From: Dave Hansen <dave.hansen@intel.com>
To: Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org
Cc: Alan Cox <alan@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Christopher Lameter <cl@linux.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
James Bottomley <jejb@linux.ibm.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Matthew Wilcox <willy@infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Tycho Andersen <tycho@tycho.ws>,
linux-api@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC PATCH] mm: extend memfd with ability to create "secret" memory areas
Date: Thu, 6 Feb 2020 10:51:13 -0800 [thread overview]
Message-ID: <df5a888b-1a11-e806-741d-94684b22c966@intel.com> (raw)
In-Reply-To: <20200130162340.GA14232@rapoport-lnx>
On 1/30/20 8:23 AM, Mike Rapoport wrote:
> include/linux/memfd.h | 9 ++
> include/uapi/linux/magic.h | 1 +
> include/uapi/linux/memfd.h | 6 +
> mm/Kconfig | 4 +
> mm/Makefile | 1 +
> mm/memfd.c | 10 +-
> mm/secretmem.c | 244 +++++++++++++++++++++++++++++++++++++
> 7 files changed, 273 insertions(+), 2 deletions(-)
It seems pretty self-contained and relatively harmless.
But, how much work is it going to be to tell the rest of the kernel that
page_to_virt() doesn't work any more? Do we need to make kmap() work on
these?
I guess fixing vm_normal_page() would fix a lot of that.
In general, my concern about creating little self-contained memory types
is that they will get popular and folks will start wanting more features
from them. For instance, what if I want NUMA affinity, migration, or
large page mappings that are secret?
Can these pages work as guest memory?
Who would the first users of this thing be?
next prev parent reply other threads:[~2020-02-06 18:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-30 16:23 [RFC PATCH] mm: extend memfd with ability to create "secret" memory areas Mike Rapoport
2020-02-06 18:51 ` Dave Hansen [this message]
2020-02-08 17:39 ` Mike Rapoport
2020-02-10 8:06 ` Reshetova, Elena
2020-02-11 19:52 ` Edgecombe, Rick P
2020-02-12 21:10 ` Jonathan Corbet
2020-02-16 6:46 ` Mike Rapoport
2020-08-14 17:46 ` Andy Lutomirski
2020-08-14 18:09 ` Dave Hansen
2020-08-26 16:54 ` Andy Lutomirski
2020-08-26 19:01 ` Florian Weimer
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=df5a888b-1a11-e806-741d-94684b22c966@intel.com \
--to=dave.hansen@intel.com \
--cc=akpm@linux-foundation.org \
--cc=alan@linux.intel.com \
--cc=cl@linux.com \
--cc=dave.hansen@linux.intel.com \
--cc=elena.reshetova@intel.com \
--cc=jejb@linux.ibm.com \
--cc=kirill@shutemov.name \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=peterz@infradead.org \
--cc=rppt@kernel.org \
--cc=tglx@linutronix.de \
--cc=tycho@tycho.ws \
--cc=willy@infradead.org \
/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;
as well as URLs for NNTP newsgroup(s).