Re: Proposal for init/kexec/hotplug format for Xen

[Jeremy Katz <katzj@redhat.com>]

On Mon, 2005-02-28 at 23:06 +1100, Rusty Russell wrote:
>On Sun, 2005-02-27 at 09:25 -0600, Anthony Liguori wrote:
>> Keir Fraser wrote:
>> > I like the idea of bringing out device discovery, bringup, teardown, 
>> > recovery all into its own driver or subsystem -- it seems the obvious 
>> > way to go. But I think the 'device tree' should be in the 
>> > to-be-designed persistent store, and we publish an interface to allow 
>> > guests to peek/poke that store.
>> 
>> I think publishing domain-information in an OF-like tree would be great.
>
>I'm not convinced of the persistent store idea, at least for this.  I
>think it's simpler to have it dropped into memory at boot (just like the
>initrd image), and then later messages are sent which update it (ie.
>hotlplug) which have a similar form.

I tend to agree wrt the persistent store.  Given the choice between
complexity in 
a) guest OS (multiplied by N guest OS's) or
b) domain0/tools

I'd rather batch my complexity up to where it only has to be written
once and not every time you port an OS.  Keeping things simple for the
guest (like this) seems reasonable to me.

>The former is implemented, but breaks when I actually test it (you can
>see that code #ifdef'ed out, debugging now).  I added simple routines so
>that you can build a device tree and pass it to the domain builder.
>
>Included below for your reading pleasure,

Cool.  I actually like this better conceptually than what I was working
on (but didn't have working due to a flurry of meetings before, after
and during LinuxWorld).  I'll play with it some here and see how easy it
can tie in with the sysfs bits, which I should also just clean up
separately and post an update.

Jeremy



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