[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] Re: APIC rework
Jeremy Fitzhardinge wrote: > On 11/17/09 06:17, Zhang, Xiantao wrote: >> Originally, this patch is target to get rid of ioapic changes in >> dom0. Before this patch, GSI irq should be mapped and setup through >> dom0 programming ioapic entries, but it depends on using ioapic >> logic in dom0. And if we remove ioapic logic from dom0, we need to >> find new way how to setup GSI irq. And this patch comes out under >> this situation. The idea is from that in Xen the interface >> MAP_PIRQ_TYPE_MSI is used to build the pirq and irq mapping for MSI >> IRQ for each domain. Since MSI IRQ can be setup through this >> hypercall, and I think we also can leverage the interface >> MAP_PIRQ_TYPE _GSI to build the mapping for GSI irq. Further >> analysis showes that this interface is only used for assigning >> devices to HVM domain in qemu, and I think it should be Okay for >> dom0 building the mapping between its pirq and irq. One different >> thing for GSI irq is that more info should be provided in the call, >> since GSI IRQ has different trigger-mode and polarity (originally it >> is provided by ioapic write in dom0). Certainly, I also think we >> need to document the related info, and if you agree to the change, I >> am happy to add it. >> > > I don't think there's any need to overload the existing interface > though. If we're adding new functionality then we can add a new > interface for it (but with luck we can reuse most of the existing code > to implement it). > If you're already considering a "treat this differently" flag in the > argument, then that's a strong pointer that a new interface is > warranted. Agree, and I also don't object to add a similar interface. Since this existing interface is only used for hvm domain before, and just want to re-use it for dom. > But also consider the question whether Xen needs to get triggering > info from dom0 at all, or whether it can correctly derive that info > from its own parsing of the relevant tables. Xen should have the ability to parse the info, but may need more logic porting to hyervisor. Xiantao _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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