diff --git a/include/semihosting/syscalls.h b/include/semihosting/syscalls.h
index 841a93d25b..c60ebafb85 100644
--- a/include/semihosting/syscalls.h
+++ b/include/semihosting/syscalls.h
@@ -42,4 +42,7 @@ void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
 void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
                         int fd, int64_t off, int gdb_whence);
 
+void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
+                         int fd);
+
 #endif /* SEMIHOSTING_SYSCALLS_H */
diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index 8c6c39daf5..4529c9df06 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -247,6 +247,19 @@ static void common_semi_rw_cb(CPUState *cs, target_ulong ret, target_ulong err)
     common_semi_set_ret(cs, arg2 - ret);
 }
 
+/*
+ * Convert from Posix ret+errno to Arm SYS_ISTTY return values.
+ * With gdbstub, err is only ever set for protocol errors to EIO.
+ */
+static void common_semi_istty_cb(CPUState *cs, target_ulong ret,
+                                 target_ulong err)
+{
+    if (err) {
+        ret = (err == ENOTTY ? 0 : -1);
+    }
+    common_semi_cb(cs, ret, err);
+}
+
 /*
  * SYS_SEEK returns 0 on success, not the resulting offset.
  */
@@ -291,14 +304,8 @@ common_semi_flen_cb(CPUState *cs, target_ulong ret, target_ulong err)
  * do the work and return the required return value to the guest
  * via common_semi_cb.
  */
-typedef void sys_isattyfn(CPUState *cs, GuestFD *gf);
 typedef void sys_flenfn(CPUState *cs, GuestFD *gf);
 
-static void host_isattyfn(CPUState *cs, GuestFD *gf)
-{
-    common_semi_cb(cs, isatty(gf->hostfd), 0);
-}
-
 static void host_flenfn(CPUState *cs, GuestFD *gf)
 {
     struct stat buf;
@@ -310,11 +317,6 @@ static void host_flenfn(CPUState *cs, GuestFD *gf)
     }
 }
 
-static void gdb_isattyfn(CPUState *cs, GuestFD *gf)
-{
-    gdb_do_syscall(common_semi_cb, "isatty,%x", gf->hostfd);
-}
-
 static void gdb_flenfn(CPUState *cs, GuestFD *gf)
 {
     gdb_do_syscall(common_semi_flen_cb, "fstat,%x,%x",
@@ -338,32 +340,23 @@ static const uint8_t featurefile_data[] = {
     SH_EXT_EXIT_EXTENDED | SH_EXT_STDOUT_STDERR, /* Feature byte 0 */
 };
 
-static void staticfile_isattyfn(CPUState *cs, GuestFD *gf)
-{
-    common_semi_cb(cs, 0, 0);
-}
-
 static void staticfile_flenfn(CPUState *cs, GuestFD *gf)
 {
     common_semi_cb(cs, gf->staticfile.len, 0);
 }
 
 typedef struct GuestFDFunctions {
-    sys_isattyfn *isattyfn;
     sys_flenfn *flenfn;
 } GuestFDFunctions;
 
 static const GuestFDFunctions guestfd_fns[] = {
     [GuestFDHost] = {
-        .isattyfn = host_isattyfn,
         .flenfn = host_flenfn,
     },
     [GuestFDGDB] = {
-        .isattyfn = gdb_isattyfn,
         .flenfn = gdb_flenfn,
     },
     [GuestFDStatic] = {
-        .isattyfn = staticfile_isattyfn,
         .flenfn = staticfile_flenfn,
     },
 };
@@ -488,12 +481,7 @@ void do_common_semihosting(CPUState *cs)
 
     case TARGET_SYS_ISTTY:
         GET_ARG(0);
-
-        gf = get_guestfd(arg0);
-        if (!gf) {
-            goto do_badf;
-        }
-        guestfd_fns[gf->type].isattyfn(cs, gf);
+        semihost_sys_isatty(cs, common_semi_istty_cb, arg0);
         break;
 
     case TARGET_SYS_SEEK:
diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c
index 9e3eb464b5..1f1baf7e2d 100644
--- a/semihosting/syscalls.c
+++ b/semihosting/syscalls.c
@@ -121,6 +121,12 @@ static void gdb_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
                    (target_ulong)gf->hostfd, off, (target_ulong)gdb_whence);
 }
 
+static void gdb_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
+                       GuestFD *gf)
+{
+    gdb_do_syscall(complete, "isatty,%x", (target_ulong)gf->hostfd);
+}
+
 /*
  * Host semihosting syscall implementations.
  */
@@ -246,6 +252,13 @@ static void host_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
     complete(cs, ret, err);
 }
 
+static void host_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
+                        GuestFD *gf)
+{
+    int ret = isatty(gf->hostfd);
+    complete(cs, ret, ret ? 0 : errno);
+}
+
 /*
  * Static file semihosting syscall implementations.
  */
@@ -437,3 +450,26 @@ void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
         g_assert_not_reached();
     }
 }
+
+void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb complete, int fd)
+{
+    GuestFD *gf = get_guestfd(fd);
+
+    if (!gf) {
+        complete(cs, 0, EBADF);
+        return;
+    }
+    switch (gf->type) {
+    case GuestFDGDB:
+        gdb_isatty(cs, complete, gf);
+        break;
+    case GuestFDHost:
+        host_isatty(cs, complete, gf);
+        break;
+    case GuestFDStatic:
+        complete(cs, 0, ENOTTY);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+}
