linux-kernel - Re: [PATCH 09/12] dmaengine: idxd: Remove unnecessary IOMMU_DEV_FEAT

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Message-ID: <94b6f4fa-8a92-47a1-8938-b838ce19d122@nvidia.com>
Date: Tue, 18 Feb 2025 14:55:57 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: Lu Baolu <baolu.lu@...ux.intel.com>, Joerg Roedel <joro@...tes.org>,
 Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
 Jason Gunthorpe <jgg@...pe.ca>, Kevin Tian <kevin.tian@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>, Dave Jiang <dave.jiang@...el.com>,
 Vinod Koul <vkoul@...nel.org>, Zhangfei Gao <zhangfei.gao@...aro.org>,
 Zhou Wang <wangzhou1@...ilicon.com>, iommu@...ts.linux.dev,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/12] dmaengine: idxd: Remove unnecessary
 IOMMU_DEV_FEAT_IOPF


On 2/13/25 22:11, Lu Baolu wrote:
> The IOMMU_DEV_FEAT_IOPF implementation in the iommu driver is just a no-op.
> It will also be removed from the iommu driver in the subsequent patch.
> Remove it to avoid dead code.
>
> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
Reviewed-by: Fenghua Yu <fenghuay@...dia.com>
> ---
>   drivers/dma/idxd/init.c | 37 ++++++-------------------------------
>   1 file changed, 6 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index 1e5038cca22c..d44944195807 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -626,21 +626,6 @@ static void idxd_disable_system_pasid(struct idxd_device *idxd)
>   	idxd->pasid = IOMMU_PASID_INVALID;
>   }
>   
> -static int idxd_enable_sva(struct pci_dev *pdev)
> -{
> -	int ret;
> -
> -	ret = iommu_dev_enable_feature(&pdev->dev, IOMMU_DEV_FEAT_IOPF);
> -	if (ret)
> -		return ret;
> -	return 0;
> -}
> -
> -static void idxd_disable_sva(struct pci_dev *pdev)
> -{
> -	iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_IOPF);
> -}
> -
>   static int idxd_probe(struct idxd_device *idxd)
>   {
>   	struct pci_dev *pdev = idxd->pdev;
> @@ -655,17 +640,13 @@ static int idxd_probe(struct idxd_device *idxd)
>   	dev_dbg(dev, "IDXD reset complete\n");
>   
>   	if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
> -		if (idxd_enable_sva(pdev)) {
> -			dev_warn(dev, "Unable to turn on user SVA feature.\n");
> -		} else {
> -			set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
> +		set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
>   
> -			rc = idxd_enable_system_pasid(idxd);
> -			if (rc)
> -				dev_warn(dev, "No in-kernel DMA with PASID. %d\n", rc);
> -			else
> -				set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
> -		}
> +		rc = idxd_enable_system_pasid(idxd);
> +		if (rc)
> +			dev_warn(dev, "No in-kernel DMA with PASID. %d\n", rc);
> +		else
> +			set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
>   	} else if (!sva) {
>   		dev_warn(dev, "User forced SVA off via module param.\n");
>   	}
> @@ -703,8 +684,6 @@ static int idxd_probe(struct idxd_device *idxd)
>    err:
>   	if (device_pasid_enabled(idxd))
>   		idxd_disable_system_pasid(idxd);
> -	if (device_user_pasid_enabled(idxd))
> -		idxd_disable_sva(pdev);
>   	return rc;
>   }
>   
> @@ -715,8 +694,6 @@ static void idxd_cleanup(struct idxd_device *idxd)
>   	idxd_cleanup_internals(idxd);
>   	if (device_pasid_enabled(idxd))
>   		idxd_disable_system_pasid(idxd);
> -	if (device_user_pasid_enabled(idxd))
> -		idxd_disable_sva(idxd->pdev);
>   }
>   
>   /*
> @@ -1248,8 +1225,6 @@ static void idxd_remove(struct pci_dev *pdev)
>   	free_irq(irq_entry->vector, irq_entry);
>   	pci_free_irq_vectors(pdev);
>   	pci_iounmap(pdev, idxd->reg_base);
> -	if (device_user_pasid_enabled(idxd))
> -		idxd_disable_sva(pdev);
>   	pci_disable_device(pdev);
>   	destroy_workqueue(idxd->wq);
>   	perfmon_pmu_remove(idxd);


Thanks.


-Fenghua