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

[Jason Gunthorpe]

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

Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>

This should go to rc

Jason