[Qemu-devel] [PATCHv2-RFC 0/2] RFC: standard pci bridge device

[Michael S. Tsirkin]

Here's a new version of the patch. It works for me.
Deep nesting of bridges is supported.
You need a small BIOS patch to support the OSHP method
if you want hotplug to work. I will post this separately.
We'd need a full ACPI driver to make hotplug work for guests
without an SHPC driver (e.g. windows XP).
Management support will also be needed.

One small wrinkle is that the pci_addr property
wants data in a format bus:device.function which is
broken as guests can change bus numbers.
For testing I used the 'addr' property which
encodes slot*8+function#. We probably want to
extend pci_addr in some way (e.g. :device.function ?
Thoughts?).

The SHPC controller supports up to 31 devices
(out of 32 slots) so slot 0 doesn't support hotplug.
Non hot-pluggable devices behind the bridge
don't work currectly (we'll try to unplug them)
so don't do this.
For now I just blocked adding devices in slot 0,
in the future it might be possible to add
a non-hotpluggable device there.

Example:

qemu-system-x86_64  -enable-kvm -m 1G
 -drive file=/home/mst/rhel6.qcow2
-netdev
tap,id=foo,ifname=msttap0,script=/home/mst/ifup,downscript=no,vhost=on
-device pci-bridge,id=bog
-device virtio-net-pci,netdev=foo,bus=bog,addr=8


Hot-unplug currently causes qemu to crash, this
happens without this patch too, so I'm not worried :)

New since v1:
        hotplug support

-- 
MST


Michael S. Tsirkin (2):
  shpc: standard hot plug controller
  pci: add standard bridge device

 Makefile.objs       |    3 +-
 hw/pci.h            |    6 +
 hw/pci_bridge_dev.c |  136 +++++++++++
 hw/shpc.c           |  646 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/shpc.h           |   40 ++++
 qemu-common.h       |    1 +
 6 files changed, 831 insertions(+), 1 deletions(-)
 create mode 100644 hw/pci_bridge_dev.c
 create mode 100644 hw/shpc.c
 create mode 100644 hw/shpc.h

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1.7.9.111.gf3fb0