Messages in this thread Patch in this message | | | From | Alexey Kardashevskiy <> | Subject | [PATCH] iommu: add a function to find an iommu group by id | Date | Fri, 22 Mar 2013 17:49:01 +1100 |
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As IOMMU groups are exposed to the user space by their numbers, the user space can use them in various kernel APIs so the kernel might need an API to find a group by its ID.
As an example, QEMU VFIO on PPC64 platform needs it to associate a logical bus number (LIOBN) with a specific IOMMU group in order to support in-kernel handling of DMA map/unmap requests.
The patch adds the iommu_group_get_by_id(id) function which performs such search.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++ include/linux/iommu.h | 1 + 2 files changed, 29 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 1065a1a..531cbb5 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -204,6 +204,34 @@ again: } EXPORT_SYMBOL_GPL(iommu_group_alloc); +struct iommu_group *iommu_group_get_by_id(int id) +{ + struct kobject *group_kobj; + struct iommu_group *grp; + const char *name; + + if (!iommu_group_kset) + return NULL; + + name = kasprintf(GFP_KERNEL, "%d", id); + if (!name) + return NULL; + + group_kobj = kset_find_obj(iommu_group_kset, name); + kfree(name); + + if (!group_kobj) + return NULL; + + grp = container_of(group_kobj, struct iommu_group, kobj); + BUG_ON(grp->id != id); + + kobject_get(grp->devices_kobj); + + return grp; +} +EXPORT_SYMBOL_GPL(iommu_group_get_by_id); + /** * iommu_group_get_iommudata - retrieve iommu_data registered for a group * @group: the group diff --git a/include/linux/iommu.h b/include/linux/iommu.h index f3b99e1..00e5d7d 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -113,6 +113,7 @@ struct iommu_ops { extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops); extern bool iommu_present(struct bus_type *bus); extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus); +extern struct iommu_group *iommu_group_get_by_id(int id); extern void iommu_domain_free(struct iommu_domain *domain); extern int iommu_attach_device(struct iommu_domain *domain, struct device *dev); -- 1.7.10.4
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