[PATCH v6 13/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU

[Nicolin Chen]

On Tue, Feb 18, 2025 at 01:18:21PM -0400, Jason Gunthorpe wrote:
> On Fri, Jan 24, 2025 at 04:30:42PM -0800, Nicolin Chen wrote:
> 
> > @@ -1831,31 +1831,30 @@ static int arm_smmu_handle_event(struct arm_smmu_device *smmu,
> >  		return -EOPNOTSUPP;
> >  	}
> 
> There is still the filter at the top:
> 
> 	switch (event->id) {
> 	case EVT_ID_TRANSLATION_FAULT:
> 	case EVT_ID_ADDR_SIZE_FAULT:
> 	case EVT_ID_ACCESS_FAULT:
> 	case EVT_ID_PERMISSION_FAULT:
> 		break;
> 	default:
> 		return -EOPNOTSUPP;
> 	}
> 
> Is that right here or should more event types be forwarded to the
> guest?

That doesn't seem to be right. Something like EVT_ID_BAD_CD_CONFIG
should be forwarded too. I will go through the list.

> >  	mutex_lock(&smmu->streams_mutex);
> [..]
>   
> > -	ret = iommu_report_device_fault(master->dev, &fault_evt);
> > +	if (event->stall) {
> > +		ret = iommu_report_device_fault(master->dev, &fault_evt);
> > +	} else {
> > +		down_read(&master->vmaster_rwsem);
> 
> This already holds the streams_mutex across all of this, do you think
> we should get rid of the vmaster_rwsem and hold the streams_mutex on
> write instead?

They are per master v.s. per smmu. The latter one would make master
commits/attaches exclusive, which feels unnecessary to me, although
it would make the code here slightly cleaner..

Thanks
Nicolin