linux-kernel - Re: [RFC PATCH v3] sparc64: Add support for Application Data Integrity (ADI)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7532a1d6-6562-b10b-dacd-931cb2a9e536@linux.intel.com>
Date:   Wed, 4 Jan 2017 16:14:53 -0800
From:   Dave Hansen <dave.hansen@...ux.intel.com>
To:     Rob Gardner <rob.gardner@...cle.com>,
        Khalid Aziz <khalid.aziz@...cle.com>, davem@...emloft.net,
        corbet@....net, arnd@...db.de, akpm@...ux-foundation.org
Cc:     hpa@...or.com, viro@...iv.linux.org.uk, nitin.m.gupta@...cle.com,
        chris.hyser@...cle.com, tushar.n.dave@...cle.com,
        sowmini.varadhan@...cle.com, mike.kravetz@...cle.com,
        adam.buchbinder@...il.com, minchan@...nel.org, hughd@...gle.com,
        kirill.shutemov@...ux.intel.com, keescook@...omium.org,
        allen.pais@...cle.com, aryabinin@...tuozzo.com,
        atish.patra@...cle.com, joe@...ches.com, pmladek@...e.com,
        jslaby@...e.cz, cmetcalf@...lanox.com,
        paul.gortmaker@...driver.com, mhocko@...e.com, jmarchan@...hat.com,
        lstoakes@...il.com, 0x7f454c46@...il.com, vbabka@...e.cz,
        tglx@...utronix.de, mingo@...hat.com, dan.j.williams@...el.com,
        iamjoonsoo.kim@....com, mgorman@...hsingularity.net,
        vdavydov.dev@...il.com, hannes@...xchg.org, namit@...are.com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        sparclinux@...r.kernel.org, linux-arch@...r.kernel.org,
        x86@...nel.org, linux-mm@...ck.org,
        Khalid Aziz <khalid@...ehiking.org>
Subject: Re: [RFC PATCH v3] sparc64: Add support for Application Data
 Integrity (ADI)

On 01/04/2017 04:05 PM, Rob Gardner wrote:
>> What if two different small pages have different tags and khugepaged
>> comes along and tries to collapse them?  Will the page be split if a
>> user attempts to set two different tags inside two different small-page
>> portions of a single THP?
> 
> The MCD tags operate at a resolution of cache lines (64 bytes). Page
> sizes don't matter except that each virtual page must have a bit set in
> its TTE to allow MCD to be enabled on the page. Any page can have many
> different tags, one for each cache line.

Is an "MCD tag" the same thing as a "ADI version tag"?

The thing that confused me here is that we're taking an entire page of
"ADI version tags" and stuffing them into a swap pte (in
set_swp_pte_at()).  Do we somehow have enough space in a swap pte on
sparc to fit PAGE_SIZE/64 "ADI version tag"s in there?