From: Dave Hansen <dave.hansen@linux.intel.com>
To: Khalid Aziz <khalid.aziz@oracle.com>,
davem@davemloft.net, corbet@lwn.net, arnd@arndb.de,
akpm@linux-foundation.org
Cc: hpa@zytor.com, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com,
chris.hyser@oracle.com, tushar.n.dave@oracle.com,
sowmini.varadhan@oracle.com, mike.kravetz@oracle.com,
adam.buchbinder@gmail.com, minchan@kernel.org, hughd@google.com,
kirill.shutemov@linux.intel.com, keescook@chromium.org,
allen.pais@oracle.com, aryabinin@virtuozzo.com,
atish.patra@oracle.com, joe@perches.com, pmladek@suse.com,
jslaby@suse.cz, cmetcalf@mellanox.com,
paul.gortmaker@windriver.com, mhocko@suse.com,
jmarchan@redhat.com, lstoakes@gmail.com, 0x7f454c46@gmail.com,
vbabka@suse.cz, tglx@linutronix.de, mingo@redhat.com,
dan.j.williams@intel.com, iamjoonsoo.kim@lge.com,
mgorman@techsingularity.net, vdavydov.dev@gmail.com,
hannes@cmpxchg.org, namit@vmware.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
linux-arch@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v4 0/4] Application Data Integrity feature introduced by SPARC M7
Date: Wed, 11 Jan 2017 08:33:30 -0800 [thread overview]
Message-ID: <621cfed0-3e56-13e6-689a-0637bce164fe@linux.intel.com> (raw)
In-Reply-To: <cover.1483999591.git.khalid.aziz@oracle.com>
On 01/11/2017 08:12 AM, Khalid Aziz wrote:
> A userspace task enables ADI through mprotect(). This patch series adds
> a page protection bit PROT_ADI and a corresponding VMA flag
> VM_SPARC_ADI. VM_SPARC_ADI is used to trigger setting TTE.mcd bit in the
> sparc pte that enables ADI checking on the corresponding page.
Is there a cost in the hardware associated with doing this "ADI
checking"? For instance, instead of having this new mprotect()
interface, why not just always set TTE.mcd on all PTEs?
Also, should this be a privileged interface in some way? The hardware
is storing these tags *somewhere* and that storage is consuming
resources *somewhere*. What stops a crafty attacker from mmap()'ing a
128TB chunk of the zero pages and storing ADI tags for all of it?
That'll be 128TB/64*4bits = 1TB worth of 4-bit tags. Page tables, for
instance, consume a comparable amount of storage, but the OS *knows*
about those and can factor them into OOM decisions.
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next prev parent reply other threads:[~2017-01-11 16:33 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-11 16:12 Khalid Aziz
2017-01-11 16:12 ` [PATCH v4 2/4] mm: Add function to support extra actions on swap in/out Khalid Aziz
2017-01-11 16:56 ` Dave Hansen
2017-01-11 17:15 ` Khalid Aziz
2017-01-11 16:12 ` [PATCH v4 4/4] sparc64: Add support for ADI (Application Data Integrity) Khalid Aziz
2017-01-17 4:39 ` David Miller
2017-01-17 19:32 ` Khalid Aziz
2017-01-17 19:42 ` David Miller
2017-01-17 20:12 ` Khalid Aziz
2017-01-18 0:14 ` Khalid Aziz
2017-01-11 16:33 ` Dave Hansen [this message]
2017-01-11 16:56 ` [PATCH v4 0/4] Application Data Integrity feature introduced by SPARC M7 Khalid Aziz
2017-01-11 18:13 ` Dave Hansen
2017-01-11 18:50 ` Khalid Aziz
2017-01-11 19:11 ` Dave Hansen
2017-01-12 0:22 ` Khalid Aziz
2017-01-12 0:49 ` Dave Hansen
2017-01-12 16:50 ` Khalid Aziz
2017-01-12 17:53 ` Dave Hansen
2017-01-13 0:22 ` Khalid Aziz
2017-01-13 1:31 ` Rob Gardner
2017-01-13 14:48 ` Khalid Aziz
2017-01-13 15:29 ` Rob Gardner
2017-01-13 15:59 ` Khalid Aziz
2017-01-13 16:08 ` Dave Hansen
2017-01-13 17:36 ` Rob Gardner
2017-01-17 4:47 ` David Miller
2017-01-17 21:43 ` Khalid Aziz
2017-01-17 4:42 ` David Miller
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