Re: [PATCH V9 10/10] iommu/vt-d: Report PASID format as domain attribute

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

On Thu, 30 Jan 2020 15:54:44 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> Hi,
> 
> On 2020/1/29 14:01, Jacob Pan wrote:
> > Report the domain attribute of PASID table format. As multiple
> > formats of PASID table entry are supported, it is important for the
> > guest to know which format to use in virtual IOMMU. The result will
> > be used for binding device with guest PASID.
> > 
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> >   drivers/iommu/intel-iommu.c | 22 ++++++++++++++++++++++
> >   include/linux/iommu.h       |  1 +
> >   2 files changed, 23 insertions(+)
> > 
> > diff --git a/drivers/iommu/intel-iommu.c
> > b/drivers/iommu/intel-iommu.c index 2f0bf7cc70ce..b3778e86dc32
> > 100644 --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -6413,6 +6413,27 @@ intel_iommu_domain_set_attr(struct
> > iommu_domain *domain, return ret;
> >   }
> >   
> > +static int intel_iommu_domain_get_attr(struct iommu_domain *domain,
> > +				       enum iommu_attr attr, void
> > *data) +{
> > +	/* Only used for guest */
> > +	switch (domain->type) {
> > +	case IOMMU_DOMAIN_DMA:
> > +		return -ENODEV;
> > +	case IOMMU_DOMAIN_UNMANAGED:
> > +		switch (attr) {
> > +		case DOMAIN_ATTR_PASID_FORMAT:
> > +			*(int *)data =
> > IOMMU_PASID_FORMAT_INTEL_VTD;
> > +			return 0;
> > +		default:
> > +			return -ENODEV;
> > +		}
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> >   const struct iommu_ops intel_iommu_ops = {
> >   	.capable		= intel_iommu_capable,
> >   	.domain_alloc		= intel_iommu_domain_alloc,
> > @@ -6432,6 +6453,7 @@ const struct iommu_ops intel_iommu_ops = {
> >   	.put_resv_regions	= intel_iommu_put_resv_regions,
> >   	.apply_resv_region	= intel_iommu_apply_resv_region,
> >   	.device_group		= pci_device_group,
> > +	.domain_get_attr	= intel_iommu_domain_get_attr,
> >   	.dev_has_feat		= intel_iommu_dev_has_feat,
> >   	.dev_feat_enabled	= intel_iommu_dev_feat_enabled,
> >   	.dev_enable_feat	= intel_iommu_dev_enable_feat,
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index f2223cbb5fd5..9718c109ea0a 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -126,6 +126,7 @@ enum iommu_attr {
> >   	DOMAIN_ATTR_FSL_PAMUV1,
> >   	DOMAIN_ATTR_NESTING,	/* two stages of translation
> > */ DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
> > +	DOMAIN_ATTR_PASID_FORMAT,
> >   	DOMAIN_ATTR_MAX,
> >   };  
> 
> Need to separate the new domain attribution definition and the vt-d
> implementation.
> 
In the current iommu uapi, VTD is the only format. However, PASID table
entry format is a generic attribute, not VT-d specific. It expected to
have more vendor format can be reported under this attribute.

struct iommu_gpasid_bind_data {
	__u32 version;
#define IOMMU_PASID_FORMAT_INTEL_VTD	1


> Best regards,
> baolu

[Jacob Pan]