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

[Paul Brook]

> 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.

Paul