Re: [PATCH v13 03/10] iommu: Separate IOMMU_DEV_FEAT_IOPF from IOMMU_DEV_FEAT_SVA

2021-03-02 Thread Lu Baolu 

On 3/2/21 5:26 PM, Jean-Philippe Brucker wrote:

Some devices manage I/O Page Faults (IOPF) themselves instead of relying
on PCIe PRI or Arm SMMU stall. Allow their drivers to enable SVA without
mandating IOMMU-managed IOPF. The other device drivers now need to first
enable IOMMU_DEV_FEAT_IOPF before enabling IOMMU_DEV_FEAT_SVA. Enabling
IOMMU_DEV_FEAT_IOPF on its own doesn't have any effect visible to the
device driver, it is used in combination with other features.

Reviewed-by: Eric Auger 
Signed-off-by: Jean-Philippe Brucker 
---
Cc: Arnd Bergmann 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Joerg Roedel 
Cc: Lu Baolu 
Cc: Will Deacon 
Cc: Zhangfei Gao 
Cc: Zhou Wang 
---
  include/linux/iommu.h | 20 +---
  1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 16ce75693d83..45c4eb372f56 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -156,10 +156,24 @@ struct iommu_resv_region {
enum iommu_resv_typetype;
  };
  
-/* Per device IOMMU features */

+/**
+ * enum iommu_dev_features - Per device IOMMU features
+ * @IOMMU_DEV_FEAT_AUX: Auxiliary domain feature
+ * @IOMMU_DEV_FEAT_SVA: Shared Virtual Addresses
+ * @IOMMU_DEV_FEAT_IOPF: I/O Page Faults such as PRI or Stall. Generally
+ *  enabling %IOMMU_DEV_FEAT_SVA requires
+ *  %IOMMU_DEV_FEAT_IOPF, but some devices manage I/O Page
+ *  Faults themselves instead of relying on the IOMMU. When
+ *  supported, this feature must be enabled before and
+ *  disabled after %IOMMU_DEV_FEAT_SVA.
+ *
+ * Device drivers query whether a feature is supported using
+ * iommu_dev_has_feature(), and enable it using iommu_dev_enable_feature().
+ */
  enum iommu_dev_features {
-   IOMMU_DEV_FEAT_AUX, /* Aux-domain feature */
-   IOMMU_DEV_FEAT_SVA, /* Shared Virtual Addresses */
+   IOMMU_DEV_FEAT_AUX,
+   IOMMU_DEV_FEAT_SVA,
+   IOMMU_DEV_FEAT_IOPF,
  };
  
  #define IOMMU_PASID_INVALID	(-1U)




Reviewed-by: Lu Baolu 

Best regards,
baolu
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[PATCH v13 03/10] iommu: Separate IOMMU_DEV_FEAT_IOPF from IOMMU_DEV_FEAT_SVA

2021-03-02 Thread Jean-Philippe Brucker 
Some devices manage I/O Page Faults (IOPF) themselves instead of relying
on PCIe PRI or Arm SMMU stall. Allow their drivers to enable SVA without
mandating IOMMU-managed IOPF. The other device drivers now need to first
enable IOMMU_DEV_FEAT_IOPF before enabling IOMMU_DEV_FEAT_SVA. Enabling
IOMMU_DEV_FEAT_IOPF on its own doesn't have any effect visible to the
device driver, it is used in combination with other features.

Reviewed-by: Eric Auger 
Signed-off-by: Jean-Philippe Brucker 
---
Cc: Arnd Bergmann 
Cc: David Woodhouse 
Cc: Greg Kroah-Hartman 
Cc: Joerg Roedel 
Cc: Lu Baolu 
Cc: Will Deacon 
Cc: Zhangfei Gao 
Cc: Zhou Wang 
---
 include/linux/iommu.h | 20 +---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 16ce75693d83..45c4eb372f56 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -156,10 +156,24 @@ struct iommu_resv_region {
enum iommu_resv_typetype;
 };
 
-/* Per device IOMMU features */
+/**
+ * enum iommu_dev_features - Per device IOMMU features
+ * @IOMMU_DEV_FEAT_AUX: Auxiliary domain feature
+ * @IOMMU_DEV_FEAT_SVA: Shared Virtual Addresses
+ * @IOMMU_DEV_FEAT_IOPF: I/O Page Faults such as PRI or Stall. Generally
+ *  enabling %IOMMU_DEV_FEAT_SVA requires
+ *  %IOMMU_DEV_FEAT_IOPF, but some devices manage I/O Page
+ *  Faults themselves instead of relying on the IOMMU. When
+ *  supported, this feature must be enabled before and
+ *  disabled after %IOMMU_DEV_FEAT_SVA.
+ *
+ * Device drivers query whether a feature is supported using
+ * iommu_dev_has_feature(), and enable it using iommu_dev_enable_feature().
+ */
 enum iommu_dev_features {
-   IOMMU_DEV_FEAT_AUX, /* Aux-domain feature */
-   IOMMU_DEV_FEAT_SVA, /* Shared Virtual Addresses */
+   IOMMU_DEV_FEAT_AUX,
+   IOMMU_DEV_FEAT_SVA,
+   IOMMU_DEV_FEAT_IOPF,
 };
 
 #define IOMMU_PASID_INVALID(-1U)
-- 
2.30.1

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