[PATCH 6/6] iommu: Make set_dev_pasid op support domain replacement

Yi Liu
2024-06-28T08:55:45Z

The iommu core is going to support domain replacement for pasid, it needs
to make the set_dev_pasid op support replacing domain and keep the old
domain config in the failure case.

Currently only the Intel iommu driver supports the latest set_dev_pasid
op definition. ARM and AMD iommu driver do not support domain replacement
for pasid yet, both drivers would fail the set_dev_pasid op to keep the
old config if the input @old is non-NULL.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/amd/pasid.c | 3 +++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 3 +++
include/linux/iommu.h | 3 ++-
3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd/pasid.c b/drivers/iommu/amd/pasid.c
index 77bf5f5f947a..30e27bda3fac 100644
--- a/drivers/iommu/amd/pasid.c
+++ b/drivers/iommu/amd/pasid.c
@@ -109,6 +109,9 @@ int iommu_sva_set_dev_pasid(struct iommu_domain *domain,
unsigned long flags;
int ret = -EINVAL;

+ if (old)
+ return -EOPNOTSUPP;
+
/* PASID zero is used for requests from the I/O device without PASID */
if (!is_pasid_valid(dev_data, pasid))
return ret;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index c058949749cb..a1e411c71efa 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -637,6 +637,9 @@ static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
int ret = 0;
struct mm_struct *mm = domain->mm;

+ if (old)
+ return -EOPNOTSUPP;
+
if (mm_get_enqcmd_pasid(mm) != id)
return -EINVAL;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a33f53aab61b..3259f77ff2e3 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -607,7 +607,8 @@ struct iommu_ops {
* * EBUSY - device is attached to a domain and cannot be changed
* * ENODEV - device specific errors, not able to be attached
* * <others> - treated as ENODEV by the caller. Use is discouraged
- * @set_dev_pasid: set an iommu domain to a pasid of device
+ * @set_dev_pasid: set or replace an iommu domain to a pasid of device. The pasid of
+ * the device should be left in the old config in error case.
* @map_pages: map a physically contiguous set of pages of the same size to
* an iommu domain.
* @unmap_pages: unmap a number of pages of the same size from an iommu domain
--
2.34.1