diff --git a/qemu-options.hx b/qemu-options.hx
index b780ed12e7..272630f639 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -35,7 +35,7 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
     "                kernel_irqchip=on|off controls accelerated irqchip support\n"
     "                kernel_irqchip=on|off|split controls accelerated irqchip support (default=off)\n"
     "                vmport=on|off|auto controls emulation of vmport (default: auto)\n"
-    "                kvm_shadow_mem=size of KVM shadow MMU\n"
+    "                kvm_shadow_mem=size of KVM shadow MMU in bytes\n"
     "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
     "                mem-merge=on|off controls memory merge support (default: on)\n"
     "                iommu=on|off controls emulated Intel IOMMU (VT-d) support (default=off)\n"