Re: [PATCH v5 5/7] qapi/qdev.json: add DEVICE_UNPLUG_ERROR QAPI event

[David Gibson]

On Mon, Jul 12, 2021 at 04:43:37PM -0300, Daniel Henrique Barboza wrote:
> 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_ERROR event that can be used by all
> unplug errors in the future. This event has a similar API as the
> existing DEVICE_DELETED event, with an extra optional 'msg' parameter
> that can be used to explain the reason for the error.
> 
> With this new generic event, MEM_UNPLUG_ERROR is now marked as deprecated.
> 
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

This no longer applies clean for me - looks like deprecated.rst has
been moved.

At this point I'm willing to queue this tentatively for 6.2, but I'll
need a rebased respin (and fold in Greg's acks, please).

> ---
>  docs/system/deprecated.rst | 10 ++++++++++
>  qapi/machine.json          |  6 +++++-
>  qapi/qdev.json             | 30 +++++++++++++++++++++++++++++-
>  stubs/qdev.c               |  7 +++++++
>  4 files changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
> index 6d438f1c8d..c0c3431ada 100644
> --- a/docs/system/deprecated.rst
> +++ b/docs/system/deprecated.rst
> @@ -204,6 +204,16 @@ The ``I7200`` guest CPU relies on the nanoMIPS ISA, 
> which is deprecated
>  (the ISA has never been upstreamed to a compiler toolchain). Therefore
>  this CPU is also deprecated.
>  
> +
> +QEMU API (QAPI) events
> +----------------------
> +
> +``MEM_UNPLUG_ERROR`` (since 6.2)
> +''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +Use the more generic event ``DEVICE_UNPLUG_ERROR`` instead.
> +
> +
>  System emulator machines
>  ------------------------
>  
> diff --git a/qapi/machine.json b/qapi/machine.json
> index c3210ee1fb..a595c753d2 100644
> --- a/qapi/machine.json
> +++ b/qapi/machine.json
> @@ -1271,6 +1271,9 @@
>  #
>  # @msg: Informative message
>  #
> +# Features:
> +# @deprecated: This event is deprecated. Use @DEVICE_UNPLUG_ERROR instead.
> +#
>  # Since: 2.4
>  #
>  # Example:
> @@ -1283,7 +1286,8 @@
>  #
>  ##
>  { 'event': 'MEM_UNPLUG_ERROR',
> -  'data': { 'device': 'str', 'msg': 'str' } }
> +  'data': { 'device': 'str', 'msg': 'str' },
> +  'features': ['deprecated'] }
>  
>  ##
>  # @SMPConfiguration:
> diff --git a/qapi/qdev.json b/qapi/qdev.json
> index d1d3681a50..52c36c7b9c 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 an error in the hot removal process is 
> detected,
> +#        the device will not be removed and a DEVICE_UNPLUG_ERROR event is
> +#        sent.  Some errors cannot be detected.
>  #
>  # Since: 0.14
>  #
> @@ -124,3 +126,29 @@
>  ##
>  { 'event': 'DEVICE_DELETED',
>    'data': { '*device': 'str', 'path': 'str' } }
> +
> +##
> +# @DEVICE_UNPLUG_ERROR:
> +#
> +# Emitted when a device hot unplug error occurs.
> +#
> +# @device: the device's ID if it has one
> +#
> +# @path: the device's path within the object model
> +#
> +# @msg: optional informative message
> +#
> +# Since: 6.2
> +#
> +# Example:
> +#
> +# <- { "event": "DEVICE_UNPLUG_ERROR"
> +#      "data": { "device": "core1",
> +#                "msg": "Device hotunplug rejected by the guest for device 
> core1",
> +#                "path": "/machine/peripheral/core1" },
> +#      },
> +#      "timestamp": { "seconds": 1615570772, "microseconds": 202844 } }
> +#
> +##
> +{ 'event': 'DEVICE_UNPLUG_ERROR',
> +  'data': { '*device': 'str', 'path': 'str' , '*msg': 'str' } }
> diff --git a/stubs/qdev.c b/stubs/qdev.c
> index 92e6143134..ffa8f7b59e 100644
> --- a/stubs/qdev.c
> +++ b/stubs/qdev.c
> @@ -21,3 +21,10 @@ void qapi_event_send_device_deleted(bool has_device,
>  {
>      /* Nothing to do. */
>  }
> +
> +void qapi_event_send_device_unplug_error(bool has_device, const char *device,
> +                                         const char *path,
> +                                         bool has_msg, const char *msg)
> +{
> +    /* Nothing to do. */
> +}

-- 
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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