Re: [PATCH v3 1/3] iommu/vt-d: Move intel_iommu info from struct intel_svm to struct intel_svm_dev

[Lu Baolu]

Hi Yi,

On 2020/12/29 11:25, Liu Yi L wrote:
> Current struct intel_svm has a field to record the struct intel_iommu
> pointer for a PASID bind. And struct intel_svm will be shared by all
> the devices bind to the same process. The devices may be behind different
> DMAR units. As the iommu driver code uses the intel_iommu pointer stored
> in intel_svm struct to do cache invalidations, it may only flush the cache
> on a single DMAR unit, for others, the cache invalidation is missed.
>
> As intel_svm struct already has a device list, this patch just moves the
> intel_iommu pointer to be a field of intel_svm_dev struct.
>
> Fixes: 1c4f88b7f1f92 ("iommu/vt-d: Shared virtual address in scalable mode")
> Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Raj Ashok <ashok.raj@xxxxxxxxx>
> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> Reported-by: Guo Kaijie <Kaijie.Guo@xxxxxxxxx>
> Reported-by: Xin Zeng <xin.zeng@xxxxxxxxx>
> Signed-off-by: Guo Kaijie <Kaijie.Guo@xxxxxxxxx>
> Signed-off-by: Xin Zeng <xin.zeng@xxxxxxxxx>
> Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>

This fix looks good to me. Thanks!

Cc: stable@xxxxxxxxxxxxxxx # v5.0+
Acked-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Best regards,
baolu

> ---
>   drivers/iommu/intel/svm.c   | 9 +++++----
>   include/linux/intel-iommu.h | 2 +-
>   2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index 4fa248b98031..69566695d032 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -142,7 +142,7 @@ static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_d
>   	}
>   	desc.qw2 = 0;
>   	desc.qw3 = 0;
> -	qi_submit_sync(svm->iommu, &desc, 1, 0);
> +	qi_submit_sync(sdev->iommu, &desc, 1, 0);
>   
>   	if (sdev->dev_iotlb) {
>   		desc.qw0 = QI_DEV_EIOTLB_PASID(svm->pasid) |
> @@ -166,7 +166,7 @@ static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_d
>   		}
>   		desc.qw2 = 0;
>   		desc.qw3 = 0;
> -		qi_submit_sync(svm->iommu, &desc, 1, 0);
> +		qi_submit_sync(sdev->iommu, &desc, 1, 0);
>   	}
>   }
>   
> @@ -211,7 +211,7 @@ static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
>   	 */
>   	rcu_read_lock();
>   	list_for_each_entry_rcu(sdev, &svm->devs, list)
> -		intel_pasid_tear_down_entry(svm->iommu, sdev->dev,
> +		intel_pasid_tear_down_entry(sdev->iommu, sdev->dev,
>   					    svm->pasid, true);
>   	rcu_read_unlock();
>   
> @@ -363,6 +363,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
>   	}
>   	sdev->dev = dev;
>   	sdev->sid = PCI_DEVID(info->bus, info->devfn);
> +	sdev->iommu = iommu;
>   
>   	/* Only count users if device has aux domains */
>   	if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX))
> @@ -546,6 +547,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
>   		goto out;
>   	}
>   	sdev->dev = dev;
> +	sdev->iommu = iommu;
>   
>   	ret = intel_iommu_enable_pasid(iommu, dev);
>   	if (ret) {
> @@ -575,7 +577,6 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
>   			kfree(sdev);
>   			goto out;
>   		}
> -		svm->iommu = iommu;
>   
>   		if (pasid_max > intel_pasid_max_id)
>   			pasid_max = intel_pasid_max_id;
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index d956987ed032..94522685a0d9 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -758,6 +758,7 @@ struct intel_svm_dev {
>   	struct list_head list;
>   	struct rcu_head rcu;
>   	struct device *dev;
> +	struct intel_iommu *iommu;
>   	struct svm_dev_ops *ops;
>   	struct iommu_sva sva;
>   	u32 pasid;
> @@ -771,7 +772,6 @@ struct intel_svm {
>   	struct mmu_notifier notifier;
>   	struct mm_struct *mm;
>   
> -	struct intel_iommu *iommu;
>   	unsigned int flags;
>   	u32 pasid;
>   	int gpasid; /* In case that guest PASID is different from host PASID */