iommu/vt-d: Implement deferred invalidate for SVM

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 82d53e15b865..a64720b5bd34 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -26,6 +26,10 @@ struct pasid_entry {
         u64 val;
 };
 
+struct pasid_state_entry {
+        u64 val;
+};
+
 int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
 {
         struct page *pages;
@@ -127,6 +131,11 @@ static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
 {
         struct intel_svm_dev *sdev;
 
+        /* Try deferred invalidate if available */
+        if (svm->iommu->pasid_state_table &&
+            !cmpxchg64(&svm->iommu->pasid_state_table[svm->pasid].val, 0, 1ULL << 63))
+                return;
+
         rcu_read_lock();
         list_for_each_entry_rcu(sdev, &svm->devs, list)
                 intel_flush_svm_range_dev(svm, sdev, address, pages, ih);