iommu/arm-smmu-v3: Add missing S2FWB feature detection

PATCH Applied Aneesh Kumar K.V (Arm) 5 participants 6 messages Apr 8, 2025 – Apr 17, 2025

Subsystems (2)

IOMMU Arm SMMU drivers

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Aneesh Kumar K.V (Arm)

author

2025-04-08 03:34 UTC #0 lore raw

PATCH 1/1 iommu/arm-smmu-v3: Add missing S2FWB feature detection

Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:

	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);

This patch adds the missing detection logic to prevent allocation failure when S2FWB is supported.

Fixes 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains")

Signed-off-by Aneesh Kumar K.V (Arm) <[email protected]>

---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 1 file changed, 2 insertions(+)

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +2 -0

index 358072b4e293..c7d297ceabdb 100644
@@ -4405,6 +4405,8 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
 	if (FIELD_GET(IDR3_RIL, reg))
 		smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
+	if (FIELD_GET(IDR3_FWB, reg))
+		smmu->features |= ARM_SMMU_FEAT_S2FWB;
 
 	/* IDR5 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);

Signature · 1 line

2.43.0

Pranjal Shrivastava

Reviewed-by on v1 1/1

2025-04-08 05:30 UTC #1 lore raw

Quoted 23 lines · Aneesh Kumar K.V (Arm)

Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:
	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);
This patch adds the missing detection logic to prevent allocation failure when S2FWB is supported.
Fixes 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains")
Signed-off-by Aneesh Kumar K.V (Arm) <[email protected]>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +0 -0
index 358072b4e293..c7d297ceabdb 100644

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) · line 4412

Quoted 8 lines

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +2 -0

@@ -4405,6 +4405,8 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
 	if (FIELD_GET(IDR3_RIL, reg))
 		smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
+	if (FIELD_GET(IDR3_FWB, reg))
+		smmu->features |= ARM_SMMU_FEAT_S2FWB;
 
 	/* IDR5 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);

Indeed. Looks like setting the feature flag was missed previously.

Reviewed-by Pranjal Shrivastava <[email protected]>

Thanks,
Praan

Nicolin Chen

Reviewed-by on v1 1/1

2025-04-08 07:31 UTC #2 lore raw

In reply to Aneesh Kumar K.V (Arm)

Quoted 9 lines · Aneesh Kumar K.V (Arm)

Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:
	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);

Quoted 5 lines

This patch adds the missing detection logic to prevent allocation failure when S2FWB is supported.
Fixes 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains")
Signed-off-by Aneesh Kumar K.V (Arm) <[email protected]>

Reviewed-by Nicolin Chen <[email protected]>

Jason Gunthorpe

Reviewed-by on v1 1/1

2025-04-08 12:09 UTC #3 lore raw

In reply to Aneesh Kumar K.V (Arm)

Quoted 9 lines · Aneesh Kumar K.V (Arm)

Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:
	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);

Quoted 8 lines

This patch adds the missing detection logic to prevent allocation failure when S2FWB is supported.
Fixes 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains")
Signed-off-by Aneesh Kumar K.V (Arm) <[email protected]>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 1 file changed, 2 insertions(+)

Reviewed-by Jason Gunthorpe <[email protected]>

This should go to rc

Jason

Will Deacon

maintainer

2025-04-11 16:03 UTC #4 lore raw

Quoted 19 lines · Jason Gunthorpe

Quoted 9 lines · Aneesh Kumar K.V (Arm)
Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:
	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);
Quoted 8 lines
This patch adds the missing detection logic to prevent allocation failure when S2FWB is supported.
Fixes 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains")
Signed-off-by Aneesh Kumar K.V (Arm) <[email protected]>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 1 file changed, 2 insertions(+)

Quoted 3 lines

Reviewed-by Jason Gunthorpe <[email protected]>
This should go to rc

Yup. I'll pick this up next week along with any other SMMU fixes kicking around.

Cheers,

Will

Will Deacon

maintainer Applied

2025-04-17 14:27 UTC #5 lore raw

In reply to Aneesh Kumar K.V (Arm)

Quoted 10 lines · Aneesh Kumar K.V (Arm)

Commit 67e4fe398513 ("iommu/arm-smmu-v3: Use S2FWB for NESTED domains") introduced S2FWB usage but omitted the corresponding feature detection. As a result, vIOMMU allocation fails on FVP in arm_vsmmu_alloc(), due to the following check:
	if (!arm_smmu_master_canwbs(master) &&
	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
		return ERR_PTR(-EOPNOTSUPP);
[...]

Applied to iommu (arm/smmu/fixes), thanks!

[1/1] iommu/arm-smmu-v3: Add missing S2FWB feature detection

      https://git.kernel.org/iommu/c/45e00e367189

Cheers,

Signature · 5 lines

Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev