Re: [PATCH 1/2] hw/misc/mos6522: Expose x-query-mos6522-devices QMP command

[Markus Armbruster <armbru@redhat.com>]

Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> This is a counterpart to the HMP "info via" command. It is being
> added with an "x-" prefix because this QMP command is intended as an
> adhoc debugging tool and will thus not be modelled in QAPI as fully
> structured data, nor will it have long term guaranteed stability.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  MAINTAINERS             |  2 +-
>  qapi/machine.json       | 17 +++++++++++++++++
>  hw/misc/mos6522-stubs.c | 18 ++++++++++++++++++
>  hw/misc/mos6522.c       |  5 +++--
>  hw/misc/meson.build     |  3 ++-
>  5 files changed, 41 insertions(+), 4 deletions(-)
>  create mode 100644 hw/misc/mos6522-stubs.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 951556224a..e86638c68c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1453,7 +1453,7 @@ F: hw/ppc/mac_newworld.c
>  F: hw/pci-host/uninorth.c
>  F: hw/pci-bridge/dec.[hc]
>  F: hw/misc/macio/
> -F: hw/misc/mos6522.c
> +F: hw/misc/mos6522*.c
>  F: hw/nvram/mac_nvram.c
>  F: hw/ppc/fw_cfg.c
>  F: hw/input/adb*
> diff --git a/qapi/machine.json b/qapi/machine.json
> index 1283d14493..a82b8dd39d 100644
> --- a/qapi/machine.json
> +++ b/qapi/machine.json

I figure you pick machine.json because it already serves as grabbag of
vaguely device-specific queries like x-query-usb.  misc-target.json is
another grabbag.

> @@ -1865,6 +1865,23 @@
>    'data': { 'filename': 'str' },
>    'if': 'CONFIG_FDT' }
>  
> +##
> +# @x-query-mos6522-devices:
> +#
> +# Query information on MOS6522 VIA devices
> +#
> +# Features:
> +#
> +# @unstable: This command is meant for debugging.
> +#
> +# Returns: MOS6522 VIA devices information
> +#
> +# Since: 9.1
> +##
> +{ 'command': 'x-query-mos6522-devices',
> +  'returns': 'HumanReadableText',
> +  'features': [ 'unstable' ]}
> +
>  ##
>  # @x-query-interrupt-controllers:
>  #

HMP "info via" is compile-time conditional on CONFIG_MOS6522.

Its new QMP counterpart x-query-mos6522-devices is unconditional.
Can you explain why?

Possibly related:

commit 409e9f7131e55e74eb09e65535779e311df5ebf5
Author: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Date:   Sat Mar 5 15:09:53 2022 +0000

    mos6522: add "info via" HMP command for debugging
    
    This displays detailed information about the device registers and timers to aid
    debugging problems with timers and interrupts.
    
--> Currently the QAPI generators for HumanReadableText don't work correctly if
--> used in qapi/target-misc.json when a non-specified target is built, so for
--> now manually add a hmp_info_via() wrapper until direct support for per-device
--> HMP/QMP commands is implemented.
    
    Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
    Reviewed-by: Laurent Vivier <laurent@vivier.eu>
    Message-Id: <20220305150957.5053-9-mark.cave-ayland@ilande.co.uk>
    Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

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