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From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: 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
Cc: 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, christian.brauner@ubuntu.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: Tue, 28 Jul 2020 14:34:37 +0300	[thread overview]
Message-ID: <46891e3b-ca08-197d-935f-fa0a52a60051@virtuozzo.com> (raw)
In-Reply-To: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com>

On 27.07.2020 20:11, 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,

So, the goal is an update of QEMU binary without a stopping of virtual machine?

> 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.
> 
> Patches 1 and 2 ensure that loading of ELF load segments does not silently
> clobber existing VMAS, and remove assumptions that the stack is the only
> VMA in the mm when the stack is set up.  Patch 1 re-introduces the use of
> MAP_FIXED_NOREPLACE to load ELF binaries that addresses the previous issues
> and could be considered on its own.
> 
> Patches 3, 4, and 5 introduce the feature and an opt-in method for its use
> using an ELF note.
> 
> Anthony Yznaga (5):
>   elf: reintroduce using MAP_FIXED_NOREPLACE for elf executable mappings
>   mm: do not assume only the stack vma exists in setup_arg_pages()
>   mm: introduce VM_EXEC_KEEP
>   exec, elf: require opt-in for accepting preserved mem
>   mm: introduce MADV_DOEXEC
> 
>  arch/x86/Kconfig                       |   1 +
>  fs/binfmt_elf.c                        | 196 +++++++++++++++++++++++++--------
>  fs/exec.c                              |  33 +++++-
>  include/linux/binfmts.h                |   7 +-
>  include/linux/mm.h                     |   5 +
>  include/uapi/asm-generic/mman-common.h |   3 +
>  kernel/fork.c                          |   2 +-
>  mm/madvise.c                           |  25 +++++
>  mm/mmap.c                              |  47 ++++++++
>  9 files changed, 266 insertions(+), 53 deletions(-)
> 


  parent reply	other threads:[~2020-07-28 12:26 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 17:11 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 ` Kirill Tkhai [this message]
2020-07-28 17:28   ` [RFC PATCH 0/5] madvise MADV_DOEXEC 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
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
2020-08-03  8:32                             ` David Laight
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
2020-08-04  8:44                     ` David Laight
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

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