Re: [libvirt] [Qemu-devel] [PATCH v7 1/3] qmp: adding 'wakeup-suspend-support' in query-target
On 05/21/2018 03:14 PM, Eduardo Habkost wrote:
> Issue#2: the flag isn't a property of the target. Due to
-no-acpi, it's
> not even a property of the machine type. If it was, query-machines
> would be the natural owner of the flag.
>
> Perhaps query-machines is still the proper owner. The value of
> wakeup-suspend-support would have to depend on -no-acpi for the machine
> types that honor it. Not ideal; I'd prefer MachineInfo to be static.
> Tolerable? I guess that's also a libvirt question.
It depends when libvirt is going to query it. Is it OK to only
query it after the VM is already up and running? If it is, then
we can simply expose it as a read-only property of the machine
object.
Or, if we don't want to rely on qom-get as a stable API, we can
add a new query command (query-machine? query-power-management?)
In the first version this logic was included in a new query command called
"query-wakeup-from-suspend-support":
https://lists.gnu.org/archive/html/qemu-devel/2017-12/msg00889.html
In that review it was suggested that this logic could be a flag in
either query-target
or query-machines API. Before sending the v2 I sent the following comment:
"After investigating, I think that it's simpler to hook the wakeup
support info into
TargetInfo than MachineInfo, given that the detection I'm using for this
new property
is based on the current runtime state. Hooking into MachineInfo would
require to
change the MachineClass to add a new property, then setting it up for
the machines
that have the wakeup support (only x86 so far). Definitely doable, but
if we don't
have any favorites between MachineInfo and TargetInfo I'd rather pick
the simpler
route.
So, if no one objects, I'll rework this series by putting the logic
inside query-target
instead of a new API."
Since no objection was made back then, this logic was put into
query-target starting
in v2. Still, I don't have any favorites though: query-target looks ok,
query-machine
looks ok and a new API looks ok too. It's all about what makes (more)
sense in the
management level, I think.
danielhb