Re: [Qemu-devel] [PATCH v4 2/3] target-i386: add migration support for Intel LMCE

[Paolo Bonzini <pbonzini@redhat.com>]

On 16/06/2016 08:06, Haozhong Zhang wrote:
> Migration is only allowed between VCPUs with the same lmce option.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> ---
>  target-i386/machine.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/target-i386/machine.c b/target-i386/machine.c
> index cb9adf2..00375a3 100644
> --- a/target-i386/machine.c
> +++ b/target-i386/machine.c
> @@ -347,6 +347,12 @@ static int cpu_post_load(void *opaque, int version_id)
>          return -EINVAL;
>      }
>  
> +    if (!cpu->enable_lmce && (env->mcg_cap & MCG_LMCE_P)) {
> +        error_report("Config mismatch: VCPU has LMCE enabled, "
> +                     "but \"lmce\" option is disabled");
> +        return -EINVAL;
> +    }
> +

I think this is unnecessary.  Apart from this, the patch is good and can
be squashed in patch 1 for v5.

Paolo

>      /*
>       * Real mode guest segments register DPL should be zero.
>       * Older KVM version were setting it wrongly.
> @@ -896,6 +902,24 @@ static const VMStateDescription vmstate_tsc_khz = {
>      }
>  };
>  
> +static bool mcg_ext_ctl_needed(void *opaque)
> +{
> +    X86CPU *cpu = opaque;
> +    CPUX86State *env = &cpu->env;
> +    return cpu->enable_lmce && env->mcg_ext_ctl;
> +}
> +
> +static const VMStateDescription vmstate_mcg_ext_ctl = {
> +    .name = "cpu/mcg_ext_ctl",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .needed = mcg_ext_ctl_needed,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT64(env.mcg_ext_ctl, X86CPU),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
>  VMStateDescription vmstate_x86_cpu = {
>      .name = "cpu",
>      .version_id = 12,
> @@ -1022,6 +1046,7 @@ VMStateDescription vmstate_x86_cpu = {
>  #ifdef TARGET_X86_64
>          &vmstate_pkru,
>  #endif
> +        &vmstate_mcg_ext_ctl,
>          NULL
>      }
>  };
>