Re: [patch 05/11] [PATCH 05/11] x86: Moved microcode.c to microcode_intel.c.

From: Giacomo A. Catenazzi
Date: Fri Sep 19 2008 - 09:53:08 EST


Peter Oruba wrote:
Giacomo A. Catenazzi schrieb:
Dmitry Adamushko wrote:
2008/9/19 Peter Oruba <peter.oruba@xxxxxxx>:
Some additonal words regarding the current user space issues:

IMHO the most convenient way to update microcode is through the
firmware loading
interface instead of microcode_ctl. This reduces user-space
responsibilities to
loading the correct module at boot time and to place the microcode
patch file at
the right location via package installation. The problems mentioned
in this
thread would then probably disappear as well. What do you guys think?
It'd still require changes for all the setups that currently rely on
the 'microcode_ctl' interface. Moreover, Arjan's setup failed not due
to the 'microcode_ctl' per se but due to the altered kernel module
name. After all, we can't break the established interface this way.

We can either reserve 'microcode' as a legacy name for intel cpus (==
microcode_intel), or maybe we can use request_module() from
microcode.ko to load a proper arch-specific module (I guess, it's not
ok for !KMOD-enabled kernels).
I agree. A wrapper "microcode.ko" module would be nice, in order
to allow independent kernel and user space upgrades.

The module name is important also on udev method: only a module
load triggers the microcode request in udev, thus also the
new method should have stable kernel module name.

ciao
cate


That sounds like a single-module solution would be the best way to go. All
dependencies would then be handled inside the module.

Single module probably is more difficult to maintain.

I was thinking about a very simple additional module:
Check the cpu: load the relevant module, and wrapper the calls to the
relevant module.

So every vendor could develop easier the own driver. Only the interface
should be stable.

Eventually we could solve it in the distribution scripts (using module
aliases), but it would be kernel version dependent, and it would works
only on the new method (or a new microcode_ctl version, but people
upgrade more often kernel than packages).

ciao
cate
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