From patchwork Mon Apr 17 12:56:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muhammad Usama Anjum X-Patchwork-Id: 13213846 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 91003C77B78 for ; Mon, 17 Apr 2023 12:57:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2DEB2900002; Mon, 17 Apr 2023 08:57:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2670F8E0001; Mon, 17 Apr 2023 08:57:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0E206900002; Mon, 17 Apr 2023 08:57:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id EE12F8E0001 for ; Mon, 17 Apr 2023 08:57:03 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id B51E9803D3 for ; Mon, 17 Apr 2023 12:57:03 +0000 (UTC) X-FDA: 80690883126.28.740E67D Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by imf24.hostedemail.com (Postfix) with ESMTP id DF978180006 for ; Mon, 17 Apr 2023 12:57:01 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=collabora.com header.s=mail header.b=FDTkSqNS; spf=pass (imf24.hostedemail.com: domain of usama.anjum@collabora.com designates 46.235.227.172 as permitted sender) smtp.mailfrom=usama.anjum@collabora.com; dmarc=pass (policy=quarantine) header.from=collabora.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1681736222; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=e1St9s4FzW8P+Gmv77WnoBmdcVvOOsoCFxd0H93ILJ4=; b=G6mWh0fdYolaBorvxL/A87LKwZQXGlF2md0zuecKTTiyMghNgQirek/FWiErqXiz6Looyf HbI2fZs7/JpEGAPgQSy4xWVK1bekG4cxS9vLOId75Pn/2BXeOPbaNYgRSlatslTTrKmTB9 gXAvuJpgxQ0grU7LN4UQvzjMY86TWJ0= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=collabora.com header.s=mail header.b=FDTkSqNS; spf=pass (imf24.hostedemail.com: domain of usama.anjum@collabora.com designates 46.235.227.172 as permitted sender) smtp.mailfrom=usama.anjum@collabora.com; dmarc=pass (policy=quarantine) header.from=collabora.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1681736222; a=rsa-sha256; cv=none; b=3jN3PhX1OXjGMMytVi9v5zjWTzEjfU+UmWB9VlGiij1bEyLZafZj9jBQkzLy4r6bucEJ9x 8o0u6lkPAl4TmizK4KL8mtZF37qQXfSwi8ClRYUAhBnpzJLWxEWHhUbk77B//To8i2UOHM 5jhJjhQZJLTq4IMQ42ZoMMqZbaCtfIY= Received: from localhost.localdomain (unknown [39.37.187.173]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madras.collabora.co.uk (Postfix) with ESMTPSA id 8B5966603244; Mon, 17 Apr 2023 13:56:52 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1681736220; bh=o6p3wXTxhFNhx+4PpUybSE97qNV/lC6eWw9YubDqMS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FDTkSqNSeCteDWy9IPXTBwCltj+sQo7p20Ykzt1dOMKwRm7BR4yn8bWXzORwvIODm zxIV//9Pd+Rw7sxzaH5Sz77TEL9DeOxtxJgVjrKSensK+IzYk2enIcfzpvgsPtk6gY YlfPhoH5GlsD1RFq8VD8fIItm3aNUxLkhjl4KoIIrMMGUHSLS6n1K883zYqfE/vCmy QKEwFih5U0L2b3nf9XyZ56R6cFTJYP9RwCYZVHSwgVQUk2fGopNIEzHrOlpAMvcLx8 G3vHLKoU7spUTDjy98bAxAqIhkNH7STJ+sFHBYmFJp5gwVLLvd3IxwtfjbYGtW4Jhb HHTJTlkolpy7w== From: Muhammad Usama Anjum To: Peter Xu , David Hildenbrand , Andrew Morton , =?utf-8?b?TWljaGHFgiBNaXJvc8WC?= =?utf-8?b?YXc=?= , Andrei Vagin , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Mike Rapoport , Nadav Amit Cc: Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Muhammad Usama Anjum , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: [PATCH v13 1/5] userfaultfd: UFFD_FEATURE_WP_ASYNC Date: Mon, 17 Apr 2023 17:56:26 +0500 Message-Id: <20230417125630.1146906-2-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230417125630.1146906-1-usama.anjum@collabora.com> References: <20230417125630.1146906-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: bnf41ez8abxegqi4xwd9ncwwer9dbrb4 X-Rspamd-Queue-Id: DF978180006 X-HE-Tag: 1681736221-494927 X-HE-Meta: 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 psHC1yzT DZaTJGbI9xYdN+Md90pLDSWSk/WV70skJ160quNX9V9VRSLWJvtVbLv/lWFtOTjhRmmGMmVVozvVC8yG60sBrfI5MbfAymSkB+uZftTgO+LZ/oagRWEF49A4W7966/trcF4uRrp3E54Fppt9FXXKwWM6nlP00O3cgzXll2ga/lzDbEOj7H0tGBRG0NPcprPvQqm/NgPLU7tKf3qoBuLWQqw34vNJ19LsY9FGRIbt3MVefwX076udwAeJcO8Klupsyk//jzvdkPCUbsSxFtfhgSvKAy48xVpEypLyAR8TqzwoM49HLKupoOCbb9sjyXOufAta9Hnp4wdr3zw32JLUjGhJLV6KvLtp/USAgJE0eyuT6O5Zb7kJBfnb4S43Wx4GDcVpQV70b3RH7SQPNDaf3PH9LiQ== 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: From: Peter Xu This patch adds a new userfaultfd-wp feature UFFD_FEATURE_WP_ASYNC, that allows userfaultfd wr-protect faults to be resolved by the kernel directly. It can be used like a high accuracy version of soft-dirty, without vma modifications during tracking, and also with ranged support by default rather than for a whole mm when reset the protections due to existence of ioctl(UFFDIO_WRITEPROTECT). Several goals of such a dirty tracking interface: 1. All types of memory should be supported and tracable. This is nature for soft-dirty but should mention when the context is userfaultfd, because it used to only support anon/shmem/hugetlb. The problem is for a dirty tracking purpose these three types may not be enough, and it's legal to track anything e.g. any page cache writes from mmap. 2. Protections can be applied to partial of a memory range, without vma split/merge fuss. The hope is that the tracking itself should not affect any vma layout change. It also helps when reset happens because the reset will not need mmap write lock which can block the tracee. 3. Accuracy needs to be maintained. This means we need pte markers to work on any type of VMA. One could question that, the whole concept of async dirty tracking is not really close to fundamentally what userfaultfd used to be: it's not "a fault to be serviced by userspace" anymore. However, using userfaultfd-wp here as a framework is convenient for us in at least: 1. VM_UFFD_WP vma flag, which has a very good name to suite something like this, so we don't need VM_YET_ANOTHER_SOFT_DIRTY. Just use a new feature bit to identify from a sync version of uffd-wp registration. 2. PTE markers logic can be leveraged across the whole kernel to maintain the uffd-wp bit as long as an arch supports, this also applies to this case where uffd-wp bit will be a hint to dirty information and it will not go lost easily (e.g. when some page cache ptes got zapped). 3. Reuse ioctl(UFFDIO_WRITEPROTECT) interface for either starting or resetting a range of memory, while there's no counterpart in the old soft-dirty world, hence if this is wanted in a new design we'll need a new interface otherwise. We can somehow understand that commonality because uffd-wp was fundamentally a similar idea of write-protecting pages just like soft-dirty. This implementation allows WP_ASYNC to imply WP_UNPOPULATED, because so far WP_ASYNC seems to not usable if without WP_UNPOPULATE. This also gives us chance to modify impl of WP_ASYNC just in case it could be not depending on WP_UNPOPULATED anymore in the future kernels. It's also fine to imply that because both features will rely on PTE_MARKER_UFFD_WP config option, so they'll show up together (or both missing) in an UFFDIO_API probe. vma_can_userfault() now allows any VMA if the userfaultfd registration is only about async uffd-wp. So we can track dirty for all kinds of memory including generic file systems (like XFS, EXT4 or BTRFS). One trick worth mention in do_wp_page() is that we need to manually update vmf->orig_pte here because it can be used later with a pte_same() check - this path always has FAULT_FLAG_ORIG_PTE_VALID set in the flags. The major defect of this approach of dirty tracking is we need to populate the pgtables when tracking starts. Soft-dirty doesn't do it like that. It's unwanted in the case where the range of memory to track is huge and unpopulated (e.g., tracking updates on a 10G file with mmap() on top, without having any page cache installed yet). One way to improve this is to allow pte markers exist for larger than PTE level for PMD+. That will not change the interface if to implemented, so we can leave that for later. Co-developed-by: Muhammad Usama Anjum Signed-off-by: Muhammad Usama Anjum Signed-off-by: Peter Xu --- Changes in v12: - Peter added the hugetlb support and revamped some other implementation - Transferred the authorship to Peter - Merge documentation to this patch Changes in v11: - Fix return code in userfaultfd_register() and minor changes here and there - Rebase on top of next-20230307 - Base patches on UFFD_FEATURE_WP_UNPOPULATED https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com - UFFD_FEATURE_WP_ASYNC depends on UFFD_FEATURE_WP_UNPOPULATED to work (correctly) Changes in v10: - Build fix - Update comments and add error condition to return error from uffd register if hugetlb pages are present when wp async flag is set Changes in v9: - Correct the fault resolution with code contributed by Peter Changes in v7: - Remove UFFDIO_WRITEPROTECT_MODE_ASYNC_WP and add UFFD_FEATURE_WP_ASYNC - Handle automatic page fault resolution in better way (thanks to Peter) --- Documentation/admin-guide/mm/userfaultfd.rst | 35 ++++++++++++++++++++ fs/userfaultfd.c | 26 ++++++++++++--- include/linux/userfaultfd_k.h | 21 +++++++++++- include/uapi/linux/userfaultfd.h | 9 ++++- mm/hugetlb.c | 32 ++++++++++-------- mm/memory.c | 27 +++++++++++++-- 6 files changed, 128 insertions(+), 22 deletions(-) diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 7c304e432205..4b7f43fbbe18 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -244,6 +244,41 @@ write-protected (so future writes will also result in a WP fault). These ioctls support a mode flag (``UFFDIO_COPY_MODE_WP`` or ``UFFDIO_CONTINUE_MODE_WP`` respectively) to configure the mapping this way. +If the userfaultfd context has ``UFFD_FEATURE_WP_ASYNC`` feature bit set, +any vma registered with write-protection will work in async mode rather +than the default sync mode. + +In async mode, there will be no message generated when a write operation +happens, meanwhile the write-protection will be resolved automatically by +the kernel. It can be seen as a more accurate version of soft-dirty +tracking and it can be different in a few ways: + + - The dirty result will not be affected by vma changes (e.g. vma + merging) because the dirty is only tracked by the pte. + + - It supports range operations by default, so one can enable tracking on + any range of memory as long as page aligned. + + - Dirty information will not get lost if the pte was zapped due to + various reasons (e.g. during split of a shmem transparent huge page). + + - Due to a reverted meaning of soft-dirty (page clean when uffd-wp bit + set; dirty when uffd-wp bit cleared), it has different semantics on + some of the memory operations. For example: ``MADV_DONTNEED`` on + anonymous (or ``MADV_REMOVE`` on a file mapping) will be treated as + dirtying of memory by dropping uffd-wp bit during the procedure. + +The user app can collect the "written/dirty" status by looking up the +uffd-wp bit for the pages being interested in /proc/pagemap. + +The page will not be under track of uffd-wp async mode until the page is +explicitly write-protected by ``ioctl(UFFDIO_WRITEPROTECT)`` with the mode +flag ``UFFDIO_WRITEPROTECT_MODE_WP`` set. Trying