On 30.05.2024 13:19, Chen, Jiqian wrote: > On 2024/5/29 20:22, Jan Beulich wrote: >> On 29.05.2024 13:13, Chen, Jiqian wrote: >>> On 2024/5/29 15:10, Jan Beulich wrote: >>>> On 29.05.2024 08:56, Chen, Jiqian wrote: >>>>> On 2024/5/29 14:31, Jan Beulich wrote: >>>>>> On 29.05.2024 04:41, Chen, Jiqian wrote: >>>>>>> But I found in function init_irq_data: >>>>>>> for ( irq = 0; irq < nr_irqs_gsi; irq++ ) >>>>>>> { >>>>>>> int rc; >>>>>>> >>>>>>> desc = irq_to_desc(irq); >>>>>>> desc->irq = irq; >>>>>>> >>>>>>> rc = init_one_irq_desc(desc); >>>>>>> if ( rc ) >>>>>>> return rc; >>>>>>> } >>>>>>> Does it mean that when irq < nr_irqs_gsi, the gsi and irq is a 1:1 >>>>>>> mapping? >>>>>> >>>>>> No, as explained before. I also don't see how you would derive that from >>>>>> the code above. >>>>> Because here set desc->irq = irq, and it seems there is no other place to >>>>> change this desc->irq, so, gsi 1 is considered to irq 1. >>>> >>>> What are you taking this from? The loop bound isn't nr_gsis, and the >>>> iteration >>>> variable isn't in GSI space either; it's in IRQ numbering space. In this >>>> loop >>>> we're merely leveraging that every GSI has a corresponding IRQ; >>>> there are no assumptions made about the mapping between the two. Afaics at >>>> least. >>>> >>>>>> "nr_irqs_gsi" describes what its name says: The number of >>>>>> IRQs mapping to a (_some_) GSI. That's to tell them from the non-GSI >>>>>> (i.e. >>>>>> mainly MSI) ones. There's no implication whatsoever on the IRQ <-> GSI >>>>>> mapping. >>>>>> >>>>>>> What's more, when using PHYSDEVOP_setup_gsi, it calls mp_register_gsi, >>>>>>> and in mp_register_gsi, it uses " desc = irq_to_desc(gsi); " to get >>>>>>> irq_desc directly. >>>>>> >>>>>> Which may be wrong, while that wrong-ness may not have hit anyone in >>>>>> practice (for reasons that would need working out). >>>>>> >>>>>>> Combining above, can we consider "gsi == irq" when irq < nr_irqs_gsi ? >>>>>> >>>>>> Again - no. >>>>> Since you are certain that they are not equal, could you tell me where >>>>> show they are not equal or where build their mappings, >>>>> so that I can know how to do a conversion gsi from irq. >>>> >>>> I did point you at the ACPI Interrupt Source Override structure before. >>>> We're parsing those in acpi_parse_int_src_ovr(), to give you a place to >>>> start going from. >>> Oh! I think I know. >>> If I want to transform gsi to irq, I need to do below: >>> int irq, entry, ioapic, pin; >>> >>> ioapic = mp_find_ioapic(gsi); >>> pin = gsi - mp_ioapic_routing[ioapic].gsi_base; >>> entry = find_irq_entry(ioapic, pin, mp_INT); >>> irq = pin_2_irq(entry, ioapic, pin); >>> >>> Am I right? >> >> This looks plausible, yes. > I dump all mpc_config_intsrc of array mp_irqs, it shows: > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 0 dstapic > 33 dstirq 2 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 15 srcbus 0 srcbusirq 9 dstapic > 33 dstirq 9 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 1 dstapic > 33 dstirq 1 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 3 dstapic > 33 dstirq 3 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 4 dstapic > 33 dstirq 4 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 5 dstapic > 33 dstirq 5 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 6 dstapic > 33 dstirq 6 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 7 dstapic > 33 dstirq 7 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 8 dstapic > 33 dstirq 8 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 10 dstapic > 33 dstirq 10 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 11 dstapic > 33 dstirq 11 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 12 dstapic > 33 dstirq 12 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 13 dstapic > 33 dstirq 13 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 14 dstapic > 33 dstirq 14 > (XEN) find_irq_entry type 3 irqtype 0 irqflag 0 srcbus 0 srcbusirq 15 dstapic > 33 dstirq 15 > > It seems only Legacy irq and gsi[0:15] has a mapping in mp_irqs. > Other gsi can be considered 1:1 mapping with irq? Or are there other places > reflect the mapping between irq and gsi?
It may be uncommon to have overrides for higher GSIs, but I don't think ACPI disallows that. Jan