Re: [Qemu-block] [Qemu-devel] [PATCH v3 12/12] docs/interop/firmware.json: Prefer -machine to if=pflash

[Markus Armbruster]

Michal Privoznik <address@hidden> writes:

> On 3/8/19 2:14 PM, Markus Armbruster wrote:
>> The previous commit added a way to configure firmware with -blockdev
>> rather than -drive if=pflash.  Document it as the preferred way.
>>
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>>   docs/interop/firmware.json | 20 ++++++++++++++------
>>   1 file changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/docs/interop/firmware.json b/docs/interop/firmware.json
>> index 28f9bc1591..ff8c2ce5f2 100644
>> --- a/docs/interop/firmware.json
>> +++ b/docs/interop/firmware.json
>> @@ -212,9 +212,13 @@
>>   #
>>   # @executable: Identifies the firmware executable. The firmware
>>   #              executable may be shared by multiple virtual machine
>> -#              definitions. The corresponding QEMU command line option
>> -#              is "-drive
>> -#              
>> if=pflash,unit=0,readonly=on,address@hidden@filename,address@hidden@format".
>> +#              definitions. The preferred corresponding QEMU command
>> +#              line options are
>> +#                  -drive 
>> if=none,id=pflash0,readonly=on,address@hidden@filename,address@hidden@format
>> +#                  -machine pflash0=pflash0
>
> I have a question. How is libvirt supposed to query for this? How can
> it learn it can use this new, preferred command line?

You can use qom-list-properties to find out whether the machine has
property pflash0.

---> {"execute": "qom-list-properties", "arguments": {"typename": 
"pc-q35-4.0-machine"}}
<--- {"return": [... {"name": "pflash0", ...} ...]}
---> {"execute": "qom-list-properties", "arguments": {"typename": 
"isapc-machine"}}
<--- {"return": [... no such property ...]}