x86/xen: Make sure X2APIC_ENABLE bit of MSR_IA32_APICBASE is not set
authorBoris Ostrovsky <boris.ostrovsky@oracle.com>
Wed, 11 Feb 2015 19:39:18 +0000 (14:39 -0500)
committerDavid Vrabel <david.vrabel@citrix.com>
Mon, 23 Feb 2015 16:30:23 +0000 (16:30 +0000)
commit31795b470b0872b66f7fa26f791b695c79821220
tree1179e7b7b6d3de349ae95103d0cdeaf14aa612c0
parentc517d838eb7d07bbe9507871fab3931deccff539
x86/xen: Make sure X2APIC_ENABLE bit of MSR_IA32_APICBASE is not set

Commit d524165cb8db ("x86/apic: Check x2apic early") tests X2APIC_ENABLE
bit of MSR_IA32_APICBASE when CONFIG_X86_X2APIC is off and panics
the kernel when this bit is set.

Xen's PV guests will pass this MSR read to the hypervisor which will
return its version of the MSR, where this bit might be set. Make sure
we clear it before returning MSR value to the caller.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
arch/x86/xen/enlighten.c