Now, it's impossible to arrange devices into multi-pci-bus,
for example:
<sound model='ac97'>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x04' function='0x0'/>
</sound>
<video>
<model type='cirrus' vram='9216' heads='1'/>
<address type='pci' domain='0x0000' bus='0x1'
slot='0x02' function='0x0'/>
</video>
libvirt will complain about "bus != 0",
fortunately, qemu supports pci-to-pci bridge,
if we want to use multi-pci-bus, we can define
2 pci bridge controllers, then attach 1 to the other
as a subordinate pci-bus, so, 2 pci-buses appear.
for example:
<controller type='pci-bridge' index='0'/>
<controller type='pci-bridge' index='1'>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x05' function='0x0'/>
</controller>
<sound model='ac97'>
<address type='pci' domain='0x0000' bus='0x01'
slot='0x02' function='0x0'/>
</sound>
<video>
<model type='cirrus' vram='9216' heads='1'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x02' function='0x0'/>
</video>
src/conf/domain_conf.c | 5 ++++-
src/conf/domain_conf.h | 1 +
docs/schemas/domaincommon.rng | 1 +
src/qemu/qemu_capabilities.c | 2 +
src/qemu/qemu_capabilities.h | 1 +
src/qemu/qemu_command.c | 70 ++++++++++++++++++++-----
6 files changed, 57 insertions(+), 23 deletions(-)