Re: [PATCH v2 2/2] xen: Simplify TSC domctls by removing double info field

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 26/05/15 12:14, Ian Campbell wrote:
> There is no need to have this twice and we can simply inline
> xen_guest_tsc_info into xen_domctl_tsc_info as well.
>
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

Nice diffstat.

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

> ---
> ---
>  tools/libxc/xc_domain.c     |   23 ++++++++---------------
>  xen/arch/x86/domctl.c       |   21 +++++++++------------
>  xen/include/public/domctl.h |    9 ++-------
>  3 files changed, 19 insertions(+), 34 deletions(-)
>
> diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
> index 7cb36d9..b01a7df 100644
> --- a/tools/libxc/xc_domain.c
> +++ b/tools/libxc/xc_domain.c
> @@ -759,10 +759,10 @@ int xc_domain_set_tsc_info(xc_interface *xch,
>      DECLARE_DOMCTL;
>      domctl.cmd = XEN_DOMCTL_settscinfo;
>      domctl.domain = (domid_t)domid;
> -    domctl.u.tsc_info.info.tsc_mode = tsc_mode;
> -    domctl.u.tsc_info.info.elapsed_nsec = elapsed_nsec;
> -    domctl.u.tsc_info.info.gtsc_khz = gtsc_khz;
> -    domctl.u.tsc_info.info.incarnation = incarnation;
> +    domctl.u.tsc_info.tsc_mode = tsc_mode;
> +    domctl.u.tsc_info.elapsed_nsec = elapsed_nsec;
> +    domctl.u.tsc_info.gtsc_khz = gtsc_khz;
> +    domctl.u.tsc_info.incarnation = incarnation;
>      return do_domctl(xch, &domctl);
>  }
>  
> @@ -775,24 +775,17 @@ int xc_domain_get_tsc_info(xc_interface *xch,
>  {
>      int rc;
>      DECLARE_DOMCTL;
> -    DECLARE_HYPERCALL_BUFFER(xen_guest_tsc_info_t, info);
> -
> -    info = xc_hypercall_buffer_alloc(xch, info, sizeof(*info));
> -    if ( info == NULL )
> -        return -1;
>  
>      domctl.cmd = XEN_DOMCTL_gettscinfo;
>      domctl.domain = (domid_t)domid;
> -    set_xen_guest_handle(domctl.u.tsc_info.out_info, info);
>      rc = do_domctl(xch, &domctl);
>      if ( rc == 0 )
>      {
> -        *tsc_mode = info->tsc_mode;
> -        *elapsed_nsec = info->elapsed_nsec;
> -        *gtsc_khz = info->gtsc_khz;
> -        *incarnation = info->incarnation;
> +        *tsc_mode = domctl.u.tsc_info.tsc_mode;
> +        *elapsed_nsec = domctl.u.tsc_info.elapsed_nsec;
> +        *gtsc_khz = domctl.u.tsc_info.gtsc_khz;
> +        *incarnation = domctl.u.tsc_info.incarnation;
>      }
> -    xc_hypercall_buffer_free(xch, info);
>      return rc;
>  }
>  
> diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
> index 6d3fe91..5ea9409 100644
> --- a/xen/arch/x86/domctl.c
> +++ b/xen/arch/x86/domctl.c
> @@ -856,16 +856,13 @@ long arch_do_domctl(
>              ret = -EINVAL;
>          else
>          {
> -            xen_guest_tsc_info_t info = { 0 };
> -
>              domain_pause(d);
> -            tsc_get_info(d, &info.tsc_mode,
> -                            &info.elapsed_nsec,
> -                            &info.gtsc_khz,
> -                            &info.incarnation);
> +            tsc_get_info(d, &domctl->u.tsc_info.tsc_mode,
> +                         &domctl->u.tsc_info.elapsed_nsec,
> +                         &domctl->u.tsc_info.gtsc_khz,
> +                         &domctl->u.tsc_info.incarnation);
>              domain_unpause(d);
> -            if ( copy_to_guest(domctl->u.tsc_info.out_info, &info, 1) )
> -                ret = -EFAULT;
> +            copyback = 1;
>          }
>          break;
>  
> @@ -875,10 +872,10 @@ long arch_do_domctl(
>          else
>          {
>              domain_pause(d);
> -            tsc_set_info(d, domctl->u.tsc_info.info.tsc_mode,
> -                         domctl->u.tsc_info.info.elapsed_nsec,
> -                         domctl->u.tsc_info.info.gtsc_khz,
> -                         domctl->u.tsc_info.info.incarnation);
> +            tsc_set_info(d, domctl->u.tsc_info.tsc_mode,
> +                         domctl->u.tsc_info.elapsed_nsec,
> +                         domctl->u.tsc_info.gtsc_khz,
> +                         domctl->u.tsc_info.incarnation);
>              domain_unpause(d);
>          }
>          break;
> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
> index 10b51ef..9eb5eb5 100644
> --- a/xen/include/public/domctl.h
> +++ b/xen/include/public/domctl.h
> @@ -698,18 +698,13 @@ typedef struct xen_domctl_disable_migrate {
>  
>  /* XEN_DOMCTL_gettscinfo */
>  /* XEN_DOMCTL_settscinfo */
> -struct xen_guest_tsc_info {
> +typedef struct xen_domctl_tsc_info {
> +    /* IN/OUT */
>      uint32_t tsc_mode;
>      uint32_t gtsc_khz;
>      uint32_t incarnation;
>      uint32_t pad;
>      uint64_aligned_t elapsed_nsec;
> -};
> -typedef struct xen_guest_tsc_info xen_guest_tsc_info_t;
> -DEFINE_XEN_GUEST_HANDLE(xen_guest_tsc_info_t);
> -typedef struct xen_domctl_tsc_info {
> -    XEN_GUEST_HANDLE_64(xen_guest_tsc_info_t) out_info; /* OUT */
> -    xen_guest_tsc_info_t info; /* IN */
>  } xen_domctl_tsc_info_t;
>  
>  /* XEN_DOMCTL_gdbsx_guestmemio      guest mem io */