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Dereferencing the pointer > >>> doesn't end well. > >>> > >>> Signed-off-by: David Woodhouse > >>> --- > >>> This is about as far as I got in my abortive attempt to use the PV shim > >>> without an actual PV console being provided by the HVM hosting > >>> environment. It still doesn't pass the guest's console through to > >>> serial; that only seems to shim to an actual PV console. > >> There's no such thing as a Xen VM without a PV console. > > Huh? There are literally millions of them. > > I'm very prepared to believe there are millions which don't overtly > malfunction when you don't fill in the HVM Params.  > > Which is very different from saying "there's a way in the Xen guest ABI > to express 'you don't have a PV console' ". FWIW, Linux assumes that either the console page or the event channel being 0 implies no console available [0], so I guess that's the ABI now. Roger. [0] https://elixir.bootlin.com/linux/latest/source/drivers/tty/hvc/hvc_xen.c#L258