Re: [Qemu-devel] [PATCH 0/2] ipmi: Allow UUID to be set for a BMC

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Nov 08, 2018 at 08:19:42AM -0600, minyard@acm.org wrote:
> The code was using the qemu UUID for the BMC.  But that's really
> not a good method.  In general, you don't want the GUID to change
> when you migrate, and you want the GUID to be the same between
> invocations of qemu (if you have a GUID).

Hrm.  Generally the qemu UUID should remain the same across a
migration too, and I think that will be the case if using libvirt.
Maybe not if running qemu by hand and not specifying the uuid on the
command line.

I don't really have an objection to allowing the BMC's id to be
explicitly controlled, but the rationale above seems a bit
disingenuous.

> Plus, if you have multiple BMCs, they need to have different
> GUIDs or the host code cannot tell them apart.  I'm not sure
> anyone really uses multiple BMCs, but I do a lot of testing
> with that scenario.
> 
> This change lets the user set the GUID on the command line, and
> if the GUID is not set return an error for the GUID fetch command.
> This maps better to how IPMI should work.
> 
> This change relies on the UUID being set to all zeros to know that
> it is not set.  This is not optimal, perhaps, but an all zero
> UUID isn't valid (it's the Nil UUID), so it should be ok.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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