[PATCH 2/5] iommu/amd: Do not loop forever when trying to increase address space

Joerg Roedel
2020-05-04T12:54:25Z

When increase_address_space() fails to allocate memory, alloc_pte()
will call it again until it succeeds. Do not loop forever while trying
to increase the address space and just return an error instead.

Tested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/amd_iommu.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 28229a38af4d..68da484a69dd 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1489,8 +1489,19 @@ static u64 *alloc_pte(struct protection_domain *domain,
amd_iommu_domain_get_pgtable(domain, &pgtable);

while (address > PM_LEVEL_SIZE(pgtable.mode)) {
- *updated = increase_address_space(domain, address, gfp) || *updated;
+ bool upd = increase_address_space(domain, address, gfp);
+
+ /* Read new values to check if update was successful */
amd_iommu_domain_get_pgtable(domain, &pgtable);
+
+ /*
+ * Return an error if there is no memory to update the
+ * page-table.
+ */
+ if (!upd && (address > PM_LEVEL_SIZE(pgtable.mode)))
+ return NULL;
+
+ *updated = *updated || upd;