Re: [PATCH] Add I/O hypercalls for i386 paravirt

Jeremy Fitzhardinge
2007-08-22T21:54:24Z

Zachary Amsden wrote:
> This patch provides hypercalls for the i386 port I/O instructions,
> which vastly helps guests which use native-style drivers. For certain
> VMI workloads, this provides a performance boost of up to 30%. We
> expect KVM and lguest to be able to achieve similar gains on I/O
> intensive workloads.

Two comments:

- I should dust off my "break up paravirt_ops" patch, and this would fit
nicely into it (I think we already discussed this)

- What happens if you *don't* want to pv some of the io instructions?
What if you have a device which is directly exposed to the guest?

J