Messages in this thread | | | Date | Thu, 19 May 2022 17:33:51 +0100 | From | Jean-Philippe Brucker <> | Subject | Re: [PATCH v7 03/10] iommu/sva: Add iommu_sva_domain support |
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On Thu, May 19, 2022 at 03:20:40PM +0800, Lu Baolu wrote: > The iommu_sva_domain represents a hardware pagetable that the IOMMU > hardware could use for SVA translation. This adds some infrastructure > to support SVA domain in the iommu common layer. It includes: > > - Add a new struct iommu_sva_domain and new IOMMU_DOMAIN_SVA domain > type. > - Add a new domain ops pointer in iommu_ops. The IOMMU drivers that > support SVA should provide the callbacks. > - Add helpers to allocate and free an SVA domain. > - Add helpers to set an SVA domain to a device and the reverse > operation. > > Some buses, like PCI, route packets without considering the PASID value. > Thus a DMA target address with PASID might be treated as P2P if the > address falls into the MMIO BAR of other devices in the group. To make > things simple, the attach/detach interfaces only apply to devices > belonging to the singleton groups, and the singleton is immutable in > fabric i.e. not affected by hotplug. > > The iommu_set/block_device_pasid() can be used for other purposes, > such as kernel DMA with pasid, mediation device, etc. Hence, it is put > in the iommu.c. > > Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > include/linux/iommu.h | 51 +++++++++++++++++++++++++ > drivers/iommu/iommu-sva-lib.h | 15 ++++++++ > drivers/iommu/iommu-sva-lib.c | 48 +++++++++++++++++++++++ > drivers/iommu/iommu.c | 71 +++++++++++++++++++++++++++++++++++ > 4 files changed, 185 insertions(+) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 0c358b7c583b..e8cf82d46ce1 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -64,6 +64,9 @@ struct iommu_domain_geometry { > #define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped */ > #define __IOMMU_DOMAIN_DMA_FQ (1U << 3) /* DMA-API uses flush queue */ > > +#define __IOMMU_DOMAIN_SHARED (1U << 4) /* Page table shared from CPU */ > +#define __IOMMU_DOMAIN_HOST_VA (1U << 5) /* Host CPU virtual address */ > + > /* > * This are the possible domain-types > * > @@ -86,6 +89,8 @@ struct iommu_domain_geometry { > #define IOMMU_DOMAIN_DMA_FQ (__IOMMU_DOMAIN_PAGING | \ > __IOMMU_DOMAIN_DMA_API | \ > __IOMMU_DOMAIN_DMA_FQ) > +#define IOMMU_DOMAIN_SVA (__IOMMU_DOMAIN_SHARED | \ > + __IOMMU_DOMAIN_HOST_VA) > > struct iommu_domain { > unsigned type; > @@ -254,6 +259,7 @@ struct iommu_ops { > int (*def_domain_type)(struct device *dev); > > const struct iommu_domain_ops *default_domain_ops; > + const struct iommu_domain_ops *sva_domain_ops; > unsigned long pgsize_bitmap; > struct module *owner; > }; > @@ -262,6 +268,8 @@ struct iommu_ops { > * struct iommu_domain_ops - domain specific operations > * @attach_dev: attach an iommu domain to a device > * @detach_dev: detach an iommu domain from a device > + * @set_dev_pasid: set an iommu domain to a pasid of device > + * @block_dev_pasid: block pasid of device from using iommu