hw/i386/intel_iommu: Fix endianness problems related to VTD_IR_TableEntry

The code already tries to do some endianness handling here, but
currently fails badly:
- While it already swaps the data when logging errors / tracing, it fails
  to byteswap the value before e.g. accessing entry->irte.present
- entry->irte.source_id is swapped with le32_to_cpu(), though this is
  a 16-bit value
- The whole union is apparently supposed to be swapped via the 64-bit
  data[2] array, but the struct is a mixture between 32 bit values
  (the first 8 bytes) and 64 bit values (the second 8 bytes), so this
  cannot work as expected.

Fix it by converting the struct to two proper 64-bit bitfields, and
by swapping the values only once for everybody right after reading
the data from memory.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230802135723.178083-3-thuth@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 13fcde8e91..4028e32701 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3328,14 +3328,15 @@ static int vtd_irte_get(IntelIOMMUState *iommu, uint16_t index,
         return -VTD_FR_IR_ROOT_INVAL;
     }
 
-    trace_vtd_ir_irte_get(index, le64_to_cpu(entry->data[1]),
-                          le64_to_cpu(entry->data[0]));
+    entry->data[0] = le64_to_cpu(entry->data[0]);
+    entry->data[1] = le64_to_cpu(entry->data[1]);
+
+    trace_vtd_ir_irte_get(index, entry->data[1], entry->data[0]);
 
     if (!entry->irte.present) {
         error_report_once("%s: detected non-present IRTE "
                           "(index=%u, high=0x%" PRIx64 ", low=0x%" PRIx64 ")",
-                          __func__, index, le64_to_cpu(entry->data[1]),
-                          le64_to_cpu(entry->data[0]));
+                          __func__, index, entry->data[1], entry->data[0]);
         return -VTD_FR_IR_ENTRY_P;
     }
 
@@ -3343,14 +3344,13 @@ static int vtd_irte_get(IntelIOMMUState *iommu, uint16_t index,
         entry->irte.__reserved_2) {
         error_report_once("%s: detected non-zero reserved IRTE "
                           "(index=%u, high=0x%" PRIx64 ", low=0x%" PRIx64 ")",
-                          __func__, index, le64_to_cpu(entry->data[1]),
-                          le64_to_cpu(entry->data[0]));
+                          __func__, index, entry->data[1], entry->data[0]);
         return -VTD_FR_IR_IRTE_RSVD;
     }
 
     if (sid != X86_IOMMU_SID_INVALID) {
         /* Validate IRTE SID */
-        source_id = le32_to_cpu(entry->irte.source_id);
+        source_id = entry->irte.source_id;
         switch (entry->irte.sid_vtype) {
         case VTD_SVT_NONE:
             break;
@@ -3404,7 +3404,7 @@ static int vtd_remap_irq_get(IntelIOMMUState *iommu, uint16_t index,
     irq->trigger_mode = irte.irte.trigger_mode;
     irq->vector = irte.irte.vector;
     irq->delivery_mode = irte.irte.delivery_mode;
-    irq->dest = le32_to_cpu(irte.irte.dest_id);
+    irq->dest = irte.irte.dest_id;
     if (!iommu->intr_eime) {
 #define  VTD_IR_APIC_DEST_MASK         (0xff00ULL)
 #define  VTD_IR_APIC_DEST_SHIFT        (8)