[PATCH AUTOSEL 5.6 127/606] iommu/amd: Do not loop forever when trying to increase address space

Sasha Levin
2020-06-08T23:18:27Z

From: Joerg Roedel <jroedel@suse.de>

[ Upstream commit 5b8a9a047b6cad361405c7900c1e1cdd378c4589 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 1d8634250afc..18c995a16d80 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1500,8 +1500,19 @@ 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;
}

--
2.25.1