Messages in this thread | | | Date | Thu, 19 May 2022 17:39:25 +0100 | From | Jean-Philippe Brucker <> | Subject | Re: [PATCH v7 06/10] iommu/sva: Refactoring iommu_sva_bind/unbind_device() |
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On Thu, May 19, 2022 at 03:20:43PM +0800, Lu Baolu wrote: > 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> > --- > include/linux/iommu.h | 48 ++++++++------ > drivers/iommu/iommu-sva-lib.h | 1 + > drivers/iommu/iommu-sva-lib.c | 113 ++++++++++++++++++++++++++++++++ > drivers/iommu/iommu.c | 119 ++++++++-------------------------- > 4 files changed, 170 insertions(+), 111 deletions(-) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index e8cf82d46ce1..d9ac5ebe5bbb 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -635,6 +635,7 @@ struct iommu_fwspec { > */ > struct iommu_sva { > struct device *dev; > + refcount_t users; > }; > > int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode, > @@ -677,11 +678,6 @@ 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); > > @@ -693,6 +689,8 @@ int iommu_set_device_pasid(struct iommu_domain *domain, struct device *dev, > ioasid_t pasid); > void iommu_block_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 {}; > @@ -1023,21 +1021,6 @@ 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; > @@ -1077,6 +1060,12 @@ static inline void iommu_block_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 */ > > /** > @@ -1108,6 +1097,10 @@ iommu_sva_alloc_domain(struct bus_type *bus, struct mm_struct *mm); > void iommu_sva_free_domain(struct iommu_domain *domain); > int iommu_sva_set_domain(struct iommu_domain *domain, struct device *dev, > ioasid_t pasid); > +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 /* CONFIG_IOMMU_SVA */ > static inline struct iommu_domain * > iommu_sva_alloc_domain(struct bus_type *bus, struct mm_struct *mm) > @@ -1124,6 +1117,21 @@ static inline int iommu_sva_set_domain(struct iommu_domain *domain, > { > return -EINVAL; > } > + > +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.h b/drivers/iommu/iommu-sva-lib.h > index 1be21e6b93ec..ebab5a8cb126 100644 > --- a/drivers/iommu/iommu-sva-lib.h > +++ b/drivers/iommu/iommu-sva-lib.h > @@ -20,6 +20,7 @@ struct iopf_queue; > struct iommu_sva_domain { > struct iommu_domain domain; > struct mm_struct *mm; > + struct iommu_sva bond; > }; > > #define to_sva_domain(d) container_of_safe(d, struct iommu_sva_domain, domain) > diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c > index 210c376f6043..568e0f64edac 100644 > --- a/drivers/iommu/iommu-sva-lib.c > +++ b/drivers/iommu/iommu-sva-lib.c > @@ -4,6 +4,8 @@ > */ > #include <linux/mutex.h> > #include <linux/sched/mm.h> > +#include <linux/pci.h> > +#include <linux/pci-ats.h> > > #include "iommu-sva-lib.h" > > @@ -117,3 +119,114 @@ int iommu_sva_set_domain(struct iommu_domain *domain, struct device *dev, > > return iommu_set_device_pasid(domain, dev, 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 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_sva_domain *sva_domain; > + struct iommu_domain *domain; > + ioasid_t max_pasid = 0; > + int ret = -EINVAL; > + > + /* Allocate mm->pasid if necessary. */ > + if (!dev->iommu->iommu_dev->pasids) > + return ERR_PTR(-EOPNOTSUPP); > + > + if (dev_is_pci(dev)) { > + max_pasid = pci_max_pasids(to_pci_dev(dev)); > + if (max_pasid < 0) > + return ERR_PTR(max_pasid); > + } else { > + ret = device_property_read_u32(dev, "pasid-num-bits", > + &max_pasid); > + if (ret) > + return ERR_PTR(ret); > + max_pasid = (1UL << max_pasid); > + }
The IOMMU driver needs this PASID width information earlier, when creating the PASID table (in .probe_device(), .attach_dev()). Since we're moving it to the IOMMU core to avoid code duplication, it should be done earlier and stored in dev->iommu
Thanks, Jean
> + max_pasid = min_t(u32, max_pasid, dev->iommu->iommu_dev->pasids); > + ret = iommu_sva_alloc_pasid(mm, 1, max_pasid - 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) { > + sva_domain = to_sva_domain(domain); > + refcount_inc(&sva_domain->bond.users); > + goto out_success; > + } > + > + /* Allocate a new domain and set it on device pasid. */ > + domain = iommu_sva_alloc_domain(dev->bus, mm); > + if (IS_ERR(domain)) { > + ret = PTR_ERR(domain); > + goto out_unlock; > + } > + > + ret = iommu_sva_set_domain(domain, dev, mm->pasid); > + if (ret) > + goto out_free_domain; > + sva_domain = to_sva_domain(domain); > + sva_domain->bond.dev = dev; > + refcount_set(&sva_domain->bond.users, 1); > + > +out_success: > + mutex_unlock(&iommu_sva_lock); > + return &sva_domain->bond; > + > +out_free_domain: > + iommu_sva_free_domain(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_sva_domain *sva_domain = > + container_of(handle, struct iommu_sva_domain, bond); > + ioasid_t pasid = iommu_sva_get_pasid(handle); > + > + mutex_lock(&iommu_sva_lock); > + if (refcount_dec_and_test(&sva_domain->bond.users)) { > + iommu_block_device_pasid(&sva_domain->domain, dev, pasid); > + iommu_sva_free_domain(&sva_domain->domain); > + } > + mutex_unlock(&iommu_sva_lock); > +} > +EXPORT_SYMBOL_GPL(iommu_sva_unbind_device); > + > +u32 iommu_sva_get_pasid(struct iommu_sva *handle) > +{ > + struct iommu_sva_domain *sva_domain = > + container_of(handle, struct iommu_sva_domain, bond); > + > + return sva_domain->mm->pasid; > +} > +EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 789816e4b9d6..e49c5a5b8cc1 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2766,97 +2766,6 @@ 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 > * > @@ -3322,3 +3231,31 @@ void iommu_block_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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