From: Peter Xu <peterx@redhat.com>
To: Nadav Amit <namit@vmware.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Dmitry V . Levin" <ldv@altlinux.org>,
Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>,
Hugh Dickins <hughd@google.com>, Jan Kara <jack@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
Mel Gorman <mgorman@techsingularity.net>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@kernel.org>, Shuah Khan <shuah@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>, zhangyi <yi.zhang@huawei.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH v4 2/5] userfaultfd: add /dev/userfaultfd for fine grained access control
Date: Tue, 19 Jul 2022 22:32:32 -0400 [thread overview]
Message-ID: <YtdpQBrAGJwMnssj@xz-m1.local> (raw)
In-Reply-To: <D8D7C973-1480-4166-86AF-AD179873B2A4@vmware.com>
On Tue, Jul 19, 2022 at 11:55:21PM +0000, Nadav Amit wrote:
> Anyhow, I do want to clarify a bit about the “cross-process support”
> userfaultfd situation. Basically, you can already get cross-process support
> today, by using calling userfaultfd() on the controlled process and calling
> pidfd_open() from another process. It does work and I do not remember any
> issues that it introduced (in contrast, for instance, to io-uring, that
> would break if you use userfaultfd+iouring+fork today).
Do you mean to base it on pidof_getfd()?
Just want to mention that this will still need collaboration of the target
process as userfaultfd needs to be created explicitly there. From that POV
it's still more similar to general SCM_RIGHTS trick to pass over the fd but
just to pass it in a different way.
IMHO the core change about having /proc/pid/userfaultfd is skipping that
only last step to create the handle.
--
Peter Xu
next prev parent reply other threads:[~2022-07-20 2:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 19:56 [PATCH v4 0/5] " Axel Rasmussen
2022-07-19 19:56 ` [PATCH v4 1/5] selftests: vm: add hugetlb_shared userfaultfd test to run_vmtests.sh Axel Rasmussen
2022-07-19 19:56 ` [PATCH v4 2/5] userfaultfd: add /dev/userfaultfd for fine grained access control Axel Rasmussen
2022-07-19 21:18 ` Peter Xu
2022-07-19 22:32 ` Nadav Amit
2022-07-19 22:45 ` Axel Rasmussen
2022-07-19 23:55 ` Nadav Amit
2022-07-20 2:32 ` Peter Xu [this message]
2022-07-20 17:42 ` Nadav Amit
2022-07-20 20:10 ` Axel Rasmussen
2022-07-20 20:14 ` Nadav Amit
2022-08-02 18:46 ` Nadav Amit
2022-07-19 19:56 ` [PATCH v4 3/5] userfaultfd: selftests: modify selftest to use /dev/userfaultfd Axel Rasmussen
2022-07-19 21:23 ` Peter Xu
2022-07-19 19:56 ` [PATCH v4 4/5] userfaultfd: update documentation to describe /dev/userfaultfd Axel Rasmussen
2022-07-19 21:23 ` Peter Xu
2022-07-19 19:56 ` [PATCH v4 5/5] selftests: vm: add /dev/userfaultfd test cases to run_vmtests.sh Axel Rasmussen
2022-07-19 20:56 ` Nadav Amit
2022-07-20 22:16 ` [PATCH v4 0/5] userfaultfd: add /dev/userfaultfd for fine grained access control Schaufler, Casey
2022-07-20 23:04 ` Axel Rasmussen
2022-07-20 23:21 ` Nadav Amit
2022-08-01 17:13 ` Axel Rasmussen
2022-08-01 19:53 ` Nadav Amit
2022-08-01 22:50 ` Axel Rasmussen
2022-08-01 23:19 ` Nadav Amit
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YtdpQBrAGJwMnssj@xz-m1.local \
--to=peterx@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=axelrasmussen@google.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=glebfm@altlinux.org \
--cc=hughd@google.com \
--cc=jack@suse.cz \
--cc=ldv@altlinux.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mike.kravetz@oracle.com \
--cc=namit@vmware.com \
--cc=rppt@kernel.org \
--cc=shuah@kernel.org \
--cc=surenb@google.com \
--cc=vbabka@suse.cz \
--cc=viro@zeniv.linux.org.uk \
--cc=yi.zhang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox