Re: [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master

[Jason Gunthorpe]

On Wed, Aug 02, 2023 at 02:35:23AM +0800, Michael Shavit wrote:
> @@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  	if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
>  		master->ats_enabled = arm_smmu_ats_supported(master);
>  
> +	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> +		if (!master->cd_table.cdtab) {
> +			ret = arm_smmu_alloc_cd_tables(master);
> +			if (ret) {

Again, I didn't look very closely at your locking, but what lock is
being held to protect the read of master->cd_table.cdtab ?

> +				master->domain = NULL;
> +				goto out_unlock;

This is only the domain lock:
	mutex_unlock(&smmu_domain->init_mutex);

Which is no longer sufficient.

You need some kind of lock in the master struct to protect the shared
cd table and everything in it?

Jason