Messages in this thread | | | Date | Thu, 11 Jun 2020 17:02:15 -0700 | From | Jacob Pan <> | Subject | Re: [PATCH v2 2/3] iommu/uapi: Add argsz for user filled data |
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On Thu, 11 Jun 2020 10:49:36 -0600 Alex Williamson <alex.williamson@redhat.com> wrote:
> On Wed, 10 Jun 2020 21:12:14 -0700 > Jacob Pan <jacob.jun.pan@linux.intel.com> wrote: > > > As IOMMU UAPI gets extended, user data size may increase. To support > > backward compatibiliy, this patch introduces a size field to each > > UAPI data structures. It is *always* the responsibility for the > > user to fill in the correct size. > > Though at the same time, argsz is user provided data which we don't > trust. The argsz field allows the user to indicate how much data > they're providing, it's still the kernel's responsibility to validate > whether it's correct and sufficient for the requested operation. > Thanks, > Yes, will add this clarification.
Thanks,
Jacob > Alex > > > Specific scenarios for user data handling are documented in: > > Documentation/userspace-api/iommu.rst > > > > Signed-off-by: Liu Yi L <yi.l.liu@intel.com> > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > > --- > > include/uapi/linux/iommu.h | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h > > index e907b7091a46..303f148a5cd7 100644 > > --- a/include/uapi/linux/iommu.h > > +++ b/include/uapi/linux/iommu.h > > @@ -135,6 +135,7 @@ enum iommu_page_response_code { > > > > /** > > * struct iommu_page_response - Generic page response information > > + * @argsz: User filled size of this data > > * @version: API version of this structure > > * @flags: encodes whether the corresponding fields are valid > > * (IOMMU_FAULT_PAGE_RESPONSE_* values) > > @@ -143,6 +144,7 @@ enum iommu_page_response_code { > > * @code: response code from &enum iommu_page_response_code > > */ > > struct iommu_page_response { > > + __u32 argsz; > > #define IOMMU_PAGE_RESP_VERSION_1 1 > > __u32 version; > > #define IOMMU_PAGE_RESP_PASID_VALID (1 << 0) > > @@ -218,6 +220,7 @@ struct iommu_inv_pasid_info { > > /** > > * struct iommu_cache_invalidate_info - First level/stage > > invalidation > > * information > > + * @argsz: User filled size of this data > > * @version: API version of this structure > > * @cache: bitfield that allows to select which caches to > > invalidate > > * @granularity: defines the lowest granularity used for the > > invalidation: @@ -246,6 +249,7 @@ struct iommu_inv_pasid_info { > > * must support the used granularity. > > */ > > struct iommu_cache_invalidate_info { > > + __u32 argsz; > > #define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1 > > __u32 version; > > /* IOMMU paging structure cache */ > > @@ -292,6 +296,7 @@ struct iommu_gpasid_bind_data_vtd { > > > > /** > > * struct iommu_gpasid_bind_data - Information about device and > > guest PASID binding > > + * @argsz: User filled size of this data > > * @version: Version of this data structure > > * @format: PASID table entry format > > * @flags: Additional information on guest bind request > > @@ -309,6 +314,7 @@ struct iommu_gpasid_bind_data_vtd { > > * PASID to host PASID based on this bind data. > > */ > > struct iommu_gpasid_bind_data { > > + __u32 argsz; > > #define IOMMU_GPASID_BIND_VERSION_1 1 > > __u32 version; > > #define IOMMU_PASID_FORMAT_INTEL_VTD 1 >
[Jacob Pan]
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