Re: [PATCH v6 COLO 05/15] send store mfn and console mfn to xl before resuming secondary vm

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

On 08/06/15 04:45, Yang Hongyang wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
>
> We will call libxl__xc_domain_restore_done() to rebuild secondary vm. But
> we need store mfn and console mfn when rebuilding secondary vm. So make
> restore_results is a function pointers in callbacks struct and struct
> {save,restore}_callbacks, and use this callback to send store mfn and
> console mfn to xl.
>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
>  tools/libxc/include/xenguest.h     | 8 ++++++++
>  tools/libxc/xc_sr_restore.c        | 8 ++++++--
>  tools/libxl/libxl_colo_restore.c   | 5 -----
>  tools/libxl/libxl_create.c         | 1 +
>  tools/libxl/libxl_save_msgs_gen.pl | 2 +-
>  5 files changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
> index d5902a6..50096b9 100644
> --- a/tools/libxc/include/xenguest.h
> +++ b/tools/libxc/include/xenguest.h
> @@ -130,6 +130,14 @@ struct restore_callbacks {
>      /* Enable qemu-dm logging dirty pages to xen */
>      int (*switch_qemu_logdirty)(int domid, unsigned enable, void *data); /* HVM only */
>  
> +    /*
> +     * callback to send store mfn and console mfn to xl
> +     * if we want to resume vm before xc_domain_save()
> +     * exits.
> +     */
> +    void (*restore_results)(unsigned long store_mfn, unsigned long console_mfn,
> +                            void *data);
> +
>      /* callback to restore toolstack specific data */
>      int (*toolstack_restore)(uint32_t domid, const uint8_t *buf,
>              uint32_t size, void* data);
> diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
> index 982a70e..5e2efd8 100644
> --- a/tools/libxc/xc_sr_restore.c
> +++ b/tools/libxc/xc_sr_restore.c
> @@ -524,7 +524,10 @@ static int handle_checkpoint(struct xc_sr_context *ctx)
>          if ( rc )
>              goto err;
>  
> -        /* TODO: call restore_results */
> +        /* call restore_results */

I would drop this comment.  It is entirely redundant now.

Otherwise, looks good.

~Andrew

> +        ctx->restore.callbacks->restore_results(ctx->restore.xenstore_gfn,
> +                                                ctx->restore.console_gfn,
> +                                                ctx->restore.callbacks->data);
>  
>          /* Resume secondary vm */
>          ret = ctx->restore.callbacks->postcopy(ctx->restore.callbacks->data);
> @@ -793,7 +796,8 @@ int xc_domain_restore2(xc_interface *xch, int io_fd, uint32_t dom,
>          /* this is COLO restore */
>          assert(callbacks->suspend &&
>                 callbacks->checkpoint &&
> -               callbacks->postcopy);
> +               callbacks->postcopy &&
> +               callbacks->restore_results);
>      }
>  
>      IPRINTF("In experimental %s", __func__);
> diff --git a/tools/libxl/libxl_colo_restore.c b/tools/libxl/libxl_colo_restore.c
> index 6c39758..c613c15 100644
> --- a/tools/libxl/libxl_colo_restore.c
> +++ b/tools/libxl/libxl_colo_restore.c
> @@ -153,11 +153,6 @@ static void colo_resume_vm(libxl__egc *egc,
>          return;
>      }
>  
> -    /*
> -     * TODO: get store mfn and console mfn
> -     *  We should call the callback restore_results in
> -     *  xc_domain_restore() before resuming the guest.
> -     */
>      libxl__xc_domain_restore_done(egc, dcs, 0, 0, 0);
>  
>      return;
> diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
> index 1548b70..6e307f3 100644
> --- a/tools/libxl/libxl_create.c
> +++ b/tools/libxl/libxl_create.c
> @@ -1157,6 +1157,7 @@ static void domcreate_bootloader_done(libxl__egc *egc,
>          rc = ERROR_INVAL;
>          goto out;
>      }
> +    callbacks->restore_results = libxl__srm_callout_callback_restore_results;
>  
>      if (checkpointed_stream == LIBXL_CHECKPOINTED_STREAM_COLO) {
>          crs->ao = ao;
> diff --git a/tools/libxl/libxl_save_msgs_gen.pl b/tools/libxl/libxl_save_msgs_gen.pl
> index fbb2d67..2ecd25d 100755
> --- a/tools/libxl/libxl_save_msgs_gen.pl
> +++ b/tools/libxl/libxl_save_msgs_gen.pl
> @@ -32,7 +32,7 @@ our @msgs = (
>      #                toolstack_save          done entirely `by hand'
>      [  7, 'rcxW',   "toolstack_restore",     [qw(uint32_t domid
>                                                  BLOCK tsdata)] ],
> -    [  8, 'r',      "restore_results",       ['unsigned long', 'store_mfn',
> +    [  8, 'rcx',    "restore_results",       ['unsigned long', 'store_mfn',
>                                                'unsigned long', 'console_mfn'] ],
>      [  9, 'srW',    "complete",              [qw(int retval
>                                                   int errnoval)] ],