Messages in this thread | | | Subject | Re: [PATCH 0/16 v6] PCI: Linux kernel SR-IOV support | From | Andi Kleen <> | Date | Fri, 07 Nov 2008 16:21:33 +0100 |
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Anthony Liguori <anthony@codemonkey.ws> writes: > > What we would rather do in KVM, is have the VFs appear in the host as > standard network devices. We would then like to back our existing PV > driver to this VF directly bypassing the host networking stack. A key > feature here is being able to fill the VF's receive queue with guest > memory instead of host kernel memory so that you can get zero-copy > receive traffic. This will perform just as well as doing passthrough > (at least) and avoid all that ugliness of dealing with SR-IOV in the > guest.
But you shift a lot of ugliness into the host network stack again. Not sure that is a good trade off.
Also it would always require context switches and I believe one of the reasons for the PV/VF model is very low latency IO and having heavyweight switches to the host and back would be against that.
-Andi
-- ak@linux.intel.com
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