Re: [Qemu-devel] [PATCH for-1.6] pc: fix up pc initialization

[Andreas Färber]

Am 13.08.2013 17:27, schrieb Paolo Bonzini:
> Il 13/08/2013 17:11, Andreas Färber ha scritto:
>>
>> mst suggested to patch stable-1.5 to disable it there, too. I am not
>> against but have doubts as to how well that works with migration, since
>> 1.5.3 is still a bit off and I would expect 1.5.2 -> 1.6.0 migration to
>> work without guest-visible changes... We could argue that having to use
>> -M pc-i440fx-1.5 we can also expect users to add -device pvpanic;
>> question would be how to convey that knowledge of
>> if-you-use-pc-x.y-then-you-also-need-to-do-Z to users, which
>> compat_props usually handle under the hood. We could misuse
>> pvpanic.ioport=0 for that purpose until we have a better solution.
> 
> pvpanic has no vmstate though, has it?  So it won't break migration
> (needs testing of course).

Just checked, you're right, it doesn't. I somehow assumed it would.

> All that should happen is that after migration you will not get panic
> notifications on the destination.

Well, how does the Linux driver cope with pvpanic device present on boot
but not present on panic? ISA PIO is not usually expected to be
hot-unplugged. ;)

Andreas

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