[RFC PATCH v4 03/10] iommu/riscv: report iommu capabilities

[Nutty.Liu]

On 9/15/2026 11:28 AM, fangyu.yu at linux.alibaba.com wrote:
> From: Tomasz Jeznach <tjeznach at rivosinc.com>
>
> Report RISC-V IOMMU capabilities required by VFIO subsystem
> to enable PCIe device assignment.
>
> Signed-off-by: Tomasz Jeznach <tjeznach at rivosinc.com>
> Signed-off-by: Fangyu Yu <fangyu.yu at linux.alibaba.com>
Reviewed-by: Nutty Liu <nutty.liu at hotmail.com>

Thanks,
Nutty
> ---
>   drivers/iommu/riscv/iommu.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
>
> diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> index cec3ddd7ab10..a6c8307e82ea 100644
> --- a/drivers/iommu/riscv/iommu.c
> +++ b/drivers/iommu/riscv/iommu.c
> @@ -1422,6 +1422,16 @@ static struct iommu_group *riscv_iommu_device_group(struct device *dev)
>   	return generic_device_group(dev);
>   }
>   
> +static bool riscv_iommu_capable(struct device *dev, enum iommu_cap cap)
> +{
> +	switch (cap) {
> +	case IOMMU_CAP_CACHE_COHERENCY:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
>   static int riscv_iommu_of_xlate(struct device *dev, const struct of_phandle_args *args)
>   {
>   	return iommu_fwspec_add_ids(dev, args->args, 1);
> @@ -1483,6 +1493,7 @@ static void riscv_iommu_release_device(struct device *dev)
>   
>   static const struct iommu_ops riscv_iommu_ops = {
>   	.of_xlate = riscv_iommu_of_xlate,
> +	.capable = riscv_iommu_capable,
>   	.identity_domain = &riscv_iommu_identity_domain,
>   	.blocked_domain = &riscv_iommu_blocking_domain,
>   	.release_domain = &riscv_iommu_blocking_domain,