On Tue, 28 Jan 2020 22:02:04 -0800 Jacob Pan <[email protected]> wrote:
> IOMMU UAPI can be extended in the future by adding new > fields at the end of each user data structure. Since we use > a unified UAPI version for compatibility checking, a lookup > function is needed to find the correct user data size to copy > from user. > > This patch adds a helper function based on a 2D lookup with > version and type as input arguments. > > Signed-off-by: Liu Yi L <[email protected]> > Signed-off-by: Jacob Pan <[email protected]> > --- > drivers/iommu/iommu.c | 22 ++++++++++++++++++++++ > include/linux/iommu.h | 6 ++++++ > 2 files changed, 28 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 7dd51c5d2ba1..9e5de9abebdf 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1696,6 +1696,28 @@ int iommu_sva_unbind_gpasid(struct iommu_domain > *domain, struct device *dev, > } > EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid); > > + > +/** > + * Maintain a UAPI version to user data structure size lookup for each > + * API function types we support. e.g. bind guest pasid, cache invalidation. > + * As data structures being extended with new members, the offsetofend() > + * will identify the new sizes. > + */ > +const static int > iommu_uapi_data_size[NR_IOMMU_UAPI_TYPE][IOMMU_UAPI_VERSION] = { > + /* IOMMU_UAPI_BIND_GPASID */ > + {offsetofend(struct iommu_gpasid_bind_data, vtd)}, > + /* IOMMU_UAPI_CACHE_INVAL */ > + {offsetofend(struct iommu_cache_invalidate_info, addr_info)}, > + /* IOMMU_UAPI_PAGE_RESP */ > + {offsetofend(struct iommu_page_response, code)}, > +}; > + > +int iommu_uapi_get_data_size(int type, int version) > +{ Seems like this is asking for a bounds check, if (type >= NR_IOMMU_UAPI_TYPE || version > IOMMU_UAPI_VERSION) return -EINVAL; If we add new types in future versions, I assume we'd back fill the table with -EINVAL as well (rather than zero). Thanks, Alex > + return iommu_uapi_data_size[type][version - 1]; > +} > +EXPORT_SYMBOL_GPL(iommu_uapi_get_data_size); > + > static void __iommu_detach_device(struct iommu_domain *domain, > struct device *dev) > { > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 9718c109ea0a..416fe02160ba 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -500,6 +500,7 @@ extern int iommu_report_device_fault(struct device *dev, > struct iommu_fault_event *evt); > extern int iommu_page_response(struct device *dev, > struct iommu_page_response *msg); > +extern int iommu_uapi_get_data_size(int type, int version); > > extern int iommu_group_id(struct iommu_group *group); > extern struct iommu_group *iommu_group_get_for_dev(struct device *dev); > @@ -885,6 +886,11 @@ static inline int iommu_page_response(struct device *dev, > return -ENODEV; > } > > +static int iommu_uapi_get_data_size(int type, int version) > +{ > + return -ENODEV; > +} > + > static inline int iommu_group_id(struct iommu_group *group) > { > return -ENODEV; _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
