[PATCH RFC 03/11] iommu: Add attach/detach_dev_pasid domain ops

Lu Baolu
2022-03-20T06:43:01Z

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):

- 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.lu@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;
+
+ ret = domain->ops->attach_dev_pasid(domain, dev, 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;
+
+ group = iommu_group_get(dev);
+ if (WARN_ON(!group))
+ return;
+
+ mutex_lock(&group->mutex);
+ domain->ops->detach_dev_pasid(domain, dev, pasid);
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+}
--
2.25.1