Re: [Qemu-devel] migration: QEMU aborts migration of "none" machine

[Daniel P. Berrange]

On Wed, Jan 25, 2017 at 11:53:06AM +0100, Thomas Huth wrote:
> On 25.01.2017 11:01, Ashijeet Acharya wrote:
> > Hi Thomas,
> > 
> > I was able to reproduce the bug you encountered while trying to migrate
> > a "none" machine.
> > 
> > After digging deep and debugging the problem with gdb, I found that
> > bitmap_new() is the function that crashes qemu as it always has
> > zero bits being passed to it.
> > 
> > I had a discussion with Dave on the IRC yesterday and he suggested the
> > reason of crash being the absence of RAM ( since machine is "none")
> > while attempting the migration.
> > 
> > I am not sure what the ideal solution will be in this case; Do any of
> > the maintainers have any suggestions or even a starting point which I
> > can ponder upon?
> 
> I'm not that familiar with the migration code either, but maybe you
> could simply check for last_ram_offset() == 0 at the beginning of
> ram_save_setup() and return with an error in that case?

Do we actually need/want migration to succeed when RAM is 0 or vCPU
count is 0 ?  If not, then we could just register a migration blocker
during machine init

Regards,
Daniel
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