Index: sys/arm64/arm64/gic_v3_its.c
===================================================================
--- sys/arm64/arm64/gic_v3_its.c
+++ sys/arm64/arm64/gic_v3_its.c
@@ -353,6 +353,22 @@
 				return (ENXIO);
 			}
 
+			/* QUIRK for Cavium ThunderX */
+			if (CPU_MATCH(CPU_IMPL_MASK | CPU_PART_MASK,
+			    CPU_IMPL_CAVIUM, CPU_PART_THUNDER, 0, 0)) {
+				/*
+				 * QUIRK: Number of pages that can be set in
+				 *        Thunder's GITS_BASER cannot exceed 0xFD
+				 */
+				if ((nitspages - 1) > 0xFDUL) {
+					device_printf(sc->dev,
+					    "QUIRK: attempting to configure 0x%lx"
+					    " pages, reducing to 0xFD\n",
+					    nitspages);
+					nitspages = 0xFDUL;
+				}
+			}
+
 			/* Clear fields under modification first */
 			gits_baser &= ~(GITS_BASER_VALID |
 			    GITS_BASER_CACHE_MASK | GITS_BASER_TYPE_MASK |