On 2012-03-28 13:44, Avi Kivity wrote: > On 03/28/2012 01:33 PM, Jan Kiszka wrote: >> On 2012-03-28 13:09, Avi Kivity wrote: >>> On 03/22/2012 01:17 AM, Jan Kiszka wrote: >>>> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >>>> >>>> This patch basically adds kvm_irqchip_send_msi, a service for sending >>>> arbitrary MSI messages to KVM's in-kernel irqchip models. >>>> >>>> As the current KVI API requires us to establish a static route from a >>> >>> s/KVI/KVM/ >>> >>>> pseudo GSI to the target MSI message and inject the MSI via toggling >>>> that GSI, we need to play some tricks to make this unfortunately >>> >>> s/unfortunately/unfortunate/ >> >> Will fix these. > > Only needed if you end up reposting. I will have to, I spotted a memory leak. > >>> >>>> interface transparent. We create those routes on demand and keep them >>>> in a hash table. Succeeding messages can then search for an existing >>>> route in the table first and reuse it whenever possible. If we should >>>> run out of limited GSIs, we simply flush the table and rebuild it as >>>> messages are sent. >>>> >>>> This approach is rather simple and could be optimized further. However, >>>> it is more efficient to enhance the KVM API so that we do not need this >>>> clumsy dynamic routing over futures kernels. >>> >>> Two APIs are clumsier than one. >> >> The current one is very clumsy for user-injected MSIs while the new one >> won't be. It will also be very simple it implement if you recall the >> patch. I think that is worth it. > > Don't see why. The clumsiness will be retained. The cpu doesn't care > how clumsy the API is, only the reader. We won't have to do any hashing/caching over the new API, just a plain "deliver this MSI" IOCTL. Specifically all our upcoming archs like Power and ARM will be able to take the shiny highway instead of the winding countryside road. > >> >>> >>> wet the patch itself, suggest replacing the home grown hash with >>> http://developer.gnome.org/glib/2.30/glib-Caches.html. >> >> Let's keep it simple :). We have no need for many of those features, and >> it would not be possible to implement the logic as compact as it is >> right now. > > Due to the callbacks? Yep. That API pays of if you have more iterations and insertions/removals. > > What if the code grows? It won't as it only has to emulate direct MSI injection over the existing API. That's a static feature. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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
