Re: [PATCH v2 1/5] iommu: Return -EMEDIUMTYPE for incompatible domain and device/group

[Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>]

On 2022/6/16 08:03, Nicolin Chen wrote:
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 44016594831d..0dd13330fe12 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4323,7 +4323,7 @@ static int prepare_domain_attach_device(struct iommu_domain *domain,
>   		return -ENODEV;
>   
>   	if (dmar_domain->force_snooping && !ecap_sc_support(iommu->ecap))
> -		return -EOPNOTSUPP;
> +		return -EMEDIUMTYPE;
>   
>   	/* check if this iommu agaw is sufficient for max mapped address */
>   	addr_width = agaw_to_width(iommu->agaw);
> @@ -4331,10 +4331,10 @@ static int prepare_domain_attach_device(struct iommu_domain *domain,
>   		addr_width = cap_mgaw(iommu->cap);
>   
>   	if (dmar_domain->max_addr > (1LL << addr_width)) {
> -		dev_err(dev, "%s: iommu width (%d) is not "
> +		dev_dbg(dev, "%s: iommu width (%d) is not "
>   		        "sufficient for the mapped address (%llx)\n",
>   		        __func__, addr_width, dmar_domain->max_addr);
> -		return -EFAULT;
> +		return -EMEDIUMTYPE;
>   	}
>   	dmar_domain->gaw = addr_width;

Can we simply remove the dev_err()? As the return value has explicitly
explained the failure reason, putting a print statement won't help much.

Best regards,
baolu