domain > * @map: map a physically contiguous memory region to an iommu domain > * @map_pages: map a physically contiguous set of pages of the same size to > * an iommu domain. > @@ -282,6 +290,10 @@ struct iommu_ops { > struct iommu_domain_ops { > int (*attach_dev)(struct iommu_domain *domain, struct device *dev); > void (*detach_dev)(struct iommu_domain *domain, struct device *dev); > + int (*set_dev_pasid)(struct iommu_domain *domain, struct device *dev, > + ioasid_t pasid); > + void (*block_dev_pasid)(struct iommu_domain *domain, struct device *dev, > + ioasid_t pasid); > > int (*map)(struct iommu_domain *domain, unsigned long iova, > phys_addr_t paddr, size_t size, int prot, gfp_t gfp); > @@ -677,6 +689,10 @@ int iommu_group_claim_dma_owner(struct iommu_group *group, void *owner); > void iommu_group_release_dma_owner(struct iommu_group *group); > bool iommu_group_dma_owner_claimed(struct iommu_group *group); > > +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); > #else /* CONFIG_IOMMU_API */ > > struct iommu_ops {}; > @@ -1050,6 +1066,17 @@ static inline bool iommu_group_dma_owner_claimed(struct iommu_group *group) > { > return false; > } > + > +static inline int iommu_set_device_pasid(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > + return -ENODEV; > +} > + > +static inline void iommu_block_device_pasid(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > +} > #endif /* CONFIG_IOMMU_API */ > > /** > @@ -1075,4 +1102,28 @@ void iommu_debugfs_setup(void); > static inline void iommu_debugfs_setup(void) {} > #endif > > +#ifdef CONFIG_IOMMU_SVA > +struct iommu_domain * > +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); > +#else /* CONFIG_IOMMU_SVA */ > +static inline struct iommu_domain * > +iommu_sva_alloc_domain(struct bus_type *bus, struct mm_struct *mm) > +{ > + return ERR_PTR(-EINVAL); > +} > + > +static inline void iommu_sva_free_domain(struct iommu_domain *domain) > +{ > +} > + > +static inline int iommu_sva_set_domain(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > + return -EINVAL; > +} > +#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 8909ea1094e3..1be21e6b93ec 100644 > --- a/drivers/iommu/iommu-sva-lib.h > +++ b/drivers/iommu/iommu-sva-lib.h > @@ -7,6 +7,7 @@ > > #include <linux/ioasid.h> > #include <linux/mm_types.h> > +#include <linux/iommu.h> > > int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max); > struct mm_struct *iommu_sva_find(ioasid_t pasid); > @@ -16,6 +17,20 @@ struct device; > struct iommu_fault; > struct iopf_queue; > > +struct iommu_sva_domain { > + struct iommu_domain domain; > + struct mm_struct *mm; > +}; > + > +#define to_sva_domain(d) container_of_safe(d, struct iommu_sva_domain, domain)
Is there a reason to use the 'safe' version of container_of()? Callers of to_sva_domain() don't check the return value before dereferencing it so they would break anyway if someone passes an error pointer as domain. I think it matters because there is no other user of container_of_safe() in the kernel (the only user, lustre, went away in 2018) so someone will want to remove it.