to resolve a page fault +that was tracked by async mode userfaultfd-wp is invalid. + +When userfaultfd-wp async mode is used alone, it can be applied to all +kinds of memory. + QEMU/KVM ======== diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 0fd96d6e39ce..3ab021521a96 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -123,6 +123,11 @@ static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx) return ctx->features & UFFD_FEATURE_INITIALIZED; } +static bool userfaultfd_wp_async_ctx(struct userfaultfd_ctx *ctx) +{ + return ctx && (ctx->features & UFFD_FEATURE_WP_ASYNC); +} + /* * Whether WP_UNPOPULATED is enabled on the uffd context. It is only * meaningful when userfaultfd_wp()==true on the vma and when it's @@ -1332,6 +1337,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, bool basic_ioctls; unsigned long start, end, vma_end; struct vma_iterator vmi; + bool wp_async = userfaultfd_wp_async_ctx(ctx); user_uffdio_register = (struct uffdio_register __user *) arg; @@ -1405,7 +1411,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, /* check not compatible vmas */ ret = -EINVAL; - if (!vma_can_userfault(cur, vm_flags)) + if (!vma_can_userfault(cur, vm_flags, wp_async)) goto out_unlock; /* @@ -1464,7 +1470,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vm_flags)); + BUG_ON(!vma_can_userfault(vma, vm_flags, wp_async)); BUG_ON(vma->vm_userfaultfd_ctx.ctx && vma->vm_userfaultfd_ctx.ctx != ctx); WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); @@ -1563,6 +1569,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, unsigned long start, end, vma_end; const void __user *buf = (void __user *)arg; struct vma_iterator vmi; + bool wp_async = userfaultfd_wp_async_ctx(ctx); ret = -EFAULT; if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) @@ -1616,7 +1623,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, * provides for more strict behavior to notice * unregistration errors. */ - if (!vma_can_userfault(cur, cur->vm_flags)) + if (!vma_can_userfault(cur, cur->vm_flags, wp_async)) goto out_unlock; found = true; @@ -1629,7 +1636,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vma->vm_flags)); + BUG_ON(!vma_can_userfault(vma, vma->vm_flags, wp_async)); /* * Nothing to do: this vma is already registered into this @@ -1966,6 +1973,11 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg) return ret; } +bool userfaultfd_wp_async(struct vm_area_struct *vma) +{ + return userfaultfd_wp_async_ctx(vma->vm_userfaultfd_ctx.ctx); +} + static inline unsigned int uffd_ctx_features(__u64 user_features) { /* @@ -1999,6 +2011,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) goto err_out; + + /* WP_ASYNC relies on WP_UNPOPULATED, choose it unconditionally */ + if (features & UFFD_FEATURE_WP_ASYNC) + features |= UFFD_FEATURE_WP_UNPOPULATED; + /* report all available features and ioctls to userland */ uffdio_api.features = UFFD_API_FEATURES; #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR @@ -2011,6 +2028,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, #ifndef CONFIG_PTE_MARKER_UFFD_WP uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; + uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; #endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index d78b01524349..ce4f9d18de3e 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -157,11 +157,22 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma) } static inline bool vma_can_userfault(struct vm_area_struct *vma, - unsigned long vm_flags) + unsigned long vm_flags, + bool wp_async) { + vm_flags &= __VM_UFFD_FLAGS; + if ((vm_flags & VM_UFFD_MINOR) && (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma))) return false; + + /* + * If wp async enabled, and WP is the only mode enabled, allow any + * memory type. + */ + if (wp_async && (vm_flags == VM_UFFD_WP)) + return true; + #ifndef CONFIG_PTE_MARKER_UFFD_WP /* * If user requested uffd-wp but not enabled pte markers for @@ -171,6 +182,8 @@ static inline bool vma_can_userfault(struct vm_area_struct *vma, if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) return false; #endif + + /* By default, allow any of anon|shmem|hugetlb */ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || vma_is_shmem(vma); } @@ -193,6 +206,7 @@ extern int userfaultfd_unmap_prep(struct mm_struct *mm, unsigned long start, extern void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf); extern bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma); +extern bool userfaultfd_wp_async(struct vm_area_struct *vma); #else /* CONFIG_USERFAULTFD */ @@ -293,6 +307,11 @@ static inline bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma) return false; } +static inline bool userfaultfd_wp_async(struct vm_area_struct *vma) +{ + return false; +} + #endif /* CONFIG_USERFAULTFD */ static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma) diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 66dd4cd277bd..cfb87a112a9f 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -39,7 +39,8 @@ UFFD_FEATURE_MINOR_SHMEM | \ UFFD_FEATURE_EXACT_ADDRESS | \ UFFD_FEATURE_WP_HUGETLBFS_SHMEM | \ - UFFD_FEATURE_WP_UNPOPULATED) + UFFD_FEATURE_WP_UNPOPULATED | \ + UFFD_FEATURE_WP_ASYNC) #define UFFD_API_IOCTLS \ ((__u64)1 << _UFFDIO_REGISTER | \ (__u64)1 << _UFFDIO_UNREGISTER | \ @@ -210,6 +211,11 @@ struct uffdio_api { * (i.e. empty ptes). This will be the default behavior for shmem * & hugetlbfs, so this flag only affects anonymous memory behavior * when userfault write-protection mode is registered. + * + * UFFD_FEATURE_WP_ASYNC indicates that userfaultfd write-protection + * asynchronous mode is supported in which the write fault is + * automatically resolved and write-protection is un-set. + * It implies UFFD_FEATURE_WP_UNPOPULATED. */ #define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) #define UFFD_FEATURE_EVENT_FORK (1<<1) @@ -225,6 +231,7 @@ struct uffdio_api { #define UFFD_FEATURE_EXACT_ADDRESS (1<<11) #define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<12) #define UFFD_FEATURE_WP_UNPOPULATED (1<<13) +#define UFFD_FEATURE_WP_ASYNC (1<<14) __u64 features; __u64 ioctls; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 155bb6712be1..0d0efd96449e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6150,21 +6150,27 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, /* Handle userfault-wp first, before trying to lock more pages */ if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) && (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { - struct vm_fault vmf = { - .vma = vma, - .address = haddr, - .real_address = address, - .flags = flags, - }; + if (!userfaultfd_wp_async(vma)) { + struct vm_fault vmf = { + .vma = vma, + .address = haddr, + .real_address = address, + .flags = flags, + }; - spin_unlock(ptl); - if (pagecache_folio) { - folio_unlock(pagecache_folio); - folio_put(pagecache_folio); + spin_unlock(ptl); + if (pagecache_folio) { + folio_unlock(pagecache_folio); + folio_put(pagecache_folio); + } + hugetlb_vma_unlock_read(vma); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + return handle_userfault(&vmf, VM_UFFD_WP); } - hugetlb_vma_unlock_read(vma); - mutex_unlock(&hugetlb_fault_mutex_table[hash]); - return handle_userfault(&vmf, VM_UFFD_WP); + + entry = huge_pte_clear_uffd_wp(entry); + set_huge_pte_at(mm, haddr, ptep, entry); + /* Fallthrough to CoW */ } /* diff --git a/mm/memory.c b/mm/memory.c index 1c5b231fe6e3..60f1a4e348b5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3331,11 +3331,28 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; struct vm_area_struct *vma = vmf->vma; struct folio *folio = NULL; + pte_t pte; if (likely(!unshare)) { if (userfaultfd_pte_wp(vma, *vmf->pte)) { - pte_unmap_unlock(vmf->pte, vmf->ptl); - return handle_userfault(vmf, VM_UFFD_WP); + if (!userfaultfd_wp_async(vma)) { + pte_unmap_unlock(vmf->pte, vmf->ptl); + return handle_userfault(vmf, VM_UFFD_WP); + } + + /* + * Nothing needed (cache flush, TLB invalidations, + * etc.) because we're only removing the uffd-wp bit, + * which is completely invisible to the user. + */ + pte = pte_clear_uffd_wp(*vmf->pte); + + set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); + /* + * Update this to be prepared for following up CoW + * handling + */ + vmf->orig_pte = pte; } /* @@ -4824,8 +4841,11 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) if (vma_is_anonymous(vmf->vma)) { if (likely(!unshare) && - userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) + userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) { + if (userfaultfd_wp_async(vmf->vma)) + goto split; return handle_userfault(vmf, VM_UFFD_WP); + } return do_huge_pmd_wp_page(vmf); } @@ -4837,6 +4857,7 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) } } +split: /* COW or write-notify handled on pte level: split pmd. */ __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); From patchwork Mon Apr 17 12:56:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muhammad Usama Anjum X-Patchwork-Id: 13213847 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 4E5F9C77B72 for ; Mon, 17 Apr 2023 12:57:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D8DC2900003; Mon, 17 Apr 2023 08:57:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D16A28E0001; Mon, 17 Apr 2023 08:57:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B689D900003; 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Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Muhammad Usama Anjum , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: [PATCH v13 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs Date: Mon, 17 Apr 2023 17:56:27 +0500 Message-Id: <20230417125630.1146906-3-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230417125630.1146906-1-usama.anjum@collabora.com> References: <20230417125630.1146906-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 97FCE140022 X-Stat-Signature: rts655a8yfjy7iypy77i3ymcqziayyea X-Rspam-User: X-HE-Tag: 1681736229-150720 X-HE-Meta: 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 VpL4Eino R1bFBgm3ksd4X4tOCtUDvR2p158giRScAZMMumTturommWbtJ7FaxAKu/ojbtnnxjglQohpVC4aL1pHS1PQyo1xw9E4ti+CRZ4ZsvblwKOCNjkVI/5eznfG23KJzicsf21K4jlJtstLVI9GXnEICffA+MQGWEbR4qOo0w3ToHPhd0Miq4hOyLIXVzP8SVB9yvgPoODk9FircN5PX3gm3sGuMahc1scq/dScQbfYxzs3wXaDTQ4bo2Uq8vfzxKpNDKbTHSCI61ZHlJTLLklUcqMe3NWl2kuKUd9Rxp/dONIOEUi1ZpecJ87SkAx5HPXEWG8Yjr 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: This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear the info about page table entries. The following operations are supported in this ioctl: - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped (PAGE_IS_SWAPPED). - Find pages which have been written-to and write protect the pages (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) This IOCTL can be extended to get information about more PTE bits. Signed-off-by: Muhammad Usama Anjum --- Changes in v13: - Review updates - mmap_read_lock_killable() instead of mmap_read_lock() - Replace uffd_wp_range() with helpers which increases performance drastically for OP_WP operations by reducing the number of tlb flushing etc - Add MMU_NOTIFY_PROTECTION_VMA notification for the memory range Changes in v12: - Add hugetlb support to cover all memory types - Merge "userfaultfd: Define dummy uffd_wp_range()" with this patch - Review updates to the code Changes in v11: - Find written pages in a better way - Fix a corner case (thanks Paul) - Improve the code/comments - remove ENGAGE_WP + ! GET operation - shorten the commit message in favour of moving documentation to pagemap.rst Changes in v10: - move changes in tools/include/uapi/linux/fs.h to separate patch - update commit message Change in v8: - Correct is_pte_uffd_wp() - Improve readability and error checks - Remove some un-needed code Changes in v7: - Rebase on top of latest next - Fix some corner cases - Base soft-dirty on the uffd wp async - Update the terminologies - Optimize the memory usage inside the ioctl Changes in v6: - Rename variables and update comments - Make IOCTL independent of soft_dirty config - Change masks and bitmap type to _u64 - Improve code quality Changes in v5: - Remove tlb flushing even for clear operation Changes in v4: - Update the interface and implementation Changes in v3: - Tighten the user-kernel interface by using explicit types and add more error checking Changes in v2: - Convert the interface from syscall to ioctl - Remove pidfd support as it doesn't make sense in ioctl task_mmu task_mmu task_mmu.c --- fs/proc/task_mmu.c | 478 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/fs.h | 53 +++++ 2 files changed, 531 insertions(+) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 38b19a757281..3d091095d404 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -1767,11 +1768,488 @@ static int pagemap_release(struct inode *inode, struct file *file) return 0; } +#define PM_SCAN_FOUND_MAX_PAGES (1) +#define PM_SCAN_BITS_ALL (PAGE_IS_WRITTEN | PAGE_IS_FILE | \ + PAGE_IS_PRESENT | PAGE_IS_SWAPPED) +#define PM_SCAN_OPS (PM_SCAN_OP_GET | PM_SCAN_OP_WP) +#define PM_SCAN_DO_UFFD_WP(a) (a->flags & PM_SCAN_OP_WP) +#define PM_SCAN_BITMAP(wt, file, present, swap) \ + ((wt) | ((file) << 1) | ((present) << 2) | ((swap) << 3)) + +struct pagemap_scan_private { + struct page_region *vec; + struct page_region cur; + unsigned long vec_len, vec_index; + unsigned int max_pages, found_pages, flags; + unsigned long required_mask, anyof_mask, excluded_mask, return_mask; +}; + +static inline bool is_pte_uffd_wp(pte_t pte) +{ + return (pte_present(pte) && pte_uffd_wp(pte)) || + pte_swp_uffd_wp_any(pte); +} + +static inline void make_uffd_wp_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *pte) +{ + pte_t ptent = *pte; + + if (pte_present(ptent)) { + pte_t old_pte; + + old_pte = ptep_modify_prot_start(vma, addr, pte); + ptent = pte_mkuffd_wp(ptent); + ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent); + } else if (is_swap_pte(ptent)) { + ptent = pte_swp_mkuffd_wp(ptent); + set_pte_at(vma->vm_mm, addr, pte, ptent); + } +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline bool is_pmd_uffd_wp(pmd_t pmd) +{ + return (pmd_present(pmd) && pmd_uffd_wp(pmd)) || + (is_swap_pmd(pmd) && pmd_swp_uffd_wp(pmd)); +} + +static inline void make_uffd_wp_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + pmd_t old, pmd = *pmdp; + + if (pmd_present(pmd)) { + old = pmdp_invalidate_ad(vma, addr, pmdp); + pmd = pmd_mkuffd_wp(old); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } else if (is_migration_entry(pmd_to_swp_entry(pmd))) { + pmd = pmd_swp_mkuffd_wp(pmd); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } +} +#endif + +#ifdef CONFIG_HUGETLB_PAGE +static inline bool is_huge_pte_uffd_wp(pte_t pte) +{ + return ((pte_present(pte) && huge_pte_uffd_wp(pte)) || + pte_swp_uffd_wp_any(pte)); +} + +static inline void make_uffd_wp_huge_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t ptent) +{ + pte_t old_pte; + + if (!huge_pte_none(ptent)) { + old_pte = huge_ptep_modify_prot_start(vma, addr, ptep); + ptent = huge_pte_mkuffd_wp(old_pte); + ptep_modify_prot_commit(vma, addr, ptep, old_pte, ptent); + } else { + set_huge_pte_at(vma->vm_mm, addr, ptep, + make_pte_marker(PTE_MARKER_UFFD_WP)); + } +} +#endif + +static inline bool pagemap_scan_check_page_written(struct pagemap_scan_private *p) +{ + return (p->required_mask | p->anyof_mask | p->excluded_mask) & + PAGE_IS_WRITTEN; +} + +static int pagemap_scan_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + + if (pagemap_scan_check_page_written(p) && (!userfaultfd_wp(vma) || + !userfaultfd_wp_async(vma))) + return -EPERM; + + if (vma->vm_flags & VM_PFNMAP) + return 1; + + return 0; +} + +static int pagemap_scan_output(bool wt, bool file, bool pres, bool swap, + struct pagemap_scan_private *p, + unsigned long addr, unsigned int n_pages) +{ + unsigned long bitmap = PM_SCAN_BITMAP(wt, file, pres, swap); + struct page_region *cur = &p->cur; + + if (!n_pages) + return -EINVAL; + + if ((p->required_mask & bitmap) != p->required_mask) + return 0; + if (p->anyof_mask && !(p->anyof_mask & bitmap)) + return 0; + if (p->excluded_mask & bitmap) + return 0; + + bitmap &= p->return_mask; + if (!bitmap) + return 0; + + if (cur->bitmap == bitmap && + cur->start + cur->len * PAGE_SIZE == addr) { + cur->len += n_pages; + p->found_pages += n_pages; + + if (p->max_pages && (p->found_pages == p->max_pages)) + return PM_SCAN_FOUND_MAX_PAGES; + + return 0; + } + + /* + * All data is copied to cur first. When more data is found, we push + * cur to vec and copy new data to cur. The vec_index represents the + * current index of vec array. We add 1 to the vec_index while + * performing checks to account for data in cur. + */ + if (p->vec_index && (p->vec_index + 1) >= p->vec_len) + return -ENOSPC; + + if (cur->len) { + memcpy(&p->vec[p->vec_index], cur, sizeof(*p->vec)); + p->vec_index++; + } + + cur->start = addr; + cur->len = n_pages; + cur->bitmap = bitmap; + p->found_pages += n_pages; + + if (p->max_pages && (p->found_pages == p->max_pages)) + return PM_SCAN_FOUND_MAX_PAGES; + + return 0; +} + +static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long addr = end; + pte_t *pte, *orig_pte; + spinlock_t *ptl; + bool is_written; + int ret = 0; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + ptl = pmd_trans_huge_lock(pmd, vma); + if (ptl) { + unsigned long n_pages = (end - start)/PAGE_SIZE; + + if (p->max_pages && n_pages > p->max_pages - p->found_pages) + n_pages = p->max_pages - p->found_pages; + + is_written = !is_pmd_uffd_wp(*pmd); + + /* + * Break huge page into small pages if the WP operation need to + * be performed is on a portion of the huge page. + */ + if (is_written && PM_SCAN_DO_UFFD_WP(p) && + n_pages < HPAGE_SIZE/PAGE_SIZE) { + spin_unlock(ptl); + split_huge_pmd(vma, pmd, start); + goto process_smaller_pages; + } + + ret = pagemap_scan_output(is_written, vma->vm_file, + pmd_present(*pmd), is_swap_pmd(*pmd), + p, start, n_pages); + + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) + make_uffd_wp_pmd(vma, addr, pmd); + + spin_unlock(ptl); + return ret; + } +process_smaller_pages: + if (pmd_trans_unstable(pmd)) + return 0; +#endif + + pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); + for (addr = start; addr < end && !ret; pte++, addr += PAGE_SIZE) { + is_written = !is_pte_uffd_wp(*pte); + + ret = pagemap_scan_output(is_written, vma->vm_file, + pte_present(*pte), is_swap_pte(*pte), + p, addr, 1); + + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) + make_uffd_wp_pte(vma, addr, pte); + } + pte_unmap_unlock(orig_pte, ptl); + + cond_resched(); + return ret; +} + +#ifdef CONFIG_HUGETLB_PAGE +static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask, + unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + unsigned long n_pages = (end - start)/PAGE_SIZE; + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + struct hstate *h = hstate_vma(vma); + int ret = -EPERM; + spinlock_t *ptl; + bool is_written; + pte_t pte; + + if (p->max_pages && n_pages > p->max_pages - p->found_pages) + n_pages = p->max_pages - p->found_pages; + + if (PM_SCAN_DO_UFFD_WP(p)) { + i_mmap_lock_write(vma->vm_file->f_mapping); + ptl = huge_pte_lock(h, vma->vm_mm, ptep); + } + + pte = huge_ptep_get(ptep); + is_written = !is_huge_pte_uffd_wp(pte); + + /* + * Partial hugetlb page clear isn't supported + */ + if (is_written && PM_SCAN_DO_UFFD_WP(p) && + n_pages < HPAGE_SIZE/PAGE_SIZE) + goto unlock_and_return; + + ret = pagemap_scan_output(is_written, vma->vm_file, pte_present(pte), + is_swap_pte(pte), p, start, n_pages); + if (ret < 0) + goto unlock_and_return; + + if (is_written && PM_SCAN_DO_UFFD_WP(p)) { + make_uffd_wp_huge_pte(vma, start, ptep, pte); +#define __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE + flush_hugetlb_tlb_range(vma, start, end); +#endif + } + +unlock_and_return: + if (PM_SCAN_DO_UFFD_WP(p)) { + spin_unlock(ptl); + i_mmap_unlock_write(vma->vm_file->f_mapping); + } + + return ret; +} +#else +#define pagemap_scan_hugetlb_entry NULL +#endif + +static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end, + int depth, struct mm_walk *walk) +{ + unsigned long n_pages = (end - addr)/PAGE_SIZE; + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + int ret = 0; + + if (!vma) + return 0; + + if (p->max_pages && p->found_pages + n_pages > p->max_pages) + n_pages = p->max_pages - p->found_pages; + + ret = pagemap_scan_output(false, vma->vm_file, false, false, p, addr, + n_pages); + return ret; +} + +static const struct mm_walk_ops pagemap_scan_ops = { + .test_walk = pagemap_scan_test_walk, + .pmd_entry = pagemap_scan_pmd_entry, + .pte_hole = pagemap_scan_pte_hole, + .hugetlb_entry = pagemap_scan_hugetlb_entry, +}; + +static int pagemap_scan_args_valid(struct pm_scan_arg *arg, unsigned long start, + struct page_region __user *vec) +{ + /* Detect illegal size, flags, len and masks */ + if (arg->size != sizeof(struct pm_scan_arg)) + return -EINVAL; + if (arg->flags & ~PM_SCAN_OPS) + return -EINVAL; + if (!arg->len) + return -EINVAL; + if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask | + arg->return_mask) & ~PM_SCAN_BITS_ALL) + return -EINVAL; + if (!arg->required_mask && !arg->anyof_mask && + !arg->excluded_mask) + return -EINVAL; + if (!arg->return_mask) + return -EINVAL; + + /* Validate memory ranges */ + if (!