diff options
| -rw-r--r-- | drivers/iommu/iommu.c | 104 | ||||
| -rw-r--r-- | include/linux/iommu.h | 70 |
2 files changed, 174 insertions, 0 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 344e27e8f188..f8fe112e507a 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2135,3 +2135,107 @@ int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev) return ret; } EXPORT_SYMBOL_GPL(iommu_aux_get_pasid); + +/** + * iommu_sva_bind_device() - Bind a process address space to a device + * @dev: the device + * @mm: the mm to bind, caller must hold a reference to it + * + * Create a bond between device and address space, allowing the device to access + * the mm using the returned PASID. If a bond already exists between @device and + * @mm, it is returned and an additional reference is taken. Caller must call + * iommu_sva_unbind_device() to release each reference. + * + * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to + * initialize the required SVA features. + * + * On error, returns an ERR_PTR value. + */ +struct iommu_sva * +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) +{ + struct iommu_group *group; + struct iommu_sva *handle = ERR_PTR(-EINVAL); + const struct iommu_ops *ops = dev->bus->iommu_ops; + + if (!ops || !ops->sva_bind) + return ERR_PTR(-ENODEV); + + group = iommu_group_get(dev); + if (!group) + return ERR_PTR(-ENODEV); + + /* Ensure device count and domain don't change while we're binding */ + mutex_lock(&group->mutex); + + /* + * To keep things simple, SVA currently doesn't support IOMMU groups + * with more than one device. Existing SVA-capable systems are not + * affected by the problems that required IOMMU groups (lack of ACS + * isolation, device ID aliasing and other hardware issues). + */ + if (iommu_group_device_count(group) != 1) + goto out_unlock; + + handle = ops->sva_bind(dev, mm, drvdata); + +out_unlock: + mutex_unlock(&group->mutex); + iommu_group_put(group); + + return handle; +} +EXPORT_SYMBOL_GPL(iommu_sva_bind_device); + +/** + * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device + * @handle: the handle returned by iommu_sva_bind_device() + * + * Put reference to a bond between device and address space. The device should + * not be issuing any more transaction for this PASID. All outstanding page + * requests for this PASID must have been flushed to the IOMMU. + * + * Returns 0 on success, or an error value + */ +void iommu_sva_unbind_device(struct iommu_sva *handle) +{ + struct iommu_group *group; + struct device *dev = handle->dev; + const struct iommu_ops *ops = dev->bus->iommu_ops; + + if (!ops || !ops->sva_unbind) + return; + + group = iommu_group_get(dev); + if (!group) + return; + + mutex_lock(&group->mutex); + ops->sva_unbind(handle); + mutex_unlock(&group->mutex); + + iommu_group_put(group); +} +EXPORT_SYMBOL_GPL(iommu_sva_unbind_device); + +int iommu_sva_set_ops(struct iommu_sva *handle, + const struct iommu_sva_ops *sva_ops) +{ + if (handle->ops && handle->ops != sva_ops) + return -EEXIST; + + handle->ops = sva_ops; + return 0; +} +EXPORT_SYMBOL_GPL(iommu_sva_set_ops); + +int iommu_sva_get_pasid(struct iommu_sva *handle) +{ + const struct iommu_ops *ops = handle->dev->bus->iommu_ops; + + if (!ops || !ops->sva_get_pasid) + return IOMMU_PASID_INVALID; + + return ops->sva_get_pasid(handle); +} +EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 8239ece9fdfc..480921dfbadf 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -48,6 +48,7 @@ struct bus_type; struct device; struct iommu_domain; struct notifier_block; +struct iommu_sva; /* iommu fault flags */ #define IOMMU_FAULT_READ 0x0 @@ -55,6 +56,8 @@ struct