Re: [PATCH v4 5/7] iommu/vt-d: Make device pasid attachment explicit

Baolu Lu
2023-04-10T03:14:54Z

On 4/10/23 10:46 AM, Baolu Lu wrote:
>> @@ -4040,6 +4100,7 @@ static void device_block_translation(struct
>> device *dev)
>>       spin_lock_irqsave(&info->domain->lock, flags);
>>       list_del(&info->link);
>> +    info->dev_attached = 0;
>>       spin_unlock_irqrestore(&info->domain->lock, flags);
>>       domain_detach_iommu(info->domain, iommu);
>> @@ -4186,7 +4247,7 @@ static int intel_iommu_attach_device(struct
>> iommu_domain *domain,
>>       if (ret)
>>           return ret;
>> -    return dmar_domain_attach_device(to_dmar_domain(domain), dev);
>> +    return dmar_domain_attach_device_pasid(to_dmar_domain(domain),
>> dev, PASID_RID2PASID);
>>   }
>
> For VT-d driver, attach_dev and attach_dev_pasid have different
> meanings. Merging them into one helper may lead to confusion. What do
> you think of the following code? The dmar_domain_attach_device_pasid()
> helper could be reused for attach_dev_pasid path.
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 7c2f4bd33582..09ae62bc3724 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -2434,6 +2434,40 @@ static int __init si_domain_init(int hw)
>      return 0;
>  }
>
> +
> +static int dmar_domain_attach_device_pasid(struct dmar_domain *domain,
> +                       struct intel_iommu *iommu,
> +                       struct device *dev, ioasid_t pasid)
> +{
> +    struct device_pasid_info *dev_pasid;
> +    unsigned long flags;
> +    int ret;
> +
> +    dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
> +    if (!dev_pasid)
> +        return -ENOMEM;
> +
> +    if (hw_pass_through && domain_type_is_si(domain))
> +        ret = intel_pasid_setup_pass_through(iommu, domain, dev, pasid);
> +    else if (domain->use_first_level)
> +        ret = domain_setup_first_level(iommu, domain, dev, pasid);
> +    else
> +        ret = intel_pasid_setup_second_level(iommu, domain, dev, pasid);
> +
> +    if (ret) {
> +        kfree(dev_pasid);
> +        return ret;
> +    }
> +
> +    dev_pasid->pasid = pasid;
> +    dev_pasid->dev = dev;
> +    spin_lock_irqsave(&domain->lock, flags);
> +    list_add(&dev_pasid->link_domain, &domain->dev_pasids);
> +    spin_unlock_irqrestore(&domain->lock, flags);
> +
> +    return 0;
> +}
> +
>  static int dmar_domain_attach_device(struct dmar_domain *domain,
>                       struct device *dev)
>  {
> @@ -2458,15 +2492,8 @@ static int dmar_domain_attach_device(struct
> dmar_domain *domain,
>      /* PASID table is mandatory for a PCI device in scalable mode. */
>      if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
>          /* Setup the PASID entry for requests without PASID: */
> -        if (hw_pass_through && domain_type_is_si(domain))
> -            ret = intel_pasid_setup_pass_through(iommu, domain,
> -                    dev, PASID_RID2PASID);
> -        else if (domain->use_first_level)
> -            ret = domain_setup_first_level(iommu, domain, dev,
> -                    PASID_RID2PASID);
> -        else
> -            ret = intel_pasid_setup_second_level(iommu, domain,
> -                    dev, PASID_RID2PASID);
> +        ret = dmar_domain_attach_device_pasid(domain, iommu, dev,
> +                              PASID_RID2PASID);
>          if (ret) {
>              dev_err(dev, "Setup RID2PASID failed\n");
>              device_block_translation(dev);

Sorry! I forgot one thing. The dev_pasid data allocated in attach_dev
path should be freed in device_block_translation(). Perhaps we need to
add below change?

@@ -4107,6 +4134,7 @@ static void device_block_translation(struct device
*dev)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
struct intel_iommu *iommu = info->iommu;
+ struct device_pasid_info *dev_pasid;
unsigned long flags;

iommu_disable_pci_caps(info);
@@ -4118,6 +4146,16 @@ static void device_block_translation(struct
device *dev)
domain_context_clear(info);
}

+ spin_lock_irqsave(&info->domain->lock, flags);
+ list_for_each_entry(dev_pasid, &domain->dev_pasids, link_domain) {
+ if (dev_pasid->dev != dev || dev_pasid->pasid != RID2PASID)
+ continue;
+
+ list_del(&dev_pasid->link_domain);
+ kfree(dev_pasid);
+ }
+ spin_unlock_irqrestore(&info->domain->lock, flags);
+
if (!info->domain)
return;

Best regards,
baolu