Hi Jacob, On 4/15/20 12:15 AM, Jacob Pan wrote: > 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. So I guess we would need both an argsz _u32 + a new flag _u32 right? I am ok with that idea. Besides how will you manage for existing IOMMU UAPIs? At some point you envisionned to have a getter at iommu api level to retrieve the size of a structure for a given version, right? Thanks Eric > > 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] >
