Marcelo Tosatti wrote: > On Fri, Jun 13, 2008 at 12:15:23AM +0800, Xu, Anthony wrote: >>> I think it would be better to avoid static PCI pin -> IOAPIC pin >>> assignments, if PCI link devices can be used (allowing the OS to >>> route IRQ's as it wishes to). >> Seems PCI link device only support irq-pin < 16, >> IOAPIC pin 16~23 can not be used. >> >> >> >>> >>> Take a look at http://www.microsoft.com/whdc/archive/acpi-mp.mspx. >>> It seems cleaner to use "bimodal link nodes" (using the parlance >>> from URL above) instead of "bimodal _PRT" as your present GSI patch >>> is using. >> Bimodal _PRT is a great idea, I never thought of it before, thanks. >> >> While in PIIX platform there are only 4 PCI link entries, how can we >> introduce more? Where to put these added entries? >> still in ISA bridge configure space. > > Would have to write an ACPI-IOAPIC "IRQ router" to replace PIIX. It > would be queried via a SystemIO region, so QEMU can know what IRQ > has been assigned to a particular slot/func (OS can then change IRQ > assignment via link device _SRS method). > > That seems to be necessary for dynamic IRQ assignment of > slots/function once you have more than one IOAPIC (note we can also > assign one IRQ to each function inside each slot, currently there's > one IRQ per _slot_). Agree, it is necessary for dynamic IRQ assignment. > >> Another concern is, can this link use irq-pin > 15? >> In the example ASL code in the web page you provided, they use >> irq-pin <=15 > > Sure it can, as long as the OS has notified its not using PIIX's PIC > (via the _PIC method). Good. Anthony -- To unsubscribe from this list: send the line "unsubscribe kvm-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
