[PATCH v2 15/19] iommu/arm-smmu-v3: Add a global static IDENTITY domain

[Nicolin Chen]

On Mon, Nov 13, 2023 at 01:53:22PM -0400, Jason Gunthorpe wrote:
> @@ -2592,13 +2578,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  			arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
>  						      NULL);
>  		break;
> -	case ARM_SMMU_DOMAIN_BYPASS:
> -		arm_smmu_make_bypass_ste(&target);
> -		arm_smmu_install_ste_for_dev(master, &target);
> -		if (master->cd_table.cdtab)
> -			arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
> -						      NULL);
> -		break;
>  	}
>  
>  	arm_smmu_enable_ats(master, smmu_domain);
> @@ -2614,6 +2593,60 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  	return ret;
>  }
>  
> +static int arm_smmu_attach_dev_ste(struct device *dev,
> +				   struct arm_smmu_ste *ste)
> +{
> +	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> +
> +	if (arm_smmu_master_sva_enabled(master))
> +		return -EBUSY;
> +
> +	/*
> +	 * Do not allow any ASID to be changed while are working on the STE,
> +	 * otherwise we could miss invalidations.
> +	 */
> +	mutex_lock(&arm_smmu_asid_lock);
> +
> +	/*
> +	 * The SMMU does not support enabling ATS with bypass/abort. When the
> +	 * STE is in bypass (STE.Config[2:0] == 0b100), ATS Translation Requests
> +	 * and Translated transactions are denied as though ATS is disabled for
> +	 * the stream (STE.EATS == 0b00), causing F_BAD_ATS_TREQ and
> +	 * F_TRANSL_FORBIDDEN events (IHI0070Ea 5.2 Stream Table Entry).
> +	 */
> +	arm_smmu_detach_dev(master);
> +
> +	arm_smmu_install_ste_for_dev(master, ste);
> +	mutex_unlock(&arm_smmu_asid_lock);
> +
> +	/*
> +	 * This has to be done after removing the master from the
> +	 * arm_smmu_domain->devices to avoid races updating the same context
> +	 * descriptor from arm_smmu_share_asid().
> +	 */
> +	if (master->cd_table.cdtab)
> +		arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, NULL);
 
This arm_smmu_write_ctx_desc was previously within the asid lock
protection, yet now it's moved out of that?