Re: Patch "iommu: Clean up open-coded ownership checks" has been added to the 6.6-stable tree

[Robin Murphy <robin.murphy@arm.com>]

On 2024-12-09 11:27 am, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>      iommu: Clean up open-coded ownership checks
> 
> to the 6.6-stable tree which can be found at:
>      http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>       iommu-clean-up-open-coded-ownership-checks.patch
> and it can be found in the queue-6.6 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.

Unless you're also going to backport the rest of the larger redesign 
which makes this commit message true, I don't think this is appropriate.

Thanks,
Robin.

> commit 302639dd441533017096f8ebccb02440090fb09d
> Author: Robin Murphy <robin.murphy@arm.com>
> Date:   Tue Nov 21 18:04:03 2023 +0000
> 
>      iommu: Clean up open-coded ownership checks
>      
>      [ Upstream commit e7080665c977ea1aafb8547a9c7bd08b199311d6 ]
>      
>      Some drivers already implement their own defence against the possibility
>      of being given someone else's device. Since this is now taken care of by
>      the core code (and via a slightly different path from the original
>      fwspec-based idea), let's clean them up.
>      
>      Acked-by: Will Deacon <will@kernel.org>
>      Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
>      Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>      Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>      Link: https://lore.kernel.org/r/58a9879ce3f03562bb061e6714fe6efb554c3907.1700589539.git.robin.murphy@arm.com
>      Signed-off-by: Joerg Roedel <jroedel@suse.de>
>      Stable-dep-of: 229e6ee43d2a ("iommu/arm-smmu: Defer probe of clients after smmu device bound")
>      Signed-off-by: Sasha Levin <sashal@kernel.org>
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 68b81f9c2f4b1..c24584754d252 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2658,9 +2658,6 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
>   	struct arm_smmu_master *master;
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>   
> -	if (!fwspec || fwspec->ops != &arm_smmu_ops)
> -		return ERR_PTR(-ENODEV);
> -
>   	if (WARN_ON_ONCE(dev_iommu_priv_get(dev)))
>   		return ERR_PTR(-EBUSY);
>   
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index d6d1a2a55cc06..8203a06014d71 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -1116,11 +1116,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>   	struct arm_smmu_device *smmu;
>   	int ret;
>   
> -	if (!fwspec || fwspec->ops != &arm_smmu_ops) {
> -		dev_err(dev, "cannot attach to SMMU, is it on the same bus?\n");
> -		return -ENXIO;
> -	}
> -
>   	/*
>   	 * FIXME: The arch/arm DMA API code tries to attach devices to its own
>   	 * domains between of_xlate() and probe_device() - we have no way to cope
> @@ -1357,10 +1352,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
>   		fwspec = dev_iommu_fwspec_get(dev);
>   		if (ret)
>   			goto out_free;
> -	} else if (fwspec && fwspec->ops == &arm_smmu_ops) {
> -		smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
>   	} else {
> -		return ERR_PTR(-ENODEV);
> +		smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
>   	}
>   
>   	ret = -EINVAL;
> diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> index bc45d18f350cb..3b8c4b33842d1 100644
> --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> @@ -79,16 +79,6 @@ static struct qcom_iommu_domain *to_qcom_iommu_domain(struct iommu_domain *dom)
>   
>   static const struct iommu_ops qcom_iommu_ops;
>   
> -static struct qcom_iommu_dev * to_iommu(struct device *dev)
> -{
> -	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> -
> -	if (!fwspec || fwspec->ops != &qcom_iommu_ops)
> -		return NULL;
> -
> -	return dev_iommu_priv_get(dev);
> -}
> -
>   static struct qcom_iommu_ctx * to_ctx(struct qcom_iommu_domain *d, unsigned asid)
>   {
>   	struct qcom_iommu_dev *qcom_iommu = d->iommu;
> @@ -374,7 +364,7 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)
>   
>   static int qcom_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
>   {
> -	struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
> +	struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
>   	struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
>   	int ret;
>   
> @@ -406,7 +396,7 @@ static int qcom_iommu_identity_attach(struct iommu_domain *identity_domain,
>   	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>   	struct qcom_iommu_domain *qcom_domain;
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> -	struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
> +	struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
>   	unsigned int i;
>   
>   	if (domain == identity_domain || !domain)
> @@ -537,7 +527,7 @@ static bool qcom_iommu_capable(struct device *dev, enum iommu_cap cap)
>   
>   static struct iommu_device *qcom_iommu_probe_device(struct device *dev)
>   {
> -	struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
> +	struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
>   	struct device_link *link;
>   
>   	if (!qcom_iommu)
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index de698463e94ad..23c7eec46fff6 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -843,16 +843,11 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
>   static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
>   {
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> -	struct mtk_iommu_data *data;
> +	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
>   	struct device_link *link;
>   	struct device *larbdev;
>   	unsigned int larbid, larbidx, i;
>   
> -	if (!fwspec || fwspec->ops != &mtk_iommu_ops)
> -		return ERR_PTR(-ENODEV); /* Not a iommu client device */
> -
> -	data = dev_iommu_priv_get(dev);
> -
>   	if (!MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM))
>   		return &data->iommu;
>   
> diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> index f1754efcfe74e..027b2ff7f33ef 100644
> --- a/drivers/iommu/mtk_iommu_v1.c
> +++ b/drivers/iommu/mtk_iommu_v1.c
> @@ -478,9 +478,6 @@ static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
>   		idx++;
>   	}
>   
> -	if (!fwspec || fwspec->ops != &mtk_iommu_v1_ops)
> -		return ERR_PTR(-ENODEV); /* Not a iommu client device */
> -
>   	data = dev_iommu_priv_get(dev);
>   
>   	/* Link the consumer device with the smi-larb device(supplier) */
> diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
> index c8e79a2d8b4c6..b5570ef887023 100644
> --- a/drivers/iommu/sprd-iommu.c
> +++ b/drivers/iommu/sprd-iommu.c
> @@ -388,13 +388,7 @@ static phys_addr_t sprd_iommu_iova_to_phys(struct iommu_domain *domain,
>   
>   static struct iommu_device *sprd_iommu_probe_device(struct device *dev)
>   {
> -	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> -	struct sprd_iommu_device *sdev;
> -
> -	if (!fwspec || fwspec->ops != &sprd_iommu_ops)
> -		return ERR_PTR(-ENODEV);
> -
> -	sdev = dev_iommu_priv_get(dev);
> +	struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
>   
>   	return &sdev->iommu;
>   }
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 17dcd826f5c20..bb2e795a80d0f 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -969,9 +969,6 @@ static struct iommu_device *viommu_probe_device(struct device *dev)
>   	struct viommu_dev *viommu = NULL;
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>   
> -	if (!fwspec || fwspec->ops != &viommu_ops)
> -		return ERR_PTR(-ENODEV);
> -
>   	viommu = viommu_get_by_fwnode(fwspec->iommu_fwnode);
>   	if (!viommu)
>   		return ERR_PTR(-ENODEV);