On Thu, Feb 3, 2011 at 7:06 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: > On 2011-02-03 20:01, Blue Swirl wrote: >> On Thu, Feb 3, 2011 at 6:01 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: >>> On 2011-02-03 18:54, Blue Swirl wrote: >>>> On Thu, Feb 3, 2011 at 5:43 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: >>>>> On 2011-02-03 18:36, Blue Swirl wrote: >>>>>> On Thu, Feb 3, 2011 at 5:18 PM, Jan Kiszka <jan.kis...@siemens.com> >>>>>> wrote: >>>>>>> On 2011-02-03 18:03, Blue Swirl wrote: >>>>>>>> On Thu, Feb 3, 2011 at 2:55 PM, Jan Kiszka <jan.kis...@siemens.com> >>>>>>>> wrote: >>>>>>>>> The registers of real IOAPICs can be relocated during runtime (via >>>>>>>>> chipset registers). We don't support this yet, but qemu-kvm carries >>>>>>>>> the >>>>>>>>> current base address in its version 2 vmstate. >>>>>>>>> >>>>>>>>> To align both implementations for migratability, add the proper >>>>>>>>> infrastructure to accept initial as well as updated base addresses and >>>>>>>>> include the current address in the vmstate. This is done in a way that >>>>>>>>> will also allow multiple IOAPICs in the future. >>>>>>>> >>>>>>>> Nack, the addresses should be device properties. >>>>>>> >>>>>>> Hmm.... we could make default_base_address a property. Will change that. >>>>>>> But current_base_address is just the same as apicbase and can't be a >>>>>>> property. >>>>>> >>>>>> Oh, right. What will current_base_address used for? Why can't board >>>>>> just unmap IOAPIC from current address and remap it at the new >>>>>> address? Then the device would not need to know its base address. >>>>> >>>>> The board could do this. The question is where we put this service, in >>>>> the context if the IOAPIC as ioapic_set_base_address (compare to >>>>> cpu_set_apic_base - which is buggy as it lacks sysbus_mmio_map) or into >>>>> each and every board code. In the latter case, the boards would also be >>>>> responsible for saving/restoring the address. >>>> >>>> How is the device relocated? Where are the chipset registers you mention? >>> >>> Intel's PIIX chipsets contain a register called APICBASE (but it means >>> the IOAPIC), and that defines the location. The analogy in the APIC >>> world is the MSR_IA32_APICBASE which we maintain via the APIC state. >> >> In ICH10 the register is called OIC—Other Interrupt Control Register >> and the interesting bits APIC Range Select (ASEL). >> >> So actually PIIX should manage IOAPIC mapping, not board level. > > The point is we need ioapic_set_base_address logic in multiple places > (once chipsets start to implement it). Better push it to a central place > from the beginning. Also the bit keeping. There is no difference to > apicbase.
In that case, the function should be made inline version in ioapic.h.
