From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>,
James Bottomley <jejb@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Christopher Lameter <cl@linux.com>,
Dan Williams <dan.j.williams@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Elena Reshetova <elena.reshetova@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Matthew Wilcox <willy@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Peter Zijlstra <peterz@infradead.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Roman Gushchin <guro@fb.com>, Shakeel Butt <shakeelb@google.com>,
Shuah Khan <shuah@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Tycho Andersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>,
linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org,
x86@kernel.org, Hagen Paul Pfeifer <hagen@jauu.net>,
Palmer Dabbelt <palmerdabbelt@google.com>
Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize direct map fragmentation
Date: Tue, 2 Feb 2021 15:34:29 +0100 [thread overview]
Message-ID: <95625b83-f7e2-b27a-2b99-d231338047fb@redhat.com> (raw)
In-Reply-To: <YBlicIupOyPF9f3D@dhcp22.suse.cz>
On 02.02.21 15:32, Michal Hocko wrote:
> On Tue 02-02-21 15:26:20, David Hildenbrand wrote:
>> On 02.02.21 15:22, Michal Hocko wrote:
>>> On Tue 02-02-21 15:12:21, David Hildenbrand wrote:
>>> [...]
>>>> I think secretmem behaves much more like longterm GUP right now
>>>> ("unmigratable", "lifetime controlled by user space", "cannot go on
>>>> CMA/ZONE_MOVABLE"). I'd either want to reasonably well control/limit it or
>>>> make it behave more like mlocked pages.
>>>
>>> I thought I have already asked but I must have forgotten. Is there any
>>> actual reason why the memory is not movable? Timing attacks?
>>
>> I think the reason is simple: no direct map, no copying of memory.
>
> This is an implementation detail though and not something terribly hard
> to add on top later on. I was more worried there would be really
> fundamental reason why this is not possible. E.g. security implications.
I don't remember all the details. Let's see what Mike thinks regarding
migration (e.g., security concerns).
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-02-02 14:34 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 12:27 [PATCH v16 00/11] mm: introduce memfd_secret system call to create "secret" memory areas Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 01/11] mm: add definition of PMD_PAGE_ORDER Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 02/11] mmap: make mlock_future_check() global Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 03/11] riscv/Kconfig: make direct map manipulation options depend on MMU Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 04/11] set_memory: allow set_direct_map_*_noflush() for multiple pages Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 05/11] set_memory: allow querying whether set_direct_map_*() is actually enabled Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 06/11] mm: introduce memfd_secret system call to create "secret" memory areas Mike Rapoport
2021-01-25 17:01 ` Michal Hocko
2021-01-25 21:36 ` Mike Rapoport
2021-01-26 7:16 ` Michal Hocko
2021-01-26 8:33 ` Mike Rapoport
2021-01-26 9:00 ` Michal Hocko
2021-01-26 9:20 ` Mike Rapoport
2021-01-26 9:49 ` Michal Hocko
2021-01-26 9:53 ` David Hildenbrand
2021-01-26 10:19 ` Michal Hocko
2021-01-26 9:20 ` Michal Hocko
2021-02-03 12:15 ` Michal Hocko
2021-02-04 11:34 ` Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 07/11] secretmem: use PMD-size pages to amortize direct map fragmentation Mike Rapoport
2021-01-26 11:46 ` Michal Hocko
2021-01-26 11:56 ` David Hildenbrand
2021-01-26 12:08 ` Michal Hocko
2021-01-28 9:22 ` Mike Rapoport
2021-01-28 13:01 ` Michal Hocko
2021-01-28 13:28 ` Christoph Lameter
2021-01-28 13:49 ` Michal Hocko
2021-01-28 15:56 ` Christoph Lameter
2021-01-28 16:23 ` Michal Hocko
2021-01-28 15:28 ` James Bottomley
2021-01-29 7:03 ` Mike Rapoport
2021-01-28 21:05 ` James Bottomley
2021-01-29 7:53 ` Michal Hocko
2021-01-29 8:23 ` Michal Hocko
2021-02-01 16:56 ` James Bottomley
2021-02-02 9:35 ` Michal Hocko
2021-02-02 12:48 ` Mike Rapoport
2021-02-02 13:14 ` David Hildenbrand
2021-02-02 13:32 ` Michal Hocko
2021-02-02 14:12 ` David Hildenbrand
2021-02-02 14:22 ` Michal Hocko
2021-02-02 14:26 ` David Hildenbrand
2021-02-02 14:32 ` Michal Hocko
2021-02-02 14:34 ` David Hildenbrand [this message]
2021-02-02 18:15 ` Mike Rapoport
2021-02-02 18:55 ` James Bottomley
2021-02-03 12:09 ` Michal Hocko
2021-02-04 11:31 ` Mike Rapoport
2021-02-02 13:27 ` Michal Hocko
2021-02-02 19:10 ` Mike Rapoport
2021-02-03 9:12 ` Michal Hocko
2021-02-04 9:58 ` Mike Rapoport
2021-02-04 13:02 ` Michal Hocko
2021-01-29 7:21 ` Mike Rapoport
2021-01-29 8:51 ` Michal Hocko
2021-02-02 14:42 ` David Hildenbrand
2021-01-21 12:27 ` [PATCH v16 08/11] secretmem: add memcg accounting Mike Rapoport
2021-01-25 16:17 ` Matthew Wilcox
2021-01-25 17:18 ` Shakeel Butt
2021-01-25 21:35 ` Mike Rapoport
2021-01-28 15:07 ` Shakeel Butt
2021-01-25 16:54 ` Michal Hocko
2021-01-25 21:38 ` Mike Rapoport
2021-01-26 7:31 ` Michal Hocko
2021-01-26 8:56 ` Mike Rapoport
2021-01-26 9:15 ` Michal Hocko
2021-01-26 14:48 ` Matthew Wilcox
2021-01-26 15:05 ` Michal Hocko
2021-01-27 18:42 ` Roman Gushchin
2021-01-28 7:58 ` Michal Hocko
2021-01-28 14:05 ` Shakeel Butt
2021-01-28 14:22 ` Michal Hocko
2021-01-28 14:57 ` Shakeel Butt
2021-01-21 12:27 ` [PATCH v16 09/11] PM: hibernate: disable when there are active secretmem users Mike Rapoport
2021-01-21 12:27 ` [PATCH v16 10/11] arch, mm: wire up memfd_secret system call where relevant Mike Rapoport
2021-01-25 18:18 ` Catalin Marinas
2021-01-21 12:27 ` [PATCH v16 11/11] secretmem: test: add basic selftest for memfd_secret(2) Mike Rapoport
2021-01-21 22:18 ` [PATCH v16 00/11] mm: introduce memfd_secret system call to create "secret" memory areas Andrew Morton
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