Re: [PATCH 2/2] iommu/sva: Remove mm parameter from SVA bind API

[Jacob Pan]

Hi Lu,

On Fri, 9 Apr 2021 20:45:22 +0800, Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
wrote:

> > -int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t
> > max) +int iommu_sva_alloc_pasid(ioasid_t min, ioasid_t max)
> >   {
> >   	int ret = 0;
> >   	ioasid_t pasid;
> > +	struct mm_struct *mm;
> >   
> >   	if (min == INVALID_IOASID || max == INVALID_IOASID ||
> >   	    min == 0 || max < min)
> >   		return -EINVAL;
> >   
> >   	mutex_lock(&iommu_sva_lock);
> > +	mm = get_task_mm(current);  
> 
> How could we allocate a supervisor PASID through iommu_sva_alloc_pasid()
> if we always use current->mm here?
I don't think you can. But I guess the current callers of this function do
not need supervisor PASID.
In reply to Jean, I suggest we split this function into mm->pasid
assignment and keep using ioasid_alloc() directly, then supervisor PASID is
caller's bind choice.

Thanks,

Jacob