[PATCH 04/14] iommu/amd: Remove amd_iommu_domain_update() from page table freeing

[Jason Gunthorpe <jgg@nvidia.com>]

It is a serious bug if the domain is still mapped to any DTEs when it is
freed as we immediately start freeing page table memory, so any remaining
HW touch will UAF.

If it is not mapped then dev_list is empty and amd_iommu_domain_update()
does nothing.

Remove it and add a WARN_ON() to catch this class of bug.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/iommu/amd/io_pgtable.c | 3 ---
 drivers/iommu/amd/iommu.c      | 2 ++
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c
index 05aed3cb46f1bf..b3991ad1ae8ea3 100644
--- a/drivers/iommu/amd/io_pgtable.c
+++ b/drivers/iommu/amd/io_pgtable.c
@@ -578,9 +578,6 @@ static void v1_free_pgtable(struct io_pgtable *iop)
 
 	/* Update data structure */
 	amd_iommu_domain_clr_pt_root(dom);
-
-	/* Make changes visible to IOMMUs */
-	amd_iommu_domain_update(dom);
 }
 
 static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index e53ffb86c3d09b..426aecacc63009 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2260,6 +2260,8 @@ void protection_domain_free(struct protection_domain *domain)
 	if (!domain)
 		return;
 
+	WARN_ON(!list_empty(&domain->dev_list));
+
 	if (domain->iop.pgtbl_cfg.tlb)
 		free_io_pgtable_ops(&domain->iop.iop.ops);
 
-- 
2.46.0