Re: [PATCH v3 00/30] qapi/qom: QAPIfy --object and object-add
On Wed, Mar 10, 2021 at 18:30:44 +0100, Kevin Wolf wrote:
Am 10.03.2021 um 15:31 hat Paolo Bonzini geschrieben:
> On 10/03/21 15:22, Peter Krempa wrote:
[...]
The keyval parser would create a list if multiple values are given
for
the same key. Some care needs to be taken to avoid mixing the magic
list feature with the normal indexed list options.
The QAPI schema would then use an alternate between 'int' and ['int'],
with the the memory-backend-ram implementation changed accordingly.
We could consider immediately deprecating the syntax and printing a
warning in the keyval parser when it automatically creates a list from
two values for a key, so that users don't start using this syntax
By 'creating a list from two values for a key' you mean:
host-nodes=0,host-nodes=1
to be converted into [0, 1] ?
instead of the normal list syntax in other places. We'd probably
still
leave the implementation around for -device and other users of the same
magic.
There's three options actually that libvirt uses, visible in one our
test files [1]
For a single value we format:
-object memory-backend-ram,id=ram-node0,size=20971520,host-nodes=3,policy=preferred
For a contiguous list:
-object memory-backend-ram,id=ram-node1,size=676331520,host-nodes=0-7,policy=bind
And for an interleaved list:
-object
memory-backend-ram,id=ram-node2,size=24578621440,host-nodes=1-2,host-nodes=5,host-nodes=7,policy=bind
If any of the above is to be deprecated we'll need to adjust our
JSON->commandline generator accordignly.
Luckily the 'host-nodes' is storeable as a bitmap and the generator is
actually modular to allow plugging an array interpretor which actually
does the above conversion from a JSON array.
So, what is the preferred syntax here? Additionally we might need a
witness property to detect when to use the new syntax if basing it on
the object-add qapification will not be enough.
[1]
https://gitlab.com/libvirt/libvirt/-/blob/master/tests/qemuxml2argvdata/n...