Hi Baolu, Per my understanding, the subject is not accurate. I think this patch is to get parent device structure for a mediate device instead of iommu device. This may be misleading for reviewers. Thanks, Yi Liu > From: Lu Baolu [mailto:baolu.lu@xxxxxxxxxxxxxxx] > Sent: Sunday, July 22, 2018 2:09 PM > > This patch adds the support to get the iommu device for a mediated device. The > assumption is that each mediated device is a minimal assignable set of a physical PCI > device. Hence, we should use the iommu device of the parent PCI device to manage > the translation. > > Cc: Ashok Raj <ashok.raj@xxxxxxxxx> > Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > Cc: Liu Yi L <yi.l.liu@xxxxxxxxx> > Signed-off-by: Sanjay Kumar <sanjay.k.kumar@xxxxxxxxx> > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > --- > drivers/iommu/intel-iommu.c | 6 ++++++ drivers/iommu/intel-pasid.h | 16 > ++++++++++++++++ > 2 files changed, 22 insertions(+) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index > 7d198ea..fc3ac1c 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -767,6 +767,12 @@ static struct intel_iommu *device_to_iommu(struct device > *dev, u8 *bus, u8 *devf > if (iommu_dummy(dev)) > return NULL; > > + if (dev_is_mdev(dev)) { > + dev = dev_mdev_parent(dev); > + if (WARN_ON(!dev_is_pci(dev))) > + return NULL; > + } > + > if (dev_is_pci(dev)) { > struct pci_dev *pf_pdev; > > diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h index > 518df72..46cde66 100644 > --- a/drivers/iommu/intel-pasid.h > +++ b/drivers/iommu/intel-pasid.h > @@ -35,6 +35,22 @@ struct pasid_table { > struct list_head dev; /* device list */ > }; > > +static inline bool dev_is_mdev(struct device *dev) { > + if (!dev) > + return false; > + > + return !strcmp(dev->bus->name, "mdev"); } > + > +static inline struct device *dev_mdev_parent(struct device *dev) { > + if (WARN_ON(!dev_is_mdev(dev))) > + return NULL; > + > + return dev->parent; > +} > + > extern u32 intel_pasid_max_id; > int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp); void > intel_pasid_free_id(int pasid); > -- > 2.7.4