Re: [libvirt] [PATCH 0/3] add pci-bridge device and address type
在 2012-12-27四的 08:47 +0800，li guang写道：
在 2012-12-26三的 18:07 +0800，Osier Yang写道：
> >>
> >> No, even it's not supported now, the proposed XML should be
> >> designed compatible enough for future. Note that as long
> >> as a new XML is added, it can't changed/removed for back-compact,
> >> so when introducing new XMLs, you should consider the future.
> >>
> >> And on other hand, the introduced XML should be general
> >> enough for all drivers, not only QEMU.
> >>
> >> Anyway, regardless of the current qemu implementation, I think
> >> you should refer to the specification of PCI SGI, so that the
> >> proposed XML could be compatible enough for the future.
> >
> > yes, I will, but any problem with the pci-bridge definition in XML?
> > it's just a simple element.
> > can you tell more details about problem of this new definition?
>
> The point is how to known the pci device is attached to which
> pci bridge *if* multiple bridge is supported. I don't think
> the two types ("root" and "subordinate") could do the work.
>
okay, let me describe the implicit map rule between bridge and device,
before this, we should bear in mind 1 bridge corresponding to only 1 bus
root bridge (bus 0)
|
----- subordinate bridge (bus 1) (slot 0, bus 0)
| |
| ----device 0 (slot 0, bus 1)
| |
| ----device 1 (slot 1, bus 1)
|
------ device 0 (slot 2, bus 0)
|
.......
this map rule was in embedded in my changes.
maybe I have to describe more detail about
the map rule between pci-bridge and devices,
demo XML:
<pci-bridge type='root'/>
<pci-bridge type='secondary'>
<address type='pci-bridge' bus='0x00' slot='0x00'
function='0x0'/>
</pci-bridge>
<pci-bridge type='subordinate'>
<address type='pci-bridge' bus='0x01' slot='0x00'
function='0x0'/>
</pci-bridge>
<device-0>
<address type='pci-bridge' bus='0x00' slot='0x01'
function='0x0'/>
</device-0>
<device-1>
<address type='pci-bridge' bus='0x01' slot='0x00'
function='0x0'/>
</device-1>
<device-2>
<address type='pci-bridge' bus='0x02' slot='0x00'
function='0x0'/>
</device-2>
will have following structure:
root bridge (bus 0)
|
-----secondary bridge (bus 1) (bus 0, slot 0)
| |
| ------subordinate bridge (bus 2) (bus 1, slot 0)
| | |
| | -------device 2 (bus 2, slot 0)
| |
| ------device 1 (bus 1, slot 1)
|
-----device 0 (bus 0, slot 1)
> >
> >>
> >>> every subordinate will attach to root bridge, and has its own slot.
> >>>
> >>>>
> >>>> To describe the relationship between bridges, perhaps we will need
> >>>> "parent" and "child" properties
for<pcibridge> device.
> >>>>
> >>>> To describe the relatioship between a pci device and a pci bridge,
> >>>> a property like "bridge" for general pci device should be
enough.
> >>>> In this case, another property for<pcibridge> is needed,
to
> >>>> indentify it, such as "id" or "name".
> >>>
> >>> only relationship is not enough, it's unsuitable for passing
'-device
> >>> pci-bridge' to qemu, so I define a new device and address type for
> >>> pci-bridge in libvirt.
> >>>
> >>>>
> >>>> Regards,
> >>>> Osier
> >>>>
> >>>>
> >>>
> >>
> >
>
--
regards!
li guang