x86, microcode: Don't request microcode from userspace unnecessarily
authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Sun, 9 Oct 2011 19:42:00 +0000 (15:42 -0400)
committerBorislav Petkov <borislav.petkov@amd.com>
Thu, 13 Oct 2011 14:20:35 +0000 (16:20 +0200)
commit70989449daccf545214b4840b112558e25c2b3fc
tree60aef1f69d98cd7e1ef4ee5d1fe15ffd2cdbae9f
parent37cf95162af4036b4198756a590aab8126fa2ce4
x86, microcode: Don't request microcode from userspace unnecessarily

Requesting the microcode from userspace *every time* when onlining CPUs
(during a CPU hotplug operation) is unnecessary. Thus, ensure that
once the kernel gets the microcode after booting, it is not freed nor
invalidated when a CPU goes offline, so that it can be reused when that
CPU comes back online, without requesting userspace for it again. As a
result, the CPU hotplug operations become faster as well.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/r/4E91F908.5010006@linux.vnet.ibm.com
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
arch/x86/kernel/microcode_core.c