Commit 0b136493 authored by Vasant Hegde's avatar Vasant Hegde Committed by Joerg Roedel
Browse files

iommu/amd: Reorder attach device code 



Ideally in attach device path, it should take dev_data lock before
making changes to device data including IOPF enablement. So far dev_data
was using spinlock and it was hitting lock order issue when it tries to
enable IOPF. Hence Commit 526606b0 ("iommu/amd: Fix Invalid wait
context issue") moved IOPF enablement outside dev_data->lock.

Previous patch converted dev_data lock to mutex. Now its safe to call
amd_iommu_iopf_add_device() with dev_data->mutex. Hence move back PCI
device capability enablement (ATS, PRI, PASID) and IOPF enablement code
inside the lock. Also in attach_device(), update 'dev_data->domain' at
the end so that error handling becomes simple.

Signed-off-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20241030063556.6104-11-vasant.hegde@amd.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent e843aedb

drivers/iommu/amd/iommu.c

+29 −36
Original line number Diff line number Diff line
@@ -2090,6 +2090,7 @@ static int attach_device(struct device *dev, 
{

	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);

	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);

	struct pci_dev *pdev;

	int ret = 0;



	mutex_lock(&dev_data->mutex);
@@ -2099,10 +2100,6 @@ static int attach_device(struct device *dev, 
		goto out;

	}



	/* Update data structures */

	dev_data->domain = domain;

	list_add(&dev_data->list, &domain->dev_list);



	/* Do reference counting */

	ret = pdom_attach_iommu(iommu, domain);

	if (ret)
@@ -2117,6 +2114,28 @@ static int attach_device(struct device *dev, 
		}

	}



	pdev = dev_is_pci(dev_data->dev) ? to_pci_dev(dev_data->dev) : NULL;

	if (pdev && pdom_is_sva_capable(domain)) {

		pdev_enable_caps(pdev);



		/*

		 * Device can continue to function even if IOPF

		 * enablement failed. Hence in error path just

		 * disable device PRI support.

		 */

		if (amd_iommu_iopf_add_device(iommu, dev_data))

			pdev_disable_cap_pri(pdev);

	} else if (pdev) {

		pdev_enable_cap_ats(pdev);

	}



	/* Update data structures */

	dev_data->domain = domain;

	list_add(&dev_data->list, &domain->dev_list);



	/* Update device table */

	dev_update_dte(dev_data, true);



out:

	mutex_unlock(&dev_data->mutex);
@@ -2131,7 +2150,6 @@ static void detach_device(struct device *dev) 
	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);

	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);

	struct protection_domain *domain = dev_data->domain;

	bool ppr = dev_data->ppr;

	unsigned long flags;



	mutex_lock(&dev_data->mutex);
@@ -2145,13 +2163,15 @@ static void detach_device(struct device *dev) 
	if (WARN_ON(!dev_data->domain))

		goto out;



	if (ppr) {

	/* Remove IOPF handler */

	if (dev_data->ppr) {

		iopf_queue_flush_dev(dev);



		/* Updated here so that it gets reflected in DTE */

		dev_data->ppr = false;

		amd_iommu_iopf_remove_device(iommu, dev_data);

	}



	if (dev_is_pci(dev))

		pdev_disable_caps(to_pci_dev(dev));



	/* Clear DTE and flush the entry */

	dev_update_dte(dev_data, false);
@@ -2173,14 +2193,6 @@ static void detach_device(struct device *dev) 


out:

	mutex_unlock(&dev_data->mutex);



	/* Remove IOPF handler */

	if (ppr)

		amd_iommu_iopf_remove_device(iommu, dev_data);



	if (dev_is_pci(dev))

		pdev_disable_caps(to_pci_dev(dev));



}



static struct iommu_device *amd_iommu_probe_device(struct device *dev)
@@ -2509,7 +2521,6 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, 
	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);

	struct protection_domain *domain = to_pdomain(dom);

	struct amd_iommu *iommu = get_amd_iommu_from_dev(dev);

	struct pci_dev *pdev;

	int ret;



	/*
@@ -2542,24 +2553,6 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, 
	}

#endif



	pdev = dev_is_pci(dev_data->dev) ? to_pci_dev(dev_data->dev) : NULL;

	if (pdev && pdom_is_sva_capable(domain)) {

		pdev_enable_caps(pdev);



		/*

		 * Device can continue to function even if IOPF

		 * enablement failed. Hence in error path just

		 * disable device PRI support.

		 */

		if (amd_iommu_iopf_add_device(iommu, dev_data))

			pdev_disable_cap_pri(pdev);

	} else if (pdev) {

		pdev_enable_cap_ats(pdev);

	}



	/* Update device table */

	dev_update_dte(dev_data, true);



	return ret;

}