From patchwork Thu Feb 23 00:57:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 13149749 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5012C61DA4 for ; Thu, 23 Feb 2023 00:58:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2DD5A6B007B; Wed, 22 Feb 2023 19:58:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 23EF86B007D; Wed, 22 Feb 2023 19:58:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 091BD6B007E; Wed, 22 Feb 2023 19:58:13 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id DA93F6B007B for ; Wed, 22 Feb 2023 19:58:13 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id A862C40DBA for ; Thu, 23 Feb 2023 00:58:13 +0000 (UTC) X-FDA: 80496745266.24.A4E74C0 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) by imf27.hostedemail.com (Postfix) with ESMTP id DF5EA40007 for ; Thu, 23 Feb 2023 00:58:11 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RIsIvNHW; spf=pass (imf27.hostedemail.com: domain of 3I7r2Yw0KCJg2P6DJ2KEMKK6F8GG8D6.4GEDAFMP-EECN24C.GJ8@flex--axelrasmussen.bounces.google.com designates 209.85.128.201 as permitted sender) smtp.mailfrom=3I7r2Yw0KCJg2P6DJ2KEMKK6F8GG8D6.4GEDAFMP-EECN24C.GJ8@flex--axelrasmussen.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1677113891; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HVEpDKkiPqP2+7hkSYLnKAL7x6oJXvVC4LelYs0FclU=; b=prMDPCije2Lm9BsxCNYfIs3JoXK3NmygxCrD34IAO2iIKStQZDCgWiqGNV0fEwGwpt4Kmk SoHRrK2kXAf9o0sIIEluz1t4/TdJRGAMZUVHwRzftaymQWxpDV5uxSzUT1SCpLQU1ex2bs BwrK45JquiTznnfcdR50DZIO0TwBn9Q= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RIsIvNHW; spf=pass (imf27.hostedemail.com: domain of 3I7r2Yw0KCJg2P6DJ2KEMKK6F8GG8D6.4GEDAFMP-EECN24C.GJ8@flex--axelrasmussen.bounces.google.com designates 209.85.128.201 as permitted sender) smtp.mailfrom=3I7r2Yw0KCJg2P6DJ2KEMKK6F8GG8D6.4GEDAFMP-EECN24C.GJ8@flex--axelrasmussen.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1677113891; a=rsa-sha256; cv=none; b=ZFliYn6+w3h1eD/T42w7W1Dsfe9eBLypkPf98bKe8Szbjv9CBIZFHKmaSKNTMfJalZvLmW shDLb1iMaTkXFBB/mwQVyDdb0X3vCPU28+q8L3S2IBT8xi0LNa+8C8qxk8K63rlxISSJhA TPxuxynuZNlR9o/PZ+rVhdun58F5zm8= Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-536c8bcae3bso91959747b3.2 for ; Wed, 22 Feb 2023 16:58:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=HVEpDKkiPqP2+7hkSYLnKAL7x6oJXvVC4LelYs0FclU=; b=RIsIvNHWqJlFjwGMxEpMMi8c9SD1LMWqPwMba6tqRkM8zClhElkzYY/Bg5r4ntdJti 6n+mzOX9cd2MKENxQtWRykO75RdzCnVvPvYyWcrKXpBeKpu2Cm2FFbOZqNNSeZnvoG9i t3N91/Ye2+2U4U3pZ1Oz6pwUBBJ7WaYEsatrwBR+v5BFNtR6iNiXRs0UHnrsG5p3YjWp GozkMA5yhgcHWljPBoH9ZRTR74W3zmNKMUKjL5WUHmSzzRo28t1AeHLg02vpqyEGvapK gjBJuSccU8cXw8LlIzu/vOCk5xpFwCq5vyCjLykVjGFoDKwQbB8T+AiowCpNiC5FvQZe hRbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=HVEpDKkiPqP2+7hkSYLnKAL7x6oJXvVC4LelYs0FclU=; b=wJjgg3xeOTFI+7iG1MtsQt3i85X+5Pi3LPU+N9RnSfNyLxk9SzfECCB8c7/Yp+q4Ml 00QjEidFz3eX/6YxomNbHo933euIoTuc1GxTNYqTb8XM4ZFlNSyj51/tcbHD+dINfNn6 qHrKsKqg4S69q8jMyd3MNxdHjzgURAraEZVnxD2jOaOoC2nZLHLNYehdanM752fn+dzA sD9TwZwJUpDsaR2LvYksRW81VB5EfGiL79Z2ntB9HwjpcWhJ+ujPCtGFPXYaEPqqVDDi x4UqyFvkjwd1VwFXiye6XckUZjfcX/uU33r1U0O3ZxxWX/kpYxq9KA6KnDqGlLwAN0jO ZsEw== X-Gm-Message-State: AO0yUKUaGkStCQJT4IFJMIOAOaHcmBJBEd4VR3tmT24kkoaJeU3jfsH8 BFjamlsOrpgdwc6PRBxjLnV/8AQgW/CwiNcYz3d1 X-Google-Smtp-Source: AK7set+TIJO70qFBQWJ2Mupda48bbmNTk3KYnmOour0IdK8ZN/UCPOHlLBM/9Hnk8mqw4mTZzFG6dK5NY8KDR5Bbda2m X-Received: from axel.svl.corp.google.com ([2620:15c:2d4:203:3e99:dd9e:9db9:449c]) (user=axelrasmussen job=sendgmr) by 2002:a81:b714:0:b0:52f:23f5:4079 with SMTP id v20-20020a81b714000000b0052f23f54079mr1366675ywh.4.1677113891031; Wed, 22 Feb 2023 16:58:11 -0800 (PST) Date: Wed, 22 Feb 2023 16:57:54 -0800 In-Reply-To: <20230223005754.2700663-1-axelrasmussen@google.com> Mime-Version: 1.0 References: <20230223005754.2700663-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.39.2.637.g21b0678d19-goog Message-ID: <20230223005754.2700663-6-axelrasmussen@google.com> Subject: [PATCH v2 5/5] mm: userfaultfd: add UFFDIO_CONTINUE_MODE_WP to install WP PTEs From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Hugh Dickins , Jan Kara , "Liam R. Howlett" , Matthew Wilcox , Mike Kravetz , Mike Rapoport , Muchun Song , Nadav Amit , Peter Xu , Shuah Khan Cc: James Houghton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Axel Rasmussen X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: DF5EA40007 X-Rspam-User: X-Stat-Signature: nurjbxy5fxunram6j16knzz35ouowha6 X-HE-Tag: 1677113891-716914 X-HE-Meta: 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 AmVFqIcX 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 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: UFFDIO_COPY already has UFFDIO_COPY_MODE_WP, so when installing a new PTE to resolve a missing fault, one can install a write-protected one. This is useful when using UFFDIO_REGISTER_MODE_{MISSING,WP} in combination. So, add an analogous UFFDIO_CONTINUE_MODE_WP, which does the same thing but for *minor* faults. Update the selftest to do some very basic exercising of the new flag. Signed-off-by: Axel Rasmussen --- fs/userfaultfd.c | 8 ++++++-- include/linux/userfaultfd_k.h | 2 +- include/uapi/linux/userfaultfd.h | 7 +++++++ mm/userfaultfd.c | 5 +++-- tools/testing/selftests/vm/userfaultfd.c | 4 ++++ 5 files changed, 21 insertions(+), 5 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index f43d8b0ae47b..5ce4502737a1 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1871,6 +1871,7 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) struct uffdio_continue uffdio_continue; struct uffdio_continue __user *user_uffdio_continue; struct uffdio_range range; + int flags = 0; user_uffdio_continue = (struct uffdio_continue __user *)arg; @@ -1893,12 +1894,15 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) /* double check for wraparound just in case. */ if (range.start + range.len <= range.start) goto out; - if (uffdio_continue.mode & ~UFFDIO_CONTINUE_MODE_DONTWAKE) + if (uffdio_continue.mode & ~(UFFDIO_CONTINUE_MODE_DONTWAKE | + UFFDIO_CONTINUE_MODE_WP)) goto out; + if (uffdio_continue.mode & UFFDIO_CONTINUE_MODE_WP) + flags |= MFILL_ATOMIC_WP; if (mmget_not_zero(ctx->mm)) { ret = mfill_atomic_continue(ctx->mm, &range, - &ctx->mmap_changing); + &ctx->mmap_changing, flags); mmput(ctx->mm); } else { return -ESRCH; diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index 3cf87f019db3..1e1229430f56 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -67,7 +67,7 @@ extern ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, atomic_t *mmap_changing); extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, const struct uffdio_range *dst, - atomic_t *mmap_changing); + atomic_t *mmap_changing, int flags); extern int mwriteprotect_range(struct mm_struct *dst_mm, const struct uffdio_range *range, bool enable_wp, atomic_t *mmap_changing); diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 005e5e306266..14059a0861bf 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -297,6 +297,13 @@ struct uffdio_writeprotect { struct uffdio_continue { struct uffdio_range range; #define UFFDIO_CONTINUE_MODE_DONTWAKE ((__u64)1<<0) + /* + * UFFDIO_CONTINUE_MODE_WP will map the page write protected on + * the fly. UFFDIO_CONTINUE_MODE_WP is available only if the + * write protected ioctl is implemented for the range + * according to the uffdio_register.ioctls. + */ +#define UFFDIO_CONTINUE_MODE_WP ((__u64)1<<1) __u64 mode; /* diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index ebbba2b9f687..03f388aaa405 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -706,10 +706,11 @@ ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, const struct uffdio_range *dst, - atomic_t *mmap_changing) + atomic_t *mmap_changing, + int flags) { return mfill_atomic(dst_mm, 0, dst, - mmap_changing, MFILL_ATOMIC_CONTINUE); + mmap_changing, flags | MFILL_ATOMIC_CONTINUE); } void uffd_wp_range(struct vm_area_struct *dst_vma, diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 7f22844ed704..41c1f9abc481 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -585,6 +585,8 @@ static void continue_range(int ufd, __u64 start, __u64 len) req.range.start = start; req.range.len = len; req.mode = 0; + if (test_uffdio_wp) + req.mode |= UFFDIO_CONTINUE_MODE_WP; if (ioctl(ufd, UFFDIO_CONTINUE, &req)) err("UFFDIO_CONTINUE failed for address 0x%" PRIx64, @@ -1332,6 +1334,8 @@ static int userfaultfd_minor_test(void) uffdio_register.range.start = (unsigned long)area_dst_alias; uffdio_register.range.len = nr_pages * page_size; uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR; + if (test_uffdio_wp) + uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP; if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) err("register failure");