Re: [PATCH v2 16/24] hw/xen: handle soft reset for primary console

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 24/10/2023 16:48, David Woodhouse wrote:
> On Tue, 2023-10-24 at 16:44 +0100, Paul Durrant wrote:
> > On 19/10/2023 16:40, David Woodhouse wrote:
> > > From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > >
> > > On soft reset, the prinary console event channel needs to be rebound to
> > > the backend port (in the xen-console driver). We could put that into the
> > > xen-console driver itself, but it's slightly less ugly to keep it within
> > > the KVM/Xen code, by stashing the backend port# on event channel reset
> > > and then rebinding in the primary console reset when it has to recreate
> > > the guest port anyway.
> > Does Xen re-bind the primary console on EVTCHNOP_reset? That's news to
> > me. I go check.
> I spent an unhapp hour trying to work out how Xen actually does any of
> this :)
>
> In the short term I'm more interested in having soft reset work, than
> an explicit EVTCHNOP_reset. And I can't work out *how*, but we do seem
> to have console again after a kexec in real Xen.
*Soft* reset may do it, but not the EVTCHNOP_reset hypercall itself, 
because there's a bunch of impenetrable toolstack magic involved the 
former. Perhaps you could just push the re-bind code up a layer into
kvm_xen_soft_reset().

  Paul