On 2022/3/21 15:13, Tian, Kevin wrote:
From: Lu Baolu<baolu...@linux.intel.com> Sent: Sunday, March 20, 2022 2:40 PMAttaching 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): - SVA - kernel DMA with PASID - hardware-assist mediated device This adds a pair of common domain ops for this purpose and implements a couple of wrapper helpers for in-kernel usage. Signed-off-by: Lu Baolu<baolu...@linux.intel.com> --- include/linux/iommu.h | 22 ++++++++++++++++++++++ drivers/iommu/iommu.c | 41 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 3e179b853380..e51845b9a146 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -268,6 +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 + * @attach_dev_pasid: attach an iommu domain to a pasid of device + * @detach_dev_pasid: detach an iommu domain from a pasid of device * @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. @@ -285,6 +287,10 @@ 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 (*attach_dev_pasid)(struct iommu_domain *domain, + struct device *dev, ioasid_t id); + void (*detach_dev_pasid)(struct iommu_domain *domain, + struct device *dev, ioasid_t id); int (*map)(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot, gfp_t gfp); @@ -678,6 +684,11 @@ 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 {}; @@ -1046,6 +1057,17 @@ 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 0c42ece25854..78c71ee15f36 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -3167,3 +3167,44 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group) return user; } EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed); + +int iommu_attach_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid) +{ + struct iommu_group *group; + int ret = -EINVAL; + + if (!domain->ops->attach_dev_pasid) + return -EINVAL; + + group = iommu_group_get(dev); + if (!group) + return -ENODEV; + + mutex_lock(&group->mutex); + if (iommu_group_device_count(group) != 1) + goto out_unlock;Need move the reason of above limitation from iommu_sva_bind_device() to here: /* * 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;
Yes. We need a comment around this code. But it's not only for SVA but also for all pasid attachment feature. I need more inputs to judge whether this limitation is reasonable.
btw I didn't see any safeguard on above assumption in device hotplug path to a group which already has SVA enabled...
Agreed. Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
