RE: [RFC v3 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)

[Liu, Yi L]

> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Friday, January 31, 2020 8:41 PM
> To: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Subject: RE: [RFC v3 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
> 
> Hi Alex,
> 
> > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx]
> > Sent: Thursday, January 30, 2020 7:56 AM
> > To: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> > Subject: Re: [RFC v3 1/8] vfio: Add
> > VFIO_IOMMU_PASID_REQUEST(alloc/free)
> >
> > On Wed, 29 Jan 2020 04:11:45 -0800
> > "Liu, Yi L" <yi.l.liu@xxxxxxxxx> wrote:
> >
> > > From: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > >
[...]
> > > +
> > > +int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max) {
> > > +	ioasid_t pasid;
> > > +	int ret = -ENOSPC;
> > > +
> > > +	mutex_lock(&vmm->pasid_lock);
> > > +	if (vmm->pasid_count >= vmm->pasid_quota) {
> > > +		ret = -ENOSPC;
> > > +		goto out_unlock;
> > > +	}
> > > +	/* Track ioasid allocation owner by mm */
> > > +	pasid = ioasid_alloc((struct ioasid_set *)vmm->mm, min,
> > > +				max, NULL);
> >
> > Is mm effectively only a token for this?  Maybe we should have a
> > struct vfio_mm_token since gets and puts are not creating a reference
> > to an mm, but to an "mm token".
> 
> yes, it is supposed to be a kind of token. vfio_mm_token is better naming. :-)

Hi Alex,

Just to double check if I got your point. Your point is to have a separate structure
which is only wrap of mm or just renaming current vfio_mm would be enough?


Regards,
Yi Liu