iommu/vt-d: Fix off-by-one in PASID allocation

[ 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>

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index fd8730b..5944d3b 100644 (file)
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -377,7 +377,7 @@ 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);