Hi Eric, There are some discussions about how to size the uAPI data. https://lkml.org/lkml/2020/4/14/939 I think the problem with the current scheme is that when uAPI data gets extended, if VFIO continue to use: minsz = offsetofend(struct vfio_iommu_type1_set_pasid_table, config); if (copy_from_user(&spt, (void __user *)arg, minsz)) It may copy more data from user than what was setup by the user. So, as suggested by Alex, we could add argsz to the IOMMU uAPI struct. So if argsz > minsz, then fail the attach_table since kernel might be old, doesn't know about the extra data. If argsz <= minsz, kernel can support the attach_table but must process the data based on flags or config. Does it make sense to you? On Tue, 14 Apr 2020 17:05:55 +0200 Eric Auger <eric.auger@xxxxxxxxxx> wrote: > From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > > In virtualization use case, when a guest is assigned > a PCI host device, protected by a virtual IOMMU on the guest, > the physical IOMMU must be programmed to be consistent with > the guest mappings. If the physical IOMMU supports two > translation stages it makes sense to program guest mappings > onto the first stage/level (ARM/Intel terminology) while the host > owns the stage/level 2. > > In that case, it is mandated to trap on guest configuration > settings and pass those to the physical iommu driver. > > This patch adds a new API to the iommu subsystem that allows > to set/unset the pasid table information. > > A generic iommu_pasid_table_config struct is introduced in > a new iommu.h uapi header. This is going to be used by the VFIO > user API. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx> > Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx> > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > --- > drivers/iommu/iommu.c | 19 ++++++++++++++ > include/linux/iommu.h | 18 ++++++++++++++ > include/uapi/linux/iommu.h | 51 > ++++++++++++++++++++++++++++++++++++++ 3 files changed, 88 > insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 2b471419e26c..b71ad56f8c99 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1723,6 +1723,25 @@ int iommu_sva_unbind_gpasid(struct > iommu_domain *domain, struct device *dev, } > EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid); > > +int iommu_attach_pasid_table(struct iommu_domain *domain, > + struct iommu_pasid_table_config *cfg) > +{ > + if (unlikely(!domain->ops->attach_pasid_table)) > + return -ENODEV; > + > + return domain->ops->attach_pasid_table(domain, cfg); > +} > +EXPORT_SYMBOL_GPL(iommu_attach_pasid_table); > + > +void iommu_detach_pasid_table(struct iommu_domain *domain) > +{ > + if (unlikely(!domain->ops->detach_pasid_table)) > + return; > + > + domain->ops->detach_pasid_table(domain); > +} > +EXPORT_SYMBOL_GPL(iommu_detach_pasid_table); > + > 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 7ef8b0bda695..3e1057c3585a 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -248,6 +248,8 @@ struct iommu_iotlb_gather { > * @cache_invalidate: invalidate translation caches > * @sva_bind_gpasid: bind guest pasid and mm > * @sva_unbind_gpasid: unbind guest pasid and mm > + * @attach_pasid_table: attach a pasid table > + * @detach_pasid_table: detach the pasid table > * @pgsize_bitmap: bitmap of all possible supported page sizes > * @owner: Driver module providing these ops > */ > @@ -307,6 +309,9 @@ struct iommu_ops { > void *drvdata); > void (*sva_unbind)(struct iommu_sva *handle); > int (*sva_get_pasid)(struct iommu_sva *handle); > + int (*attach_pasid_table)(struct iommu_domain *domain, > + struct iommu_pasid_table_config > *cfg); > + void (*detach_pasid_table)(struct iommu_domain *domain); > > int (*page_response)(struct device *dev, > struct iommu_fault_event *evt, > @@ -446,6 +451,9 @@ extern int iommu_sva_bind_gpasid(struct > iommu_domain *domain, struct device *dev, struct > iommu_gpasid_bind_data *data); extern int > iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device > *dev, ioasid_t pasid); +extern int iommu_attach_pasid_table(struct > iommu_domain *domain, > + struct iommu_pasid_table_config > *cfg); +extern void iommu_detach_pasid_table(struct iommu_domain > *domain); extern struct iommu_domain *iommu_get_domain_for_dev(struct > device *dev); extern struct iommu_domain *iommu_get_dma_domain(struct > device *dev); extern int iommu_map(struct iommu_domain *domain, > unsigned long iova, @@ -1048,6 +1056,16 @@ iommu_aux_get_pasid(struct > iommu_domain *domain, struct device *dev) return -ENODEV; > } > > +static inline > +int iommu_attach_pasid_table(struct iommu_domain *domain, > + struct iommu_pasid_table_config *cfg) > +{ > + return -ENODEV; > +} > + > +static inline > +void iommu_detach_pasid_table(struct iommu_domain *domain) {} > + > static inline struct iommu_sva * > iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void > *drvdata) { > diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h > index 4ad3496e5c43..8d00be10dc6d 100644 > --- a/include/uapi/linux/iommu.h > +++ b/include/uapi/linux/iommu.h > @@ -321,4 +321,55 @@ struct iommu_gpasid_bind_data { > }; > }; > > +/** > + * struct iommu_pasid_smmuv3 - ARM SMMUv3 Stream Table Entry stage 1 > related > + * information > + * @version: API version of this structure > + * @s1fmt: STE s1fmt (format of the CD table: single CD, linear table > + * or 2-level table) > + * @s1dss: STE s1dss (specifies the behavior when @pasid_bits != 0 > + * and no PASID is passed along with the incoming > transaction) > + * @padding: reserved for future use (should be zero) > + * > + * The PASID table is referred to as the Context Descriptor (CD) > table on ARM > + * SMMUv3. Please refer to the ARM SMMU 3.x spec (ARM IHI 0070A) for > full > + * details. > + */ > +struct iommu_pasid_smmuv3 { > +#define PASID_TABLE_SMMUV3_CFG_VERSION_1 1 > + __u32 version; > + __u8 s1fmt; > + __u8 s1dss; > + __u8 padding[2]; > +}; > + > +/** > + * struct iommu_pasid_table_config - PASID table data used to bind > guest PASID > + * table to the host IOMMU > + * @version: API version to prepare for future extensions > + * @format: format of the PASID table > + * @base_ptr: guest physical address of the PASID table > + * @pasid_bits: number of PASID bits used in the PASID table > + * @config: indicates whether the guest translation stage must > + * be translated, bypassed or aborted. > + * @padding: reserved for future use (should be zero) > + * @smmuv3: table information when @format is > %IOMMU_PASID_FORMAT_SMMUV3 > + */ > +struct iommu_pasid_table_config { > +#define PASID_TABLE_CFG_VERSION_1 1 > + __u32 version; > +#define IOMMU_PASID_FORMAT_SMMUV3 1 > + __u32 format; > + __u64 base_ptr; > + __u8 pasid_bits; > +#define IOMMU_PASID_CONFIG_TRANSLATE 1 > +#define IOMMU_PASID_CONFIG_BYPASS 2 > +#define IOMMU_PASID_CONFIG_ABORT 3 > + __u8 config; > + __u8 padding[6]; > + union { > + struct iommu_pasid_smmuv3 smmuv3; > + }; > +}; > + > #endif /* _UAPI_IOMMU_H */ [Jacob Pan]
