intel_iommu: Add missed reserved bit check for IEC descriptor

IEC descriptor is 128-bit invalidation descriptor, must be padded with
128-bits of 0s in the upper bytes to create a 256-bit descriptor when
the invalidation queue is configured for 256-bit descriptors (IQA_REG.DW=1).

Fixes: 02a2cbc872df ("x86-iommu: introduce IEC notifiers")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20241104125536.1236118-4-zhenzhong.duan@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/intel_iommu.c

@@ -2692,6 +2692,14 @@ static bool vtd_process_iotlb_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 static bool vtd_process_inv_iec_desc(IntelIOMMUState *s,
                                      VTDInvDesc *inv_desc)
 {
+    uint64_t mask[4] = {VTD_INV_DESC_IEC_RSVD, VTD_INV_DESC_ALL_ONE,
+                        VTD_INV_DESC_ALL_ONE, VTD_INV_DESC_ALL_ONE};
+
+    if (!vtd_inv_desc_reserved_check(s, inv_desc, mask, false,
+                                     __func__, "iec inv")) {
+        return false;
+    }
+
     trace_vtd_inv_desc_iec(inv_desc->iec.granularity,
                            inv_desc->iec.index,
                            inv_desc->iec.index_mask);

hw/i386/intel_iommu_internal.h

@@ -410,6 +410,9 @@ typedef union VTDInvDesc VTDInvDesc;
 #define VTD_INV_DESC_DEVICE_IOTLB_RSVD_HI 0xffeULL
 #define VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO 0xffff0000ffe0f1f0
 
+/* Masks for Interrupt Entry Invalidate Descriptor */
+#define VTD_INV_DESC_IEC_RSVD           0xffff000007fff1e0ULL
+
 /* Rsvd field masks for spte */
 #define VTD_SPTE_SNP 0x800ULL