Thread (12 messages) 12 messages, 5 authors, 2006-08-29

Re: [PATCH] powerpc: ibmveth: Harden driver initilisation for kexec

From: Randy.Dunlap <hidden>
Date: 2006-03-03 04:12:42

Possibly related (same subject, not in this thread)

On Fri, 3 Mar 2006 12:10:47 +1100 Michael Ellerman wrote:
On Fri, 3 Mar 2006 11:34, Randy.Dunlap wrote:
quoted
On Fri, 3 Mar 2006 11:22:45 +1100 Michael Ellerman wrote:
quoted
Hi Jeff,

I realise it's late, but it'd be really good if you could send this up
for 2.6.16, we're hosed without it.
I'm wondering if this means that for every virtual/hypervisor
situation, we have to modify any $interested_drivers.
Why wouldn't we come up with a cleaner solution (in the long term)?

E.g., could the hypervisor know when one of it's virtual OSes
dies or reboots and release its resources then?
It does exactly that for a regular reboot, but when we kexec we _don't_ die or 
reboot, as far as the Hypervisor is concerned it's all systems go.

It's something of a double-edged sword, we're totally in control which gives 
us lots of flexibility, and _fast_ reboot times, but we also have to do a bit 
of extra stuff (ie. this patch) to keep things sane.
s/this patch/some patch/

Yes, you have certainly thought about this more/longer than I have,
so why is something more generic like this bad instead of good:

Somewhere early in start_kernel() (e.g.), do an hv call that says
"free all assigned resources".

Maybe hv doesn't know "all assigned resources."
Maybe it's just that this patch is simpler than an hv change,
although this (current) patch could leave some other drivers that
need to be "fixed," while an hv change wouldn't do that.

So I'm not opposed to this current patch as a short-term solution,
but I don't think it's the right long-term solution.

---
~Randy
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