Re: Stubdom breakage in 4.5

[Ian Campbell <Ian.Campbell@citrix.com>]

On Tue, 2015-02-03 at 14:11 +0000, Paul Durrant wrote:
> How about this as a slightly hacky solution that I think may work in both cases?
> 
> If Xen finds no emulator at all for an HVM guest then it waits around
> for at least one to show up before processing an emulation request.
> Until one does it stalls the vcpu in question indefinitely, but on the
> first emulator attach (i.e. ioreq server creations) then the IO will
> always be processed, even if it doesn't match the ioreq server.

It sounds plausible to me and seems like it would probably be
backportable.

Longer term I think we still need to fix the domain creation interlock
for launching multiple qemu's, ioreq servers and any other type of
service thing we might launch (whether in a stub dom or not), at which
point we may be able to remove the above workaround too.

Ian.