linux-kernel - Re: [PATCH 2/7] xen/gntdev,x86: Remove apply_to_page

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:   Mon, 12 Apr 2021 11:20:45 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Christoph Hellwig <hch@....de>
Cc:     akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        boris.ostrovsky@...cle.com, jgross@...e.com,
        sstabellini@...nel.org, x86@...nel.org,
        jani.nikula@...ux.intel.com, joonas.lahtinen@...ux.intel.com,
        rodrigo.vivi@...el.com, chris@...is-wilson.co.uk,
        intel-gfx@...ts.freedesktop.org, linux-mm@...ck.org,
        keescook@...omium.org
Subject: Re: [PATCH 2/7] xen/gntdev,x86: Remove apply_to_page_range() use
 from module

On Mon, Apr 12, 2021 at 10:26:40AM +0200, Christoph Hellwig wrote:
> On Mon, Apr 12, 2021 at 10:00:14AM +0200, Peter Zijlstra wrote:
> > Instead of relying on apply_to_page_range() being available to
> > modules, move its use into core kernel code and export it's
> > application.
> 
> This doesn't exactly look great, but at least it contains the damage..

That was just about as far as I got...

> > NOTE: ideally we do: use_ptemod = !auto_translate_physmap &&
> > gnttab_map_avail_bits and remove this hack.
> 
> Given how much pain the !auto_translate_physmap case causes all over
> the kernel I wonder what a realistic timeline might be for dropping
> support for this case might be..

I've no experience with any of that; it looks absolutely disguisting,
all of it. I figured that's part of the Xen 'charm' :-)