diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h
index ad8e10169b108ad76be26b1b21cc4f666af76eb6..913fc5d3125641a724ea889c0f9059ccdec7ed06 100644
--- a/include/libvirt/virterror.h
+++ b/include/libvirt/virterror.h
@@ -277,6 +277,8 @@ typedef enum {
     VIR_ERR_MIGRATE_UNSAFE = 81,        /* Migration is not safe */
     VIR_ERR_OVERFLOW = 82,              /* integer overflow */
     VIR_ERR_BLOCK_COPY_ACTIVE = 83,     /* action prevented by block copy job */
+    VIR_ERR_OPERATION_UNSUPPORTED = 84, /* The requested operation is not
+                                           supported */
 } virErrorNumber;
 
 /**
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 3ede88d67c5d446783eb4fcf6e570a30d977cd18..7e482d132bef6693e0f028746105863b83a11959 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -3652,11 +3652,11 @@ int qemuMonitorJSONOpenGraphics(qemuMonitorPtr mon,
     if (virJSONValueObjectGetNumberUlong(inserted,                            \
                                          FIELD,                               \
                                          &reply->STORE) < 0) {                \
-        virReportError(VIR_ERR_INTERNAL_ERROR,                                \
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,                         \
                        _("block_io_throttle field '%s' missing "              \
                          "in qemu's output"),                                 \
                        #STORE);                                               \
-            goto cleanup;                                                     \
+        goto cleanup;                                                         \
     }
 static int
 qemuMonitorJSONBlockIoThrottleInfo(virJSONValuePtr result,
diff --git a/src/util/virterror.c b/src/util/virterror.c
index a40cfe0b381e42c31b74893de974d800127ff293..c438de8457dad26278fe8e768145d01ca64d5656 100644
--- a/src/util/virterror.c
+++ b/src/util/virterror.c
@@ -1185,6 +1185,12 @@ virErrorMsg(virErrorNumber error, const char *info)
             else
                 errmsg = _("block copy still active: %s");
             break;
+        case VIR_ERR_OPERATION_UNSUPPORTED:
+            if (!info)
+                errmsg = _("Operation not supported");
+            else
+                errmsg = _("Operation not supported: %s");
+            break;
     }
     return errmsg;
 }