Re: [Qemu-devel] [PATCH v5 1/5] arm: qmp: add GICCapability struct

[Peter Xu]

On Wed, Mar 23, 2016 at 01:21:52PM +0100, Markus Armbruster wrote:
> Can you tell me what a management application is supposed to do with the
> information returned by query-gic-capabilities?  Not just in general
> terms, like "using this information, libvirt can warn the user during
> configuration of guests when specified GIC device type is not supported,
> but specifics.  Something like "-frobnicate mutter=mumble won't work
> unless query-gic-capabilities reports emulated version 2 is supported"
> for every piece of configuration that should be vetted against
> query-gic-capabilities.

I suppose that won't be a very big problem since possibly only
libvirt will use it... I agree that it's better to explain it more
clearly though. How about adding these lines into patch 1 commit
message:

"""
For example, if we got the query result:

{"return": {"capabilities":
  [ {"emulated": false, "version": 3, "kernel": true},
    {"emulated": true, "version": 2, "kernel": false} ] } }

Then it means that we support emulated GIC version 2 using:

  qemu-system-aarch64 -M virt,gic-version=2 ...

or kvm-accelerated GIC version 3 using:

  qemu-system-aarch64 -enable-kvm -M virt,gic-version=3 ...

If we specify other explicit GIC version rather than the above, QEMU
will not be able to boot.
"""

Thanks.

-- peterx