Currently, a lot of the virtio code assumes that bus (i.e. hypervisor) addresses are the same as physical address. This is false on Xen, so virtio is completely broken. I wouldn't be surprised if it also becomes a problem the first time that someone sticks a physical "virtio" device on a 32-bit bus on an ARM SOC with more than 4G RAM.
Would you accept patches to convert virtio_ring and virtio_pci to use the DMA APIs? I think that the only real catch will be that virtio_ring's approach to freeing indirect blocks is currently incompatible with the DMA API -- it assumes that knowing the bus address is enough to call kfree, and I don't think that the DMA API provides a reverse mapping like that. --Andy -- Andy Lutomirski AMA Capital Management, LLC _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
