From: Christian Brauner <christian.brauner@ubuntu.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, x86@kernel.org, hpa@zytor.com,
viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org,
gerg@linux-m68k.org, ktkhai@virtuozzo.com, peterz@infradead.org,
esyr@redhat.com, jgg@ziepe.ca, christian@kellner.me,
areber@redhat.com, cyphar@cyphar.com, steven.sistare@oracle.com
Subject: Re: [RFC PATCH 0/5] madvise MADV_DOEXEC
Date: Thu, 30 Jul 2020 17:27:05 +0200 [thread overview]
Message-ID: <20200730152705.ol42jppnl4xfhl32@wittgenstein> (raw)
In-Reply-To: <20200730152250.GG23808@casper.infradead.org>
On Thu, Jul 30, 2020 at 04:22:50PM +0100, Matthew Wilcox wrote:
> On Mon, Jul 27, 2020 at 10:11:22AM -0700, Anthony Yznaga wrote:
> > This patchset adds support for preserving an anonymous memory range across
> > exec(3) using a new madvise MADV_DOEXEC argument. The primary benefit for
> > sharing memory in this manner, as opposed to re-attaching to a named shared
> > memory segment, is to ensure it is mapped at the same virtual address in
> > the new process as it was in the old one. An intended use for this is to
> > preserve guest memory for guests using vfio while qemu exec's an updated
> > version of itself. By ensuring the memory is preserved at a fixed address,
> > vfio mappings and their associated kernel data structures can remain valid.
> > In addition, for the qemu use case, qemu instances that back guest RAM with
> > anonymous memory can be updated.
>
> I just realised that something else I'm working on might be a suitable
> alternative to this. Apologies for not realising it sooner.
>
> http://www.wil.cx/~willy/linux/sileby.html
Just skimming: make it O_CLOEXEC by default. ;)
>
> To use this, you'd mshare() the anonymous memory range, essentially
> detaching the VMA from the current process's mm_struct and reparenting
> it to this new mm_struct, which has an fd referencing it.
>
> Then you call exec(), and the exec'ed task gets to call mmap() on that
> new fd to attach the memory range to its own address space.
>
> Presto!
next prev parent reply other threads:[~2020-07-30 15:27 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 17:11 [RFC PATCH 0/5] madvise MADV_DOEXEC Anthony Yznaga
2020-07-27 17:07 ` Eric W. Biederman
2020-07-27 18:00 ` Steven Sistare
2020-07-28 13:40 ` Christian Brauner
2020-07-27 17:11 ` [RFC PATCH 1/5] elf: reintroduce using MAP_FIXED_NOREPLACE for elf executable mappings Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 2/5] mm: do not assume only the stack vma exists in setup_arg_pages() Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 3/5] mm: introduce VM_EXEC_KEEP Anthony Yznaga
2020-07-28 13:38 ` Eric W. Biederman
2020-07-28 17:44 ` Anthony Yznaga
2020-07-29 13:52 ` Kirill A. Shutemov
2020-07-29 23:20 ` Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 4/5] exec, elf: require opt-in for accepting preserved mem Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 5/5] mm: introduce MADV_DOEXEC Anthony Yznaga
2020-07-28 13:22 ` Kirill Tkhai
2020-07-28 14:06 ` Steven Sistare
2020-07-28 11:34 ` [RFC PATCH 0/5] madvise MADV_DOEXEC Kirill Tkhai
2020-07-28 17:28 ` Anthony Yznaga
2020-07-28 14:23 ` Andy Lutomirski
2020-07-28 14:30 ` Steven Sistare
2020-07-30 15:22 ` Matthew Wilcox
2020-07-30 15:27 ` Christian Brauner [this message]
2020-07-30 15:34 ` Matthew Wilcox
2020-07-30 15:54 ` Christian Brauner
2020-07-31 9:12 ` Stefan Hajnoczi
2020-07-30 15:59 ` Steven Sistare
2020-07-30 17:12 ` Matthew Wilcox
2020-07-30 17:35 ` Steven Sistare
2020-07-30 17:49 ` Matthew Wilcox
2020-07-30 18:27 ` Steven Sistare
2020-07-30 21:58 ` Eric W. Biederman
2020-07-31 14:57 ` Steven Sistare
2020-07-31 15:27 ` Matthew Wilcox
2020-07-31 16:11 ` Steven Sistare
2020-07-31 16:56 ` Jason Gunthorpe
2020-07-31 17:15 ` Steven Sistare
2020-07-31 17:48 ` Jason Gunthorpe
2020-07-31 17:55 ` Steven Sistare
2020-07-31 17:23 ` Matthew Wilcox
2020-08-03 15:28 ` Eric W. Biederman
2020-08-03 15:42 ` James Bottomley
2020-08-03 20:03 ` Steven Sistare
[not found] ` <9371b8272fd84280ae40b409b260bab3@AcuMS.aculab.com>
2020-08-04 11:13 ` Matthew Wilcox
2020-08-03 19:29 ` Steven Sistare
2020-07-31 19:41 ` Steven Sistare
2021-07-08 9:52 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-07-08 12:48 ` Steven Sistare
2021-07-12 1:05 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-07-12 1:30 ` Matthew Wilcox
2021-07-13 0:57 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-13 19:49 ` Khalid Aziz
2021-08-14 20:07 ` David Laight
2021-08-16 0:26 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-16 8:07 ` David Laight
2021-08-16 6:54 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-16 8:02 ` David Hildenbrand
2021-08-16 12:07 ` Matthew Wilcox
2021-08-16 12:20 ` David Hildenbrand
2021-08-16 12:42 ` David Hildenbrand
2021-08-16 12:46 ` Matthew Wilcox
2021-08-16 13:24 ` David Hildenbrand
2021-08-16 13:32 ` Matthew Wilcox
2021-08-16 14:10 ` David Hildenbrand
2021-08-16 14:27 ` Matthew Wilcox
2021-08-16 14:33 ` David Hildenbrand
2021-08-16 14:40 ` Matthew Wilcox
2021-08-16 15:01 ` David Hildenbrand
2021-08-16 15:59 ` Matthew Wilcox
2021-08-16 16:06 ` Khalid Aziz
2021-08-16 16:15 ` Matthew Wilcox
2021-08-16 16:13 ` David Hildenbrand
2021-08-16 12:27 ` [private] " David Hildenbrand
2021-08-16 12:30 ` David Hildenbrand
2021-08-17 0:47 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-17 0:55 ` Matthew Wilcox
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