[PATCH 2/2] intel-iommu: block output address in interrupt address range

[Jason Wang]

According to vtd spec v3.3 3.14:

"""
Software must not program paging-structure entries to remap any
address to the interrupt address range. Untranslated requests and
translation requests that result in an address in the interrupt range
will be blocked with condition code LGN.4 or SGN.8.
"""

This patch blocks the request that result in interrupt address range.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/i386/intel_iommu.c          | 27 ++++++++++++++++++++++++++-
 hw/i386/intel_iommu_internal.h |  4 ++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 55281ee1b4..5ef48271d8 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1020,6 +1020,7 @@ static int vtd_iova_to_slpte(IntelIOMMUState *s, 
VTDContextEntry *ce,
     uint32_t offset;
     uint64_t slpte;
     uint64_t access_right_check;
+    uint64_t xlat, size;
 
     if (!vtd_iova_range_check(s, iova, ce, aw_bits)) {
         error_report_once("%s: detected IOVA overflow (iova=0x%" PRIx64 ")",
@@ -1064,11 +1065,33 @@ static int vtd_iova_to_slpte(IntelIOMMUState *s, 
VTDContextEntry *ce,
         if (vtd_is_last_slpte(slpte, level)) {
             *slptep = slpte;
             *slpte_level = level;
-            return 0;
+            break;
         }
         addr = vtd_get_slpte_addr(slpte, aw_bits);
         level--;
     }
+
+    xlat = vtd_get_slpte_addr(*slptep, aw_bits);
+    size = ~vtd_slpt_level_page_mask(level) + 1;
+
+    /*
+     * From VT-d spec 3.14: Untranslated requests and translation
+     * requests that result in an address in the interrupt range will be
+     * blocked with condition code LGN.4 or SGN.8.
+     */
+    if ((xlat > VTD_INTERRUPT_ADDR_LAST ||
+         xlat + size - 1 < VTD_INTERRUPT_ADDR_FIRST)) {
+        return 0;
+    } else {
+        error_report_once("%s: xlat address is in interrupt range "
+                          "(iova=0x%" PRIx64 ", level=0x%" PRIx32 ", "
+                          "slpte=0x%" PRIx64 ", write=%d, "
+                          "xlat=0x%" PRIx64 ", size=0x%" PRIx64 ")",
+                          __func__, iova, level, slpte, is_write,
+                          xlat, size);
+        return s->scalable_mode ? -VTD_FR_SM_INTERRUPT_ADDR :
+                                  -VTD_FR_INTERRUPT_ADDR;
+    }
 }
 
 typedef int (*vtd_page_walk_hook)(IOMMUTLBEvent *event, void *private);
@@ -1620,10 +1643,12 @@ static const bool vtd_qualified_faults[] = {
     [VTD_FR_PAGING_ENTRY_INV] = true,
     [VTD_FR_ROOT_TABLE_INV] = false,
     [VTD_FR_CONTEXT_TABLE_INV] = false,
+    [VTD_FR_INTERRUPT_ADDR] = true,
     [VTD_FR_ROOT_ENTRY_RSVD] = false,
     [VTD_FR_PAGING_ENTRY_RSVD] = true,
     [VTD_FR_CONTEXT_ENTRY_TT] = true,
     [VTD_FR_PASID_TABLE_INV] = false,
+    [VTD_FR_SM_INTERRUPT_ADDR] = true,
     [VTD_FR_MAX] = false,
 };
 
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index d0bb43ae87..730e1b97d6 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -288,6 +288,8 @@ typedef enum VTDFaultReason {
      * context-entry.
      */
     VTD_FR_CONTEXT_ENTRY_TT,
+    /* Output address in the interrupt address range */
+    VTD_FR_INTERRUPT_ADDR = 0xE,
 
     /* Interrupt remapping transition faults */
     VTD_FR_IR_REQ_RSVD = 0x20, /* One or more IR request reserved
@@ -303,6 +305,8 @@ typedef enum VTDFaultReason {
 
     VTD_FR_PASID_TABLE_INV = 0x58,  /*Invalid PASID table entry */
 
+    /* Output address in the interrupt address range for scalable mode */
+    VTD_FR_SM_INTERRUPT_ADDR = 0x87,
     VTD_FR_MAX,                 /* Guard */
 } VTDFaultReason;
 
-- 
2.25.1