From patchwork Fri Jan 15 17:08:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 1366038 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97C8EC43381 for ; Fri, 15 Jan 2021 17:12:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 770162333E for ; Fri, 15 Jan 2021 17:12:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733264AbhAORLT (ORCPT ); Fri, 15 Jan 2021 12:11:19 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:26946 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733234AbhAORLO (ORCPT ); Fri, 15 Jan 2021 12:11:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610730588; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=w6siyxttlu7KCpWlkxB4VjYp+yZ18KeXRH4qtrNiwZw=; b=VqXDcHVGCh8qUN0/9qu7AUxUK+F3zwai7xvtlBoDIApL9x5b1gpvQDHYd8p5nSjxtpISqA BrjHUdw67J5nYJJSHcZl6L7jEPXUfwn+N1VD0kTXoq6jCUjYZDX5J20G1RCcqHiB0mMRv/ pMzr/NjnsGnws78CN6R4Q2N945DbZSw= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-43-fFGrO0bUNrCrYdeWtf58Mg-1; Fri, 15 Jan 2021 12:09:46 -0500 X-MC-Unique: fFGrO0bUNrCrYdeWtf58Mg-1 Received: by mail-qk1-f199.google.com with SMTP id l138so8616767qke.4 for ; Fri, 15 Jan 2021 09:09:46 -0800 (PST) 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=w6siyxttlu7KCpWlkxB4VjYp+yZ18KeXRH4qtrNiwZw=; b=FqZxei6kU9MlC6aa6L9Qh2KFXx7mo+0oKhJc1ocjcpmrdHIx/oonD8bsMI/MUV3Myj jYppOYcc6nFv8qD0vINuCDHHM6E17Ee2q7/ciAIT4wiUvk5aXPYUyyrT2aT/O74O9hSN +pa3Xw3unT/wTM3qZgdmS1hX97CDenirkntlOKPYo0w0XGYeFjauN2YjJhPJh5dmy+Uy MzGtWWSrxhiodfq4F/KVC0d2tWAkFfeVnrJ4EDrmPXZ5mPMzalBo87rol6WHKLyG40Qc /0OVG7G8vxM/HWouV1sR3RLk8G+JNEYxfZGLvKpOKntAWsLA5LyY4Trkgka+dCnOugEx uWgg== X-Gm-Message-State: AOAM531W5l2ujTBkbVTmFHJJ4TzyuTmUzuvonyq42yt9vSYsoOOQ0Q3r DVzd4ybSB6q40rgGl0R6jary7brVOh0F768UTbGhReCmGzV2FDDPsjYjKfoZ5VKLhjs0jy8f1G6 MM+2ANw5eW7kpWFcXmIsaWN/wHrBwUAjyzyOPaeiWxQ1GRgqooPP0Gf8YLndYv4BozWjB1qGFsQ == X-Received: by 2002:a37:4a4e:: with SMTP id x75mr13396472qka.89.1610730586008; Fri, 15 Jan 2021 09:09:46 -0800 (PST) X-Google-Smtp-Source: ABdhPJy247OPfvvMBFwBHFtTUpj3tm1FUibXTgft3ZPmifm23yeptWRPKyFEZ5qXtk/qtx/VoM7IRQ== X-Received: by 2002:a37:4a4e:: with SMTP id x75mr13396416qka.89.1610730585574; Fri, 15 Jan 2021 09:09:45 -0800 (PST) Received: from localhost.localdomain ([142.126.83.202]) by smtp.gmail.com with ESMTPSA id d123sm5187840qke.95.2021.01.15.09.09.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Jan 2021 09:09:44 -0800 (PST) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Mike Rapoport , Mike Kravetz , peterx@redhat.com, Jerome Glisse , "Kirill A . Shutemov" , Hugh Dickins , Axel Rasmussen , Matthew Wilcox , Andrew Morton , Andrea Arcangeli , Nadav Amit Subject: [PATCH RFC 18/30] hugetlb/userfaultfd: Hook page faults for uffd write protection Date: Fri, 15 Jan 2021 12:08:55 -0500 Message-Id: <20210115170907.24498-19-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210115170907.24498-1-peterx@redhat.com> References: <20210115170907.24498-1-peterx@redhat.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hook up hugetlbfs_fault() with the capability to handle userfaultfd-wp faults. We do this slightly earlier than hugetlb_cow() so that we can avoid taking some extra locks that we definitely don't need. Signed-off-by: Peter Xu --- mm/hugetlb.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d029d938d26d..dcbbba53bd10 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4544,6 +4544,25 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) goto out_ptl; + /* Handle userfault-wp first, before trying to lock more pages */ + if (userfaultfd_pte_wp(vma, huge_ptep_get(ptep)) && + (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { + struct vm_fault vmf = { + .vma = vma, + .address = haddr, + .flags = flags, + }; + + spin_unlock(ptl); + if (pagecache_page) { + unlock_page(pagecache_page); + put_page(pagecache_page); + } + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + i_mmap_unlock_read(mapping); + return handle_userfault(&vmf, VM_UFFD_WP); + } + /* * hugetlb_cow() requires page locks of pte_page(entry) and * pagecache_page, so here we need take the former one