On Thursday 19 February 2009 10:01:42 Simon Horman wrote: > On Wed, Feb 18, 2009 at 10:08:00PM +1030, Rusty Russell wrote: > > > > 2) Direct NIC attachment This is particularly interesting with SR-IOV or > > other multiqueue nics, but for boutique cases or benchmarks, could be for > > normal NICs. So far I have some very sketched-out patches: for the > > attached nic dev_alloc_skb() gets an skb from the guest (which supplies > > them via some kind of AIO interface), and a branch in netif_receive_skb() > > which returned it to the guest. This bypasses all firewalling in the > > host though; we're basically having the guest process drive the NIC > > directly. > > Hi Rusty, > > Can I clarify that the idea with utilising SR-IOV would be to assign > virtual functions to guests? That is, something conceptually similar to > PCI pass-through in Xen (although I'm not sure that anyone has virtual > function pass-through working yet). Not quite: I think PCI passthrough IMHO is the *wrong* way to do it: it makes migrate complicated (if not impossible), and requires emulation or the same NIC on the destination host. This would be the *host* seeing the virtual functions as multiple NICs, then the ability to attach a given NIC directly to a process. This isn't guest-visible: the kvm process is configured to connect directly to a NIC, rather than (say) bridging through the host. > If so, wouldn't this also be useful > on machines that have multiple NICs? Yes, but mainly as a benchmark hack AFAICT :) Hope that clarifies, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
