On 26/02/13 12:18, Michael S. Tsirkin wrote: > On Tue, Feb 26, 2013 at 01:04:21PM +0200, Michael S. Tsirkin wrote: >> On Mon, Feb 25, 2013 at 04:27:45PM +0100, Cornelia Huck wrote: >>> Here's the latest version of my patch series enabling ioeventfds >>> on s390, again against kvm-next. >>> >>> Patches 1 and 2 (cleaning up initialization and exporting the virtio-ccw >>> api) would make sense even independent of the ioeventfd enhancements. >>> >>> Patches 3-5 are concerned with adding a new type of ioeventfds for >>> virtio-ccw notifications on s390. The naming is now hopefully clearer. >>> We won't add ioeventfd support for the legacy s390-virtio transport. >>> >>> Please consider applying. >> >> I just had a thought: this makes us lookup the device on the bus >> for each notification. It would be better to simply get the >> device index from guest instead. >> >> We could validate that it matches the correct device, >> if not - fallback to the current linear scan. >> >> We could return the index to guest for the next call. >> >> I know this needs guest changes but it's still not too late to >> fix this for 3.9 guests so that we won't need to worry >> about compatibility going forward. >> >> Hmm? > > And just to clarify, here's what I mean (BTW, why doesn't > this code use the interfaces from kvm_para.h?) > I think it's a good idea to merge this before 3.9 so we don't > need to worry about legacy going forward. > > Completely untested, just to give you the idea. Thinking more about it: Isnt the index on the kvm bus just an implementation detail? In other words, what happens if we want to re-arrange the kvm io bus to a tree like structure. Then the index becomes pretty much useless. Do we really want to put such an internal thing into an interface? CHristian -- 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
