[Xen-changelog] [xen master] libxl: Prevent qemu closing QMP socket on shutdown before libxl is done with it.

[patchbot@xxxxxxx]

commit 9ba80a722b193c912432d544338f8daf9a846cd7
Author:     Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
AuthorDate: Thu Jan 22 18:21:40 2015 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Tue Jan 27 16:45:29 2015 +0000

    libxl: Prevent qemu closing QMP socket on shutdown before libxl is done 
with it.

    At present on shutdown when using pci-passthrough with qemu-xen, qemu
    closes the QMP socket before libxl is done with it causing these
    errors to be logged by libxl:

        Waiting for domain test (domid 1) to die [pid 11568]
        Domain 1 has shut down, reason code 0 0x0
        Action for shutdown reason code 0 is destroy
        Domain 1 needs to be cleaned up: destroying the domain
        libxl: error: libxl_qmp.c:443:qmp_next: Socket read error: Connection 
reset by peer
        libxl: error: libxl_qmp.c:701:libxl__qmp_initialize: Failed to connect 
to QMP
        libxl: error: libxl_qmp.c:686:libxl__qmp_initialize: Connection error: 
Connection refused
        libxl: error: libxl_dm.c:1588:kill_device_model: Device Model already 
exited
        Done. Exiting now

    Prevent this by using the qemu '-no-shutdown' parameter which is
    described as doing:

        "Donâ??t exit QEMU on guest shutdown, but instead only stop the 
emulation.
         This allows for instance switching to monitor to commit changes to the 
disk image."

    So Qemu will stop emulating, but keeps the QMP socket open and waits
    for libxl to kill the qemu process when it is done, preventing the
    race and resulting in this to be logged by libxl:

        Waiting for domain test (domid 1) to die [pid 10859]
        Domain 1 has shut down, reason code 0 0x0
        Action for shutdown reason code 0 is destroy
        Domain 1 needs to be cleaned up: destroying the domain
        Done. Exiting now

    Signed-off-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
    Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 tools/libxl/libxl_dm.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index d8d6f0c..73de5c3 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -443,6 +443,7 @@ static char ** libxl__build_device_model_args_new(libxl__gc 
*gc,
                                     "path=%s/qmp-libxl-%d,server,nowait",
                                     libxl__run_dir_path(), guest_domid));

+    flexarray_append(dm_args, "-no-shutdown");
     flexarray_append(dm_args, "-mon");
     flexarray_append(dm_args, "chardev=libxl-cmd,mode=control");

--
generated by git-patchbot for /home/xen/git/xen.git#master

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog