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From: Peter Xu <peterx@redhat.com>
To: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: "David Hildenbrand" <david@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michał Mirosław" <emmir@google.com>,
	"Andrei Vagin" <avagin@gmail.com>,
	"Danylo Mocherniuk" <mdanylo@google.com>,
	"Paul Gofman" <pgofman@codeweavers.com>,
	"Cyrill Gorcunov" <gorcunov@gmail.com>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Shuah Khan" <shuah@kernel.org>,
	"Christian Brauner" <brauner@kernel.org>,
	"Yang Shi" <shy828301@gmail.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	"Yun Zhou" <yun.zhou@windriver.com>,
	"Suren Baghdasaryan" <surenb@google.com>,
	"Alex Sierra" <alex.sierra@amd.com>,
	"Matthew Wilcox" <willy@infradead.org>,
	"Pasha Tatashin" <pasha.tatashin@soleen.com>,
	"Mike Rapoport" <rppt@kernel.org>,
	"Nadav Amit" <namit@vmware.com>,
	"Axel Rasmussen" <axelrasmussen@google.com>,
	"Gustavo A . R . Silva" <gustavoars@kernel.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	"Greg KH" <gregkh@linuxfoundation.org>,
	kernel@collabora.com
Subject: Re: [PATCH v7 1/4] userfaultfd: Add UFFD WP Async support
Date: Tue, 24 Jan 2023 12:26:08 -0500	[thread overview]
Message-ID: <Y9AUsCxgitOI2lUA@x1n> (raw)
In-Reply-To: <328f54c1-171f-22a1-10c9-8b7a25bd8027@collabora.com>

On Mon, Jan 23, 2023 at 03:11:20PM +0500, Muhammad Usama Anjum wrote:
> > One thing worth mention is, I think for async wp it doesn't need to be
> > restricted by UFFD_USER_MODE_ONLY, because comparing to the sync messages
> > it has no risk of being utilized for malicious purposes.
> I think with updated handling path updated in do_wp_page() and
> wp_huge_pmd() in version, UFFD_USER_MODE_ONLY will not affect us.

This is more or less a comment for the design, the new code should work (by
bypassing handle_userfaultfd(), where this bit was checked).

We'll need an man page update if this feature will be merged [1], and if so
it'll need to be updated for the UFFD_USER_MODE_ONLY section regarding to
async uffd-wp support too.  I think that can also be worked out after the
series being accepted first, so just a heads up.

[1] https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git

-- 
Peter Xu



  reply	other threads:[~2023-01-24 17:26 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-09  6:45 [PATCH v7 0/4] Implement IOCTL to get and/or the clear info about PTEs Muhammad Usama Anjum
2023-01-09  6:45 ` [PATCH v7 1/4] userfaultfd: Add UFFD WP Async support Muhammad Usama Anjum
2023-01-18 16:54   ` Peter Xu
2023-01-19 15:09     ` Muhammad Usama Anjum
2023-01-19 16:35       ` Peter Xu
2023-01-20 14:53         ` Peter Xu
2023-01-23 10:11           ` Muhammad Usama Anjum
2023-01-24 17:26             ` Peter Xu [this message]
2023-01-25 12:18               ` Muhammad Usama Anjum
2023-01-09  6:45 ` [PATCH v7 2/4] userfaultfd: split mwriteprotect_range() Muhammad Usama Anjum
2023-01-09  6:45 ` [PATCH v7 3/4] fs/proc/task_mmu: Implement IOCTL to get and/or the clear info about PTEs Muhammad Usama Anjum
2023-01-18 22:28   ` Peter Xu
2023-01-23 12:18     ` Muhammad Usama Anjum
2023-01-24 17:30       ` Peter Xu
2023-01-26 14:32         ` Muhammad Usama Anjum
2023-01-09  6:45 ` [PATCH v7 4/4] selftests: vm: add pagemap ioctl tests Muhammad Usama Anjum
2023-01-18  6:55 ` [PATCH v7 0/4] Implement IOCTL to get and/or the clear info about PTEs Muhammad Usama Anjum
2023-01-18 22:12 ` Peter Xu
2023-01-23 13:15   ` Muhammad Usama Anjum
2023-01-24 19:49     ` Peter Xu
2023-01-25 14:45       ` Danylo Mocherniuk

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