On Wed, 15 Apr 2020 16:52:10 +0200 Auger Eric <eric.auger@xxxxxxxxxx> wrote: > 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? > Yes. > I am ok with that idea. Besides how will you manage for existing IOMMU > UAPIs? I plan to add argsz and flags (if not already have one) > 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? > This idea is shot down. There is no version-size lookup. So the current plan is for user to fill out argsz in each IOMMU uAPI struct. VFIO does the copy_from_user() based on argsz (sanitized against the size of current kernel struct). IOMMU vendor driver process the data based on flags which indicates new capability/extensions. > 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] > > > [Jacob Pan] _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
