Re: [Qemu-devel] [PATCH 08/11] s390x/flic: introduce modify_ais_mode callback

[Christian Borntraeger]

On 07/13/2017 09:27 AM, Cornelia Huck wrote:
> On Thu, 13 Jul 2017 09:12:50 +0200
> Christian Borntraeger <address@hidden> wrote:
> 
>> On 07/12/2017 05:07 PM, Cornelia Huck wrote:
>>>> +
>>>> +    switch (mode) {
>>>> +    case SIC_IRQ_MODE_ALL:
>>>> +        flic->simm &= ~AIS_MODE_MASK(isc);
>>>> +        flic->nimm &= ~AIS_MODE_MASK(isc);
>>>> +        break;
>>>> +    case SIC_IRQ_MODE_SINGLE:
>>>> +        flic->simm |= AIS_MODE_MASK(isc);
>>>> +        flic->nimm &= ~AIS_MODE_MASK(isc);  
>>>
>>> Can we have some documentation about the meaning of simm/nimm in qemu?
>>> The one from the patch description of the respective kernel patch would
>>> be fine.  
>>
>> Do you want to have that description as part of the patch description or
>> somewhere in the docs folder or somewhere in the code?
> 
> A comment near the definition of simm/nimm would be nice. Or in the
> commit message, as for the kernel.
> 

I  think I will just add this to the commit message:

We introduce the 'simm' and 'nimm' fields to QEMUS390FLICState
to store interruption modes for each ISC. Each bit in 'simm' and
'nimm' targets to one ISC, and collaboratively indicate three modes:
ALL-Interruptions, SINGLE-Interruption and NO-Interruptions. This
interface can initiate most transitions between the states; transition
from SINGLE-Interruption to NO-Interruptions via adapter interrupt
injection will be introduced in a following patch. The meaningful
combinations are as follows:
    
    interruption mode | simm bit | nimm bit
    ------------------|----------|----------
             ALL      |    0     |     0
           SINGLE     |    1     |     0
             NO       |    1     |     1