xen: Allow PV-OPS kernel to detect whether XSAVE is supported
authorShan Haitao <haitao.shan@intel.com>
Tue, 9 Nov 2010 19:43:36 +0000 (11:43 -0800)
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Wed, 6 Apr 2011 12:31:13 +0000 (08:31 -0400)
commit947ccf9c3c30307b774af3666ee74fcd9f47f646
treeade0284004bf6cb7a16a6afd85c3e79b2538fc4d
parent61f4237d5b005767a76f4f3694e68e6f78f392d9
xen: Allow PV-OPS kernel to detect whether XSAVE is supported

Xen fails to mask XSAVE from the cpuid feature, despite not historically
supporting guest use of XSAVE.  However, now that XSAVE support has been
added to Xen, we need to reliably detect its presence.

The most reliable way to do this is to look at the OSXSAVE feature in
cpuid which is set iff the OS (Xen, in this case), has set
CR4.OSXSAVE.

[ Cleaned up conditional a bit. - Jeremy ]

Signed-off-by: Shan Haitao <haitao.shan@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
arch/x86/xen/enlighten.c