Re: [Xen-devel] [rfc 00/18] ioemu: use devfn instead of slots as the unit for passthrough

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 04/03/2009 22:26, "Simon Horman" <horms@xxxxxxxxxxxx> wrote:

>> Please note that _PRT method in ACPI AML should reflect GSIs. If you expand
>> GSIs, it will be necessary to change the _PRT method. Please see
>> tools/firmware/hvmloader/acpi/dsdt.asl.
> 
> Could someone explain why the current code uses 32 GSIs rather than using 128?

32 should be plenty, and I'd want to emulate multiple IO-APICs beyond that
just out of fear that some OS will choke on an IO-APIC with 128 pins (since
no real single IO-APIC has so many pins). It just seemed a bit unnecessary
when this support was originally implemented. At this point I haven't heard
any concrete evidence so far that 32 GSIs is insufficient in any real
scenario. So that's what we'll be sticking with for the time being, I think.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel