On 01/20/11 20:39, Anthony Liguori wrote:
On 01/20/2011 02:44 AM, Gerd Hoffmann wrote:
Hi,
For (2), you cannot use bus=X,addr=Y because it makes assumptions about
the PCI topology which may change in newer -M pc's.
Why should the PCI topology for 'pc' ever change?
We'll probably get q35 support some day, but when this lands I expect
we'll see a new machine type 'q35', so '-m q35' will pick the ich9
chipset (which will have a different pci topology of course) and '-m
pc' will pick the existing piix chipset (which will continue to look
like it looks today).
But then what's the default machine type? When I say -M pc, I really
mean the default machine.
I'd tend to leave pc as default for a release cycle or two so we can
hash out issues with q35, then flip the default once it got broader
testing and runs stable.
At some point, "qemu-system-x86_64 -device virtio-net-pci,addr=2.0"
Is not going to be a reliable way to invoke qemu because there's no way
we can guarantee that slot 2 isn't occupied by a chipset device or some
other default device.
Indeed. But qemu -M pc should continue to work though. 'pc' would
better named 'piix3', but renaming it now is probably not worth the trouble.
cheers,
Gerd
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