[libvirt] [PATCH v4 8/8] qemu_driver: hook up query-cpu-model-comparison

[Collin Walling]

[...]

>> +
>> +virCPUCompareResult
>> +virQEMUCapsCPUModelComparison(virQEMUCapsPtr qemuCaps,
>> +                              const char *libDir,
>> +                              uid_t runUid,
>> +                              gid_t runGid,
>> +                              virCPUDefPtr cpu_a,
>> +                              virCPUDefPtr cpu_b,
>> +                              bool failIncompatible)
>> +{
>> +    qemuProcessQMPPtr proc = NULL;
>> +    qemuMonitorCPUModelInfoPtr result = NULL;

Set ret = VIR_CPU_COMPARE_INCOMPATIBLE

>> +    int ret = -1;
>> +
>> +    if (!(proc = qemuProcessQMPNew(qemuCaps->binary, libDir,
>> +                                   runUid, runGid, false)))
>> +        goto cleanup;
>> +
>> +    if (qemuProcessQMPStart(proc) < 0)
>> +        goto cleanup;
>> +
>> +    if (qemuMonitorGetCPUModelComparison(proc->mon, cpu_a->model,
>> +                                         cpu_a->nfeatures, 
>> cpu_a->features,
>> +                                         cpu_b->model, cpu_b->nfeatures,
>> +                                         cpu_b->features, &result) < 0)
>> +        goto cleanup;
>> +
>> +    if (STREQ(result->name, "incompatible") ||
>> +        STREQ(result->name, "subset"))
>> +        ret = VIR_CPU_COMPARE_INCOMPATIBLE;
>> +    else if (STREQ(result->name, "identical"))
>> +        ret = VIR_CPU_COMPARE_IDENTICAL;
>> +    else if (STREQ(result->name, "superset"))
>> +        ret = VIR_CPU_COMPARE_SUPERSET;

and change this:

>> +
>> +    if (failIncompatible && ret == VIR_CPU_COMPARE_INCOMPATIBLE) {
>> +        ret = VIR_CPU_COMPARE_ERROR;
>> +        virReportError(VIR_ERR_CPU_INCOMPATIBLE, NULL);
>> +    }
>> +
>> + cleanup:
>> +    if (ret < 0)
>> +        virQEMUCapsLogProbeFailure(qemuCaps->binary);

To this:

  cleanup:
     if (failIncompatible && ret == VIR_CPU_COMPARE_INCOMPATIBLE) {
         ret = VIR_CPU_COMPARE_ERROR;
         virReportError(VIR_ERR_CPU_INCOMPATIBLE, NULL);
         virQEMUCapsLogProbeFailure(qemuCaps->binary);
     }

>> +
>> +    qemuMonitorCPUModelInfoFree(result);
>> +    qemuProcessQMPFree(proc);
>> +    return ret;
>> +}

And now the output will look like this when the xml contains an
erroneous CPU model or feature:

virsh hypervisor-cpu-compare cpufail.xml
CPU described in cpufail.xml is incompatible with the CPU provided by 
hypervisor on the host


virsh hypervisor-cpu-compare cpufail.xml --error
error: Failed to compare hypervisor CPU with cpufail.xml
error: the CPU is incompatible with host CPU

If this output is not acceptable, then perhaps we should further explore
option 2 that I described on patch 5.

[...]