Re: HVMlite ABI specification DRAFT A

["Roger Pau Monné" <roger.pau@citrix.com>]

El 5/2/16 a les 12:45, Jan Beulich ha escrit:
>>>> On 05.02.16 at 12:30, <roger.pau@citrix.com> wrote:
>> El 5/2/16 a les 11:40, Jan Beulich ha escrit:
>>>>>> On 05.02.16 at 10:50, <roger.pau@citrix.com> wrote:
>>>> For legacy PCI interrupts, we can parse the MADT inside of Xen in order
>>>> to properly setup the lines/overwrites and inject the interrupts that
>>>> are not handled by Xen straight into the hardware domain. This will
>>>> require us to be able to emulate the same topology as what is found in
>>>> native (eg: if there are two IO APICs in the hardware we should also
>>>> provide two emulated ones to the hw domain).
>>>
>>> I don't think MADT contains all the needed information, or else we
>>> wouldn't need PHYSDEVOP_setup_gsi.
>>
>> AFAICT, I think we could do something like:
>>
>>  - IRQs [0, 15]: edge-trigger, low-polarity.
>>  - IRQs [16, n]: level-triggered, high-polarity.
> 
> That's not a valid assumption - I've seen systems with other settings
> on GSI >= 16 ...

Then we just propagate how the emulated IO APIC pins are setup to the
real one, this should match reality, and is no different from using
PHYSDEVOP_setup_gsi. AFAICT it's just a different way of getting the
same information.

Roger.