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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, 14 Jul 2020 13:57:02 +0800 Lu Baolu wrote: > The device driver needs an API to get its aux-domain. A typical usage > scenario is: > > unsigned long pasid; > struct iommu_domain *domain; > struct device *dev = mdev_dev(mdev); > struct device *iommu_device = vfio_mdev_get_iommu_device(dev); > > domain = iommu_aux_get_domain_for_dev(dev); > if (!domain) > return -ENODEV; > > pasid = iommu_aux_get_pasid(domain, iommu_device); > if (pasid <= 0) > return -EINVAL; > > /* Program the device context */ > .... > > This adds an API for such use case. > > Suggested-by: Alex Williamson > Signed-off-by: Lu Baolu > --- > drivers/iommu/iommu.c | 18 ++++++++++++++++++ > include/linux/iommu.h | 7 +++++++ > 2 files changed, 25 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index cad5a19ebf22..434bf42b6b9b 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2817,6 +2817,24 @@ void iommu_aux_detach_group(struct iommu_domain *domain, > } > EXPORT_SYMBOL_GPL(iommu_aux_detach_group); > > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device *dev) > +{ > + struct iommu_domain *domain = NULL; > + struct iommu_group *group; > + > + group = iommu_group_get(dev); > + if (!group) > + return NULL; > + > + if (group->aux_domain_attached) > + domain = group->domain; Why wouldn't the aux domain flag be on the domain itself rather than the group? Then if we wanted sanity checking in patch 1/ we'd only need to test the flag on the object we're provided. If we had such a flag, we could create an iommu_domain_is_aux() function and then simply use iommu_get_domain_for_dev() and test that it's an aux domain in the example use case. It seems like that would resolve the jump from a domain to an aux-domain just as well as adding this separate iommu_aux_get_domain_for_dev() interface. The is_aux test might also be useful in other cases too. Thanks, Alex > + > + iommu_group_put(group); > + > + return domain; > +} > +EXPORT_SYMBOL_GPL(iommu_aux_get_domain_for_dev); > + > /** > * iommu_sva_bind_device() - Bind a process address space to a device > * @dev: the device > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 9506551139ab..cda6cef7579e 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -639,6 +639,7 @@ int iommu_aux_attach_group(struct iommu_domain *domain, > struct iommu_group *group, struct device *dev); > void iommu_aux_detach_group(struct iommu_domain *domain, > struct iommu_group *group, struct device *dev); > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device *dev); > > struct iommu_sva *iommu_sva_bind_device(struct device *dev, > struct mm_struct *mm, > @@ -1040,6 +1041,12 @@ iommu_aux_detach_group(struct iommu_domain *domain, > { > } > > +static inline struct iommu_domain * > +iommu_aux_get_domain_for_dev(struct device *dev) > +{ > + return NULL; > +} > + > static inline struct iommu_sva * > iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) > { _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu