Re: [PATCH v14 05/13] iommu/smmuv3: Implement attach/detach_pasid_table

Keqian Zhu
2021-03-02T08:35:36Z

Hi Eric,

On 2021/2/24 4:56, Eric Auger wrote:
> On attach_pasid_table() we program STE S1 related info set
> by the guest into the actual physical STEs. At minimum
> we need to program the context descriptor GPA and compute
> whether the stage1 is translated/bypassed or aborted.
>
> On detach, the stage 1 config is unset and the abort flag is
> unset.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
[...]

> +
> + /*
> + * we currently support a single CD so s1fmt and s1dss
> + * fields are also ignored
> + */
> + if (cfg->pasid_bits)
> + goto out;
> +
> + smmu_domain->s1_cfg.cdcfg.cdtab_dma = cfg->base_ptr;
only the "cdtab_dma" field of "cdcfg" is set, we are not able to locate a specific cd using arm_smmu_get_cd_ptr().

Maybe we'd better use a specialized function to fill other fields of "cdcfg" or add a sanity check in arm_smmu_get_cd_ptr()
to prevent calling it under nested mode?

As now we just call arm_smmu_get_cd_ptr() during finalise_s1(), no problem found. Just a suggestion ;-)

Thanks,
Keqian

> + smmu_domain->s1_cfg.set = true;
> + smmu_domain->abort = false;
> + break;
> + default:
> + goto out;
> + }
> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
> + list_for_each_entry(master, &smmu_domain->devices, domain_head)
> + arm_smmu_install_ste_for_dev(master);
> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
> + ret = 0;
> +out:
> + mutex_unlock(&smmu_domain->init_mutex);
> + return ret;
> +}
> +
> +static void arm_smmu_detach_pasid_table(struct iommu_domain *domain)
> +{
> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> + struct arm_smmu_master *master;
> + unsigned long flags;
> +
> + mutex_lock(&smmu_domain->init_mutex);
> +
> + if (smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> + goto unlock;
> +
> + smmu_domain->s1_cfg.set = false;
> + smmu_domain->abort = false;
> +
> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
> + list_for_each_entry(master, &smmu_domain->devices, domain_head)
> + arm_smmu_install_ste_for_dev(master);
> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
> +
> +unlock:
> + mutex_unlock(&smmu_domain->init_mutex);
> +}
> +
> static bool arm_smmu_dev_has_feature(struct device *dev,
> enum iommu_dev_features feat)
> {
> @@ -2939,6 +3026,8 @@ static struct iommu_ops arm_smmu_ops = {
> .of_xlate = arm_smmu_of_xlate,
> .get_resv_regions = arm_smmu_get_resv_regions,
> .put_resv_regions = generic_iommu_put_resv_regions,
> + .attach_pasid_table = arm_smmu_attach_pasid_table,
> + .detach_pasid_table = arm_smmu_detach_pasid_table,
> .dev_has_feat = arm_smmu_dev_has_feature,
> .dev_feat_enabled = arm_smmu_dev_feature_enabled,
> .dev_enable_feat = arm_smmu_dev_enable_feature,