diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 4dec0046df4f0728a6e71ef0e6f5e2cda055c904..853e8cefcff4444926214ce0b6c94e6e8afba5ce 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1978,6 +1978,9 @@ virQEMUCapsProcessStringFlags(virQEMUCapsPtr qemuCaps,
 {
     size_t i, j;
     for (i = 0; i < nflags; i++) {
+        if (virQEMUCapsGet(qemuCaps, flags[i].flag))
+            continue;
+
         for (j = 0; j < nvalues; j++) {
             if (STREQ(values[j], flags[i].value)) {
                 virQEMUCapsSet(qemuCaps, flags[i].flag);