Re: [Qemu-devel] [RFC PATCH] target-ppc: enable migration within the same CPU family

[Alexey Kardashevskiy]

On 03/24/2014 04:28 PM, Alexey Kardashevskiy wrote:
> Currently only migration fails if CPU version is different even a bit.
> For example, migration from POWER7 v2.0 to POWER7 v2.1 fails because of
> that. Since there is no difference between CPU versions which could
> affect migration stream, we can safely enable it.
> 
> This adds a helper to find the closest POWERPC family class (i.e. first
> abstract class in hierarchy).
> 
> This replaces VMSTATE_UINTTL_EQUAL statement with a custom handler which
> checks if the source and destination CPUs belong to the same family and
> fails if they are not.
> 
> This adds a PVR reset to the default value as it will be overwritten
> by VMSTATE_UINTTL_ARRAY(env.spr, PowerPCCPU, 1024).
> 
> Since the actual migration format is not changed by this patch,
> @version_id of vmstate_ppc_cpu does not have to be changed either.
> 
> Signed-off-by: Bharata B Rao <address@hidden>
> Signed-off-by: Alexey Kardashevskiy <address@hidden>


Ping?


> ---
>  target-ppc/cpu-qom.h        |  1 +
>  target-ppc/machine.c        | 40 ++++++++++++++++++++++++++++++++++++++--
>  target-ppc/translate_init.c | 12 ++++++++++++
>  3 files changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
> index 47dc8e6..5eb56ea 100644
> --- a/target-ppc/cpu-qom.h
> +++ b/target-ppc/cpu-qom.h
> @@ -105,6 +105,7 @@ static inline PowerPCCPU *ppc_env_get_cpu(CPUPPCState 
> *env)
>  
>  PowerPCCPUClass *ppc_cpu_class_by_pvr(uint32_t pvr);
>  PowerPCCPUClass *ppc_cpu_class_by_pvr_mask(uint32_t pvr);
> +PowerPCCPUClass *ppc_cpu_family_class_by_pvr_mask(uint32_t pvr);
>  
>  void ppc_cpu_do_interrupt(CPUState *cpu);
>  void ppc_cpu_dump_state(CPUState *cpu, FILE *f, fprintf_function cpu_fprintf,
> diff --git a/target-ppc/machine.c b/target-ppc/machine.c
> index 063b379..834297e 100644
> --- a/target-ppc/machine.c
> +++ b/target-ppc/machine.c
> @@ -160,6 +160,11 @@ static int cpu_post_load(void *opaque, int version_id)
>      CPUPPCState *env = &cpu->env;
>      int i;
>  
> +    /*
> +     * Allow migration between hosts of same processor family
> +     * by restoring the default PVR for this VM on this host.
> +     */
> +    env->spr[SPR_PVR] = env->spr_cb[SPR_PVR].default_value;
>      env->lr = env->spr[SPR_LR];
>      env->ctr = env->spr[SPR_CTR];
>      env->xer = env->spr[SPR_XER];
> @@ -462,6 +467,37 @@ static const VMStateDescription vmstate_tlbmas = {
>      }
>  };
>  
> +static int get_pvr(QEMUFile *f, void *pv, size_t size)
> +{
> +    target_ulong pvrdest = *(target_ulong *)pv;
> +#if TARGET_LONG_BITS == 64
> +    target_ulong pvrsrc = qemu_get_be64(f);
> +#else
> +    target_ulong pvrsrc = qemu_get_be32(f);
> +#endif
> +    PowerPCCPUClass *pccdest = ppc_cpu_family_class_by_pvr_mask(pvrdest);
> +    PowerPCCPUClass *pccsrc = ppc_cpu_family_class_by_pvr_mask(pvrsrc);
> +
> +    return (pccdest == pccsrc) ? 0 : -1;
> +}
> +
> +static void put_pvr(QEMUFile *f, void *pv, size_t size)
> +{
> +    target_ulong pvr = *(target_ulong *)pv;
> +
> +#if TARGET_LONG_BITS == 64
> +    qemu_put_be64(f, pvr);
> +#else
> +    qemu_put_be32(f, pvr);
> +#endif
> +}
> +
> +static const VMStateInfo vmstate_pvr = {
> +    .name = "PVR",
> +    .get  = get_pvr,
> +    .put  = put_pvr,
> +};
> +
>  const VMStateDescription vmstate_ppc_cpu = {
>      .name = "cpu",
>      .version_id = 5,
> @@ -471,8 +507,8 @@ const VMStateDescription vmstate_ppc_cpu = {
>      .pre_save = cpu_pre_save,
>      .post_load = cpu_post_load,
>      .fields      = (VMStateField []) {
> -        /* Verify we haven't changed the pvr */
> -        VMSTATE_UINTTL_EQUAL(env.spr[SPR_PVR], PowerPCCPU),
> +        VMSTATE_SINGLE(env.spr[SPR_PVR], PowerPCCPU, 0, vmstate_pvr,
> +                       target_ulong),
>  
>          /* User mode architected state */
>          VMSTATE_UINTTL_ARRAY(env.gpr, PowerPCCPU, 32),
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index cdb2d2a..0c5c6a8 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8146,6 +8146,18 @@ PowerPCCPUClass *ppc_cpu_class_by_pvr_mask(uint32_t 
> pvr)
>      return pcc;
>  }
>  
> +PowerPCCPUClass *ppc_cpu_family_class_by_pvr_mask(uint32_t pvr)
> +{
> +    PowerPCCPUClass *pcc = ppc_cpu_class_by_pvr_mask(pvr);
> +    ObjectClass *oc = OBJECT_CLASS(pcc);
> +
> +    while (oc && !object_class_is_abstract(oc)) {
> +        oc = object_class_get_parent(oc);
> +    }
> +
> +    return POWERPC_CPU_CLASS(oc);
> +}
> +
>  static gint ppc_cpu_compare_class_name(gconstpointer a, gconstpointer b)
>  {
>      ObjectClass *oc = (ObjectClass *)a;
> 


-- 
Alexey