iommu/amd: Do not loop forever when trying to increase address space

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.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200504125413.16798-3-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 28229a3..68da484 100644 (file)
--- 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;
        }