Messages in this thread | | | Date | Thu, 27 Apr 2017 00:04:48 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS if forced to zero |
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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.
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