Re: [Xen-users] How to patch cpu with xen

[Tony Lill <ajlill@xxxxxxxxxxxxxxxxxxx>]

On 05/28/2018 03:18 AM, Christoph wrote:
> 
> Hi
> 
> is there any step by step howto for patching cpu with xen/dom0?
> 
> microcode service cant do it because there is no
> /sys/devices/system/cpu/microcode/reload in dom0
> 
> ------
> Greetz
> 

It's hard to find the info, but here's what I use. It works for amd, but
my only intel box doesn't have updated firmware, so I can't confirm. I
looked in the xen source, and xen looks for both microcode bundles in
the same directory, so it should work.

The latest amd microcode in now in git with all the other firmware, get
it with

git clone -q
git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
The latest intel microcode can be downloaded from their website google
intel microcode download.

Add ucode=scan to the xen command line args in grub.

# Assuming you have the new micrcode in /lib/firmware
# Set up for early firmware load for xen
rm -rf /var/tmp/initrd-for-xen-with_append
mkdir -p /var/tmp/initrd-for-xen-with_append/kernel/x86/microcode

# For intel
iucode_tool -tb -w
/var/tmp/initrd-for-xen-with_append/kernel/x86/microcode/GenuineIntel.bin
 /lib/firmware/intel-ucode/*

# For amd
cat /lib/firmware/amd-ucode/*.bin >
/var/tmp/initrd-for-xen-with_append/kernel/x86/microcode/AuthenticAMD.bin

cd /var/tmp/initrd-for-xen-with_append
find . | cpio -o -H newc > /boot/ucode.cpio

cd /boot
cat ucode.cpio initrd.img-4.4.73 > initrd.new
mv initrd.new initrd.img-4.4.73
-- 
Tony Lill, OCT,                       ajlill@xxxxxxxxxxxxxxxxxxx
President, A. J. Lill Consultants                 (519) 650 0660
539 Grand Valley Dr., Cambridge, Ont. N3H 2S2     (519) 241 2461
--------------- http://www.ajlc.waterloo.on.ca/ ----------------



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