Re: [Qemu-devel] [RFC PATCH v0 1/1] spapr: Support setting of compat CPU type for CPU cores

[Thomas Huth <thuth@redhat.com>]

On 18.06.2016 10:34, Bharata B Rao wrote:
> Compat CPU type is typically specified on -cpu cmdline option like:
> -cpu host,compat=power7 or -cpu POWER8E,compat=power7 etc.
> With the introduction of sPAPR CPU core devices, we need to support
> the same for core devices too.
> 
> Support the specification of CPU compat type on device_add command for
> sPAPRCPUCore devices like:
> (qemu) device_add POWER8E-spapr-cpu-core,id=core3,compat=power7,core-id=24
>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> ---
> Applies on ppc-for-2.7 branch of David Gibson's tree.
> 
>  hw/ppc/spapr.c                  |  8 +++++
>  hw/ppc/spapr_cpu_core.c         | 73 +++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr_cpu_core.h |  2 ++
>  3 files changed, 83 insertions(+)
[...]
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 3a5da09..9eb63cc 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -96,6 +96,24 @@ char *spapr_get_cpu_core_type(const char *model)
>      return core_type;
>  }
>  
> +/*
> + * Returns the CPU compat type specified in -cpu @model.
> + */
> +char *spapr_get_cpu_compat_type(const char *model)
> +{
> +    char *compat_type = NULL;
> +    gchar **model_pieces = g_strsplit(model, ",", 2);
> +
> +    if (model_pieces[1]) {
> +        gchar **compat_pieces = g_strsplit(model_pieces[1], "=", 2);
> +
> +        compat_type = g_strdup_printf("%s", compat_pieces[1]);
> +    }
> +
> +    g_strfreev(model_pieces);
> +    return compat_type;
> +}

Shouldn't you check for "compat=" somewhere in this function (and
properly iterate over all parts of the comma separated string)? In case
we support more properties than "compat=" some day, this will go wrong
otherwise...

 Thomas