Messages in this thread | | | Date | Sun, 31 Jul 2022 20:10:06 +0800 | Subject | Re: [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu interface | From | Yi Liu <> |
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On 2022/7/5 13:07, Lu Baolu wrote: > Attaching an IOMMU domain to a PASID of a device is a generic operation > for modern IOMMU drivers which support PASID-granular DMA address > translation. Currently visible usage scenarios include (but not limited):
s/visible/known/? "known" seems better. up to you. :-)
> > - SVA (Shared Virtual Address) > - kernel DMA with PASID > - hardware-assist mediated device > > This adds a pair of domain ops for this purpose and adds the interfaces > for device drivers to attach/detach a domain to/from a {device, PASID}. > 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, these interfaces only apply to devices belonging to the > singleton groups, and the singleton is immutable in fabric (i.e. not > affected by hotplug). > > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> > Tested-by: Tony Zhu <tony.zhu@intel.com> > --- > include/linux/iommu.h | 21 ++++++++++++ > drivers/iommu/iommu.c | 75 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 96 insertions(+)
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index f41eb2b3c7da..f2b5aa7efe43 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -262,6 +262,8 @@ 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 +284,10 @@ 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 +685,10 @@ 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_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 +1062,17 @@ static inline bool iommu_group_dma_owner_claimed(struct iommu_group *group) > { > return false; > } > + > +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 74a0a3ec0907..be48b09371f4 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -39,6 +39,7 @@ 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); > @@ -660,6 +661,7 @@ 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_alloc(&iommu_group_ida, GFP_KERNEL); > if (ret < 0) { > @@ -3271,3 +3273,76 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group) > return user; > } > EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed); > + > +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); > + > + /* > + * 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; > + void *curr; > + int ret; > + > + 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) { > + ret = xa_err(curr) ? : -EBUSY; > + 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); > +}
-- Regards, Yi Liu
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