Re: [Xen-devel] [PATCH v2 09/12] x86/vmce, tools/libxl: expose LMCE capability in guest MSR_IA32_MCG_CAP

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Mar 17, 2017 at 02:46:11PM +0800, Haozhong Zhang wrote:
> If LMCE is supported by host and ' mca_caps = [ "lmce" ] ' is present
> in xl config, the LMCE capability will be exposed in guest MSR_IA32_MCG_CAP.
> By default, LMCE is not exposed to guest so as to keep the backwards migration
> compatibility.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
[...]
> +static int hvm_set_mca_capabilities(libxl__gc *gc, uint32_t domid,
> +                                    libxl_domain_build_info *const info)
> +{
> +    int i, rc = 0;
> +    const libxl_string_list xl_caps = info->u.hvm.mca_caps;
> +    unsigned long caps = 0;
> +
> +    if (!xl_caps)
> +        return 0;
> +
> +    for (i = 0; xl_caps[i] != NULL; i++) {
> +        if (!strcmp(xl_caps[i], "lmce"))
> +            caps |= HVMMCA_CAP_LMCE;
> +        else {
> +            LOG(ERROR, "Unsupported MCA capability %s", xl_caps[i]);
> +            rc = ERROR_FAIL;
> +            break;
> +        }
> +    }
> +

This is not how we normally do this.  Parsing should normally be done in
xl. Is there any particular reason you chose to parse here?

> +    if (!rc)
> +        rc = xc_hvm_param_set(CTX->xch, domid, HVM_PARAM_MCA_CAP, caps);
> +
> +    return rc;
> +}
>  #endif
>  
>  static void hvm_set_conf_params(xc_interface *handle, uint32_t domid,
> @@ -438,6 +464,10 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
>          rc = hvm_set_viridian_features(gc, domid, info);
>          if (rc)
>              return rc;
> +
> +        rc = hvm_set_mca_capabilities(gc, domid, info);
> +        if (rc)
> +            return rc;
>  #endif
>      }
>  
> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
> index a612d1f..71c6c33 100644
> --- a/tools/libxl/libxl_types.idl
> +++ b/tools/libxl/libxl_types.idl
> @@ -550,6 +550,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
>                                         ("serial_list",      
> libxl_string_list),
>                                         ("rdm", libxl_rdm_reserve),
>                                         ("rdm_mem_boundary_memkb", MemKB),
> +                                       ("mca_caps",         
> libxl_string_list),

You need to add a LIBXL_HAVE_MCA_CAPS to libxl.h

Wei.

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