Re: [libvirt] [PATCH 4/4] Implement QMP support for extracting CPU thread ID

The KVM build of QEMU includs the thread ID of each vCPU in the 'query-cpus' output. This is required for pinning guests to particular host CPUs * src/qemu/qemu_monitor_json.c: Extract 'thread_id' from CPU info --- src/qemu/qemu_monitor_json.c | 82 +++++++++++++++++++++++++++++++++++++++++- 1 files changed, 81 insertions(+), 1 deletions(-) diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c index 7dd2bdb..8e88c7e 100644 --- a/src/qemu/qemu_monitor_json.c +++ b/src/qemu/qemu_monitor_json.c @@ -536,6 +536,85 @@ int qemuMonitorJSONSystemPowerdown(qemuMonitorPtr mon) } +/* + * [ { "CPU": 0, "current": true, "halted": false, "pc": 3227107138 }, + * { "CPU": 1, "current": false, "halted": true, "pc": 7108165 } ] + */ +static int +qemuMonitorJSONExtractCPUInfo(virJSONValuePtr reply, + int **pids) +{ + virJSONValuePtr data; + int ret = -1; + int i; + int *threads = NULL; + int ncpus; + + if (!(data = virJSONValueObjectGet(reply, "return"))) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("cpu reply was missing return data")); + goto cleanup; + } + + if (data->type != VIR_JSON_TYPE_ARRAY) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("cpu information was not an array")); + goto cleanup; + } + + if ((ncpus = virJSONValueArraySize(data)) <= 0) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("cpu information was empty")); + goto cleanup; + } + + if (VIR_REALLOC_N(threads, ncpus) < 0) { + virReportOOMError(NULL); + goto cleanup; + } + + for (i = 0 ; i < ncpus ; i++) { + virJSONValuePtr entry = virJSONValueArrayGet(data, i); + int cpu; + int thread; + if (!entry) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("character device information was missing aray element")); + goto cleanup; + } + + if (virJSONValueObjectGetNumberInt(entry, "CPU", &cpu) < 0) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("cpu information was missing cpu number")); + goto cleanup; + } + + if (virJSONValueObjectGetNumberInt(entry, "thread_id", &thread) < 0) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s", + _("cpu information was missing thread ID")); + goto cleanup; + } + + if (cpu != i) { + qemudReportError(NULL, NULL, NULL, VIR_ERR_INTERNAL_ERROR, + _("unexpected cpu index %d expecting %d"), + i, cpu); + goto cleanup; + } + + threads[i] = thread; + } + + *pids = threads; + threads = NULL; + ret = 0; + +cleanup: + VIR_FREE(threads); + return ret; +} + + int qemuMonitorJSONGetCPUInfo(qemuMonitorPtr mon, int **pids) { @@ -554,7 +633,8 @@ int qemuMonitorJSONGetCPUInfo(qemuMonitorPtr mon, if (ret == 0) ret = qemuMonitorJSONCheckError(cmd, reply); - /* XXX extract PIDs if present - QEMU hasn't implement this yet :-( */ + if (ret == 0) + ret = qemuMonitorJSONExtractCPUInfo(reply, pids); virJSONValueFree(cmd); virJSONValueFree(reply);