CentOS virt - May 2019 - centos-virt CPU microcode updates?

Hi,

is there any guide for CPU microcode updates on CentOS6, Xen 4.10, 
kernel 4.9 ?

Thanks
Karel

On 5/16/19 2:12 AM, Karel Hendrych wrote:
> Hi,
> 
> is there any guide for CPU microcode updates on CentOS6, Xen 4.10, kernel
4.9 ?
I'm not sure off the top of my head.

You can add ucode=scan to the xen command line, add a file
/path/to/microcode_file as the last item in your boot list, and generate that
microcode
file using something like:

iucode_tool --write-earlyfw "${OUT_BLOB_FILE}" \
            "${TEMP_DIR_NAME}/intel-ucode" \
            "${TEMP_DIR_NAME}/intel-ucode-with-caveats"

Where the last two items have been extracted from the intel microcode tarball.

--Sarah

Not sure about CentOS 6, but this was covered previously (at least for 7...not
sure how much they differ)...not that I can find the message now, but here's
what I recall/pieced together from bash history that works on CentOS 7:


If the microcode you want is in the microcode_ctl package:

mkdir -p /etc/microcode_ctl/ucode_with_caveats/
touch /etc/microcode_ctl/ucode_with_caveats/force
yum reinstall microcode_ctl   (there were arguably better ways to do this part,
but I cant recall)

add ucode=scan to your GRUB_CMDLINE_XEN_DEFAULT line
grub2-mkconfig to update your grub config
reboot


Once that's done, every time microcode_ctl updates, you'll get the
microcode on the next reboot just like any other centos machine.



Feel free to jump in if I missed any steps/caveats/notes, but that looks to be
how I set it up on my machines last year.



Thanks,
-Dave

> On May 16, 2019, at 12:03, Sarah Newman <srn at prgmr.com> wrote:
> 
> On 5/16/19 2:12 AM, Karel Hendrych wrote:
>> Hi,
>> 
>> is there any guide for CPU microcode updates on CentOS6, Xen 4.10,
kernel 4.9 ?
> 
> I'm not sure off the top of my head.
> 
> You can add ucode=scan to the xen command line, add a file
/path/to/microcode_file as the last item in your boot list, and generate that
microcode
> file using something like:
> 
> iucode_tool --write-earlyfw "${OUT_BLOB_FILE}" \
>            "${TEMP_DIR_NAME}/intel-ucode" \
>            "${TEMP_DIR_NAME}/intel-ucode-with-caveats"
> 
> Where the last two items have been extracted from the intel microcode
tarball.
> 
> --Sarah
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