x86, microcode: Don't initialize microcode code on paravirt

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commit a18a0f6850 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Boris Ostrovsky 2014-12-01 16:27:44 -05:00 • committed by Greg Kroah-Hartman

parent 97d0906a89

commit 44c4db3ab0

1 changed files with 1 additions and 1 deletions

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arch/x86/kernel/cpu/microcode/core.c

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