Re: [Qemu-devel] [PATCH 0/5][RFC] virtio-net: MAC filtering

Avi Kivity
2009-01-09T19:39:50Z

Paul Brook wrote:
>> A concern here is the growing size of the virtio-net I/O port space
>> config. This series brings it up to 256 bytes with PCI resource
>> rounding. The VLAN filter bitmap would increase that by another 512
>> bytes, making it 1kB and limiting us to something less than 64 such
>> devices per guest. Is anyone worried? Should filter tables live in
>> MMIO space for virtio devices? I'll send out the guest side patches for
>> virtio-net in a separate thread. Thanks,
>>
>
> This is one reason why IO ports are a reallybad idea. Use memory mapped
> register spaces like any other sane system and you won't have a problem.
>

mmio is slower for virtualization. But I agree pio is baroque.

Luckily we didn't implement the 768 pci slot thing, that wouldn't have
flown (for yet another reason).

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.