On 08/19/2009 06:28 PM, Ira W. Snyder wrote:
Well, if you can't do that, you can't use virtio-pci on the host.
You'll need another virtio transport (equivalent to "fake pci" you
mentioned above).
Ok.
Is there something similar that I can study as an example? Should I look
at virtio-pci?
There's virtio-lguest, virtio-s390, and virtio-vbus.
I think you tried to take two virtio-nets and make them talk together?
That won't work. You need the code from qemu to talk to virtio-net
config space, and vhost-net to pump the rings.
It *is* possible to make two unmodified virtio-net's talk together. I've
done it, and it is exactly what the virtio-over-PCI patch does. Study it
and you'll see how I connected the rx/tx queues together.
Right, crossing the cables works, but feature negotiation is screwed up,
and both sides think the data is in their RAM.
vhost-net doesn't do negotiation and doesn't assume the data lives in
its address space.
Please find a name other than virtio-over-PCI since it conflicts with
virtio-pci. You're tunnelling virtio config cycles (which are usually
done on pci config cycles) on a new protocol which is itself tunnelled
over PCI shared memory.
Sorry about that. Do you have suggestions for a better name?
virtio-$yourhardware or maybe virtio-dma
I called it virtio-over-PCI in my previous postings to LKML, so until a
new patch is written and posted, I'll keep referring to it by the name
used in the past, so people can search for it.
When I post virtio patches, should I CC another mailing list in addition
to LKML?
virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx is virtio's home.
That said, I'm not sure how qemu-system-ppc running on x86 could
possibly communicate using virtio-net. This would mean the guest is an
emulated big-endian PPC, while the host is a little-endian x86. I
haven't actually tested this situation, so perhaps I am wrong.
I'm confused now. You don't actually have any guest, do you, so why
would you run qemu at all?
The x86 side only needs to run virtio-net, which is present in RHEL 5.3.
You'd only need to run virtio-tunnel or however it's called. All the
eventfd magic takes place on the PCI agents.
I can upgrade the kernel to anything I want on both the x86 and ppc's.
I'd like to avoid changing the x86 (RHEL5) userspace, though. On the
ppc's, I have full control over the userspace environment.
You don't need any userspace on virtio-net's side.
Your ppc boards emulate a virtio-net device, so all you need is the
virtio-net module (and virtio bindings). If you chose to emulate, say,
an e1000 card all you'd need is the e1000 driver.
--
error compiling committee.c: too many arguments to function
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