Commit 4a552f78 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Joerg Roedel
Browse files

iommu/amd: Put list_add/del(dev_data) back under the domain->lock 



The list domain->dev_list is protected by the domain->lock spinlock.
Any iteration, addition or removal must be under the lock.

Move the list_del() up into the critical section. pdom_is_sva_capable(),
and destroy_gcr3_table() do not interact with the list element.

Wrap the list_add() in a lock, it would make more sense if this was under
the same critical section as adjusting the refcounts earlier, but that
requires more complications.

Fixes: d6b47dec ("iommu/amd: Reduce domain lock scope in attach device path")
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/1-v1-3b9edcf8067d+3975-amd_dev_list_locking_jgg@nvidia.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent fac04efc

drivers/iommu/amd/iommu.c

+4 −1
Original line number Diff line number Diff line
@@ -2073,6 +2073,7 @@ 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;

	unsigned long flags;

	int ret = 0;



	mutex_lock(&dev_data->mutex);
@@ -2113,7 +2114,9 @@ static int attach_device(struct device *dev, 


	/* Update data structures */

	dev_data->domain = domain;

	spin_lock_irqsave(&domain->lock, flags);

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

	spin_unlock_irqrestore(&domain->lock, flags);



	/* Update device table */

	dev_update_dte(dev_data, true);
@@ -2160,6 +2163,7 @@ static void detach_device(struct device *dev) 
	/* Flush IOTLB and wait for the flushes to finish */

	spin_lock_irqsave(&domain->lock, flags);

	amd_iommu_domain_flush_all(domain);

	list_del(&dev_data->list);

	spin_unlock_irqrestore(&domain->lock, flags);



	/* Clear GCR3 table */
@@ -2168,7 +2172,6 @@ static void detach_device(struct device *dev) 


	/* Update data structures */

	dev_data->domain = NULL;

	list_del(&dev_data->list);



	/* decrease reference counters - needs to happen after the flushes */

	pdom_detach_iommu(iommu, domain);