Re: [libvirt] [PATCH] qemu-capabilities: Fix query-cpu-model-expansion on s390 with older kernel

On Thu, Jan 12, 2017 at 11:18:11 -0500, Collin L. Walling wrote: > When running on s390 with a kernel that does not support cpu model checking and > with a Qemu new enough to support query-cpu-model-expansion, the gathering of qemu > capabilities will fail. Qemu responds to the query-cpu-model-expansion qmp > command with an error because the needed kernel ioct does not exist. When this > happens a guest cannot even be defined due to missing qemu capabilities data. > > This patch fixes the problem by silently ignoring generic errors stemming from > calls to query-cpu-model-expansion. > > Reported-by: Farhan Ali <alifm(a)linux.vnet.ibm.com&gt; > Signed-off-by: Collin L. Walling <walling(a)linux.vnet.ibm.com&gt; > Signed-off-by: Jason J. Herne <jjherne(a)linux.vnet.ibm.com&gt; > --- > src/qemu/qemu_monitor_json.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c > index e767437..1662749 100644 > --- a/src/qemu/qemu_monitor_json.c > +++ b/src/qemu/qemu_monitor_json.c > @@ -5041,6 +5041,15 @@ qemuMonitorJSONGetCPUModelExpansion(qemuMonitorPtr mon, > if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0) > goto cleanup; > > + /* Some QEMU architectures have the query-cpu-model-expansion > + * command, but return 'GenericError' instead of simply omitting > + * the command entirely. > + */ Hmm, this comment says something a bit different than the commit message. I hope the issue described by this comment was fixed in QEMU within the same release the query-cpu-model-expansion command was introduced. But we need to fix this nevertheless to address what the commit message describes. > + if (qemuMonitorJSONHasError(reply, "GenericError")) { > + ret = 0; > + goto cleanup; > + } > + > if (qemuMonitorJSONCheckError(cmd, reply) < 0) > goto cleanup; However, we need to do a little bit more than just ignoring this error. I'll send a v2 soon.