diff --git a/riscv/execute.h b/riscv/execute.h
index 96aa8350..1005a535 100644
--- a/riscv/execute.h
+++ b/riscv/execute.h
@@ -2438,6 +2438,15 @@ switch((insn.bits >> 0x0) & 0x7f)
         }
         throw trap_illegal_instruction;
       }
+      case 0x5:
+      {
+        if((insn.bits & 0xffffffff) == 0x2fb)
+        {
+          #include "insns/cflush.h"
+          break;
+        }
+        throw trap_illegal_instruction;
+      }
       default:
       {
         throw trap_illegal_instruction;
diff --git a/riscv/insns/cflush.h b/riscv/insns/cflush.h
new file mode 100644
index 00000000..5117ca0b
--- /dev/null
+++ b/riscv/insns/cflush.h
@@ -0,0 +1 @@
+require_supervisor;