VFIO IOMMU driver for sPAPR TCE locks the whole DMA window by setting
ones to iommu_table.it_map. However this was not protected by the locks
which other clients of iommu_table use.
The patch fixes this.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
v1->v2:
* Fixed a potential warning from lockdep.
---
arch/powerpc/kernel/iommu.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index b20ff17..5c1fc89 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1076,25 +1076,42 @@ EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
int iommu_take_ownership(struct iommu_table *tbl)
{
unsigned long sz = (tbl->it_size + 7) >> 3;
+ unsigned long i, flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&tbl->large_pool.lock, flags);
+ for (i = 0; i < tbl->nr_pools; i++)
+ spin_lock(&tbl->pools[i].lock);
if (tbl->it_offset == 0)
clear_bit(0, tbl->it_map);
if (!bitmap_empty(tbl->it_map, tbl->it_size)) {
pr_err("iommu_tce: it_map is not empty");
- return -EBUSY;
+ ret = -EBUSY;
+ goto unlock_exit;
}
memset(tbl->it_map, 0xff, sz);
iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
- return 0;
+unlock_exit:
+ for (i = 0; i < tbl->nr_pools; i++)
+ spin_unlock(&tbl->pools[i].lock);
+ spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(iommu_take_ownership);
void iommu_release_ownership(struct iommu_table *tbl)
{
unsigned long sz = (tbl->it_size + 7) >> 3;
+ unsigned long i, flags;
+
+ spin_lock_irqsave(&tbl->large_pool.lock, flags);
+ for (i = 0; i < tbl->nr_pools; i++)
+ spin_lock(&tbl->pools[i].lock);
iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
memset(tbl->it_map, 0, sz);
@@ -1102,6 +1119,10 @@ void iommu_release_ownership(struct iommu_table *tbl)
/* Restore bit#0 set by iommu_init_table() */
if (tbl->it_offset == 0)
set_bit(0, tbl->it_map);
+
+ for (i = 0; i < tbl->nr_pools; i++)
+ spin_unlock(&tbl->pools[i].lock);
+ spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
}
EXPORT_SYMBOL_GPL(iommu_release_ownership);
--
1.7.10.4
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