missing reserved checks for NL PTEs

ved-rivos · Jul 4, 2024 · 4672bfa · 4672bfa
1 parent db2335a
commit 4672bfa
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diff --git a/iommu_ref_model/libiommu/src/iommu_second_stage_trans.c b/iommu_ref_model/libiommu/src/iommu_second_stage_trans.c
@@ -154,6 +154,14 @@ second_stage_address_translation(
     //    a = gpte.ppn × PAGESIZE and go to step 2.
     if ( gpte->R == 1 || gpte->X == 1 ) goto step_5;
 
+    // For non-leaf PTEs, bits 62–61 are reserved for future standard use. Until
+    // their use is defined by a standard extension, they must be cleared by
+    // software for forward compatibility, or else a page-fault exception is raised.
+    if ( gpte->PBMT != 0 ) return GST_PAGE_FAULT;
+
+    // For non-leaf PTEs, the D, A, and U bits are reserved for future standard use.
+    if ( gpte->D != 0 || gpte->A != 0 || gpte->U != 0) return GST_PAGE_FAULT;
+
     i = i - 1;
     if ( i < 0 ) return GST_PAGE_FAULT;
     a = gpte->PPN * PAGESIZE;

diff --git a/iommu_ref_model/libiommu/src/iommu_two_stage_trans.c b/iommu_ref_model/libiommu/src/iommu_two_stage_trans.c
@@ -185,6 +185,9 @@ two_stage_address_translation(
     // software for forward compatibility, or else a page-fault exception is raised.
     if ( pte->PBMT != 0 ) goto page_fault;
 
+    // For non-leaf PTEs, the D, A, and U bits are reserved for future standard use.
+    if ( pte->D != 0 || pte->A != 0 || pte->U != 0) goto page_fault;
+
     i = i - 1;
     if ( i < 0 ) goto page_fault;
     a = pte->PPN * PAGESIZE;