[PATCH v2] libqtest: refuse QTEST_QEMU_BINARY=qemu-kvm

[Stefan Hajnoczi <stefanha@redhat.com>]

Some downstreams rename the QEMU binary to "qemu-kvm". This breaks
qtest_get_arch(), which attempts to parse the target architecture from
the QTEST_QEMU_BINARY environment variable.

Print an error instead of returning the architecture "kvm". Things fail
in weird ways when the architecture string is bogus.

Arguably qtests should always be run in a build directory instead of
against an installed QEMU. In any case, printing a clear error when this
happens is helpful.

Reported-by: Qin Wang <qinwang@rehdat.com>
Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/qtest/libqtest.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 71e359efcd..7caf20f56b 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -910,6 +910,16 @@ const char *qtest_get_arch(void)
         abort();
     }
 
+    if (!strstr(qemu, "-system-")) {
+        fprintf(stderr, "QTEST_QEMU_BINARY must end with *-system-<arch> where "
+                        "'arch' is the target architecture (x86_64, aarch64, "
+                        "etc). If you are using qemu-kvm or another custom "
+                        "name, please create a symlink like ln -s "
+                        "path/to/qemu-kvm qemu-system-x86_64 and use that "
+                        "instead.\n");
+        abort();
+    }
+
     return end + 1;
 }
 
-- 
2.30.2