notifier_block; typedef int (*iommu_fault_handler_t)(struct iommu_domain *, struct device *, unsigned long, int, void *); +typedef int (*iommu_mm_exit_handler_t)(struct device *dev, struct iommu_sva *, + void *); struct iommu_domain_geometry { dma_addr_t aperture_start; /* First address that can be mapped */ @@ -159,6 +162,28 @@ struct iommu_resv_region { /* Per device IOMMU features */ enum iommu_dev_features { IOMMU_DEV_FEAT_AUX, /* Aux-domain feature */ + IOMMU_DEV_FEAT_SVA, /* Shared Virtual Addresses */ +}; + +#define IOMMU_PASID_INVALID (-1U) + +/** + * struct iommu_sva_ops - device driver callbacks for an SVA context + * + * @mm_exit: called when the mm is about to be torn down by exit_mmap. After + * @mm_exit returns, the device must not issue any more transaction + * with the PASID given as argument. + * + * The @mm_exit handler is allowed to sleep. Be careful about the + * locks taken in @mm_exit, because they might lead to deadlocks if + * they are also held when dropping references to the mm. Consider the + * following call chain: + * mutex_lock(A); mmput(mm) -> exit_mm() -> @mm_exit() -> mutex_lock(A) + * Using mmput_async() prevents this scenario. + * + */ +struct iommu_sva_ops { + iommu_mm_exit_handler_t mm_exit; }; #ifdef CONFIG_IOMMU_API @@ -196,6 +221,9 @@ enum iommu_dev_features { * @dev_feat_enabled: check enabled feature * @aux_attach/detach_dev: aux-domain specific attach/detach entries. * @aux_get_pasid: get the pasid given an aux-domain + * @sva_bind: Bind process address space to device + * @sva_unbind: Unbind process address space from device + * @sva_get_pasid: Get PASID associated to a SVA handle * @pgsize_bitmap: bitmap of all possible supported page sizes */ struct iommu_ops { @@ -251,6 +279,11 @@ struct iommu_ops { void (*aux_detach_dev)(struct iommu_domain *domain, struct device *dev); int (*aux_get_pasid)(struct iommu_domain *domain, struct device *dev); + struct iommu_sva *(*sva_bind)(struct device *dev, struct mm_struct *mm, + void *drvdata); + void (*sva_unbind)(struct iommu_sva *handle); + int (*sva_get_pasid)(struct iommu_sva *handle); + unsigned long pgsize_bitmap; }; @@ -417,6 +450,14 @@ struct iommu_fwspec { u32 ids[1]; }; +/** + * struct iommu_sva - handle to a device-mm bond + */ +struct iommu_sva { + struct device *dev; + const struct iommu_sva_ops *ops; +}; + int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode, const struct iommu_ops *ops); void iommu_fwspec_free(struct device *dev); @@ -445,6 +486,14 @@ int iommu_aux_attach_device(struct iommu_domain *domain, struct device *dev); void iommu_aux_detach_device(struct iommu_domain *domain, struct device *dev); int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev); +struct iommu_sva *iommu_sva_bind_device(struct device *dev, + struct mm_struct *mm, + void *drvdata); +void iommu_sva_unbind_device(struct iommu_sva *handle); +int iommu_sva_set_ops(struct iommu_sva *handle, + const struct iommu_sva_ops *ops); +int iommu_sva_get_pasid(struct iommu_sva *handle); + #else /* CONFIG_IOMMU_API */ struct iommu_ops {}; @@ -770,6 +819,27 @@ iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev) return -ENODEV; } +static inline struct iommu_sva * +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) +{ + return NULL; +} + +static inline void iommu_sva_unbind_device(struct iommu_sva *handle) +{ +} + +static inline int iommu_sva_set_ops(struct iommu_sva *handle, + const struct iommu_sva_ops *ops) +{ + return -EINVAL; +} + +static inline int iommu_sva_get_pasid(struct iommu_sva *handle) +{ + return IOMMU_PASID_INVALID; +} + #endif /* CONFIG_IOMMU_API */ #ifdef CONFIG_IOMMU_DEBUGFS |