Re: [PATCH v7 10/10] (lib)xl: soft reset support

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-05-27 at 17:25 +0200, Vitaly Kuznetsov wrote:
> Perform soft reset when a domain did SHUTDOWN_soft_reset. Migrate the
> content with xc_domain_soft_reset(), reload dm and toolstack.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> Changes in v7:
> - Save toolstack earlier.
> - Introduce LIBXL_HAVE_SOFT_RESET [Wei Liu]
> ---
>  docs/man/xl.cfg.pod.5        |  12 +++++
>  tools/libxl/libxl.c          |   4 ++
>  tools/libxl/libxl.h          |  14 +++++
>  tools/libxl/libxl_create.c   | 119 +++++++++++++++++++++++++++++++++++++++----
>  tools/libxl/libxl_internal.h |  26 ++++++++++
>  tools/libxl/libxl_types.idl  |   3 ++
>  tools/libxl/xl.h             |   1 +
>  tools/libxl/xl_cmdimpl.c     |  33 +++++++++++-
>  8 files changed, 201 insertions(+), 11 deletions(-)
> 
> diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
> index 8e4154f..ced5cc0 100644
> --- a/docs/man/xl.cfg.pod.5
> +++ b/docs/man/xl.cfg.pod.5
> @@ -368,6 +368,13 @@ destroy the domain.
>  write a "coredump" of the domain to F</var/xen/dump/NAME> and then
>  restart the domain.
>  
> +=item B<soft-reset>
> +
> +create a new domain with the same configuration, reassign all the domain's
> +memory to this new domain, kill the original domain, and continue execution

s/this/a/ I think?

> @@ -1529,20 +1545,67 @@ static void domcreate_destruction_cb(libxl__egc *egc,
>  typedef struct {
>      libxl__domain_create_state dcs;
>      uint32_t *domid_out;
> +    libxl__domain_destroy_state dds;
> +    uint8_t *toolstack_buf;
> +    uint32_t toolstack_len;

I think a libxl__domain_soft_reset_state would be appropriate here,
perhaps containing the app_domain_create_state rather than adding all
the fields next to it.

>  } libxl__app_domain_create_state;
> [...]
> @@ -1550,12 +1613,34 @@ static int do_domain_create(libxl_ctx *ctx, libxl_domain_config *d_config,
>      libxl_domain_config_init(&cdcs->dcs.guest_config_saved);
>      libxl_domain_config_copy(ctx, &cdcs->dcs.guest_config_saved, d_config);
>      cdcs->dcs.restore_fd = restore_fd;
> +    cdcs->dcs.domid_soft_reset = domid_soft_reset;
>      cdcs->dcs.callback = domain_create_cb;
>      cdcs->dcs.checkpointed_stream = checkpointed_stream;
>      libxl__ao_progress_gethow(&cdcs->dcs.aop_console_how, aop_console_how);
>      cdcs->domid_out = domid;

Since the backend of this function has very little in common between the
create and soft/reset cases, perhaps refactor the first half into a new
function to initialise a cdcs to be called by do_domain_create and the
soft reset function, the latter of which would go on to do the body of
the following if here.

Ian.