From: Paolo Bonzini <pbonzini@redhat.com>
To: "Florian Weimer" <fw@deneb.enyo.de>,
"Adalbert Lazăr" <alazar@bitdefender.com>
Cc: linux-mm@kvack.org, linux-api@vger.kernel.org,
"Andrew Morton" <akpm@linux-foundation.org>,
"Alexander Graf" <graf@amazon.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Jerome Glisse" <jglisse@redhat.com>,
"Mihai Donțu" <mdontu@bitdefender.com>,
"Mircea Cirjaliu" <mcirjaliu@bitdefender.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Sargun Dhillon" <sargun@sargun.me>,
"Aleksa Sarai" <cyphar@cyphar.com>,
"Oleg Nesterov" <oleg@redhat.com>, "Jann Horn" <jannh@google.com>,
"Kees Cook" <keescook@chromium.org>,
"Matthew Wilcox" <willy@infradead.org>,
"Christian Brauner" <christian.brauner@ubuntu.com>
Subject: Re: [RESEND RFC PATCH 0/5] Remote mapping
Date: Fri, 4 Sep 2020 22:18:17 +0200 [thread overview]
Message-ID: <5447a405-4e4f-8034-eb86-ec2f6ddf45f0@redhat.com> (raw)
In-Reply-To: <87pn71gxi8.fsf@mid.deneb.enyo.de>
On 04/09/20 21:19, Florian Weimer wrote:
> I'm not sure what the advantage is of returning separate file
> descriptors, and nit operating directly on the pidfd.
For privilege separation. So far, the common case of pidfd operations
has been that whoever possesses a pidfd has "power" over the target
process. Here however we also want to cover the case where one
privileged process wants to set up and manage a memory range for
multiple children. The privilege process can do so by passing the
access file descriptor via SCM_RIGHTS.
We also want different children to have visibility over different
ranges, which is why there are multiple control fds rather than using
the pidfd itself as control fd. You could have the map/unmap/lock ioctl
on the pidfd itself and the access fd as an argument of the ioctl, but
it seems cleaner to represent the pidfd-mem control capability as its
own file descriptor.
Paolo
next prev parent reply other threads:[~2020-09-04 20:18 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 11:31 [RESEND RFC PATCH 0/5] Remote mapping Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 1/5] mm: add atomic capability to zap_details Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 2/5] mm: let the VMA decide how zap_pte_range() acts on mapped pages Adalbert Lazăr
2020-09-04 11:31 ` [RESEND RFC PATCH 3/5] mm/mmu_notifier: remove lockdep map, allow mmu notifier to be used in nested scenarios Adalbert Lazăr
2020-09-04 12:03 ` Jason Gunthorpe
2020-09-04 11:31 ` [RESEND RFC PATCH 4/5] mm/remote_mapping: use a pidfd to access memory belonging to unrelated process Adalbert Lazăr
2020-09-04 17:55 ` Oleg Nesterov
2020-09-07 14:30 ` Oleg Nesterov
2020-09-07 15:16 ` Adalbert Lazăr
2020-09-09 8:32 ` Mircea CIRJALIU - MELIU
2020-09-10 16:43 ` Oleg Nesterov
2020-09-07 15:02 ` Christian Brauner
2020-09-07 16:04 ` Mircea CIRJALIU - MELIU
2020-09-04 11:31 ` [RESEND RFC PATCH 5/5] pidfd_mem: implemented remote memory mapping system call Adalbert Lazăr
2020-09-04 19:18 ` Florian Weimer
2020-09-07 14:55 ` Christian Brauner
2020-09-04 12:11 ` [RESEND RFC PATCH 0/5] Remote mapping Jason Gunthorpe
2020-09-04 13:24 ` Mircea CIRJALIU - MELIU
2020-09-04 13:39 ` Jason Gunthorpe
2020-09-04 14:18 ` Mircea CIRJALIU - MELIU
2020-09-04 14:39 ` Jason Gunthorpe
2020-09-04 15:40 ` Mircea CIRJALIU - MELIU
2020-09-04 16:11 ` Jason Gunthorpe
2020-09-04 19:41 ` Matthew Wilcox
2020-09-04 19:49 ` Jason Gunthorpe
2020-09-04 20:08 ` Paolo Bonzini
2020-12-01 18:01 ` Jason Gunthorpe
2020-09-04 19:19 ` Florian Weimer
2020-09-04 20:18 ` Paolo Bonzini [this message]
2020-09-07 8:33 ` Christian Brauner
2020-09-04 19:39 ` Andy Lutomirski
2020-09-04 20:09 ` Paolo Bonzini
2020-09-04 20:34 ` Andy Lutomirski
2020-09-04 21:58 ` Paolo Bonzini
2020-09-04 23:17 ` Andy Lutomirski
2020-09-05 18:27 ` Paolo Bonzini
2020-09-07 8:38 ` Christian Brauner
2020-09-07 12:41 ` Mircea CIRJALIU - MELIU
2020-09-07 7:05 ` Christoph Hellwig
2020-09-07 8:44 ` Paolo Bonzini
2020-09-07 10:25 ` Mircea CIRJALIU - MELIU
2020-09-07 15:05 ` Christian Brauner
2020-09-07 20:43 ` Andy Lutomirski
2020-09-09 11:38 ` Stefan Hajnoczi
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