lkml.org 
[lkml]   [2015]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] xen/x86: Adjust stack pointer in xen_sysexit
On Mon, Nov 16, 2015 at 11:03:22AM -0800, Andy Lutomirski wrote:

> ...
> The reader surely doesn't remember that this isn't guaranteed to be a
> swapgs instruction on native. Using:
>
> ALTERNATIVE "swapgs" "" X86_FEATURE_XENPV
>
> would be safer (it would get rid of the SWAPGS_UNSAFE_STACK mess) and
> much clearer. We could hide *that* behind a macro and no one would be
> confused. (Well, they'd be confused by the fact that Xen PV handles
> gsbase very differently from native, but that has nothing to do with
> the macro.)
>
> I think we could convert piecemeal, and I wonder if this new patch for
> 32-bit native on 4.4 (this is needed for 4.4, right?) would be a good
> starting point. Borislav, what do you think? Would you be okay with
> adding a Xen PV pseudofeature?

AFAICT, I'd prefer this becomes rather a jump label which gets enabled
on xen. Especially if a single pseudofeature might not be enough,
apprently...

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.


\
 
 \ /
  Last update: 2015-11-16 21:21    [W:0.075 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site