[libvirt] [PATCH 3/6] qemu: qmp query-cpu-model-expansion command

[Jiri Denemark]

On Mon, Nov 21, 2016 at 14:11:53 -0500, Jason J. Herne wrote:
> From: "Collin L. Walling" <walling at linux.vnet.ibm.com>
> 
> query-cpu-model-expansion is used to get a list of features for a given cpu
> model name or to get the model and features of the host hardware/environment
> as seen by Qemu/kvm.
> 
> 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.c      | 60 ++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor.h      | 22 +++++++++++
>  src/qemu/qemu_monitor_json.c | 94 ++++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |  6 +++
>  4 files changed, 182 insertions(+)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index 0bfc1a8..927ef39 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -3615,6 +3615,66 @@ qemuMonitorCPUDefInfoFree(qemuMonitorCPUDefInfoPtr cpu)
>  
>  
>  int
> +qemuMonitorGetCPUModelExpansion(qemuMonitorPtr mon,
> +                                const char *type,
> +                                const char *model_name,
> +                                qemuMonitorCPUModelInfoPtr *model_info)
> +{
> +    VIR_DEBUG("model_info=%p", model_info);

Printing type and model_name would be even more interesting than
model_info pointer.

> +
> +    QEMU_CHECK_MONITOR_JSON(mon);
> +
> +    return qemuMonitorJSONGetCPUModelExpansion(mon, type, model_name, model_info);
> +}
> +
> +
> +void
> +qemuMonitorCPUModelInfoFree(qemuMonitorCPUModelInfoPtr model_info)
> +{
> +    size_t i;
> +
> +    if (!model_info)
> +        return;
> +    VIR_FREE(model_info->name);
> +    for (i = 0; i < model_info->nprops; i++)
> +        VIR_FREE(model_info->props[i].name);
> +    VIR_FREE(model_info);

I think this code would be slightly nicer in the following form:

    if (!model_info)
        return;

    for (i = 0; i < model_info->nprops; i++)
        VIR_FREE(model_info->props[i].name);

    VIR_FREE(model_info->name);
    VIR_FREE(model_info);

> +}
...
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index ef8672c..af50997 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -4930,6 +4930,100 @@ qemuMonitorJSONGetCPUDefinitions(qemuMonitorPtr mon,
>      return ret;
>  }
>  
> +int
> +qemuMonitorJSONGetCPUModelExpansion(qemuMonitorPtr mon,
> +                                    const char *type,
> +                                    const char *model_name,
> +                                    qemuMonitorCPUModelInfoPtr *model_info)
> +{
> +    int ret = -1;
> +    virJSONValuePtr model;
> +    virJSONValuePtr cmd = NULL;
> +    virJSONValuePtr reply = NULL;
> +    virJSONValuePtr data;
> +    virJSONValuePtr cpu_model;
> +    virJSONValuePtr cpu_props;
> +    qemuMonitorCPUModelInfoPtr newmodel = NULL;

Hmm, would you mind s/newmodel/cpu/ or something similar? I found the
"newmodel" name to be quite confusing.

> +    char const *cpu_name;
> +    int n;

I think the "n" variable is not really necessary.

> +    size_t i;
> +
> +    *model_info = NULL;
> +
> +    if (!(model = virJSONValueNewObject()))
> +        goto cleanup;
> +
> +    if (virJSONValueObjectAppendString(model, "name", model_name) < 0)
> +        goto cleanup;
> +
> +    if (!(cmd = qemuMonitorJSONMakeCommand("query-cpu-model-expansion",
> +                                           "s:type", type,
> +                                           "a:model", model,
> +                                           NULL)))
> +        goto cleanup;
> +
> +    if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
> +        goto cleanup;
> +
> +    if (qemuMonitorJSONCheckError(cmd, reply) < 0)
> +        goto cleanup;
> +
> +    if (!(data = virJSONValueObjectGetObject(reply, "return"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-cpu-model-expansion reply was missing return data"));
> +        goto cleanup;
> +    }

Just drop this condition, "return" object is guaranteed to exist if
qemuMonitorJSONCheckError() returns zero. It's perfectly OK to do

    data = virJSONValueObjectGetObject(reply, "return");
    if (!(cpu_model = virJSONValueObjectGetObject(data, "model")))
        ...

> +
> +    if (!(cpu_model = virJSONValueObjectGetObject(data, "model")))

An error message should be reported here.

> +        goto cleanup;
> +
> +    if (!(cpu_name = virJSONValueObjectGetString(cpu_model, "name")))

And here.

> +        goto cleanup;
> +
> +    if (!(cpu_props = virJSONValueObjectGetObject(cpu_model, "props")))

I believe this should be

    if (!(cpu_props = virJSONValueObjectGetArray(cpu_model, "props")))

and an error should be reported here.

> +        goto cleanup;
> +
> +    if (VIR_ALLOC(newmodel) < 0)
> +        goto cleanup;
> +
> +    if (VIR_STRDUP(newmodel->name, cpu_name) < 0)
> +        goto cleanup;
> +
> +    n = newmodel->nprops = cpu_props->data.object.npairs;

newmodel->nprops = virJSONValueArraySize(cpu_props)

> +
> +    if (VIR_ALLOC_N(newmodel->props, n) < 0)
> +        goto cleanup;
> +
> +    for (i = 0; i < n; i++) {
> +        const char *prop_name;
> +        bool supported;
> +
> +        if (!(prop_name = virJSONValueObjectGetKey(cpu_props, i))) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("query-cpu-model-expansion reply data is missing a"
> +                             " property name"));
> +            goto cleanup;
> +        }
> +        if (VIR_STRDUP(newmodel->props[i].name, prop_name) < 0)
> +            goto cleanup;
> +
> +        if (virJSONValueObjectGetBoolean(cpu_props, prop_name, &supported) < 0)

An error should be reported here.

> +            goto cleanup;
> +        newmodel->props[i].supported = supported;
> +    }
> +
> +    ret = 0;
> +    *model_info = newmodel;
> +    newmodel = NULL;
> +
> + cleanup:
> +    qemuMonitorCPUModelInfoFree(newmodel);
> +    virJSONValueFree(cmd);
> +    virJSONValueFree(reply);
> +    virJSONValueFree(model);
> +    return ret;
> +}
> +
>  
>  int qemuMonitorJSONGetCommands(qemuMonitorPtr mon,
>                                 char ***commands)
...

Jirka