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

[Nicolin Chen]

On Tue, Apr 08, 2025 at 09:03:51AM +0530, Aneesh Kumar K.V (Arm) wrote:
> 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) <aneesh.kumar@xxxxxxxxxx>

Reviewed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>