linux-kernel - Re: [PATCH 2/2] drm/ttm: Fix vm page protection handling

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]

Date:   Tue, 3 Dec 2019 10:58:09 +0100
From:   Christian König <christian.koenig@....com>
To:     "Kirill A. Shutemov" <kirill@...temov.name>,
        Thomas Hellström (VMware) 
        <thomas_os@...pmail.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        dri-devel@...are.com, pv-drivers@...are.com,
        linux-graphics-maintainer@...are.com,
        Thomas Hellstrom <thellstrom@...are.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        Jérôme Glisse <jglisse@...hat.com>
Subject: Re: [PATCH 2/2] drm/ttm: Fix vm page protection handling

Am 03.12.19 um 10:55 schrieb Kirill A. Shutemov:
> On Tue, Dec 03, 2019 at 08:54:46AM +0100, Thomas Hellström (VMware) wrote:
>> From: Thomas Hellstrom <thellstrom@...are.com>
>>
>> We were using an ugly hack to set the page protection correctly.
>> Fix that and instead use vmf_insert_mixed_prot() and / or
>> vmf_insert_pfn_prot().
>> Also get the default page protection from
>> struct vm_area_struct::vm_page_prot rather than using vm_get_page_prot().
>> This way we catch modifications done by the vm system for drivers that
>> want write-notification.
> Hm. Why doesn't your VMA have the right prot flags in the first place? Why
> do you need to override them? More context, please.

TTM allows for graphics buffer to move between system and IO memory. So 
the prot flags can change on the fly for a VMA.

Regards,
Christian.