Re: [libvirt] [PATCH] qemu_monitor_json: add support to search QOM device path by device alias

Commit ce745914 introduced detection of actual video ram sizes to fix migration if QEMU decide to modify the values provided by libvirt. This works perfectly for domains with number of video devices up to two. If there are more than two video devices in the guest all the secondary devices in the XML will have the same memory values. This is because our current code search for QOM device path only by the device type name and all the secondary video devices has the same name "qxl". This patch introduces a new search function that will try to search a QOM device path using also device's alias if the alias is available. After that it will fallback to the old recursive code if the alias search found no results. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1358728 Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; --- src/qemu/qemu_monitor.c | 11 ++++--- src/qemu/qemu_monitor_json.c | 74 ++++++++++++++++++++++++++++++++++++++------ src/qemu/qemu_monitor_json.h | 3 +- 3 files changed, 74 insertions(+), 14 deletions(-) diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index 098e654..1fac4de 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -1084,10 +1084,11 @@ qemuMonitorInitBalloonObjectPath(qemuMonitorPtr mon) } mon->ballooninit = true; - flp_ret = qemuMonitorJSONFindLinkPath(mon, "virtio-balloon-pci", &path); + flp_ret = qemuMonitorJSONFindLinkPath(mon, "virtio-balloon-pci", NULL, &path); if (flp_ret == -2) { /* pci object was not found retry search for ccw object */ - if (qemuMonitorJSONFindLinkPath(mon, "virtio-balloon-ccw", &path) < 0) + if (qemuMonitorJSONFindLinkPath(mon, "virtio-balloon-ccw", + NULL, &path) < 0)

diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c index bb426dc..5d24e26 100644 --- a/src/qemu/qemu_monitor_json.c +++ b/src/qemu/qemu_monitor_json.c @@ -6810,7 +6810,55 @@ qemuMonitorJSONGetMemoryDeviceInfo(qemuMonitorPtr mon, /** - * Recursively search for a QOM object link. + * Search for a QOM object link by alias and name. + * + * For @alias and @name, this function tries to find QOM object named @name + * with id @alias in /machine/peripheral. + * + * Returns: + * 0 - Found + * -1 - Error - bail out + * -2 - Not found + */ +static int +qemuMonitorJSONFindObjectPathByAlias(qemuMonitorPtr mon, + const char *name, + const char *alias, + char **path) +{ + qemuMonitorJSONListPathPtr *paths = NULL; + char *child = NULL; + int npaths; + int ret = -1; + size_t i; + + npaths = qemuMonitorJSONGetObjectListPaths(mon, "/machine/peripheral", &paths); + if (npaths < 0) + return -1; + + if (virAsprintf(&child, "child<%s>", name) < 0) + return -1; + + for (i = 0; i < npaths; i++) { + if (STREQ(paths[i]->name, alias) && STREQ(paths[i]->type, child)) { + if (virAsprintf(path, "/machine/peripheral/%s", alias) < 0) + goto cleanup; + + ret = 0; + goto cleanup; + } + } + + ret = -2; + + cleanup: + VIR_FREE(child); + return ret; +} +