linux-kernel - Re: [PATCH v5 3/9] mm: Add write-protect and clean utilities for address space ranges

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: <a004e1a5-bdc5-6508-039e-8d97a9d3cb68@vmwopensource.org>
Date:   Wed, 12 Jun 2019 14:20:03 +0200
From:   Thomas Hellström (VMware) 
        <thellstrom@...opensource.org>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-graphics-maintainer@...are.com, pv-drivers@...are.com,
        linux-kernel@...r.kernel.org, nadav.amit@...il.com,
        Thomas Hellstrom <thellstrom@...are.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Matthew Wilcox <willy@...radead.org>,
        Will Deacon <will.deacon@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Rik van Riel <riel@...riel.com>,
        Minchan Kim <minchan@...nel.org>,
        Michal Hocko <mhocko@...e.com>,
        Huang Ying <ying.huang@...el.com>,
        Souptick Joarder <jrdr.linux@...il.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        linux-mm@...ck.org, Ralph Campbell <rcampbell@...dia.com>
Subject: Re: [PATCH v5 3/9] mm: Add write-protect and clean utilities for
 address space ranges

On 6/12/19 1:23 PM, Christoph Hellwig wrote:
> On Wed, Jun 12, 2019 at 08:42:37AM +0200, Thomas Hellström (VMware) wrote:
>> From: Thomas Hellstrom <thellstrom@...are.com>
>>
>> Add two utilities to a) write-protect and b) clean all ptes pointing into
>> a range of an address space.
>> The utilities are intended to aid in tracking dirty pages (either
>> driver-allocated system memory or pci device memory).
>> The write-protect utility should be used in conjunction with
>> page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page
>> accesses. Typically one would want to use this on sparse accesses into
>> large memory regions. The clean utility should be used to utilize
>> hardware dirtying functionality and avoid the overhead of page-faults,
>> typically on large accesses into small memory regions.
> Please use EXPORT_SYMBOL_GPL, just like for apply_to_page_range and
> friends.

Sounds reasonable if this uses already EXPORT_SYMBOL_GPL'd 
functionality. I'll respin.

>    Also in general new core functionality like this should go
> along with the actual user, we don't need to repeat the hmm disaster.

I see in your later message that you noticed the other patches. There's 
also user-space functionality in mesa that excercises this.

/Thomas