Apart from that
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> + > +static inline struct mm_struct *domain_to_mm(struct iommu_domain *domain) > +{ > + struct iommu_sva_domain *sva_domain = to_sva_domain(domain); > + > + return sva_domain->mm; > +} > + > #ifdef CONFIG_IOMMU_SVA > int iommu_queue_iopf(struct iommu_fault *fault, void *cookie); > > diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c > index 106506143896..210c376f6043 100644 > --- a/drivers/iommu/iommu-sva-lib.c > +++ b/drivers/iommu/iommu-sva-lib.c > @@ -69,3 +69,51 @@ 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 driver-oriented interfaces > + */ > +struct iommu_domain * > +iommu_sva_alloc_domain(struct bus_type *bus, struct mm_struct *mm) > +{ > + struct iommu_sva_domain *sva_domain; > + struct iommu_domain *domain; > + > + if (!bus->iommu_ops || !bus->iommu_ops->sva_domain_ops) > + return ERR_PTR(-ENODEV); > + > + sva_domain = kzalloc(sizeof(*sva_domain), GFP_KERNEL); > + if (!sva_domain) > + return ERR_PTR(-ENOMEM); > + > + mmgrab(mm); > + sva_domain->mm = mm; > + > + domain = &sva_domain->domain; > + domain->type = IOMMU_DOMAIN_SVA; > + domain->ops = bus->iommu_ops->sva_domain_ops; > + > + return domain; > +} > + > +void iommu_sva_free_domain(struct iommu_domain *domain) > +{ > + struct iommu_sva_domain *sva_domain = to_sva_domain(domain); > + > + mmdrop(sva_domain->mm); > + kfree(sva_domain); > +} > + > +int iommu_sva_set_domain(struct iommu_domain *domain, struct device *dev, > + ioasid_t pasid) > +{ > + struct bus_type *bus = dev->bus; > + > + if (!bus || !bus->iommu_ops || !bus->iommu_ops->sva_domain_ops) > + return -ENODEV; > + > + if (domain->ops != bus->iommu_ops->sva_domain_ops) > + return -EINVAL; > + > + return iommu_set_device_pasid(domain, dev, pasid); > +} > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 9955f58bd08c..789816e4b9d6 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -38,6 +38,7 @@ struct iommu_group { > struct kobject kobj; > struct kobject *devices_kobj; > struct list_head devices; > + struct xarray pasid_array; > struct mutex mutex; > void *iommu_data; > void (*iommu_data_release)(void *iommu_data); > @@ -640,6 +641,7 @@ struct iommu_group *iommu_group_alloc(void) > mutex_init(&group->mutex); > INIT_LIST_HEAD(&group->devices); > INIT_LIST_HEAD(&group->entry); > + xa_init(&group->pasid_array); > > ret = ida_simple_get(&iommu_group_ida, 0, 0, GFP_KERNEL); > if (ret < 0) { > @@ -3251,3 +3253,72 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group) > return user; > } > EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed); > + > +static bool device_group_immutable_singleton(struct device *dev) > +{ > + struct iommu_group *group = iommu_group_get(dev); > + int count; > + > + if (!group) > + return false; > + > + mutex_lock(&group->mutex); > + count = iommu_group_device_count(group); > + mutex_unlock(&group->mutex); > + iommu_group_put(group); > + > + if (count != 1) > + return false; > + > + /* > + * The PCI device could be considered to be fully isolated if all > + * devices on the path from the device to the host-PCI bridge are > + * protected from peer-to-peer DMA by ACS. > + */ > + if (dev_is_pci(dev)) > + return pci_acs_path_enabled(to_pci_dev(dev), NULL, > + REQ_ACS_FLAGS); > + > + return true; > +} > + > +int iommu_set_device_pasid(struct iommu_domain *domain, struct device *dev, > + ioasid_t pasid) > +{ > + struct iommu_group *group; > + int ret = -EBUSY; > + void *curr; > + > + if (!domain->ops->set_dev_pasid) > + return -EOPNOTSUPP; > + > + if (!device_group_immutable_singleton(dev)) > + return -EINVAL; > + > + group = iommu_group_get(dev); > + mutex_lock(&group->mutex); > + curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain, GFP_KERNEL); > + if (curr) > + goto out_unlock; > + ret = domain->ops->set_dev_pasid(domain, dev, pasid); > + if (ret) > + xa_erase(&group->pasid_array, pasid); > +out_unlock: > + mutex_unlock(&group->mutex); > + iommu_group_put(group); > + > + return ret; > +} > + > +void iommu_block_device_pasid(struct iommu_domain *domain, struct device *dev, > + ioasid_t pasid) > +{ > + struct iommu_group *group = iommu_group_get(dev); > + > + mutex_lock(&group->mutex); > + domain->ops->block_dev_pasid(domain, dev, pasid); > + xa_erase(&group->pasid_array, pasid); > + mutex_unlock(&group->mutex); > + > + iommu_group_put(group); > +} > -- > 2.25.1 >
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