diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index f03d58300f..c3871ae067 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -279,6 +279,10 @@ static void smmuv3_init_regs(SMMUv3State *s)
     s->idr[1] = FIELD_DP32(s->idr[1], IDR1, CMDQS,   SMMU_CMDQS);
 
     s->idr[3] = FIELD_DP32(s->idr[3], IDR3, HAD, 1);
+    if (FIELD_EX32(s->idr[0], IDR0, S2P)) {
+        /* XNX is a stage-2-specific feature */
+        s->idr[3] = FIELD_DP32(s->idr[3], IDR3, XNX, 1);
+    }
     s->idr[3] = FIELD_DP32(s->idr[3], IDR3, RIL, 1);
     s->idr[3] = FIELD_DP32(s->idr[3], IDR3, BBML, 2);