Re: [PATCH v2 3/3] hw/misc/pvpanic: add support for normal shutdowns

[Thomas Weißschuh]

On 2023-11-29 09:23:46+0100, Cornelia Huck wrote:
> On Tue, Nov 28 2023, Thomas Weißschuh <thomas@t-8ch.de> wrote:
> 
> > Shutdown requests are normally hardware dependent.
> > By extending pvpanic to also handle shutdown requests, guests can
> > submit such requests with an easily implementable and cross-platform
> > mechanism.
> >
> > Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
> > ---
> >  docs/specs/pvpanic.rst                   | 2 ++
> >  hw/misc/pvpanic.c                        | 5 +++++
> >  include/hw/misc/pvpanic.h                | 2 +-
> >  include/standard-headers/linux/pvpanic.h | 1 +
> >  4 files changed, 9 insertions(+), 1 deletion(-)
> 
> (...)
> 
> > diff --git a/include/standard-headers/linux/pvpanic.h 
> > b/include/standard-headers/linux/pvpanic.h
> > index 54b7485390d3..38e53ad45929 100644
> > --- a/include/standard-headers/linux/pvpanic.h
> > +++ b/include/standard-headers/linux/pvpanic.h
> > @@ -5,5 +5,6 @@
> >  
> >  #define PVPANIC_PANICKED   (1 << 0)
> >  #define PVPANIC_CRASH_LOADED       (1 << 1)
> > +#define PVPANIC_SHUTDOWN           (1 << 2)
> >  
> >  #endif /* __PVPANIC_H__ */
> >
> 
> This hunk needs to come in via a separate headers update, or has to be
> split out into a placeholder patch if it is not included in the Linux
> kernel yet.

Greg KH actually want this header removed from the Linux UAPI headers,
as it is not in fact a Linux UAPI [0].
It's also a weird workflow to have the specification in qemu but the
header as part of Linux that is re-imported in qemu.

What do you think about maintaining the header as a private part of qemu
and dropping it from Linux UAPI?

Contrary to my response to Greg this wouldn't break old versions of
qemu, as qemu is using a private copy that would still exist there.

[0] https://lore.kernel.org/lkml/2023110431-pacemaker-pruning-0e4c@gregkh/