Messages in this thread Patch in this message | | | From | Lu Baolu <> | Subject | [PATCH v10 08/12] iommu/sva: Refactoring iommu_sva_bind/unbind_device() | Date | Tue, 5 Jul 2022 13:07:06 +0800 |
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The existing iommu SVA interfaces are implemented by calling the SVA specific iommu ops provided by the IOMMU drivers. There's no need for any SVA specific ops in iommu_ops vector anymore as we can achieve this through the generic attach/detach_dev_pasid domain ops.
This refactors the IOMMU SVA interfaces implementation by using the set/block_pasid_dev ops and align them with the concept of the SVA iommu domain. Put the new SVA code in the sva related file in order to make it self-contained.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Tested-by: Tony Zhu <tony.zhu@intel.com> --- include/linux/iommu.h | 67 +++++++++++-------- drivers/iommu/iommu-sva-lib.c | 98 ++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 119 ++++++++-------------------------- 3 files changed, 165 insertions(+), 119 deletions(-)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 42f0418dc22c..f59b0ecd3995 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -39,7 +39,6 @@ struct device; struct iommu_domain; struct iommu_domain_ops; struct notifier_block; -struct iommu_sva; struct iommu_fault_event; struct iommu_dma_cookie; @@ -57,6 +56,14 @@ struct iommu_domain_geometry { bool force_aperture; /* DMA only allowed in mappable range? */ }; +/** + * struct iommu_sva - handle to a device-mm bond + */ +struct iommu_sva { + struct device *dev; + refcount_t users; +}; + /* Domain feature flags */ #define __IOMMU_DOMAIN_PAGING (1U << 0) /* Support for iommu_map/unmap */ #define __IOMMU_DOMAIN_DMA_API (1U << 1) /* Domain for use in DMA-API @@ -105,6 +112,7 @@ struct iommu_domain { }; struct { /* IOMMU_DOMAIN_SVA */ struct mm_struct *mm; + struct iommu_sva bond; }; }; }; @@ -638,13 +646,6 @@ struct iommu_fwspec { /* ATS is supported */ #define IOMMU_FWSPEC_PCI_RC_ATS (1 << 0) -/** - * struct iommu_sva - handle to a device-mm bond - */ -struct iommu_sva { - struct device *dev; -}; - int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode, const struct iommu_ops *ops); void iommu_fwspec_free(struct device *dev); @@ -685,11 +686,6 @@ int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features f); int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features f); bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features f); -struct iommu_sva *iommu_sva_bind_device(struct device *dev, - struct mm_struct *mm); -void iommu_sva_unbind_device(struct iommu_sva *handle); -u32 iommu_sva_get_pasid(struct iommu_sva *handle); - int iommu_device_use_default_domain(struct device *dev); void iommu_device_unuse_default_domain(struct device *dev); @@ -703,6 +699,8 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid); void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid); +struct iommu_domain * +iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid); #else /* CONFIG_IOMMU_API */ struct iommu_ops {}; @@ -1033,21 +1031,6 @@ iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat) return -ENODEV; } -static inline struct iommu_sva * -iommu_sva_bind_device(struct device *dev, struct mm_struct *mm) -{ - return NULL; -} - -static inline void iommu_sva_unbind_device(struct iommu_sva *handle) -{ -} - -static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle) -{ - return IOMMU_PASID_INVALID; -} - static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct device *dev) { return NULL; @@ -1093,6 +1076,12 @@ static inline void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid) { } + +static inline struct iommu_domain * +iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid) +{ + return NULL; +} #endif /* CONFIG_IOMMU_API */ /** @@ -1118,4 +1107,26 @@ void iommu_debugfs_setup(void); static inline void iommu_debugfs_setup(void) {} #endif +#ifdef CONFIG_IOMMU_SVA +struct iommu_sva *iommu_sva_bind_device(struct device *dev, + struct mm_struct *mm); +void iommu_sva_unbind_device(struct iommu_sva *handle); +u32 iommu_sva_get_pasid(struct iommu_sva *handle); +#else +static inline struct iommu_sva * +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm) +{ + return NULL; +} + +static inline void iommu_sva_unbind_device(struct iommu_sva *handle) +{ +} + +static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle) +{ + return IOMMU_PASID_INVALID; +} +#endif /* CONFIG_IOMMU_SVA */ + #endif /* __LINUX_IOMMU_H */ diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c index 106506143896..751366980232 100644 --- a/drivers/iommu/iommu-sva-lib.c +++ b/drivers/iommu/iommu-sva-lib.c @@ -4,6 +4,7 @@ */ #include <linux/mutex.h> #include <linux/sched/mm.h> +#include <linux/iommu.h> #include "iommu-sva-lib.h" @@ -69,3 +70,100 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid) return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero); } EXPORT_SYMBOL_GPL(iommu_sva_find); + +/** + * 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 mm_users + * + * 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) +{ + struct iommu_domain *domain; + ioasid_t max_pasids; + int ret = -EINVAL; + + max_pasids = dev->iommu->max_pasids; + if (!max_pasids) + return ERR_PTR(-EOPNOTSUPP); + + /* Allocate mm->pasid if necessary. */ + ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1); + if (ret) + return ERR_PTR(ret); + + mutex_lock(&iommu_sva_lock); + /* Search for an existing domain. */ + domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid); + if (domain) { + refcount_inc(&domain->bond.users); + goto out_success; + } + + /* Allocate a new domain and set it on device pasid. */ + domain = iommu_sva_domain_alloc(dev, mm); + if (!domain) { + ret = -ENOMEM; + goto out_unlock; + } + + ret = iommu_attach_device_pasid(domain, dev, mm->pasid); + if (ret) + goto out_free_domain; + domain->bond.dev = dev; + refcount_set(&domain->bond.users, 1); + +out_success: + mutex_unlock(&iommu_sva_lock); + return &domain->bond; + +out_free_domain: + iommu_domain_free(domain); +out_unlock: + mutex_unlock(&iommu_sva_lock); + + return ERR_PTR(ret); +} +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. + */ +void iommu_sva_unbind_device(struct iommu_sva *handle) +{ + struct device *dev = handle->dev; + struct iommu_domain *domain = + container_of(handle, struct iommu_domain, bond); + ioasid_t pasid = iommu_sva_get_pasid(handle); + + mutex_lock(&iommu_sva_lock); + if (refcount_dec_and_test(&domain->bond.users)) { + iommu_detach_device_pasid(domain, dev, pasid); + iommu_domain_free(domain); + } + mutex_unlock(&iommu_sva_lock); +} +EXPORT_SYMBOL_GPL(iommu_sva_unbind_device); + +u32 iommu_sva_get_pasid(struct iommu_sva *handle) +{ + struct iommu_domain *domain = + container_of(handle, struct iommu_domain, bond); + + return domain->mm->pasid; +} +EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 10479c5e4d23..e1491eb3c7b6 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2789,97 +2789,6 @@ bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features feat) } EXPORT_SYMBOL_GPL(iommu_dev_feature_enabled); -/** - * 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) -{ - struct iommu_group *group; - struct iommu_sva *handle = ERR_PTR(-EINVAL); - const struct iommu_ops *ops = dev_iommu_ops(dev); - - if (!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); - -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. - */ -void iommu_sva_unbind_device(struct iommu_sva *handle) -{ - struct iommu_group *group; - struct device *dev = handle->dev; - const struct iommu_ops *ops = dev_iommu_ops(dev); - - if (!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); - -u32 iommu_sva_get_pasid(struct iommu_sva *handle) -{ - const struct iommu_ops *ops = dev_iommu_ops(handle->dev); - - if (!ops->sva_get_pasid) - return IOMMU_PASID_INVALID; - - return ops->sva_get_pasid(handle); -} -EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); - /* * Changes the default domain of an iommu group that has *only* one device * @@ -3366,3 +3275,31 @@ void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev, iommu_group_put(group); } + +/* + * This is a variant of iommu_get_domain_for_dev(). It returns the existing + * domain attached to pasid of a device. It's only for internal use of the + * IOMMU subsystem. The caller must take care to avoid any possible + * use-after-free case. + */ +struct iommu_domain * +iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid) +{ + struct iommu_domain *domain; + struct iommu_group *group; + + if (!pasid_valid(pasid)) + return NULL; + + group = iommu_group_get(dev); + if (!group) + return NULL; + /* + * The xarray protects its internal state with RCU. Hence the domain + * obtained is either NULL or fully formed. + */ + domain = xa_load(&group->pasid_array, pasid); + iommu_group_put(group); + + return domain; +} -- 2.25.1
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