Re: [PATCH v3 2/2] iommu/arm-smmu-v3: Adopt arm_smmu_event in handlers

[Pranjal Shrivastava <praan@google.com>]

On Fri, Oct 11, 2024 at 11:21:48AM +0100, Robin Murphy wrote:
> On 2024-10-11 8:55 am, Pranjal Shrivastava wrote:
> > On Thu, Oct 03, 2024 at 03:53:15PM -0700, Nicolin Chen wrote:
> > > On Thu, Oct 03, 2024 at 09:34:35PM +0000, Pranjal Shrivastava wrote:
> > > > > The master and master_name are not that necessary to be in the
> > > > > arm_smmu_event. I would keep both of them as local variables in
> > > > > arm_smmu_handle_evt and pass master_name in to dump().
> > > > 
> > > > Hmm, right or maybe ONLY have the master_name in arm_smmu_event?
> > > 
> > > Just move both out of arm_smmu_event. Keep the master_name as a
> > > local variable like the "master". You'd just need to pass it in
> > > to the dump(). They both are in that same handle_evt().
> > > 
> > 
> > Ack.
> > 
> > > > > > Also, shall we rename it to `arm_smmu_read_evt_info` ?
> > > > > 
> > > > > I'd probably use arm_smmu_event_get_from_raw()? Trying to high-
> > > > > light struct arm_smmu_event v.s. u64 evt[EVTQ_ENT_DWORDS]. Yet,
> > > > > no strong feeling about that.
> > > > > 
> > > > 
> > > > Ack. How about `read_arm_smmu_event` :)
> > > > Unless, we wanna follow the arm_smmu_<func> convention?
> > > 
> > > I think it'd be nicer if we do.
> > > 
> > 
> > Ack. `arm_smmu_get_evt_from_raw` it is!
> 
> FWIW that sounds needlessly overcomplicated to me - the "raw" event array
> should be a member of arm_smmu_event itself, since it seems silly to have
> them separate with one pointing to the other when they have the exact same
> scope and lifetime anyway. There still shouldn't need to be more than a
> single logical step to process an evtq record into a finished
> arm_smmu_event, just that that processing is now going to go a bit further
> than simply le64_to_cpu().

Hmm, are you suggesting something like queue_remove_raw(q, event->raw)?
OR do you mean we should have our own queue_parse_evt(q, &event) that
parses out the raw event into an `arm_smmu_event` record eliminating the
need for the `arm_smmu_read_evt_info` altogether?

Because we'd still need to store the raw event anyway since we're still
logging the raw event.

I think we can go with the former, i.e. queue_remove_raw(q, event->raw)
and then use ``arm_smmu_read_evt_info` to populate other `event` fields 

> Thanks,
> Robin.

Thanks,
Pranjal