[libvirt] [PATCH] qemu-capabilities: Fix query-cpu-model-expansion on s390 with older kernel
Jiri Denemark
jdenemar at redhat.com
Fri Jan 13 10:04:21 UTC 2017
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 at linux.vnet.ibm.com>
> Signed-off-by: Collin L. Walling <walling at linux.vnet.ibm.com>
> Signed-off-by: Jason J. Herne <jjherne at linux.vnet.ibm.com>
> ---
> 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.
Jirka
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