Re: [PATCH v4 07/13] iommu/arm-smmu-v3: Keep track of attached ssids

[Nicolin Chen <nicolinc@nvidia.com>]

On Wed, Jun 21, 2023 at 02:37:19PM +0800, Michael Shavit wrote:
 
> +/* List of {masters, ssid} that a domain is attached to */
> +struct arm_smmu_attached_domain {
> +       struct list_head        domain_head;
> +       struct arm_smmu_domain  *domain;
> +       struct arm_smmu_master  *master;
> +       int                     ssid;
> +};
> +
>  /* SMMU private data for each master */
>  struct arm_smmu_master {
>         struct arm_smmu_device          *smmu;
>         struct device                   *dev;
> -       struct arm_smmu_domain          *domain;
> +       struct arm_smmu_attached_domain non_pasid_domain;
>         struct list_head                domain_head;
>         struct arm_smmu_stream          *streams;
>         struct arm_smmu_s1_cfg          owned_s1_cfg;
> @@ -724,8 +732,8 @@ struct arm_smmu_domain {
> 
>         struct iommu_domain                     domain;
> 
> -       struct list_head                        devices;
> -       spinlock_t                              devices_lock;
> +       struct list_head                        attached_domains;
> +       spinlock_t                              attached_domains_lock;

Yea, I think that this arm_smmu_attached_domain is similar to
the "subdomain" that I was talking about in the previous reply,
though having a list of attached domains under a domain doesn't
feel very clear.

Perhaps it would be good to have some renaming and kdoc too.

And since we have a group of subdomains that are simply indexed
by ssids, perhaps we can add an xarray to store a subdomain ptr
along with an ssid, replacing the list?

Thanks
Nicolin