Re: [PATCH v2 23/30] xen+tools: Export maximum host and guest cpu featuresets via SYSCTL

[Wei Liu <wei.liu2@citrix.com>]

On Fri, Feb 05, 2016 at 01:42:16PM +0000, Andrew Cooper wrote:
> And provide stubs for toolstack use.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Tim Deegan <tim@xen.org>
> CC: Ian Campbell <Ian.Campbell@citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
> CC: David Scott <dave@recoil.org>
> CC: Rob Hoes <Rob.Hoes@citrix.com>
> 
> v2:
>  * Rebased to use libxencall
>  * Improve hypercall documentation
> ---
>  tools/libxc/include/xenctrl.h       |  3 ++
>  tools/libxc/xc_cpuid_x86.c          | 27 +++++++++++++++
>  tools/ocaml/libs/xc/xenctrl.ml      |  3 ++
>  tools/ocaml/libs/xc/xenctrl.mli     |  4 +++
>  tools/ocaml/libs/xc/xenctrl_stubs.c | 35 ++++++++++++++++++++
>  xen/arch/x86/sysctl.c               | 66 +++++++++++++++++++++++++++++++++++++
>  xen/include/public/sysctl.h         | 25 ++++++++++++++
>  7 files changed, 163 insertions(+)
> 
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index 1a5f4ec..5a7500a 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -2571,6 +2571,9 @@ int xc_psr_cat_get_domain_data(xc_interface *xch, uint32_t domid,
>  int xc_psr_cat_get_l3_info(xc_interface *xch, uint32_t socket,
>                             uint32_t *cos_max, uint32_t *cbm_len,
>                             bool *cdp_enabled);
> +
> +int xc_get_cpu_featureset(xc_interface *xch, uint32_t index,
> +                          uint32_t *nr_features, uint32_t *featureset);
>  #endif
>  
>  /* Compat shims */
> diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
> index c142595..7b802da 100644
> --- a/tools/libxc/xc_cpuid_x86.c
> +++ b/tools/libxc/xc_cpuid_x86.c
> @@ -33,6 +33,33 @@
>  #define DEF_MAX_INTELEXT  0x80000008u
>  #define DEF_MAX_AMDEXT    0x8000001cu
>  
> +int xc_get_cpu_featureset(xc_interface *xch, uint32_t index,
> +                          uint32_t *nr_features, uint32_t *featureset)
> +{
> +    DECLARE_SYSCTL;
> +    DECLARE_HYPERCALL_BOUNCE(featureset,
> +                             *nr_features * sizeof(*featureset),
> +                             XC_HYPERCALL_BUFFER_BOUNCE_OUT);
> +    int ret;
> +
> +    if ( xc_hypercall_bounce_pre(xch, featureset) )
> +        return -1;
> +
> +    sysctl.cmd = XEN_SYSCTL_get_cpu_featureset;
> +    sysctl.u.cpu_featureset.index = index;
> +    sysctl.u.cpu_featureset.nr_features = *nr_features;
> +    set_xen_guest_handle(sysctl.u.cpu_featureset.features, featureset);
> +
> +    ret = do_sysctl(xch, &sysctl);
> +
> +    xc_hypercall_bounce_post(xch, featureset);
> +
> +    if ( !ret )
> +        *nr_features = sysctl.u.cpu_featureset.nr_features;
> +
> +    return ret;
> +}
> +

Looks like a sensible wrapper, so 

Acked-by: Wei Liu <wei.liu2@citrix.com>