x86, microcode: Don't initialize microcode code on paravirt
authorBoris Ostrovsky <boris.ostrovsky@oracle.com>
Mon, 1 Dec 2014 21:27:44 +0000 (16:27 -0500)
committerBorislav Petkov <bp@suse.de>
Sat, 6 Dec 2014 11:59:03 +0000 (12:59 +0100)
commita18a0f6850d4b286a5ebf02cd5b22fe496b86349
tree9140df8e429762b81fef6b80f286e87c8e8c7956
parent47768626c6db42cd06ff077ba12dd2cb10ab818b
x86, microcode: Don't initialize microcode code on paravirt

Paravirtual guests are not expected to load microcode into processors
and therefore it is not necessary to initialize microcode loading
logic.

In fact, under certain circumstances initializing this logic may cause
the guest to crash. Specifically, 32-bit kernels use __pa_nodebug()
macro which does not work in Xen (the code path that leads to this macro
happens during resume when we call mc_bp_resume()->load_ucode_ap()
->check_loader_disabled_ap())

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1417469264-31470-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Borislav Petkov <bp@suse.de>
arch/x86/kernel/cpu/microcode/core.c