mcopy_atomic_hugetlb(st 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, @@ -576,7 +579,8 @@ retry: */ 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; _ Patches currently in -mm which might be from peterx@redhat.com are