Re: [PATCH v7 5/7] qapi/qdev.json: add DEVICE_UNPLUG_GUEST_ERROR QAPI event

[David Gibson]

On Wed, Sep 01, 2021 at 03:19:26PM +0200, Markus Armbruster wrote:
> Daniel Henrique Barboza <danielhb413@gmail.com> writes:
> 
> > At this moment we only provide one event to report a hotunplug error,
> > MEM_UNPLUG_ERROR. As of Linux kernel 5.12 and QEMU 6.0.0, the pseries
> > machine is now able to report unplug errors for other device types, such
> > as CPUs.
> >
> > Instead of creating a (device_type)_UNPLUG_ERROR for each new device,
> > create a generic DEVICE_UNPLUG_GUEST_ERROR event that can be used by all
> > guest side unplug errors in the future. This event has a similar API as
> > the existing DEVICE_DELETED event, always providing the QOM path of the
> > device and dev->id if there's any.
> >
> > With this new generic event, MEM_UNPLUG_ERROR is now marked as deprecated.
> >
> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> > ---
> 
> [...]
> 
> > diff --git a/qapi/qdev.json b/qapi/qdev.json
> > index 0e9cb2ae88..8b1a1dd43b 100644
> > --- a/qapi/qdev.json
> > +++ b/qapi/qdev.json
> > @@ -84,7 +84,9 @@
> >  #        This command merely requests that the guest begin the hot removal
> >  #        process.  Completion of the device removal process is signaled 
> > with a
> >  #        DEVICE_DELETED event. Guest reset will automatically complete 
> > removal
> > -#        for all devices.
> > +#        for all devices.  If a guest-side error in the hot removal 
> > process is
> > +#        detected, the device will not be removed and a 
> > DEVICE_UNPLUG_GUEST_ERROR
> > +#        event is sent.  Some errors cannot be detected.
> >  #
> >  # Since: 0.14
> >  #
> > @@ -124,3 +126,27 @@
> >  ##
> >  { 'event': 'DEVICE_DELETED',
> >    'data': { '*device': 'str', 'path': 'str' } }
> > +
> > +##
> > +# @DEVICE_UNPLUG_GUEST_ERROR:
> > +#
> > +# Emitted when a device hot unplug fails due to an internal guest
> > +# error.
> 
> Suggest to scratch "internal".

I'd suggest s/internal guest/guest reported/.  "guest error" is a bit
vague, this doesn't neccessarily indicate a bug in the guest.  The key
point is that we're reporting this event because the guest performed
some explicit action to tell us something went wrong with the plug
attempt.

> 
> > +#
> > +# @device: the device's ID if it has one
> > +#
> > +# @path: the device's QOM path
> > +#
> > +# Since: 6.2
> > +#
> > +# Example:
> > +#
> > +# <- { "event": "DEVICE_UNPLUG_GUEST_ERROR"
> > +#      "data": { "device": "core1",
> > +#                "path": "/machine/peripheral/core1" },
> > +#      },
> > +#      "timestamp": { "seconds": 1615570772, "microseconds": 202844 } }
> > +#
> > +##
> > +{ 'event': 'DEVICE_UNPLUG_GUEST_ERROR',
> > +  'data': { '*device': 'str', 'path': 'str' } }
> 
> [...]
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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