Re: [Qemu-devel] [PATCH v2] qdev: Keep global allocation counter per bus

[Paolo Bonzini <pbonzini@redhat.com>]

Leaving only those that will be affected by the patch:

Il 07/01/2014 18:34, Markus Armbruster ha scritto:
>     target      machine         bus id              times
>     aarch64     n800            i2c-bus.0           2
>     aarch64     n810            i2c-bus.0           2
>     arm         n800            i2c-bus.0           2
>     arm         n810            i2c-bus.0           2

Devices are created explicitly on one of the two buses, using
s->mpu->i2c[0], so no change to the guest.

>     aarch64     vexpress-a15    virtio-mmio-bus.0   4
>     aarch64     vexpress-a9     virtio-mmio-bus.0   4
>     aarch64     virt            virtio-mmio-bus.0   32
>     arm         vexpress-a15    virtio-mmio-bus.0   4
>     arm         vexpress-a9     virtio-mmio-bus.0   4
>     arm         virt            virtio-mmio-bus.0   32

With Alex's patch we get the ability to plug the device in a particular
slot.  If anyone was using virtio-mmio-bus.0 explicitly, they get the
first slot instead of the 4th or 32nd.  Bugfix.

>     aarch64     xilinx-zynq-a9  usb-bus.0           2
>     arm         xilinx-zynq-a9  usb-bus.0           2
>     mips64el    fulong2e        usb-bus.0           2

With Alex's patch we get the ability to plug the device in a particular
controller.  If anyone was using usb-bus.0 explicitly, they get the
"other" controller.  Guest visible change and not really a bugfix but it
doesn't break working configurations (the position of USB devices should
not be part of a device tree or firmware blob).  It may break migration.

>     i386        isapc           ide.0               2
>     x86_64      isapc           ide.0               2

(Ugly) fix in Alex's patch.  The macio approach (using QOM children) is
better.  No need for a perfect fix now.

>     mips        mips            ide.0               2
>     mips64      mips            ide.0               2
>     mips64el    mips            ide.0               2
>     mipsel      mips            ide.0               2

Not affected, the bus is not stored anywhere.

>     ppc         g3beige         ide.0               2
>     ppc         mac99           ide.0               2
>     ppc         prep            ide.0               2
>     ppc64       g3beige         ide.0               2
>     ppc64       mac99           ide.0               2
>     ppc64       prep            ide.0               2

Trusting Alex's tests here.

Paolo