Hi Baolu some minor nits.
On Tue, Jun 07, 2022 at 09:49:35AM +0800, Lu Baolu wrote: > The sva iommu_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: > > - Extend the iommu_domain to support a new IOMMU_DOMAIN_SVA domain > type. The IOMMU drivers that support SVA should provide the sva > domain specific iommu_domain_ops. > - Add a helper to allocate an SVA domain. The iommu_domain_free() > is still used to free an SVA domain. > - Add helpers to attach 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_attach/detach_device_pasid() can be used for other purposes, > such as kernel DMA with pasid, mediation device, etc. > > Suggested-by: Jean-Philippe Brucker <jean-phili...@linaro.org> > Suggested-by: Jason Gunthorpe <j...@nvidia.com> > Signed-off-by: Lu Baolu <baolu...@linux.intel.com> > Reviewed-by: Jean-Philippe Brucker <jean-phili...@linaro.org> > --- > include/linux/iommu.h | 45 ++++++++++++++++++++- > drivers/iommu/iommu.c | 93 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 136 insertions(+), 2 deletions(-) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 3fbad42c0bf8..9173c5741447 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 */ s/from CPU/with CPU > +#define __IOMMU_DOMAIN_HOST_VA (1U << 5) /* Host CPU virtual address > */ Do you mean general CPU VA? or Host CPU VA, I'm reading the latter as 2nd stage? > + > /* > * This are the possible domain-types > * > @@ -86,15 +89,24 @@ 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) Doesn't shared automatically mean CPU VA? Do we need another flag? > > struct iommu_domain { > unsigned type; > const struct iommu_domain_ops *ops; > unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */ > - iommu_fault_handler_t handler; > - void *handler_token; > struct iommu_domain_geometry geometry; > struct iommu_dma_cookie *iova_cookie; > + union { > + struct { /* IOMMU_DOMAIN_DMA */ > + iommu_fault_handler_t handler; > + void *handler_token; > + }; > + struct { /* IOMMU_DOMAIN_SVA */ > + struct mm_struct *mm; > + }; > + }; > }; > > static inline bool iommu_is_dma_domain(struct iommu_domain *domain) > @@ -262,6 +274,8 @@ 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 +296,10 @@ 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); > @@ -679,6 +697,12 @@ 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); > > +struct iommu_domain *iommu_sva_domain_alloc(struct device *dev, > + struct mm_struct *mm); > +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); > #else /* CONFIG_IOMMU_API */ > > struct iommu_ops {}; > @@ -1052,6 +1076,23 @@ static inline bool > iommu_group_dma_owner_claimed(struct iommu_group *group) > { > return false; > } > + > +static inline struct iommu_domain * > +iommu_sva_domain_alloc(struct device *dev, struct mm_struct *mm) > +{ > + return NULL; > +} > + > +static inline int iommu_attach_device_pasid(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > + return -ENODEV; > +} > + > +static inline void iommu_detach_device_pasid(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > +} > #endif /* CONFIG_IOMMU_API */ > > /** > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index d1ec855b1f72..e92391dcce33 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -27,6 +27,7 @@ > #include <linux/module.h> > #include <linux/cc_platform.h> > #include <trace/events/iommu.h> > +#include <linux/sched/mm.h> > > static struct kset *iommu_group_kset; > static DEFINE_IDA(iommu_group_ida); > @@ -39,6 +40,7 @@ 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); > @@ -666,6 +668,7 @@ 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) { > @@ -1961,6 +1964,8 @@ EXPORT_SYMBOL_GPL(iommu_domain_alloc); > > void iommu_domain_free(struct iommu_domain *domain) > { > + if (domain->type == IOMMU_DOMAIN_SVA) > + mmdrop(domain->mm); > iommu_put_dma_cookie(domain); > domain->ops->free(domain); > } > @@ -3277,3 +3282,91 @@ bool iommu_group_dma_owner_claimed(struct iommu_group > *group) > return user; > } > EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed); > + > +struct iommu_domain *iommu_sva_domain_alloc(struct device *dev, > + struct mm_struct *mm) > +{ > + const struct iommu_ops *ops = dev_iommu_ops(dev); > + struct iommu_domain *domain; > + > + domain = ops->domain_alloc(IOMMU_DOMAIN_SVA); > + if (!domain) > + return NULL; > + > + domain->type = IOMMU_DOMAIN_SVA; > + mmgrab(mm); > + domain->mm = mm; > + > + return domain; > +} > + > +static bool iommu_group_immutable_singleton(struct iommu_group *group, > + struct device *dev) > +{ > + int count; > + > + mutex_lock(&group->mutex); > + count = iommu_group_device_count(group); > + mutex_unlock(&group->mutex); > + > + 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); Does this comprehend RCiEP devices? Since they are optional even if ACS is lacking. > + > + /* > + * Otherwise, the device came from DT/ACPI, assume it is static and > + * then singleton can know from the device count in the group. > + */ > + return true; > +} > + > +int iommu_attach_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; > + > + group = iommu_group_get(dev); > + if (!group || !iommu_group_immutable_singleton(group, dev)) { > + iommu_group_put(group); > + return -EINVAL; > + } > + > + 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_detach_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 > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu