On 20/10/2023 3:50 pm, Durrant, Paul wrote: > On 20/10/2023 14:37, David Woodhouse wrote: > [snip] >>> >>> [0] >>> https://elixir.bootlin.com/linux/latest/source/drivers/tty/hvc/hvc_xen.c#L258 >> >> I'm not convinced I believe what the comment says there about evtchn 0 >> being theoretically valid. I don't believe zero is a valid evtchn#, is >> it? > > gfn 0 might be valid, but I'm also pretty sure evtchn 0 is not valid.
GFN 0 very much is valid. evtchn 0 OTOH is explicitly not valid. From evtchn_init(): evtchn_from_port(d, 0)->state = ECS_RESERVED; However, the fields being 0 doesn't mean not available. That's the signal to saying "not connected yet", because that's what dom0 gets before xenconsoled starts up. ~Andrew