(arg->flags & PM_SCAN_OP_GET)) + return -EINVAL; + if (!arg->vec) + return -EINVAL; + if (arg->vec_len == 0) + return -EINVAL; + + if (!IS_ALIGNED(start, PAGE_SIZE)) + return -EINVAL; + if (!access_ok((void __user *)start, arg->len)) + return -EFAULT; + + if (!PM_SCAN_DO_UFFD_WP(arg)) + return 0; + + if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask) & + ~PAGE_IS_WRITTEN) + return -EINVAL; + + return 0; +} + +static long do_pagemap_scan(struct mm_struct *mm, + struct pm_scan_arg __user *uarg) +{ + unsigned long start, end, walk_start, walk_end; + unsigned long empty_slots, vec_index = 0; + struct mmu_notifier_range range; + struct page_region __user *vec; + struct pagemap_scan_private p; + struct pm_scan_arg arg; + int ret = 0; + + if (copy_from_user(&arg, uarg, sizeof(arg))) + return -EFAULT; + + start = untagged_addr((unsigned long)arg.start); + vec = (struct page_region *)untagged_addr((unsigned long)arg.vec); + + ret = pagemap_scan_args_valid(&arg, start, vec); + if (ret) + return ret; + + end = start + arg.len; + p.max_pages = arg.max_pages; + p.found_pages = 0; + p.flags = arg.flags; + p.required_mask = arg.required_mask; + p.anyof_mask = arg.anyof_mask; + p.excluded_mask = arg.excluded_mask; + p.return_mask = arg.return_mask; + p.cur.len = 0; + p.cur.start = 0; + p.vec = NULL; + p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT; + + /* + * Allocate smaller buffer to get output from inside the page walk + * functions and walk page range in PAGEMAP_WALK_SIZE size chunks. As + * we want to return output to user in compact form where no two + * consecutive regions should be continuous and have the same flags. + * So store the latest element in p.cur between different walks and + * store the p.cur at the end of the walk to the user buffer. + */ + p.vec = kmalloc_array(p.vec_len, sizeof(*p.vec), GFP_KERNEL); + if (!p.vec) + return -ENOMEM; + + if (p.flags & PM_SCAN_OP_WP) { + mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0, + vma->vm_mm, start, end); + mmu_notifier_invalidate_range_start(&range); + } + + walk_start = walk_end = start; + while (walk_end < end && !ret) { + p.vec_index = 0; + + empty_slots = arg.vec_len - vec_index; + p.vec_len = min(p.vec_len, empty_slots); + + walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK; + if (walk_end > end) + walk_end = end; + + ret = mmap_read_lock_killable(mm); + if (ret) + goto free_data; + ret = walk_page_range(mm, walk_start, walk_end, + &pagemap_scan_ops, &p); + mmap_read_unlock(mm); + + if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES) + goto free_data; + + walk_start = walk_end; + if (p.vec_index) { + if (copy_to_user(&vec[vec_index], p.vec, + p.vec_index * sizeof(*p.vec))) { + /* + * Return error even though the OP succeeded + */ + ret = -EFAULT; + goto free_data; + } + vec_index += p.vec_index; + } + } + + if (p.flags & PM_SCAN_OP_WP) { + mmu_notifier_invalidate_range_end(&range); + flush_tlb_mm_range(mm, start, end, PAGE_SHIFT, false); + } + + if (p.cur.len) { + if (copy_to_user(&vec[vec_index], &p.cur, sizeof(*p.vec))) { + ret = -EFAULT; + goto free_data; + } + vec_index++; + } + + ret = vec_index; + +free_data: + kfree(p.vec); + return ret; +} + +static long do_pagemap_cmd(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct pm_scan_arg __user *uarg = (struct pm_scan_arg __user *)arg; + struct mm_struct *mm = file->private_data; + + switch (cmd) { + case PAGEMAP_SCAN: + return do_pagemap_scan(mm, uarg); + + default: + return -EINVAL; + } +} + const struct file_operations proc_pagemap_operations = { .llseek = mem_lseek, /* borrow this */ .read = pagemap_read, .open = pagemap_open, .release = pagemap_release, + .unlocked_ioctl = do_pagemap_cmd, + .compat_ioctl = do_pagemap_cmd, }; #endif /* CONFIG_PROC_PAGE_MONITOR */ diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index b7b56871029c..47879c38ce2f 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -305,4 +305,57 @@ typedef int __bitwise __kernel_rwf_t; #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ RWF_APPEND) +/* Pagemap ioctl */ +#define PAGEMAP_SCAN _IOWR('f', 16, struct pm_scan_arg) + +/* Bits are set in the bitmap of the page_region and masks in pm_scan_args */ +#define PAGE_IS_WRITTEN (1 << 0) +#define PAGE_IS_FILE (1 << 1) +#define PAGE_IS_PRESENT (1 << 2) +#define PAGE_IS_SWAPPED (1 << 3) + +/* + * struct page_region - Page region with bitmap flags + * @start: Start of the region + * @len: Length of the region in pages + * bitmap: Bits sets for the region + */ +struct page_region { + __u64 start; + __u64 len; + __u64 bitmap; +}; + +/* + * struct pm_scan_arg - Pagemap ioctl argument + * @size: Size of the structure + * @flags: Flags for the IOCTL + * @start: Starting address of the region + * @len: Length of the region (All the pages in this length are included) + * @vec: Address of page_region struct array for output + * @vec_len: Length of the page_region struct array + * @max_pages: Optional max return pages + * @required_mask: Required mask - All of these bits have to be set in the PTE + * @anyof_mask: Any mask - Any of these bits are set in the PTE + * @excluded_mask: Exclude mask - None of these bits are set in the PTE + * @return_mask: Bits that are to be reported in page_region + */ +struct pm_scan_arg { + __u64 size; + __u64 flags; + __u64 start; + __u64 len; + __u64 vec; + __u64 vec_len; + __u64 max_pages; + __u64 required_mask; + __u64 anyof_mask; + __u64 excluded_mask; + __u64 return_mask; +}; + +/* Supported flags */ +#define PM_SCAN_OP_GET (1 << 0) +#define PM_SCAN_OP_WP (1 << 1) + #endif /* _UAPI_LINUX_FS_H */ From patchwork Mon Apr 17 12:56:28 2023 Content-Type: text/plain; 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d=collabora.com; s=mail; t=1681736238; bh=ZpDkuHO27naMA3P55LraZJjP93DvvWKsAguR36UqCHo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JsyPkv1wEMdN1syicLfNVVqWXefHlCC69dZWmHKFb12UNwgVkNTd1I7jVE8btnmtE n7DTTQgYdGJPpitvR912Yis4+2W+ZPiT+Ez293+pnVNPr3TgKD+gR9hBJounNZJNj7 nEDIMP/M0vbAEoeCN86vuaF8CEVS9KFCG3z5lZQ7qLTRaZynPJrG+hvWbQ56V4oofS 2XqFnfFLGoaNTGGUjvIn5eeYtDYsr24/qygd4UbuUiuAXalhzLpgzE+m5Rdv2c0NO9 qpNNTSXTZWJoYKoSjaCKfX1p0xgTkj0PW3RPPDbkVLpyIbRaoud20j1Y6R2ewEoAeO 4/grKIa3hKDZg== From: Muhammad Usama Anjum To: Peter Xu , David Hildenbrand , Andrew Morton , =?utf-8?b?TWljaGHFgiBNaXJvc8WC?= =?utf-8?b?YXc=?= , Andrei Vagin , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Mike Rapoport , Nadav Amit Cc: Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Muhammad Usama Anjum , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: [PATCH v13 3/5] tools headers UAPI: Update linux/fs.h with the kernel sources Date: Mon, 17 Apr 2023 17:56:28 +0500 Message-Id: <20230417125630.1146906-4-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230417125630.1146906-1-usama.anjum@collabora.com> References: <20230417125630.1146906-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 3987514001A X-Rspam-User: X-Stat-Signature: kyxuxx7xnjqe8cu6qhf9rindqqoe56qk X-HE-Tag: 1681736238-850574 X-HE-Meta: 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 ZhxguyeV merBDMzu7jd0JhtOn2SSssUH190gWnbvMCowRmje5GL97onOVZwsh2I0Nvs8OfDXft3txOmxJpZQGjIvCVmAEMvAMJz+kHFoO9lYuraJct7NiddmVJsRMxdBASv1wQRnG2pBZ6AqbDzNZ5nzvslBJkGr/sU3gU7rNZA+d0XT8hR1TKinA/l9wSR1IaPtowl4yDOtKsInYtenfoo80jllyAFEfz3R1AS2Y6doD+uUABRV/bSp/D9KVVTOKcO0QRuyd7VW7RPMKhhfPVS0= 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: New IOCTL and macros has been added in the kernel sources. Update the tools header file as well. Signed-off-by: Muhammad Usama Anjum --- tools/include/uapi/linux/fs.h | 53 +++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/tools/include/uapi/linux/fs.h b/tools/include/uapi/linux/fs.h index b7b56871029c..47879c38ce2f 100644 --- a/tools/include/uapi/linux/fs.h +++ b/tools/include/uapi/linux/fs.h @@ -305,4 +305,57 @@ typedef int __bitwise __kernel_rwf_t; #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ RWF_APPEND) +/* Pagemap ioctl */ +#define PAGEMAP_SCAN _IOWR('f', 16, struct pm_scan_arg) + +/* Bits are set in the bitmap of the page_region and masks in pm_scan_args */ +#define PAGE_IS_WRITTEN (1 << 0) +#define PAGE_IS_FILE (1 << 1) +#define PAGE_IS_PRESENT (1 << 2) +#define PAGE_IS_SWAPPED (1 << 3) + +/* + * struct page_region - Page region with bitmap flags + * @start: Start of the region + * @len: Length of the region in pages + * bitmap: Bits sets for the region + */ +struct page_region { + __u64 start; + __u64 len; + __u64 bitmap; +}; + +/* + * struct pm_scan_arg - Pagemap ioctl argument + * @size: Size of the structure + * @flags: Flags for the IOCTL + * @start: Starting address of the region + * @len: Length of the region (All the pages in this length are included) + * @vec: Address of page_region struct array for output + * @vec_len: Length of the page_region struct array + * @max_pages: Optional max return pages + * @required_mask: Required mask - All of these bits have to be set in the PTE + * @anyof_mask: Any mask - Any of these bits are set in the PTE + * @excluded_mask: Exclude mask - None of these bits are set in the PTE + * @return_mask: Bits that are to be reported in page_region + */ +struct pm_scan_arg { + __u64 size; + __u64 flags; + __u64 start; + __u64 len; + __u64 vec; + __u64 vec_len; + __u64 max_pages; + __u64 required_mask; + __u64 anyof_mask; + __u64 excluded_mask; + __u64 return_mask; +}; + +/* Supported flags */ +#define PM_SCAN_OP_GET (1 << 0) +#define PM_SCAN_OP_WP (1 << 1) + #endif /* _UAPI_LINUX_FS_H */ From patchwork Mon Apr 17 12:56:29 2023 Content-Type: text/plain; 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d=collabora.com; s=mail; t=1681736250; bh=VHJ3s/rDqou65z21qPz74d3WACjlrCHoe/eBuZI6JGE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DH1RiVxG2jP9FQk93eveMBEoMUFiLX3uXUkbI5XSkS1skkx6wMGjldZsAIMsS5zzH JZUVTqDJlkgrbYk8f93p4a/jn0BYXdpnJ5P1BPcBjjyHZatdSC1I25FVEy/Rnrfpoq mGpnRnmBViqhdBXZUifB7lbwBsv8LnFDwCLpAR6Vug4Ld0vM9nA2iAjpQoWGdgG72H ldFb+FWGIAxNgrR5qnRBKHVSXA7jOV2+K+8yjVovcIoMV1x45egFgkCVPkQvD8HjZ1 1CDMIpxlptmrDdhwSZ9UaY9qOIaCAkQJipx69lFohqqGm9ftWgxEuaW4F36Sx10Kqc bBi62gdVEY2RA== From: Muhammad Usama Anjum To: Peter Xu , David Hildenbrand , Andrew Morton , =?utf-8?b?TWljaGHFgiBNaXJvc8WC?= =?utf-8?b?YXc=?= , Andrei Vagin , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Mike Rapoport , Nadav Amit Cc: Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Muhammad Usama Anjum , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: [PATCH v13 4/5] mm/pagemap: add documentation of PAGEMAP_SCAN IOCTL Date: Mon, 17 Apr 2023 17:56:29 +0500 Message-Id: <20230417125630.1146906-5-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230417125630.1146906-1-usama.anjum@collabora.com> References: <20230417125630.1146906-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6AF8FC0005 X-Rspam-User: X-Stat-Signature: hg8qm68t9x981tzd8ib35mhk3yjrx69h X-HE-Tag: 1681736251-331934 X-HE-Meta: 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 eZJAlCwp xtyaZWNwzH3JI4ADCt/z1s40aU7GhU5UOxEumv/+Bk7uPilbv5E1N225lSfY2SHkvfrfRLAkwXwxBHwsIaL3Nt3BiqhkIl4l6g4x3+DvIjANiNHUNlA2ZEAowfDNFsaDKv14viq+ZTbM5AAcY17lvuWzZbPKomCny43NrTJcfMvTve+fd/PZtItwTqsfXkh5ZvnXe7ZtirbqBAuwSrGWAttZqVVW8C8Ils06gtH4K8CjpzFLIg9HZ7htrMJ2QvSzqOfA4O0wICPkjrOBiR6xa14Rz+kXkFhbMB8Km0PEzToGnWHA0EBq2mKaW49ymMA8wxri7 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: Add some explanation and method to use write-protection and written-to on memory range. Signed-off-by: Muhammad Usama Anjum --- Changes in v11: - Add more documentation --- Documentation/admin-guide/mm/pagemap.rst | 56 ++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index c8f380271cad..a3e08f15b433 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -227,3 +227,59 @@ Before Linux 3.11 pagemap bits 55-60 were used for "page-shift" (which is always 12 at most architectures). Since Linux 3.11 their meaning changes after first clear of soft-dirty bits. Since Linux 4.2 they are used for flags unconditionally. + +Pagemap Scan IOCTL +================== + +The ``PAGEMAP_SCAN`` IOCTL on the pagemap file can be used to get or optionally +clear the info about page table entries. The following operations are supported +in this IOCTL: +- Get the information if the pages have been written-to (``PAGE_IS_WRITTEN``), + file mapped (``PAGE_IS_FILE``), present (``PAGE_IS_PRESENT``) or swapped + (``PAGE_IS_SWAPPED``). +- Find pages which have been written-to and write protect the pages atomically + (atomic ``PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE``) + +The ``struct pm_scan_arg`` is used as the argument of the IOCTL. + 1. The size of the ``struct pm_scan_arg`` must be specified in the ``size`` + field. This field will be helpful in recognizing the structure if extensions + are done later. + 2. The flags can be specified in the ``flags`` field. The ``PM_SCAN_OP_GET`` + and ``PM_SCAN_OP_WP`` are the only added flag at this time. + 3. The range is specified through ``start`` and ``len``. + 4. The output buffer of ``struct page_region`` array and size is specified in + ``vec`` and ``vec_len``. + 5. The optional maximum requested pages are specified in the ``max_pages``. + 6. The masks are specified in ``required_mask``, ``anyof_mask``, + ``excluded_ mask`` and ``return_mask``. + 1. To find if ``PAGE_IS_WRITTEN`` flag is set for pages which have + ``PAGE_IS_FILE`` set and ``PAGE_IS_SWAPPED`` un-set, ``required_mask`` + is set to ``PAGE_IS_FILE``, ``exclude_mask`` is set to + ``PAGE_IS_SWAPPED`` and ``return_mask`` is set to ``PAGE_IS_WRITTEN``. + The output buffer in ``vec`` and length must be specified in ``vec_len``. + 2. To find pages which have either ``PAGE_IS_FILE`` or ``PAGE_IS_SWAPPED`` + set, ``anyof_masks`` is set to ``PAGE_IS_FILE | PAGE_IS_SWAPPED``. + 3. To find written pages and engage write protect, ``PAGE_IS_WRITTEN`` is + specified in ``required_mask`` and ``return_mask``. In addition to + specifying the output buffer in ``vec`` and length in ``vec_len``, the + ``PAGEMAP_WP_ENGAGE`` is specified in ``flags`` to perform write protect + on the range as well. + +The ``PAGE_IS_WRITTEN`` flag can be considered as the better and correct +alternative of soft-dirty flag. It doesn't get affected by household chores (VMA +merging) of the kernel and hence the user can find the true soft-dirty pages +only. This IOCTL adds the atomic way to find which pages have been written and +write protect those pages again. This kind of operation is needed to efficiently +find out which pages have changed in the memory. + +To get information about which pages have been written-to or optionally write +protect the pages, following must be performed first in order: + 1. The userfaultfd file descriptor is created with ``userfaultfd`` syscall. + 2. The ``UFFD_FEATURE_WP_UNPOPULATED`` and ``UFFD_FEATURE_WP_ASYNC`` features + are set by ``UFFDIO_API`` IOCTL. + 3. The memory range is registered with ``UFFDIO_REGISTER_MODE_WP`` mode + through ``UFFDIO_REGISTER`` IOCTL. + 4. Then the any part of the registered memory or the whole memory region must + be write protected using the ``UFFDIO_WRITEPROTECT`` IOCTL. + 5. Now the ``PAGEMAP_SCAN`` IOCTL can be used to either just find pages which + have been written-to or optionally write protect the pages as well. 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Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Muhammad Usama Anjum , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: [PATCH v13 5/5] selftests: mm: add pagemap ioctl tests Date: Mon, 17 Apr 2023 17:56:30 +0500 Message-Id: <20230417125630.1146906-6-usama.anjum@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230417125630.1146906-1-usama.anjum@collabora.com> References: <20230417125630.1146906-1-usama.anjum@collabora.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 143784000F X-Stat-Signature: aazuyhry8tg3rtj6w5xnwd1fu7ua98rt X-HE-Tag: 1681736264-556702 X-HE-Meta: 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 ULulDHys 4cReHO7wvAGthjAqy8G8bWzqXUjv080c7zqBxIoI+0lmRxmrJNGYksAX2ORg7i2oQlSgNclGqqUC/kd1EtbB2N9Xlk+AtJV7vU3sljAfM+ccwHzpC3IZWAJ1Julo/ESJ4Cu7wI23VtQqKFIL7KYMOD3qNkZFEikLkZgHZBvkWh1TdZt9rHWAlj7tvOCxmiYaUXnMOm1a6seW1uEX5t6StKUbW1QsgB59P51ReLMQ0wcuJ4Pm+3hjL42LqYJuAuEjIpgc+vfIpZJUSo4HgxihNMbpEhxuCuefwElwR4RH7jPlNe1Z09+aicD8x7r6HT8pk2q4B 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: Add pagemap ioctl tests. Add several different types of tests to judge the correction of the interface. Signed-off-by: Muhammad Usama Anjum --- Changes in v13: - Update tests and rebase Makefile Changes in v12: - Updates and add more memory type tests Changes in v11: - Rebase on top of next-20230216 and update tests Chages in v7: - Add and update all test cases Changes in v6: - Rename variables Changes in v4: - Updated all the tests to conform to new IOCTL Changes in v3: - Add another test to do sanity of flags Changes in v2: - Update the tests to use the ioctl interface instead of syscall selftests --- tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 3 +- tools/testing/selftests/mm/config | 1 + tools/testing/selftests/mm/pagemap_ioctl.c | 1326 ++++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 5 files changed, 1334 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/mm/pagemap_ioctl.c mode change 100644 => 100755 tools/testing/selftests/mm/run_vmtests.sh diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 8917455f4f51..f1a06f842d55 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -17,6 +17,7 @@ mremap_dontunmap mremap_test on-fault-limit transhuge-stress +pagemap_ioctl protection_keys protection_keys_32 protection_keys_64 diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index dda8598bf5ef..f28c10c3dc8b 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -30,7 +30,7 @@ MACHINE ?= $(shell echo $(uname_M) | sed -e 's/aarch64.*/arm64/' -e 's/ppc64.*/p MAKEFLAGS += --no-builtin-rules CFLAGS = -Wall -I $(top_srcdir) $(EXTRA_CFLAGS) $(KHDR_INCLUDES) -LDLIBS = -lrt -lpthread +LDLIBS = -lrt -lpthread -lm TEST_GEN_PROGS = cow TEST_GEN_PROGS += compaction_test @@ -55,6 +55,7 @@ TEST_GEN_PROGS += mrelease_test TEST_GEN_PROGS += mremap_dontunmap TEST_GEN_PROGS += mremap_test TEST_GEN_PROGS += on-fault-limit +TEST_GEN_PROGS += pagemap_ioctl TEST_GEN_PROGS += thuge-gen TEST_GEN_PROGS += transhuge-stress TEST_GEN_PROGS += uffd-stress diff --git a/tools/testing/selftests/mm/config b/tools/testing/selftests/mm/config index be087c4bc396..4309916f629e 100644 --- a/tools/testing/selftests/mm/config +++ b/tools/testing/selftests/mm/config @@ -1,5 +1,6 @@ CONFIG_SYSVIPC=y CONFIG_USERFAULTFD=y +CONFIG_PTE_MARKER_UFFD_WP=y CONFIG_TEST_VMALLOC=m CONFIG_DEVICE_PRIVATE=y CONFIG_TEST_HMM=m diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c new file mode 100644 index 000000000000..deee7c618d6b --- /dev/null +++ b/tools/testing/selftests/mm/pagemap_ioctl.c @@ -0,0 +1,1326 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include "vm_util.h" +#include "../kselftest.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define PAGEMAP_BITS_ALL (PAGE_IS_WRITTEN | PAGE_IS_FILE | \ + PAGE_IS_PRESENT | PAGE_IS_SWAPPED) +#define PAGEMAP_NON_WRITTEN_BITS (PAGE_IS_FILE | PAGE_IS_PRESENT | \ + PAGE_IS_SWAPPED) + +#define TEST_ITERATIONS 10 +#define PAGEMAP "/proc/self/pagemap" +int pagemap_fd; +int uffd; +int page_size; +int hpage_size; + +static long pagemap_ioctl(void *start, int len, void *vec, int vec_len, int flag, + int max_pages, long required_mask, long anyof_mask, long excluded_mask, + long return_mask) +{ + struct pm_scan_arg arg; + + arg.start = (uintptr_t)start; + arg.len = len; + arg.vec = (uintptr_t)vec; + arg.vec_len = vec_len; + arg.flags = flag; + arg.size = sizeof(struct pm_scan_arg); + arg.max_pages = max_pages; + arg.required_mask = required_mask; + arg.anyof_mask = anyof_mask; + arg.excluded_mask = excluded_mask; + arg.return_mask = return_mask; + + return ioctl(pagemap_fd, PAGEMAP_SCAN, &arg); +} + +int init_uffd(void) +{ + struct uffdio_api uffdio_api; + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); + if (uffd == -1) + ksft_exit_fail_msg("uffd syscall failed\n"); + + uffdio_api.api = UFFD_API; + uffdio_api.features = UFFD_FEATURE_WP_UNPOPULATED | UFFD_FEATURE_WP_ASYNC | + UFFD_FEATURE_WP_HUGETLBFS_SHMEM; + if (ioctl(uffd, UFFDIO_API, &uffdio_api)) + ksft_exit_fail_msg("UFFDIO_API\n"); + + if (!(uffdio_api.api & UFFDIO_REGISTER_MODE_WP) || + !(uffdio_api.features & UFFD_FEATURE_WP_UNPOPULATED) || + !(uffdio_api.features & UFFD_FEATURE_WP_ASYNC) || + !(uffdio_api.features & UFFD_FEATURE_WP_HUGETLBFS_SHMEM)) + ksft_exit_fail_msg("UFFDIO_API error %llu\n", uffdio_api.api); + + return 0; +} + +int wp_init(void *lpBaseAddress, int dwRegionSize) +{ + struct uffdio_register uffdio_register; + struct uffdio_writeprotect wp; + + uffdio_register.range.start = (unsigned long)lpBaseAddress; + uffdio_register.range.len = dwRegionSize; + uffdio_register.mode = UFFDIO_REGISTER_MODE_WP; + if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) + ksft_exit_fail_msg("ioctl(UFFDIO_REGISTER) %d %s\n", errno, strerror(errno)); + + if (!