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

Auger Eric
2021-03-19T13:16:13Z

Hi Keqian,

On 3/2/21 9:35 AM, Keqian Zhu wrote:
> 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 ;-)

forgive me for the delay. yes I can indeed make sure that code is not
called in nested mode. Please could you detail why you would need to
call arm_smmu_get_cd_ptr()?

Thanks

Eric
>
> 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,
>>