On Fri, May 02, 2014 at 03:45:03PM +0200, Igor Mammedov wrote:
On Wed, 30 Apr 2014 17:29:28 -0300 Eduardo Habkost <ehabkost@redhat.com> wrote:
This series allows management code to use object-add on X86CPU subclasses, so it Is there any reason why "device-add" couldn't be used?
It needs to work with "-machine none", device_add requires a bus to exist, and there is no icc-bus on machine_none. The first thing I considered was making icc-bus user-creatable. Then I noticed it wouldn't work because object-add always add objects to /objects, not inside the qdev hierarchy (that's where device_add looks for the bus). So, allowing device_add could be possible, but would require changing more basic infrastructure: either allowing bus-less devices on device_add, or allowing device_add to add devices outside the qdev hierarchy, or allowing object-add to create objects outside /objects. Simply making CPU objects work with object-add was much simpler and less intrusive. And it had the interesting side-effect of _not_ doing things that are not required for CPU model probing (like creating an actual VCPU thread).
can use it to probe for CPU model information without re-running QEMU. The main use case for this is to allow management code to create CPU objects and query the "feature-words" and "filtered-features" properties on the new objects, to find out which features each CPU model needs, and to do the same using the "host" CPU model to check which features can be enabled in a given host.
There's experimental libvirt code to use the new command at: https://github.com/ehabkost/libvirt/tree/work/cpu-feature-word-query The experimental code just create the CPU objects to query for feature information, but doesn't do anything with that data.
Eduardo Habkost (5): cpu: Initialize cpu->stopped=true earlier cpu: Don't try to pause CPUs if they are already stopped pc: Don't crash on apic_accept_pic_intr() if CPU has no apic_state target-i386: Make CPU objects user-creatable target-i386: Report QOM class name for CPU definitions
cpus.c | 13 ++++++++++--- exec.c | 1 + hw/i386/pc.c | 2 +- qapi-schema.json | 6 +++++- target-i386/cpu.c | 7 +++++++ 5 files changed, 24 insertions(+), 5 deletions(-)
-- Eduardo