(uffdio_register.ioctls & UFFDIO_WRITEPROTECT)) + ksft_exit_fail_msg("ioctl set is incorrect\n"); + + wp.range.start = (unsigned long)lpBaseAddress; + wp.range.len = dwRegionSize; + wp.mode = UFFDIO_WRITEPROTECT_MODE_WP; + + if (ioctl(uffd, UFFDIO_WRITEPROTECT, &wp)) + ksft_exit_fail_msg("ioctl(UFFDIO_WRITEPROTECT)\n"); + + return 0; +} + +int wp_free(void *lpBaseAddress, int dwRegionSize) +{ + struct uffdio_register uffdio_register; + + uffdio_register.range.start = (unsigned long)lpBaseAddress; + uffdio_register.range.len = dwRegionSize; + uffdio_register.mode = UFFDIO_REGISTER_MODE_WP; + if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) + ksft_exit_fail_msg("ioctl unregister failure\n"); + return 0; +} + +int wp_addr_range(void *lpBaseAddress, int dwRegionSize) +{ + struct uffdio_writeprotect wp; + + wp.range.start = (unsigned long)lpBaseAddress; + wp.range.len = dwRegionSize; + wp.mode = UFFDIO_WRITEPROTECT_MODE_WP; + + if (ioctl(uffd, UFFDIO_WRITEPROTECT, &wp)) + ksft_exit_fail_msg("ioctl(UFFDIO_WRITEPROTECT)\n"); + + return 0; +} + +void *gethugetlb_mem(int size, int *shmid) +{ + char *mem; + + if (shmid) { + *shmid = shmget(2, size, SHM_HUGETLB | IPC_CREAT | SHM_R | SHM_W); + if (*shmid < 0) + return NULL; + + mem = shmat(*shmid, 0, 0); + if (mem == (char *)-1) { + shmctl(*shmid, IPC_RMID, NULL); + ksft_exit_fail_msg("Shared memory attach failure\n"); + } + } else { + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_HUGETLB | MAP_PRIVATE, -1, 0); + if (mem == MAP_FAILED) + return NULL; + } + + return mem; +} + +int userfaultfd_tests(void) +{ + int mem_size, vec_size, written, num_pages = 16; + char *mem, *vec; + + mem_size = num_pages * page_size; + mem = mmap(NULL, mem_size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + wp_init(mem, mem_size); + + /* Change protection of pages differently */ + mprotect(mem, mem_size/8, PROT_READ|PROT_WRITE); + mprotect(mem + 1 * mem_size/8, mem_size/8, PROT_READ); + mprotect(mem + 2 * mem_size/8, mem_size/8, PROT_READ|PROT_WRITE); + mprotect(mem + 3 * mem_size/8, mem_size/8, PROT_READ); + mprotect(mem + 4 * mem_size/8, mem_size/8, PROT_READ|PROT_WRITE); + mprotect(mem + 5 * mem_size/8, mem_size/8, PROT_NONE); + mprotect(mem + 6 * mem_size/8, mem_size/8, PROT_READ|PROT_WRITE); + mprotect(mem + 7 * mem_size/8, mem_size/8, PROT_READ); + + wp_addr_range(mem + (mem_size/16), mem_size - 2 * (mem_size/8)); + wp_addr_range(mem, mem_size); + + vec_size = mem_size/page_size; + vec = malloc(sizeof(struct page_region) * vec_size); + + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + vec_size - 2, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 0, "%s all new pages must not be written (dirty)\n", __func__); + + wp_free(mem, mem_size); + munmap(mem, mem_size); + free(vec); + return 0; +} + +int sanity_tests_sd(void) +{ + char *mem, *m[2]; + int mem_size, vec_size, ret, ret2, ret3, i, num_pages = 10; + struct page_region *vec, *vec2; + + vec_size = 100; + mem_size = num_pages * page_size; + + vec = malloc(sizeof(struct page_region) * vec_size); + if (!vec) + ksft_exit_fail_msg("error nomem\n"); + + vec2 = malloc(sizeof(struct page_region) * vec_size); + if (!vec2) + ksft_exit_fail_msg("error nomem\n"); + + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + /* 1. wrong operation */ + ksft_test_result(pagemap_ioctl(mem, 0, vec, vec_size, PM_SCAN_OP_GET, + 0, PAGEMAP_BITS_ALL, 0, 0, PAGEMAP_BITS_ALL) < 0, + "%s memory size must be valid\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, NULL, vec_size, PM_SCAN_OP_GET, + 0, PAGEMAP_BITS_ALL, 0, 0, PAGEMAP_BITS_ALL) < 0, + "%s output buffer must be specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, 0, PM_SCAN_OP_GET, + 0, PAGEMAP_BITS_ALL, 0, 0, PAGEMAP_BITS_ALL) < 0, + "%s output buffer size must be valid\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, -1, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) < 0, + "%s wrong flag specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_WP, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) < 0, + "%s PM_SCAN_OP_WP cannot be used without PM_SCAN_OP_GET\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, + PM_SCAN_OP_GET | PM_SCAN_OP_WP | 0xFF, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) < 0, + "%s flag has extra bits specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, + 0, 0, 0, 0, PAGE_IS_WRITTEN) < 0, + "%s no selection mask is specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, + 0, PAGE_IS_WRITTEN, PAGE_IS_WRITTEN, 0, 0) < 0, + "%s no return mask is specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, + 0, PAGE_IS_WRITTEN, 0, 0, 0x1000) < 0, + "%s wrong return mask specified\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + 0, 0xFFF, PAGE_IS_WRITTEN, 0, PAGE_IS_WRITTEN) < 0, + "%s mixture of correct and wrong flag\n", __func__); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + 0, 0, 0, PAGEMAP_BITS_ALL, PAGE_IS_WRITTEN) < 0, + "%s PAGEMAP_BITS_ALL cannot be specified with PM_SCAN_OP_WP\n", __func__); + + /* 2. Clear area with larger vec size */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + ksft_test_result(ret >= 0, "%s Clear area with larger vec size\n", __func__); + + /* 3. Repeated pattern of written and non-written pages */ + for (i = 0; i < mem_size; i += 2 * page_size) + mem[i]++; + + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, 0, + 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == mem_size/(page_size * 2), + "%s Repeated pattern of written and non-written pages\n", __func__); + + /* 4. Repeated pattern of written and non-written pages in parts */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + num_pages/2 - 2, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ret2 = pagemap_ioctl(mem, mem_size, vec, 2, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, 0, 0, + PAGE_IS_WRITTEN); + if (ret2 < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret2, errno, strerror(errno)); + + ret3 = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret3 < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret3, errno, strerror(errno)); + + ksft_test_result((ret + ret3) == num_pages/2 && ret2 == 2, + "%s Repeated pattern of written and non-written pages in parts\n", + __func__); + + /* 5. only get 2 dirty pages and clear them as well */ + vec_size = mem_size/page_size; + memset(mem, -1, mem_size); + + /* get and clear second and third pages */ + ret = pagemap_ioctl(mem + page_size, 2 * page_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + 2, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ret2 = pagemap_ioctl(mem, mem_size, vec2, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret2 < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret2, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == 2 && + vec[0].start == (uintptr_t)(mem + page_size) && + ret2 == 2 && vec2[0].len == 1 && vec2[0].start == (uintptr_t)mem && + vec2[1].len == vec_size - 3 && + vec2[1].start == (uintptr_t)(mem + 3 * page_size), + "%s only get 2 written pages and clear them as well\n", __func__); + + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 6. Two regions */ + m[0] = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (m[0] == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + m[1] = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (m[1] == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + wp_init(m[0], mem_size); + wp_init(m[1], mem_size); + wp_addr_range(m[0], mem_size); + wp_addr_range(m[1], mem_size); + + memset(m[0], 'a', mem_size); + memset(m[1], 'b', mem_size); + + wp_addr_range(m[0], mem_size); + + ret = pagemap_ioctl(m[1], mem_size, vec, 1, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, 0, 0, + PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == mem_size/page_size, + "%s Two regions\n", __func__); + + wp_free(m[0], mem_size); + wp_free(m[1], mem_size); + munmap(m[0], mem_size); + munmap(m[1], mem_size); + + free(vec); + free(vec2); + return 0; +} + +int base_tests(char *prefix, char *mem, int mem_size, int skip) +{ + int vec_size, written; + struct page_region *vec, *vec2; + + if (skip) { + ksft_test_result_skip("%s all new pages must not be written (dirty)\n", prefix); + ksft_test_result_skip("%s all pages must be written (dirty)\n", prefix); + ksft_test_result_skip("%s all pages dirty other than first and the last one\n", + prefix); + ksft_test_result_skip("%s PM_SCAN_OP_WP\n", prefix); + ksft_test_result_skip("%s only middle page dirty\n", prefix); + ksft_test_result_skip("%s only two middle pages dirty\n", prefix); + return 0; + } + + vec_size = mem_size/page_size; + vec = malloc(sizeof(struct page_region) * vec_size); + vec2 = malloc(sizeof(struct page_region) * vec_size); + + /* 1. all new pages must be not be written (dirty) */ + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, vec_size - 2, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 0, "%s all new pages must not be written (dirty)\n", prefix); + + /* 2. all pages must be written */ + memset(mem, -1, mem_size); + + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, 0, 0, + PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 1 && vec[0].len == mem_size/page_size, + "%s all pages must be written (dirty)\n", prefix); + + /* 3. all pages dirty other than first and the last one */ + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + memset(mem + page_size, 0, mem_size - (2 * page_size)); + + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 1 && vec[0].len >= vec_size - 2 && vec[0].len <= vec_size, + "%s all pages dirty other than first and the last one\n", prefix); + + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 0, + "%s PM_SCAN_OP_WP\n", prefix); + + /* 4. only middle page dirty */ + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + mem[vec_size/2 * page_size]++; + + written = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, + 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 1 && vec[0].len >= 1, + "%s only middle page dirty\n", prefix); + + /* 5. only two middle pages dirty and walk over only middle pages */ + written = pagemap_ioctl(mem, mem_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + mem[vec_size/2 * page_size]++; + mem[(vec_size/2 + 1) * page_size]++; + + written = pagemap_ioctl(&mem[vec_size/2 * page_size], 2 * page_size, vec, 1, PM_SCAN_OP_GET, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written == 1 && vec[0].start == (uintptr_t)(&mem[vec_size/2 * page_size]) + && vec[0].len == 2, + "%s only two middle pages dirty\n", prefix); + + free(vec); + free(vec2); + return 0; +} + +void *gethugepage(int map_size) +{ + int ret; + char *map; + + map = memalign(hpage_size, map_size); + if (!map) + ksft_exit_fail_msg("memalign failed %d %s\n", errno, strerror(errno)); + + ret = madvise(map, map_size, MADV_HUGEPAGE); + if (ret) + return NULL; + + memset(map, 0, map_size); + + return map; +} + +int hpage_unit_tests(void) +{ + char *map; + int ret, ret2; + size_t num_pages = 10; + int map_size = hpage_size * num_pages; + int vec_size = map_size/page_size; + struct page_region *vec, *vec2; + + vec = malloc(sizeof(struct page_region) * vec_size); + vec2 = malloc(sizeof(struct page_region) * vec_size); + if (!vec || !vec2) + ksft_exit_fail_msg("malloc failed\n"); + + map = gethugepage(map_size); + if (map) { + wp_init(map, map_size); + wp_addr_range(map, map_size); + + /* 1. all new huge page must not be written (dirty) */ + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 0, "%s all new huge page must not be written (dirty)\n", + __func__); + + /* 2. all the huge page must not be written */ + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 0, "%s all the huge page must not be written\n", __func__); + + /* 3. all the huge page must be written and clear dirty as well */ + memset(map, -1, map_size); + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + 0, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].start == (uintptr_t)map && + vec[0].len == vec_size && vec[0].bitmap == PAGE_IS_WRITTEN, + "%s all the huge page must be written and clear\n", __func__); + + /* 4. only middle page written */ + wp_free(map, map_size); + free(map); + map = gethugepage(map_size); + wp_init(map, map_size); + wp_addr_range(map, map_size); + map[vec_size/2 * page_size]++; + + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len > 0, + "%s only middle page written\n", __func__); + + wp_free(map, map_size); + free(map); + } else { + ksft_test_result_skip("%s all new huge page must be written\n", __func__); + ksft_test_result_skip("%s