[Qemu-devel] [RFC PATCH 0/2] qom: custom link properties

[Paolo Bonzini <pbonzini@redhat.com>]

Both Marcelo's rtc patches and Peter's MemoryRegion patches showed
the interest in having link properties with a custom representation
and/or a different way to store the property.

Such properties would still be link<>s for the outside world, but
the internal implementation in QEMU would be different.

This series proposes a way to introduce such custom link properties,
using a new property callback "resolve" that generalizes the if/else
ladder in object_resolve_path_component.

The second patch shows how the mechanism could be used to add a simple
immutable "alias" link.  Example:

    $ ./qom-list -s /tmp/m1 /machine
    @rtc/                              # this is an alias
    i440fx/
    fw_cfg/
    icc-bridge/
    unattached/
    peripheral/
    peripheral-anon/
    ...

    $ ./qom-get -s /tmp/m1 /machine.rtc
    /machine/unattached/device[8]      # later could become /machine/piix3/rtc
                                       # or /machine/ich9/rtc and so on

    $ ./qom-get -s /tmp/m1 /machine/rtc.date
    tm_sec: 58
    tm_hour: 11
    tm_mday: 5
    tm_year: 114
    tm_mon: 5
    tm_min: 16

Paolo

Paolo Bonzini (2):
  qom: add a generic mechanism to resolve paths
  qom: add object_property_add_alias

 include/qom/object.h | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 qom/object.c         | 68 +++++++++++++++++++++++++++++++++--------------
 2 files changed, 123 insertions(+), 19 deletions(-)

-- 
1.8.3.1