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

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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: d6b47dec36 ("iommu/amd: Reduce domain lock scope in attach device path")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Vasant 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: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jason Gunthorpe
2024-12-05 20:13:41 -04:00
committed by Joerg Roedel
parent fac04efc5c
commit 4a552f7890
1 changed files with 4 additions and 1 deletions
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5
drivers/iommu/amd/iommu.c
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@@ -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);