Index: sys/arch/arm/cortex/gicv3_its.c
===================================================================
RCS file: /cvsroot/src/sys/arch/arm/cortex/gicv3_its.c,v
retrieving revision 1.41
diff -u -p -r1.41 gicv3_its.c
--- sys/arch/arm/cortex/gicv3_its.c	28 Jan 2025 21:20:45 -0000	1.41
+++ sys/arch/arm/cortex/gicv3_its.c	30 Apr 2026 10:15:19 -0000
@@ -191,7 +191,8 @@ gits_command_mapd(struct gicv3_its *its,
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.dw[0] = GITS_CMD_MAPD | ((uint64_t)deviceid << 32);
 	if (v) {
-		cmd.dw[1] = uimax(1, size) - 1;
+		KASSERT(size >= 1);
+		cmd.dw[1] = size - 1;
 		cmd.dw[2] = itt_addr | __BIT(63);
 	}
 
@@ -409,9 +410,12 @@ gicv3_its_device_map(struct gicv3_its *i
 	while (!powerof2(vectors))
 		vectors++;
 
+	KASSERT(vectors >= 2);
+	KASSERT(powerof2(vectors));
+
 	const uint64_t typer = gits_read_8(its, GITS_TYPER);
 	const u_int itt_entry_size = __SHIFTOUT(typer, GITS_TYPER_ITT_entry_size) + 1;
-	const u_int itt_size = roundup(uimax(vectors, 2) * itt_entry_size, GITS_ITT_ALIGN);
+	const u_int itt_size = roundup(vectors * itt_entry_size, GITS_ITT_ALIGN);
 
 	LIST_FOREACH(dev, &its->its_devices, dev_list)
 		if (dev->dev_id == devid) {
@@ -461,7 +465,7 @@ gicv3_its_device_map(struct gicv3_its *i
 	/*
 	 * Map the device to the ITT
 	 */
-	const u_int size = __SHIFTOUT(typer, GITS_TYPER_ID_bits) + 1;
+	const u_int size = fls32(vectors);
 	mutex_enter(its->its_lock);
 	error = gits_command_mapd(its, devid, dev->dev_itt.segs[0].ds_addr, size, true);
 	if (error == 0) {