diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
index 614fd76695..f76e8588c5 100644
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@@ -43,6 +43,35 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
+static int host_to_gdb_errno(int err)
+{
+#define E(X)  case E##X: return GDB_E##X
+    switch (err) {
+    E(PERM);
+    E(NOENT);
+    E(INTR);
+    E(BADF);
+    E(ACCES);
+    E(FAULT);
+    E(BUSY);
+    E(EXIST);
+    E(NODEV);
+    E(NOTDIR);
+    E(ISDIR);
+    E(INVAL);
+    E(NFILE);
+    E(MFILE);
+    E(FBIG);
+    E(NOSPC);
+    E(SPIPE);
+    E(ROFS);
+    E(NAMETOOLONG);
+    default:
+        return GDB_EUNKNOWN;
+    }
+#undef E
+}
+
 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 {
     Nios2CPU *cpu = NIOS2_CPU(cs);
@@ -50,7 +79,7 @@ static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
     target_ulong args = env->regs[R_ARG1];
 
     if (put_user_u32(ret, args) ||
-        put_user_u32(err, args + 4)) {
+        put_user_u32(host_to_gdb_errno(err), args + 4)) {
         /*
          * The nios2 semihosting ABI does not provide any way to report this
          * error to the guest, so the best we can do is log it in qemu.
@@ -69,7 +98,7 @@ static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
 
     if (put_user_u32(ret >> 32, args) ||
         put_user_u32(ret, args + 4) ||
-        put_user_u32(err, args + 8)) {
+        put_user_u32(host_to_gdb_errno(err), args + 8)) {
         /* No way to report this via nios2 semihosting ABI; just log it */
         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
                       "discarded because argument block not writable\n");