Re: [Xen-users] ucode=-1: did anybody have success?

[Atom2 <ariel.atom2@xxxxxxxxxx>]

Sorry for my delay - I was away for a couple of days ...

Am 06.05.14 23:35, schrieb Sven Köhler:
> Am 06.05.2014 21:39, schrieb Atom2:
> > Am 06.05.14 15:27, schrieb Sven Köhler:
> > > Or maybe the file is taken from /lib/firmware/intel-ucode/ and is copied
> > > to the initrd when it is updates?
> > The truth is that you can't use the microcode.dat file directly - this
> > is a text file whereas the CPU expects a binary file.
> It's a pity the hypervisor doesn't understand the microcode.dat format.
>
> > You should be able
> > to do 'cat /lib/firmware/intel_ucode/* > /boot/microcode.blob'
> > and that should do it - although I have used another approach that
> > results in a much smaller blob file: My file is now onyl 10,240 bytes as
> > opposed to 576,512 bytes compared to cat /lib/firmware/... as described
> > above) as it only contains the required binary files for my specific CPU:
> The "cat /lib/firmware/intel_ucode/* > /boot/microcode.blob"-approach
> seems dangerous to me. Are you sure, that simply concatenating the files
> leaves you with a valid database?
I assume you have already read the answer straight from the horse's 
mouth: According to Konrad this is safe and I fully trust him on this 
(and many more things XEN).
> I think it's safer to use the iucode-tool. The following command simply
> converts microcode.dat to the binary format, right?
>
>    ./iucode_tool -w /boot/microcode.blob /lib/firmware/microcode.dat
Right. The -w defines the name of the output file and failing any other 
option iucode_tool will merge all binary files described in 
microcode.dat into a binary blob file (named microcode.blob).
> Can you confirm that /lib/firmware/intel-ucode/06-25-02 (for example)
> is the file that contains all microcode for a CPU of family 6, model
> 37=0x25, and stepping 2 (which according to /proc/cpuinfo is the CPU I
> have in my laptop, for example). These files already exist and are very
> small.
To be honest, I don't know and I think it is much safer to let 
iucode_tool do the magic in selecting those files required for your 
specific CPU model by adding the -S option.
The reason I did not investigate on this is that I was not sure whether 
there is a 1:1 relation between "family & model" / "stepping" and 
"signature" / "pf [processor flags] mask" which seems to be the relevant 
piece of information to select the relevant files from (see -s [that is: 
lowercase 's'] option of iucode_tool).
But if you really want to get to the grounds of Intel's naming schema, 
you could always use the -S option (for the CPU you run iucode_tool on) 
and crosscheck its output with those files you came up with based on 
family/model and stepping.
> > I have used a tool called 'iucode-tool' to convert the Intel
> > distribution files to the blob binary file (I decided to name it
> > microcode.bin and that's what I use in the module line above). This tool
> > has a number of options that allow to include only those parts of the
> > microcode patches that are required for your specific CPU model (it is
> > able to scan for your CPU or you can provide the model as a command line
> > argument)
> To include only the microcode for my CPU, I have to use the -S option of
> iucode-tool, right?
Right - see above.
> > Your best bet is to check whether your distribution offers iucode-tool
> > and install it. Failing this you can also download the source and
> > compile it (I had to do this for gentoo) - that was pretty easy.
> I'm using Gentoo too. I will request an ebuild for iucode-tool. Maybe I
> can also convince the microcode-data maintainer to install a binary BLOB
> in addition to microcode.dat (depending on some use-flag).
I have seen that - no answer up to now ...
> > Hope this helps,
> You helped a lot!
>
>
> Thanks,
>    Sven
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