Re: [PATCH v4 2/6] iommu: Add a helper to do PASID lookup from domain

[Baolu Lu]

On 2022/5/19 02:21, Jacob Pan wrote:

IOMMU group maintains a PASID array which stores the associated IOMMU
domains. This patch introduces a helper function to do domain to PASID
look up. It will be used by TLB flush and device-PASID attach verification.

Do you really need this?

The IOMMU driver has maintained a device tracking list for each domain.
It has been used for cache invalidation when unmap() is called against
dma domain.

Best regards,
baolu

Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
---
  drivers/iommu/iommu.c | 22 ++++++++++++++++++++++
  include/linux/iommu.h |  6 +++++-
  2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 00d0262a1fe9..22f44833db64 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3199,3 +3199,25 @@ struct iommu_domain *iommu_get_domain_for_iopf(struct 
device *dev,

return domain;

  }
+
+ioasid_t iommu_get_pasid_from_domain(struct device *dev, struct iommu_domain 
*domain)
+{
+       struct iommu_domain *tdomain;
+       struct iommu_group *group;
+       unsigned long index;
+       ioasid_t pasid = INVALID_IOASID;
+
+       group = iommu_group_get(dev);
+       if (!group)
+               return pasid;
+
+       xa_for_each(&group->pasid_array, index, tdomain) {
+               if (domain == tdomain) {
+                       pasid = index;
+                       break;
+               }
+       }
+       iommu_group_put(group);
+
+       return pasid;
+}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 36ad007084cc..c0440a4be699 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -694,7 +694,7 @@ void iommu_detach_device_pasid(struct iommu_domain *domain,
                               struct device *dev, ioasid_t pasid);
  struct iommu_domain *
  iommu_get_domain_for_iopf(struct device *dev, ioasid_t pasid);
-
+ioasid_t iommu_get_pasid_from_domain(struct device *dev, struct iommu_domain 
*domain);
  #else /* CONFIG_IOMMU_API */

struct iommu_ops {};

@@ -1070,6 +1070,10 @@ iommu_get_domain_for_iopf(struct device *dev, ioasid_t 
pasid)
  {
        return NULL;
  }
+static ioasid_t iommu_get_pasid_from_domain(struct device *dev, struct 
iommu_domain *domain)
+{
+       return INVALID_IOASID;
+}
  #endif /* CONFIG_IOMMU_API */

#ifdef CONFIG_IOMMU_SVA

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