all the huge page must not be written\n", __func__); + ksft_test_result_skip("%s all the huge page must be written and clear\n", __func__); + ksft_test_result_skip("%s only middle page written\n", __func__); + } + + /* 5. clear first half of huge page */ + map = gethugepage(map_size); + if (map) { + wp_init(map, map_size); + wp_addr_range(map, map_size); + + memset(map, 0, map_size); + + wp_addr_range(map, map_size/2); + + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == vec_size/2 && + vec[0].start == (uintptr_t)(map + map_size/2), + "%s clear first half of huge page\n", __func__); + wp_free(map, map_size); + free(map); + } else { + ksft_test_result_skip("%s clear first half of huge page\n", __func__); + } + + /* 6. clear first half of huge page with limited buffer */ + map = gethugepage(map_size); + if (map) { + wp_init(map, map_size); + wp_addr_range(map, map_size); + + memset(map, 0, map_size); + + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + vec_size/2, PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == vec_size/2 && + vec[0].start == (uintptr_t)(map + map_size/2), + "%s clear first half of huge page with limited buffer\n", + __func__); + wp_free(map, map_size); + free(map); + } else { + ksft_test_result_skip("%s clear first half of huge page with limited buffer\n", + __func__); + } + + /* 7. clear second half of huge page */ + map = gethugepage(map_size); + if (map) { + wp_init(map, map_size); + wp_addr_range(map, map_size); + + memset(map, -1, map_size); + + ret = pagemap_ioctl(map + map_size/2, map_size/2, vec, vec_size, + PM_SCAN_OP_GET | PM_SCAN_OP_WP, vec_size/2, PAGE_IS_WRITTEN, 0, + 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ret = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == vec_size/2, + "%s clear second half huge page\n", __func__); + wp_free(map, map_size); + free(map); + } else { + ksft_test_result_skip("%s clear second half huge page\n", __func__); + } + + /* 8. get half huge page */ + map = gethugepage(map_size); + if (map) { + wp_init(map, map_size); + wp_addr_range(map, map_size); + + memset(map, -1, map_size); + usleep(100); + + ret = pagemap_ioctl(map, map_size, vec, 1, PM_SCAN_OP_GET | PM_SCAN_OP_WP, + hpage_size/(2*page_size), PAGE_IS_WRITTEN, 0, 0, + PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec[0].len == hpage_size/(2*page_size), + "%s get half huge page\n", __func__); + + ret2 = pagemap_ioctl(map, map_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN); + if (ret2 < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret2, errno, strerror(errno)); + + ksft_test_result(ret2 == 1 && vec[0].len == (map_size - hpage_size/2)/page_size, + "%s get half huge page\n", __func__); + + wp_free(map, map_size); + free(map); + } else { + ksft_test_result_skip("%s get half huge page\n", __func__); + ksft_test_result_skip("%s get half huge page\n", __func__); + } + + free(vec); + free(vec2); + return 0; +} + +int unmapped_region_tests(void) +{ + void *start = (void *)0x10000000; + int written, len = 0x00040000; + int vec_size = len / page_size; + struct page_region *vec = malloc(sizeof(struct page_region) * vec_size); + + /* 1. Get written pages */ + written = pagemap_ioctl(start, len, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGEMAP_NON_WRITTEN_BITS, 0, 0, PAGEMAP_NON_WRITTEN_BITS); + if (written < 0) + ksft_exit_fail_msg("error %d %d %s\n", written, errno, strerror(errno)); + + ksft_test_result(written >= 0, "%s Get status of pages\n", __func__); + + free(vec); + return 0; +} + +static void test_simple(void) +{ + int i; + char *map; + struct page_region vec; + + map = aligned_alloc(page_size, page_size); + if (!map) + ksft_exit_fail_msg("aligned_alloc failed\n"); + + wp_init(map, page_size); + wp_addr_range(map, page_size); + + for (i = 0 ; i < TEST_ITERATIONS; i++) { + if (pagemap_ioctl(map, page_size, &vec, 1, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) == 1) { + ksft_print_msg("written bit was 1, but should be 0 (i=%d)\n", i); + break; + } + + wp_addr_range(map, page_size); + /* Write something to the page to get the written bit enabled on the page */ + map[0]++; + + if (pagemap_ioctl(map, page_size, &vec, 1, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) == 0) { + ksft_print_msg("written bit was 0, but should be 1 (i=%d)\n", i); + break; + } + + wp_addr_range(map, page_size); + } + wp_free(map, page_size); + free(map); + + ksft_test_result(i == TEST_ITERATIONS, "Test %s\n", __func__); +} + +int sanity_tests(void) +{ + int mem_size, vec_size, ret, fd, i, buf_size; + struct page_region *vec; + char *mem, *fmem; + struct stat sbuf; + + /* 1. wrong operation */ + mem_size = 10 * page_size; + vec_size = mem_size / page_size; + + vec = malloc(sizeof(struct page_region) * vec_size); + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED || vec == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, + PM_SCAN_OP_GET | PM_SCAN_OP_WP, 0, PAGEMAP_BITS_ALL, 0, 0, + PAGEMAP_BITS_ALL) < 0, + "%s clear op can only be specified with PAGE_IS_WRITTEN\n", __func__); + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGEMAP_BITS_ALL, 0, 0, PAGEMAP_BITS_ALL) >= 0, + "%s required_mask specified\n", __func__); + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, PAGEMAP_BITS_ALL, 0, PAGEMAP_BITS_ALL) >= 0, + "%s anyof_mask specified\n", __func__); + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, 0, PAGEMAP_BITS_ALL, PAGEMAP_BITS_ALL) >= 0, + "%s excluded_mask specified\n", __func__); + ksft_test_result(pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGEMAP_BITS_ALL, PAGEMAP_BITS_ALL, 0, + PAGEMAP_BITS_ALL) >= 0, + "%s required_mask and anyof_mask specified\n", __func__); + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 2. Get sd and present pages with anyof_mask */ + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + memset(mem, 0, mem_size); + + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, PAGEMAP_BITS_ALL, 0, PAGEMAP_BITS_ALL); + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)mem && vec[0].len == vec_size && + vec[0].bitmap == (PAGE_IS_WRITTEN | PAGE_IS_PRESENT), + "%s Get sd and present pages with anyof_mask\n", __func__); + + /* 3. Get sd and present pages with required_mask */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGEMAP_BITS_ALL, 0, 0, PAGEMAP_BITS_ALL); + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)mem && vec[0].len == vec_size && + vec[0].bitmap == (PAGE_IS_WRITTEN | PAGE_IS_PRESENT), + "%s Get all the pages with required_mask\n", __func__); + + /* 4. Get sd and present pages with required_mask and anyof_mask */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, PAGE_IS_PRESENT, 0, PAGEMAP_BITS_ALL); + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)mem && vec[0].len == vec_size && + vec[0].bitmap == (PAGE_IS_WRITTEN | PAGE_IS_PRESENT), + "%s Get sd and present pages with required_mask and anyof_mask\n", + __func__); + + /* 5. Don't get sd pages */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, 0, PAGE_IS_WRITTEN, PAGEMAP_BITS_ALL); + ksft_test_result(ret == 0, "%s Don't get sd pages\n", __func__); + + /* 6. Don't get present pages */ + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, 0, PAGE_IS_PRESENT, PAGEMAP_BITS_ALL); + ksft_test_result(ret == 0, "%s Don't get present pages\n", __func__); + + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 8. Find written present pages with return mask */ + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + memset(mem, 0, mem_size); + + ret = pagemap_ioctl(mem, mem_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, PAGEMAP_BITS_ALL, 0, PAGE_IS_WRITTEN); + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)mem && vec[0].len == vec_size && + vec[0].bitmap == PAGE_IS_WRITTEN, + "%s Find written present pages with return mask\n", __func__); + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 9. Memory mapped file */ + fd = open(__FILE__, O_RDONLY); + if (fd < 0) + ksft_exit_fail_msg("%s Memory mapped file\n"); + + ret = stat(__FILE__, &sbuf); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + fmem = mmap(NULL, sbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (fmem == MAP_FAILED) + ksft_exit_fail_msg("error nomem %ld %s\n", errno, strerror(errno)); + + ret = pagemap_ioctl(fmem, sbuf.st_size, vec, vec_size, PM_SCAN_OP_GET, 0, + 0, PAGEMAP_NON_WRITTEN_BITS, 0, PAGEMAP_NON_WRITTEN_BITS); + + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)fmem && + vec[0].len == ceilf((float)sbuf.st_size/page_size) && + vec[0].bitmap == PAGE_IS_FILE, + "%s Memory mapped file\n", __func__); + + munmap(fmem, sbuf.st_size); + close(fd); + + /* 10. Create and read/write to a memory mapped file*/ + buf_size = page_size * 10; + + fd = open(__FILE__".tmp2", O_RDWR | O_CREAT, 0777); + if (fd < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file: %s\n", + strerror(errno)); + + for (i = 0; i < buf_size; i++) + if (write(fd, "c", 1) < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file\n"); + + fmem = mmap(NULL, buf_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + if (fmem == MAP_FAILED) + ksft_exit_fail_msg("error nomem %ld %s\n", errno, strerror(errno)); + + wp_init(fmem, buf_size); + wp_addr_range(fmem, buf_size); + + for (i = 0; i < buf_size; i++) + fmem[i] = i; + + ret = pagemap_ioctl(fmem, buf_size, vec, vec_size, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN | PAGE_IS_FILE, PAGE_IS_PRESENT | PAGE_IS_SWAPPED, 0, + PAGEMAP_BITS_ALL); + + ksft_test_result(ret >= 0 && vec[0].start == (uintptr_t)fmem && + vec[0].len == (buf_size/page_size) && + (vec[0].bitmap | PAGE_IS_WRITTEN) && (vec[0].bitmap | PAGE_IS_FILE), + "%s Read/write to private memory mapped file\n", __func__); + + wp_free(fmem, buf_size); + munmap(fmem, buf_size); + close(fd); + + free(vec); + return 0; +} + +int mprotect_tests(void) +{ + int ret; + char *mem, *mem2; + struct page_region vec; + int pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + + if (pagemap_fd < 0) { + fprintf(stderr, "open() failed\n"); + exit(1); + } + + /* 1. Map two pages */ + mem = mmap(0, 2 * page_size, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem, 2 * page_size); + wp_addr_range(mem, 2 * page_size); + + /* Populate both pages. */ + memset(mem, 1, 2 * page_size); + + ret = pagemap_ioctl(mem, 2 * page_size, &vec, 1, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, + 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec.len == 2, "%s Both pages written\n", __func__); + + /* 2. Start tracking */ + wp_addr_range(mem, 2 * page_size); + + ksft_test_result(pagemap_ioctl(mem, 2 * page_size, &vec, 1, PM_SCAN_OP_GET, 0, + PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN) == 0, + "%s Both pages are not written (dirty)\n", __func__); + + /* 3. Remap the second page */ + mem2 = mmap(mem + page_size, page_size, PROT_READ|PROT_WRITE, + MAP_PRIVATE|MAP_ANON|MAP_FIXED, -1, 0); + if (mem2 == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem2, page_size); + wp_addr_range(mem2, page_size); + + /* Protect + unprotect. */ + mprotect(mem, page_size, PROT_NONE); + mprotect(mem, 2 * page_size, PROT_READ); + mprotect(mem, 2 * page_size, PROT_READ|PROT_WRITE); + + /* Modify both pages. */ + memset(mem, 2, 2 * page_size); + + /* Protect + unprotect. */ + mprotect(mem, page_size, PROT_NONE); + mprotect(mem, page_size, PROT_READ); + mprotect(mem, page_size, PROT_READ|PROT_WRITE); + + ret = pagemap_ioctl(mem, 2 * page_size, &vec, 1, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, + 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec.len == 2, + "%s Both pages written after remap and mprotect\n", __func__); + + /* 4. Clear and make the pages written */ + wp_addr_range(mem, 2 * page_size); + + memset(mem, 'A', 2 * page_size); + + ret = pagemap_ioctl(mem, 2 * page_size, &vec, 1, PM_SCAN_OP_GET, 0, PAGE_IS_WRITTEN, + 0, 0, PAGE_IS_WRITTEN); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret == 1 && vec.len == 2, + "%s Clear and make the pages written\n", __func__); + + wp_free(mem, 2 * page_size); + munmap(mem, 2 * page_size); + return 0; +} + +/* transact test */ +static const unsigned int nthreads = 6, pages_per_thread = 32, access_per_thread = 8; +static pthread_barrier_t start_barrier, end_barrier; +static unsigned int extra_thread_faults; +static unsigned int iter_count = 1000; +static volatile int finish; + +static ssize_t get_dirty_pages_reset(char *mem, unsigned int count, + int reset, int page_size) +{ + struct pm_scan_arg arg = {0}; + struct page_region rgns[256]; + int i, j, cnt, ret; + + arg.size = sizeof(struct pm_scan_arg); + arg.start = (uintptr_t)mem; + arg.max_pages = count; + arg.len = count * page_size; + arg.vec = (uintptr_t)rgns; + arg.vec_len = sizeof(rgns) / sizeof(*rgns); + arg.flags = PM_SCAN_OP_GET; + if (reset) + arg.flags |= PM_SCAN_OP_WP; + arg.required_mask = PAGE_IS_WRITTEN; + arg.return_mask = PAGE_IS_WRITTEN; + + ret = ioctl(pagemap_fd, PAGEMAP_SCAN, &arg); + if (ret < 0) + ksft_exit_fail_msg("ioctl failed\n"); + + cnt = 0; + for (i = 0; i < ret; ++i) { + if (rgns[i].bitmap != PAGE_IS_WRITTEN) + ksft_exit_fail_msg("wrong bitmap\n"); + + for (j = 0; j < rgns[i].len; ++j) + cnt++; + } + + return cnt; +} + +void *thread_proc(void *mem) +{ + int *m = mem; + long curr_faults, faults; + struct rusage r; + unsigned int i; + int ret; + + if (getrusage(RUSAGE_THREAD, &r)) + ksft_exit_fail_msg("getrusage\n"); + + curr_faults = r.ru_minflt; + + while (!finish) { + ret = pthread_barrier_wait(&start_barrier); + if (ret && ret != PTHREAD_BARRIER_SERIAL_THREAD) + ksft_exit_fail_msg("pthread_barrier_wait\n"); + + for (i = 0; i < access_per_thread; ++i) + __atomic_add_fetch(m + i * (0x1000 / sizeof(*m)), 1, __ATOMIC_SEQ_CST); + + ret = pthread_barrier_wait(&end_barrier); + if (ret && ret != PTHREAD_BARRIER_SERIAL_THREAD) + ksft_exit_fail_msg("pthread_barrier_wait\n"); + + if (getrusage(RUSAGE_THREAD, &r)) + ksft_exit_fail_msg("getrusage\n"); + + faults = r.ru_minflt - curr_faults; + if (faults < access_per_thread) + ksft_exit_fail_msg("faults < access_per_thread"); + + __atomic_add_fetch(&extra_thread_faults, faults - access_per_thread, + __ATOMIC_SEQ_CST); + curr_faults = r.ru_minflt; + } + + return NULL; +} + +static void transact_test(int page_size) +{ + unsigned int i, count, extra_pages; + pthread_t th; + char *mem; + int ret, c; + + if (pthread_barrier_init(&start_barrier, NULL, nthreads + 1)) + ksft_exit_fail_msg("pthread_barrier_init\n"); + + if (pthread_barrier_init(&end_barrier, NULL, nthreads + 1)) + ksft_exit_fail_msg("pthread_barrier_init\n"); + + mem = mmap(NULL, 0x1000 * nthreads * pages_per_thread, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("Error mmap %s.\n", strerror(errno)); + + wp_init(mem, 0x1000 * nthreads * pages_per_thread); + wp_addr_range(mem, 0x1000 * nthreads * pages_per_thread); + + memset(mem, 0, 0x1000 * nthreads * pages_per_thread); + + count = get_dirty_pages_reset(mem, nthreads * pages_per_thread, 1, page_size); + ksft_test_result(count > 0, "%s count %d\n", __func__, count); + count = get_dirty_pages_reset(mem, nthreads * pages_per_thread, 1, page_size); + ksft_test_result(count == 0, "%s count %d\n", __func__, count); + + finish = 0; + for (i = 0; i < nthreads; ++i) + pthread_create(&th, NULL, thread_proc, mem + 0x1000 * i * pages_per_thread); + + extra_pages = 0; + for (i = 0; i < iter_count; ++i) { + count = 0; + + ret = pthread_barrier_wait(&start_barrier); + if (ret && ret != PTHREAD_BARRIER_SERIAL_THREAD) + ksft_exit_fail_msg("pthread_barrier_wait\n"); + + count = get_dirty_pages_reset(mem, nthreads * pages_per_thread, 1, + page_size); + + ret = pthread_barrier_wait(&end_barrier); + if (ret && ret != PTHREAD_BARRIER_SERIAL_THREAD) + ksft_exit_fail_msg("pthread_barrier_wait\n"); + + if (count > nthreads * access_per_thread) + ksft_exit_fail_msg("Too big count %d expected %d, iter %d\n", + count, nthreads * access_per_thread, i); + + c = get_dirty_pages_reset(mem, nthreads * pages_per_thread, 1, page_size); + count += c; + + if (c > nthreads * access_per_thread) { + ksft_test_result_fail(" %s count > nthreads\n", __func__); + return; + } + + if (count != nthreads * access_per_thread) { + /* + * The purpose of the test is to make sure that no page updates are lost + * when the page updates and read-resetting soft dirty flags are performed + * in parallel. However, it is possible that the application will get the + * soft dirty flags twice on the two consecutive read-resets. This seems + * unavoidable as soft dirty flag is handled in software through page faults + * in kernel. While the updating the flags is supposed to be synchronized + * between page fault handling and read-reset, it is possible that + * read-reset happens after page fault PTE update but before the application + * re-executes write instruction. So read-reset gets the flag, clears write + * access and application gets page fault again for the same write. + */ + if (count < nthreads * access_per_thread) { + ksft_test_result_fail("Lost update, iter %d, %d vs %d.\n", i, count, + nthreads * access_per_thread); + return; + } + + extra_pages += count - nthreads * access_per_thread; + } + } + + pthread_barrier_wait(&start_barrier); + finish = 1; + pthread_barrier_wait(&end_barrier); + + ksft_test_result_pass("%s Extra pages %u (%.1lf%%), extra thread faults %d.\n", __func__, + extra_pages, + 100.0 * extra_pages / (iter_count * nthreads * access_per_thread), + extra_thread_faults); +} + +int main(void) +{ + int mem_size, shmid, buf_size, fd, i, ret; + char *mem, *map, *fmem; + struct stat sbuf; + + ksft_print_header(); + ksft_set_plan(90); + + page_size = getpagesize(); + hpage_size = read_pmd_pagesize(); + + pagemap_fd = open(PAGEMAP, O_RDWR); + if (pagemap_fd < 0) + return -EINVAL; + + if (init_uffd()) + ksft_exit_fail_msg("uffd init failed\n"); + + /* + * Written (dirty) PTE bit tests + */ + + /* 1. Sanity testing */ + sanity_tests_sd(); + + /* 2. Normal page testing */ + mem_size = 10 * page_size; + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + base_tests("Page testing:", mem, mem_size, 0); + + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 3. Large page testing */ + mem_size = 512 * 10 * page_size; + mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem == MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + base_tests("Large Page testing:", mem, mem_size, 0); + + wp_free(mem, mem_size); + munmap(mem, mem_size); + + /* 4. Huge page testing */ + map = gethugepage(hpage_size); + if (map) { + wp_init(map, hpage_size); + wp_addr_range(map, hpage_size); + base_tests("Huge page testing:", map, hpage_size, 0); + wp_free(map, hpage_size); + free(map); + } else { + base_tests("Huge page testing:", NULL, 0, 1); + } + + /* 5. Hugetlb page testing */ + mem_size = 2*1024*1024; + mem = gethugetlb_mem(mem_size, &shmid); + if (mem) { + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + base_tests("Hugetlb shmem testing:", mem, mem_size, 0); + + wp_free(mem, mem_size); + shmctl(shmid, IPC_RMID, NULL); + } else { + base_tests("Hugetlb shmem testing:", NULL, 0, 1); + } + + /* 6. Hugetlb page testing */ + mem = gethugetlb_mem(mem_size, NULL); + if (mem) { + wp_init(mem, mem_size); + wp_addr_range(mem, mem_size); + + base_tests("Hugetlb mem testing:", mem, mem_size, 0); + + wp_free(mem, mem_size); + } else { + base_tests("Hugetlb mem testing:", NULL, 0, 1); + } + + /* 7. file memory testing */ + buf_size = page_size * 10; + + fd = open(__FILE__".tmp0", O_RDWR | O_CREAT, 0777); + if (fd < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file: %s\n", + strerror(errno)); + + for (i = 0; i < buf_size; i++) + if (write(fd, "c", 1) < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file\n"); + + ret = stat(__FILE__".tmp0", &sbuf); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + fmem = mmap(NULL, sbuf.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + if (fmem == MAP_FAILED) + ksft_exit_fail_msg("error nomem %ld %s\n", errno, strerror(errno)); + + wp_init(fmem, sbuf.st_size); + wp_addr_range(fmem, sbuf.st_size); + + base_tests("File memory testing:", fmem, sbuf.st_size, 0); + + wp_free(fmem, sbuf.st_size); + munmap(fmem, sbuf.st_size); + close(fd); + + /* 8. file memory testing */ + buf_size = page_size * 10; + + fd = memfd_create(__FILE__".tmp00", MFD_NOEXEC_SEAL); + if (fd < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file: %s\n", + strerror(errno)); + + if (ftruncate(fd, buf_size)) + ksft_exit_fail_msg("Error ftruncate\n"); + + for (i = 0; i < buf_size; i++) + if (write(fd, "c", 1) < 0) + ksft_exit_fail_msg("Create and read/write to a memory mapped file\n"); + + fmem = mmap(NULL, buf_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + if (fmem == MAP_FAILED) + ksft_exit_fail_msg("error nomem %ld %s\n", errno, strerror(errno)); + + wp_init(fmem, buf_size); + wp_addr_range(fmem, buf_size); + + base_tests("File anonymous memory testing:", fmem, buf_size, 0); + + wp_free(fmem, buf_size); + munmap(fmem, buf_size); + close(fd); + + /* 9. Huge page tests */ + hpage_unit_tests(); + + /* 10. Iterative test */ + test_simple(); + + /* 11. Mprotect test */ + mprotect_tests(); + + /* 12. Transact test */ + transact_test(page_size); + + /* + * Other PTE bit tests + */ + + /* 1. Sanity testing */ + sanity_tests(); + + /* 2. Unmapped address test */ + unmapped_region_tests(); + + /* 3. Userfaultfd tests */ + userfaultfd_tests(); + + close(pagemap_fd); + return ksft_exit_pass(); +} diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh old mode 100644 new mode 100755 index eb25f238f5b8..fa77c8af2b0c --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -53,6 +53,8 @@ separated by spaces: memory protection key tests - soft_dirty test soft dirty page bit semantics +- pagemap + test pagemap_scan IOCTL - cow test copy-on-write semantics example: ./run_vmtests.sh -t "hmm mmap ksm" @@ -282,6 +284,8 @@ fi CATEGORY="soft_dirty" run_test ./soft-dirty +CATEGORY="pagemap" run_test ./pagemap_ioctl + # COW tests CATEGORY="cow" run_test ./cow