Re: Current state of Xen microcode (Was: Re: uploading 3.16~rc5-1~exp1)

["Jan Beulich" <JBeulich@suse.com>]

>>> On 15.07.14 at 16:59, <konrad.wilk@oracle.com> wrote:
> On Tue, Jul 15, 2014 at 09:53:32AM +0100, Ian Campbell wrote:
>> Adding xen-devel and some of the Linux maints,
>> 
>> On Mon, 2014-07-14 at 23:22 +0200, maximilian attems wrote:
>> > I will upload tomorrow Tuesday around 22h00 UT to experimental.
>> > 
>> > There are two TODOS concerning the not yet forwarded Debian patches:
>> > - cgroups
>> > - xen microcode
>> > 
>> > 
>> > I consider both not a blocker, but would be happy if Xen guys could
>> > have a look for what is needed.
>> 
>> The xen microcode patches which maks is referring to are these:
>> 
> http://anonscm.debian.org/viewvc/kernel/dists/trunk/linux/debian/patches/feat 
> ures/all/xen/
>> which are a forward port of Jeremy's old microcode_xen.ko driver.
> 
> They are also at my branch
> http://git.kernel.org/cgit/linux/kernel/git/konrad/xen.git/log/?h=stable/mis 
> c
> 
> Hm, I should rebase them at some point.
>> 
>> I've not been keeping up on Xen x86 microcode stuff these days but I
>> think we don't need this any more with modern Xen since we can parse the
>> microcode blob off the front of the initrd, is that right?
> 
> Right. And best of it, the support for that is in dracut so
> it automatically can happen (thought you still need to add
> 'ucode=scan' in the /etc/default/grub.cfg in the GRUB_CMDLINE_XEN
> parameter) and also in /etc/dracut.conf add 'early_microcode=yes'.

Except that all this still doesn't take care of updating microcode at
runtime. Yet that should - like kexec - be implemented in the
respective tools such that no kernel involvement it required.

Jan