[Qemu-devel] [PATCHv3 0/4] standard pci bridge device

["Michael S. Tsirkin" <mst@redhat.com>]

Here's a new version of the patch.

TODOs:
- windows guest testing

Changes from v2:
- added slot id capability
- migration support
- misc fixes
- fix checkpatch errors

I also include a patch to make all bridges have a user-friendly id.
You don't absolutely have to have it for testing,
but this makes use easier. Without it, you must replace
bus=<id> in instructions below with bus=<id>.0
(add ".0" literally after the id).

Changes from v1:
- hotplug support

Status: tested with a linux guest on x86.
Deep nesting of bridges is supported.
You need a small BIOS patch to support the OSHP method
if you want hotplug to work. Posted 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
used for pci_add command wants data in a format
bus:device.function which is
broken as guests can change bus numbers.
I don't intend to fix it short term.
So, don't use the pci_add command.
Only device_add works with a bridge.

(Side note: the 'addr' property
 encodes slot*8+function#. It is not user-friendly.
 Let's add optional slot= func= ?)

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.

Each bridge must have a unique chassis #.
You *must* set it to a value > 0.
I don't check that it is unique, just that it is >0.
If you make it non unique, guest will be confused.

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,chassis_nr=1
-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 :)




Michael S. Tsirkin (4):
  pci_bridge: user-friendly default bus name
  shpc: standard hot plug controller
  slotid: add slot id capability
  pci: add standard bridge device

 Makefile.objs       |    4 +-
 hw/pci.h            |    8 +
 hw/pci_bridge.c     |   10 +
 hw/pci_bridge_dev.c |  151 ++++++++++++
 hw/shpc.c           |  673 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/shpc.h           |   45 ++++
 hw/slotid_cap.c     |   44 ++++
 hw/slotid_cap.h     |   11 +
 qemu-common.h       |    1 +
 9 files changed, 946 insertions(+), 1 deletions(-)
 create mode 100644 hw/pci_bridge_dev.c
 create mode 100644 hw/shpc.c
 create mode 100644 hw/shpc.h
 create mode 100644 hw/slotid_cap.c
 create mode 100644 hw/slotid_cap.h

-- 
1.7.9.111.gf3fb0