[PATCH 2/2] tools/libxl: enable in-band reconnect marker for stubdom QMP proxy

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

This enables stubdom reliably detect when it needs to reconnect QMP
socket. It is critical, as otherwise QEMU will not send its handshake,
and so libxl will timeout while waiting on one. When it happens during
domain startup, it can result in error like this:

libxl: libxl_pci.c:1772:device_pci_add_done: Domain 3:libxl__device_pci_add 
failed for PCI device 0:0:14.0 (rc -9)
libxl: libxl_create.c:1904:domcreate_attach_devices: Domain 3:unable to add pci 
devices

See vchan-socket-proxy commit message for details about this reconnect
corner case.

Stubdomain side needs to use --reconnect-marker=1 option too.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
---
 tools/libs/light/libxl_dm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index fc264a3a13a6..cc9c5bea1e7f 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -2625,10 +2625,11 @@ static void spawn_qmp_proxy(libxl__egc *egc,
     sdss->qmp_proxy_spawn.failure_cb = qmp_proxy_startup_failed;
     sdss->qmp_proxy_spawn.detached_cb = qmp_proxy_detached;
 
-    const int arraysize = 6;
+    const int arraysize = 7;
     GCNEW_ARRAY(args, arraysize);
     args[nr++] = STUBDOM_QMP_PROXY_PATH;
     args[nr++] = GCSPRINTF("--state-path=%s", sdss->qmp_proxy_spawn.xspath);
+    args[nr++] = "--reconnect-marker=1";
     args[nr++] = GCSPRINTF("%u", dm_domid);
     args[nr++] = GCSPRINTF("%s/device-model/%u/qmp-vchan", dom_path, 
guest_domid);
     args[nr++] = (char*)libxl__qemu_qmp_path(gc, guest_domid);
-- 
2.35.3