lkml.org 
[lkml]   [2017]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS if forced to zero
On Wed, Apr 26, 2017 at 08:24:12PM +0200, Juergen Gross wrote:
> I'm not feeling strong about it. So if you want to test for
> X86_FEATURE_XENPV to avoid setting X86_BUG_SYSRET_SS_ATTRS I'm fine
> with it.
>
> Will send V2 with that change.

And remove the corresponding

clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);

in xen_set_cpu_features().

So that we can set it once, only on !XENPV feature set.

/me looks again at the code...

Gah, except that we do

set_cpu_cap(c, X86_FEATURE_XENPV);

and that runs as part of init_hypervisor() and it runs *after* c_init().

So, back to square one. :-\

So lemme try to explain again what I mean:

I'd like to have a generic way of detecting whether I'm running as a xen
guest at ->c_init() time and depending on the result of that detection,
to set X86_BUG_SYSRET_SS_ATTRS or not set it.

Does that make more sense?

Thanks.

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

\
 
 \ /
  Last update: 2017-04-27 00:06    [W:0.050 / U:0.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site