[PATCH 5.4 043/344] iommu/vt-d: Fix off-by-one in PASID allocation

Greg Kroah-Hartman
2020-02-21T08:02:56Z

From: Jacob Pan <jacob.jun.pan@linux.intel.com>

[ Upstream commit 39d630e332144028f56abba83d94291978e72df1 ]

PASID allocator uses IDR which is exclusive for the end of the
allocation range. There is no need to decrement pasid_max.

Fixes: af39507305fb ("iommu/vt-d: Apply global PASID in SVA")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/intel-svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index dca88f9fdf29a..ff7a3f9add325 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -317,7 +317,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
ret = intel_pasid_alloc_id(svm,
!!cap_caching_mode(iommu->cap),
- pasid_max - 1, GFP_KERNEL);
+ pasid_max, GFP_KERNEL);
if (ret < 0) {
kfree(svm);
kfree(sdev);
--
2.20.1