Re: [Xen-devel] [PATCH v5 19/22] hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 16.03.16 at 16:03, <julien.grall@xxxxxxx> wrote:
> On 04/03/2016 10:16, Jan Beulich wrote:
>>>>> On 04.03.16 at 07:15, <zhaoshenglong@xxxxxxxxxx> wrote:
> 
> [...]
> 
>>> --- a/xen/include/public/hvm/params.h
>>> +++ b/xen/include/public/hvm/params.h
>>> @@ -55,6 +55,16 @@
>>>    * if this delivery method is available.
>>>    */
>>>
>>> +#define HVM_PARAM_CALLBACK_TYPE_EVENT    3
>>> +/*
>>> + * val[55:16] need to be zero.
>>> + * val[15:8] is flag of event-channel interrupt:
>>> + *  bit 8: interrupt is edge(1) or level(0) triggered
>>> + *  bit 9: interrupt is active low(1) or high(0)
>>> + * val[7:0] is PPI number used by event-channel.
> 
> is a PPI
> 
>>> + * This is only used by ARM/ARM64.
>>> + */
> 
> [...]
> 
>> And then I'm now also wondering about the description of bits
>> 8 and 9 - event channels don't know of edge/level triggering
>> or high/low polarity, so it looks to me as if the comment is at
>> least misleading too.
> 
> bit 8 and bit 9 are related to the PPI configuration. We need to know if 
> the interrupt is level/edge trigger active low/high to configure 
> correctly the interrupt controller.
> 
> What about renaming "interrupt" to "PPI" to make clear is related to the 
> PPI?

Maybe. What has confused me more was the "event-channel
interrupt" part in the comment.

Jan


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