[CentOS] /lib/firmware/microcode.dat update on CentOS 6

Thu Jan 18 18:55:37 UTC 2018
Matthew Miller <mattdm at mattdm.org>

On Thu, Jan 18, 2018 at 11:45:42AM -0500, Pete Geenhuizen wrote:
> >>Do we update the microcode now or do we wait until the latest
> >>microcode_ctl rpm is available and then tackle this issue?
> >Check with your hardware vendor for BIOS/EFI firmware updates. Apply
> >those.
> >
> Thanks for the reply, but you missed what I was asking.  I've
> already downloaded the appropriate files from the links that Johnny
> provided in a previous posting.
> My question is, do we wait until the latest microcode_ctl rpm is
> installed or do it now?  My concern is that if I do it now the new
> rpm might undo what I've done.

It does not matter. The microcode_ctl package contains CPU firmware
that is loaded at by the kernel early in the boot process if it's newer
than the one provided by the system firmware/BIOS. It is never
permanently stored in NVRAM or anything — it's loaded at each boot.

You should get a BIOS/EFI firmware update from your hardware vendor
which includes updated microcode. Then, you'll get the IBRS-capable
microcode at boot, every boot. This makes microcode_ctl moot.

Read more about this here: https://access.redhat.com/solutions/3315431

Matthew Miller
<mattdm at fedoraproject.org>
Fedora Project Leader