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

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Jul 15, 2014 at 04:06:00PM +0100, Ian Campbell wrote:
> On Tue, 2014-07-15 at 10:59 -0400, Konrad Rzeszutek Wilk 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/features/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/misc
> > 
> > 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'.
> 
> Hrm, I thought it was transparent. Debian doesn't use dracut, it uses
> initramfs-tools. So perhaps there is some work to be done here.
> 
> I understand ucode=scan, but what does the dracut option do?

Packages the blobs and sticks them to the initramfs.

I think 'initframfs-tools' will need some code there. Here is what
I did in dracut:

http://git.kernel.org/cgit/boot/dracut/dracut.git/commit/?id=5f2c30d9bcd614d546d5c55c6897e33f88b9ab90

http://git.kernel.org/cgit/boot/dracut/dracut.git/commit/?id=b5b608e44ade93bee54d274f5edc6aad6dc45288

http://git.kernel.org/cgit/boot/dracut/dracut.git/commit/?id=d8b04dc1840047a7533d19f577f30f19d42e2d33
> 
> > > (this is predicated on Xen 4.4 hitting unstable, which is underway)
> > 
> > unstable == Debian unstable?
> 
> Yes.
> 
> Ian.
>