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 9D487C433F5 for ; Wed, 6 Apr 2022 01:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1573351AbiDFB55 (ORCPT ); Tue, 5 Apr 2022 21:57:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347258AbiDEUeJ (ORCPT ); Tue, 5 Apr 2022 16:34:09 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 55151FDE08 for ; Tue, 5 Apr 2022 13:17:32 -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 sin.source.kernel.org (Postfix) with ESMTPS id F364CCE1FC8 for ; Tue, 5 Apr 2022 20:17:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 369D4C385A0; Tue, 5 Apr 2022 20:17:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1649189827; bh=N95JzxYGfdiiJZ86XuCqTcRbJgxniBBC8i/TE65Yqrc=; h=Date:To:From:Subject:From; b=wyKuR6ApxL9ZfnPoeOCiMnOzfmdudJ9R4sF8WeT3Bn6lbor5Rq4HtGQ7wW7F1QZIC Ux8Vn6QV9fbYPt36Coh5OYn40Ehf8kgeULbPxaKAU9sfhVwXe/EsuqGNpEsF1AoPe9 RzOL2fYiwR+Wmpt88tDEJZK7tmg15TCkQH7HeYK4= Date: Tue, 05 Apr 2022 13:17:06 -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: + mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch added to -mm tree Message-Id: <20220405201707.369D4C385A0@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/hugetlb: allow uffd wr-protect none ptes has been added to the -mm tree. Its filename is mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Peter Xu Subject: mm/hugetlb: allow uffd wr-protect none ptes Teach hugetlbfs code to wr-protect none ptes just in case the page cache existed for that pte. Meanwhile we also need to be able to recognize a uffd-wp marker pte and remove it for uffd_wp_resolve. Since at it, introduce a variable "psize" to replace all references to the huge page size fetcher. Link: https://lkml.kernel.org/r/20220405014912.14815-1-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Mike Kravetz 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 Rapoport Cc: Nadav Amit Signed-off-by: Andrew Morton --- mm/hugetlb.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-allow-uffd-wr-protect-none-ptes +++ a/mm/hugetlb.c @@ -6225,7 +6225,7 @@ unsigned long hugetlb_change_protection( pte_t *ptep; pte_t pte; struct hstate *h = hstate_vma(vma); - unsigned long pages = 0; + unsigned long pages = 0, psize = huge_page_size(h); bool shared_pmd = false; struct mmu_notifier_range range; bool uffd_wp = cp_flags & MM_CP_UFFD_WP; @@ -6245,13 +6245,19 @@ unsigned long hugetlb_change_protection( mmu_notifier_invalidate_range_start(&range); i_mmap_lock_write(vma->vm_file->f_mapping); - for (; address < end; address += huge_page_size(h)) { + for (; address < end; address += psize) { spinlock_t *ptl; - ptep = huge_pte_offset(mm, address, huge_page_size(h)); + ptep = huge_pte_offset(mm, address, psize); if (!ptep) continue; ptl = huge_pte_lock(h, mm, ptep); if (huge_pmd_unshare(mm, vma, &address, ptep)) { + /* + * When uffd-wp is enabled on the vma, unshare + * shouldn't happen at all. Warn about it if it + * happened due to some reason. + */ + WARN_ON_ONCE(uffd_wp || uffd_wp_resolve); pages++; spin_unlock(ptl); shared_pmd = true; @@ -6281,12 +6287,20 @@ unsigned long hugetlb_change_protection( else if (uffd_wp_resolve) newpte = pte_swp_clear_uffd_wp(newpte); set_huge_swap_pte_at(mm, address, ptep, - newpte, huge_page_size(h)); + newpte, psize); pages++; } spin_unlock(ptl); continue; } + if (unlikely(pte_marker_uffd_wp(pte))) { + /* + * This is changing a non-present pte into a none pte, + * no need for huge_ptep_modify_prot_start/commit(). + */ + if (uffd_wp_resolve) + huge_pte_clear(mm, address, ptep, psize); + } if (!huge_pte_none(pte)) { pte_t old_pte; unsigned int shift = huge_page_shift(hstate_vma(vma)); @@ -6300,6 +6314,12 @@ unsigned long hugetlb_change_protection( pte = huge_pte_clear_uffd_wp(pte); huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); pages++; + } else { + /* None pte */ + if (unlikely(uffd_wp)) + /* Safe to modify directly (none->non-present). */ + set_huge_pte_at(mm, address, ptep, + make_pte_marker(PTE_MARKER_UFFD_WP)); } spin_unlock(ptl); } _ Patches currently in -mm which might be from peterx@redhat.com are mm-introduce-pte_marker-swap-entry.patch mm-teach-core-mm-about-pte-markers.patch mm-check-against-orig_pte-for-finish_fault.patch mm-uffd-pte_marker_uffd_wp.patch mm-shmem-take-care-of-uffdio_copy_mode_wp.patch mm-shmem-handle-uffd-wp-special-pte-in-page-fault-handler.patch mm-shmem-persist-uffd-wp-bit-across-zapping-for-file-backed.patch mm-shmem-allow-uffd-wr-protect-none-pte-for-file-backed-mem.patch mm-shmem-allows-file-back-mem-to-be-uffd-wr-protected-on-thps.patch mm-shmem-handle-uffd-wp-during-fork.patch mm-hugetlb-introduce-huge-pte-version-of-uffd-wp-helpers.patch mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch mm-hugetlb-take-care-of-uffdio_copy_mode_wp.patch mm-hugetlb-handle-uffdio_writeprotect.patch mm-hugetlb-handle-pte-markers-in-page-faults.patch mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch mm-hugetlb-only-drop-uffd-wp-special-pte-if-required.patch mm-hugetlb-handle-uffd-wp-during-fork.patch mm-khugepaged-dont-recycle-vma-pgtable-if-uffd-wp-registered.patch mm-pagemap-recognize-uffd-wp-bit-for-shmem-hugetlbfs.patch mm-uffd-enable-write-protection-for-shmem-hugetlbfs.patch mm-enable-pte-markers-by-default.patch selftests-uffd-enable-uffd-wp-for-shmem-hugetlbfs.patch