[CentOS-virt] how to update ucode with xen

Wed Sep 19 18:27:19 UTC 2018
Christoph <mangel at gmx.de>

it is working thx a lot...

but it has included the GenuineIntel.bin only in actually used kernel... 
do I need to reinstall microcode_ctl every time I update the kernel?
And second question, I quess I still need the ucode = scan as xen 
parameter right?

Am 2018-09-19 20:08, schrieb Kevin Stange:
> On 9/19/18 1:55 AM, Christoph wrote:
>> Hi
>> can someone say me how to update the µcode of the cpu with xen?
>> I have added the ucode=scan parameter to xen but it does not seem to
>> work...
>> the µcode version of my xeon is really old :/
>> model name    : Intel(R) Xeon(R) CPU E3-1271 v3 @ 3.60GHz
>> microcode    : 0x10
> There is a "caveat" in the current version of microcode_ctl which means
> it doesn't automatically install the microcode into the initramfs if 
> the
> kernel isn't "known good" because of various issues with Linux kernel
> patches being needed for certain microcode features.  There is a quick
> way to get it to force the microcode into the initramfs of any kernel:
> mkdir -p /etc/microcode_ctl/ucode_with_caveats/
> touch /etc/microcode_ctl/ucode_with_caveats/force
> This only works with the most recent version of microcode_ctl
> (2.1-29.16.el7_5.x86_64).  If you do this, you can then run 'yum
> reinstall microcode_ctl' and you should get the microcode in the
> initramfs after it finishes.  Note that this will cause it to trust ALL
> kernels and all microcode versions which might not always be a good
> thing.  See this file for info:
> /usr/share/doc/microcode_ctl/README.caveats
> You can test that the initramfs has the microcode by running cpio:
> cpio -t < /boot/initramfs-4.9.112-32.el7.x86_64.img
> If there is a GenuineIntel.bin you should be good.  If you get spammed
> with errors, then it isn't included.