Messages in this thread | | | Date | Fri, 31 Jan 2020 09:56:21 -0800 | From | Jacob Pan <> | Subject | Re: [PATCH 3/3] iommu/uapi: Add helper function for size lookup |
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On Wed, 29 Jan 2020 14:40:46 -0700 Alex Williamson <alex.williamson@redhat.com> wrote:
> On Tue, 28 Jan 2020 22:02:04 -0800 > Jacob Pan <jacob.jun.pan@linux.intel.com> 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 <yi.l.liu@intel.com> > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > > --- > > 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; > yes, agreed. > If we add new types in future versions, I assume we'd back fill the > table with -EINVAL as well (rather than zero). Thanks, > right, if the array increase due to new types, the older version with the new type should be filled with -EINVAL. Let me document this in the rules of extensions.
> 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; >
[Jacob Pan]
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