RE: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)

Liu, Yi L
2020-04-03T12:45:00Z

> From: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Sent: Friday, April 3, 2020 8:40 PM
> Subject: Re: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
>
> On Fri, Apr 03, 2020 at 11:56:09AM +0000, Liu, Yi L wrote:
> > > > /**
> > > > + * VFIO_MM objects - create, release, get, put, search
> > > > + * Caller of the function should have held vfio.vfio_mm_lock.
> > > > + */
> > > > +static struct vfio_mm *vfio_create_mm(struct mm_struct *mm) {
> > > > + struct vfio_mm *vmm;
> > > > + struct vfio_mm_token *token;
> > > > + int ret = 0;
> > > > +
> > > > + vmm = kzalloc(sizeof(*vmm), GFP_KERNEL);
> > > > + if (!vmm)
> > > > + return ERR_PTR(-ENOMEM);
> > > > +
> > > > + /* Per mm IOASID set used for quota control and group operations */
> > > > + ret = ioasid_alloc_set((struct ioasid_set *) mm,
> > >
> > > Hmm, either we need to change the token of ioasid_alloc_set() to
> > > "void *", or pass an actual ioasid_set struct, but this cast doesn't
> > > look good :)
> > >
> > > As I commented on the IOASID series, I think we could embed a struct
> > > ioasid_set into vfio_mm, pass that struct to all other ioasid_*
> > > functions, and get rid of ioasid_sid.
> >
> > I think change to "void *" is better as we needs the token to ensure
> > all threads within a single VM share the same ioasid_set.
>
> Don't they share the same vfio_mm?

that's right. then both works well for me.

Regards,
Yi Liu