Re: [PATCH v3 01/10] iommu: Introduce Shared Virtual Addressing API

[Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Tue, 25 Sep 2018 15:16:47 +0200
Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> wrote:

> On Sun, Sep 23, 2018 at 10:39:25AM +0800, Lu Baolu wrote:
> > > +int iommu_sva_init_device(struct device *dev, unsigned long
> > > features,
> > > +		       unsigned int min_pasid, unsigned int
> > > max_pasid) +{
> > > +	int ret;
> > > +	struct iommu_sva_param *param;
> > > +	struct iommu_domain *domain =
> > > iommu_get_domain_for_dev(dev);  
> > 
> > This doesn't work for vt-d. The domains for host iova are
> > self-managed by vt-d driver itself. Hence,
> > iommu_get_domain_for_dev() will always return NULL unless an
> > UNMANAGED domain is attached to the device.
> > 
> > How about
> > 
> >       const struct iommu_ops *ops = dev->bus->iommu_ops;
> > 
> > instead?  
> 
> The per-bus iommu-ops might go away sooner or later as we move to
> per-device iommu-ops. How about fixing the VT-d driver to not keep
> that domain internal to itself?
> 
Just to understand more specifically, you mean let VT-d driver also
support IOMMU_DOMAIN_DMA as default domain?

But I think the ordering issue is still there in that the DOMAIN_DMA
domain will not be created until DMA map call is invoked. I think
sva_init_device should not depend on the default domain.

> Regards,
> 
> 	Joerg

[Jacob Pan]