iommu/vt-d: Use real PASID for flush in caching mode

If caching mode is supported, the hardware will cache
none-present or erroneous translation entries. Hence,
software should explicitly invalidate the PASID cache
after a PASID table entry becomes present. We should
issue such invalidation with the PASID value that we
have changed. PASID 0 is not reserved for this case.

Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Sankaran Rajesh <rajesh.sankaran@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 6 insertions, 10 deletions

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 3d4b9245542d..43737d37fdf2 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -423,17 +423,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
                 iommu->pasid_table[svm->pasid].val = pasid_entry_val;
 
                 wmb();
-                /* In caching mode, we still have to flush with PASID 0 when
-                 * a PASID table entry becomes present. Not entirely clear
-                 * *why* that would be the case — surely we could just issue
-                 * a flush with the PASID value that we've changed? The PASID
-                 * is the index into the table, after all. It's not like domain
-                 * IDs in the case of the equivalent context-entry change in
-                 * caching mode. And for that matter it's not entirely clear why
-                 * a VMM would be in the business of caching the PASID table
-                 * anyway. Surely that can be left entirely to the guest? */
+
+                /*
+                 * Flush PASID cache when a PASID table entry becomes
+                 * present.
+                 */
                 if (cap_caching_mode(iommu->cap))
-                        intel_flush_pasid_dev(svm, sdev, 0);
+                        intel_flush_pasid_dev(svm, sdev, svm->pasid);
         }
         list_add_rcu(&sdev->list, &svm->devs);