Re: [Qemu-devel] [PATCH v2 4/7] ppc: open code cpu creation for machine types

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Sat, Jul 02, 2016 at 12:41:48AM +0200, Greg Kurz wrote:
> If we want to generate cpu_dt_id in the machine code, this must occur
> before the cpu gets realized. We must open code the cpu creation to be
> able to do this.
> 
> This patch just does that. It borrows some lines from previous work
> from Bharata to handle the feature parsing.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
>  hw/ppc/ppc.c |   39 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index dc3d214009c5..57f4ddd073d0 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -32,6 +32,7 @@
>  #include "sysemu/cpus.h"
>  #include "hw/timer/m48t59.h"
>  #include "qemu/log.h"
> +#include "qapi/error.h"
>  #include "qemu/error-report.h"
>  #include "hw/loader.h"
>  #include "sysemu/kvm.h"
> @@ -1353,5 +1354,41 @@ PowerPCCPU *ppc_get_vcpu_by_dt_id(int cpu_dt_id)
> 
>  PowerPCCPU *ppc_cpu_init(const char *cpu_model)
>  {
> -    return POWERPC_CPU(cpu_generic_init(TYPE_POWERPC_CPU, cpu_model));
> +    PowerPCCPU *cpu;
> +    CPUClass *cc;
> +    ObjectClass *oc;
> +    gchar **model_pieces;
> +    Error *err = NULL;
> +
> +    model_pieces = g_strsplit(cpu_model, ",", 2);
> +    if (!model_pieces[0]) {
> +        error_report("Invalid/empty CPU model name");
> +        return NULL;
> +    }
> +
> +    oc = cpu_class_by_name(TYPE_POWERPC_CPU, model_pieces[0]);
> +    if (oc == NULL) {
> +        error_report("Unable to find CPU definition: %s", model_pieces[0]);
> +        return NULL;
> +    }
> +
> +    cpu = POWERPC_CPU(object_new(object_class_get_name(oc)));
> +
> +    cc = CPU_CLASS(oc);
> +    cc->parse_features(CPU(cpu), model_pieces[1], &err);

Igor is working on a patchset to convert -cpu features into global properties.
IIUC, after that patchset, it is not recommended to parse the -cpu features
for every CPU but do it only once.

That is what I attempted here in the context of supporting compat cpu type
for pseries-2.7:

https://www.mail-archive.com/qemu-devel@nongnu.org/msg381660.html

Regards,
Bharata.