From: Wei Liu <wei.liu@xxxxxxxxxx> Sent: Monday, February 1, 2021 11:53 AM > > On Wed, Jan 27, 2021 at 12:23:45PM -0800, Michael Kelley wrote: > [...] > > +static int hv_setup_stimer0_irq(void) > > +{ > > + int ret; > > + > > + ret = acpi_register_gsi(NULL, HYPERV_STIMER0_VECTOR, > > + ACPI_EDGE_SENSITIVE, ACPI_ACTIVE_HIGH); > > When IO-APIC is enabled on x86, acpi_register_gsi calls > mp_map_gsi_to_irq. That function then calls mp_find_ioapic. Is > HYPERV_STIMER0_VECTOR, when used as a GSI, associated with an IO-APIC? > If not, wouldn't mp_find_ioapic return an error causing > acpi_register_gsi to fail? > > Ah, it appears that this function is not called on x86. I haven't > checked how ARM handles GSI, but presumably this works for you. It > would be good if a comment can be added to clarify things. > > Wei. Will do. Michael