Re: [PATCH 3/3] iommu/vt-d: A fix to iommu_flush_dev_iotlb() for aux-domain

[Lu Baolu <baolu.lu@linux.intel.com>]

Hi,

On 2020/12/20 8:03, Liu Yi L wrote:
> iommu_flush_dev_iotlb() is called to invalidate caches on device. It only
> loops the devices which are full-attached to the domain. For sub-devices,
> this is ineffective. This results in invalid caching entries left on the
> device. Fix it by adding loop for subdevices as well. Also, update the
> domain->has_iotlb_device for both device/subdevice attach/detach and
> ATS enabling/disabling.
> 
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

The same here.

Best regards,
baolu

> ---
>   drivers/iommu/intel/iommu.c | 90 +++++++++++++++++++++++++++++--------
>   1 file changed, 72 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 4274b4acc325..d9b6037b72b1 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1437,6 +1437,10 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
>   			(unsigned long long)DMA_TLB_IAIG(val));
>   }
>   
> +/**
> + * For a given bus/devfn, fetch its device_domain_info if it supports
> + * device tlb. Only needs to loop devices attached in normal manner.
> + */
>   static struct device_domain_info *
>   iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu,
>   			 u8 bus, u8 devfn)
> @@ -1459,6 +1463,18 @@ iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu,
>   	return NULL;
>   }
>   
> +static bool dev_iotlb_enabled(struct device *dev)
> +{
> +	struct pci_dev *pdev;
> +
> +	if (!dev || !dev_is_pci(dev))
> +		return false;
> +
> +	pdev = to_pci_dev(dev);
> +
> +	return !!pdev->ats_enabled;
> +}
> +
>   static void domain_update_iotlb(struct dmar_domain *domain)
>   {
>   	struct device_domain_info *info;
> @@ -1467,21 +1483,37 @@ static void domain_update_iotlb(struct dmar_domain *domain)
>   	assert_spin_locked(&device_domain_lock);
>   
>   	list_for_each_entry(info, &domain->devices, link) {
> -		struct pci_dev *pdev;
> -
> -		if (!info->dev || !dev_is_pci(info->dev))
> -			continue;
> -
> -		pdev = to_pci_dev(info->dev);
> -		if (pdev->ats_enabled) {
> +		if (dev_iotlb_enabled(info->dev)) {
>   			has_iotlb_device = true;
>   			break;
>   		}
>   	}
>   
> +	if (!has_iotlb_device) {
> +		struct subdevice_domain_info *subinfo;
> +
> +		list_for_each_entry(subinfo, &domain->sub_devices, link_phys) {
> +			if (dev_iotlb_enabled(subinfo->dev)) {
> +				has_iotlb_device = true;
> +				break;
> +			}
> +		}
> +	}
>   	domain->has_iotlb_device = has_iotlb_device;
>   }
>   
> +static void dev_update_domain_iotlb(struct device_domain_info *info)
> +{
> +	struct subdevice_domain_info *subinfo;
> +
> +	assert_spin_locked(&device_domain_lock);
> +
> +	domain_update_iotlb(info->domain);
> +
> +	list_for_each_entry(subinfo, &info->auxiliary_domains, link_domain)
> +		domain_update_iotlb(subinfo->domain);
> +}
> +
>   static void iommu_enable_dev_iotlb(struct device_domain_info *info)
>   {
>   	struct pci_dev *pdev;
> @@ -1524,7 +1556,7 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
>   	if (info->ats_supported && pci_ats_page_aligned(pdev) &&
>   	    !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
>   		info->ats_enabled = 1;
> -		domain_update_iotlb(info->domain);
> +		dev_update_domain_iotlb(info);
>   		info->ats_qdep = pci_ats_queue_depth(pdev);
>   	}
>   }
> @@ -1543,7 +1575,7 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info)
>   	if (info->ats_enabled) {
>   		pci_disable_ats(pdev);
>   		info->ats_enabled = 0;
> -		domain_update_iotlb(info->domain);
> +		dev_update_domain_iotlb(info);
>   	}
>   #ifdef CONFIG_INTEL_IOMMU_SVM
>   	if (info->pri_enabled) {
> @@ -1557,26 +1589,43 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info)
>   #endif
>   }
>   
> +static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
> +				    u64 addr, unsigned mask)
> +{
> +	u16 sid, qdep;
> +
> +	if (!info || !info->ats_enabled)
> +		return;
> +
> +	sid = info->bus << 8 | info->devfn;
> +	qdep = info->ats_qdep;
> +	qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
> +			   qdep, addr, mask);
> +}
> +
>   static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
>   				  u64 addr, unsigned mask)
>   {
> -	u16 sid, qdep;
>   	unsigned long flags;
>   	struct device_domain_info *info;
> +	struct subdevice_domain_info *subinfo;
>   
>   	if (!domain->has_iotlb_device)
>   		return;
>   
>   	spin_lock_irqsave(&device_domain_lock, flags);
> -	list_for_each_entry(info, &domain->devices, link) {
> -		if (!info->ats_enabled)
> -			continue;
> +	list_for_each_entry(info, &domain->devices, link)
> +		__iommu_flush_dev_iotlb(info, addr, mask);
> +
> +	/*
> +	 * Besides looping all devices attached normally, also
> +	 * needs to loop all devices attached via auxiliary
> +	 * manner.
> +	 */
> +	list_for_each_entry(subinfo, &domain->sub_devices, link_phys)
> +		__iommu_flush_dev_iotlb(get_domain_info(subinfo->dev),
> +					addr, mask);
>   
> -		sid = info->bus << 8 | info->devfn;
> -		qdep = info->ats_qdep;
> -		qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
> -				qdep, addr, mask);
> -	}
>   	spin_unlock_irqrestore(&device_domain_lock, flags);
>   }
>   
> @@ -5208,6 +5257,9 @@ static void auxiliary_link_device(struct dmar_domain *domain,
>   	subinfo->dev = dev;
>   	list_add(&subinfo->link_domain, &info->auxiliary_domains);
>   	list_add(&subinfo->link_phys, &domain->sub_devices);
> +	if (dev_iotlb_enabled(dev))
> +		domain_update_iotlb(domain);
> +
>   	_auxiliary_link_device(domain, subinfo, dev);
>   	domain->auxd_refcnt++;
>   }
> @@ -5242,6 +5294,8 @@ static int auxiliary_unlink_device(struct dmar_domain *domain,
>   		list_del(&subinfo->link_domain);
>   		list_del(&subinfo->link_phys);
>   		kfree(subinfo);
> +		if (domain->has_iotlb_device)
> +			domain_update_iotlb(domain);
>   	}
>   	domain->auxd_refcnt--;
>   
> 
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