Re: [PATCH 03/27] tools/libxl: Stash all restore parameters in domain_create_state

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

On 16/06/15 14:37, Ian Campbell wrote:
> On Mon, 2015-06-15 at 14:44 +0100, Andrew Cooper wrote:
>> Shortly more parameters will appear, and this saves unboxing each one.
>>
>> No functional change.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> CC: Ian Campbell <Ian.Campbell@citrix.com>
>> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
>> CC: Wei Liu <wei.liu2@citrix.com>
>> ---
>>  tools/libxl/libxl_create.c       |   12 ++++++------
>>  tools/libxl/libxl_internal.h     |    2 +-
>>  tools/libxl/libxl_save_callout.c |    2 +-
>>  3 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
>> index 86384d2..385891c 100644
>> --- a/tools/libxl/libxl_create.c
>> +++ b/tools/libxl/libxl_create.c
>> @@ -1577,8 +1577,8 @@ static void domain_create_cb(libxl__egc *egc,
>>                               int rc, uint32_t domid);
>>  
>>  static int do_domain_create(libxl_ctx *ctx, libxl_domain_config *d_config,
>> -                            uint32_t *domid,
>> -                            int restore_fd, int checkpointed_stream,
>> +                            uint32_t *domid, int restore_fd,
>> +                            const libxl_domain_restore_params *params,
>>                              const libxl_asyncop_how *ao_how,
>>                              const libxl_asyncprogress_how *aop_console_how)
>>  {
>> @@ -1591,8 +1591,8 @@ 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;
>> +    if (params) cdcs->dcs.restore_params = *params;
> Is this eventually going to become non-optional? I think not and its
> validity is entirely intertwined with the validity of restore_fd (as I
> suspect it was before, but I've not checked).
>
> Perhaps an error check to that effect would be useful?

It is mandatory for restore, and currently unused for plain create. 
restore_fd being > -1 does appear to be the canonical switch between a
restore and a create, so should be the qualification of validity.

>
> Anyway, I think what you've done here is correct, so:
>         Acked-by: Ian Campbell <ian.campbell@citrix.com>
>         
> [...]
>> @@ -3122,11 +3122,11 @@ struct libxl__domain_create_state {
>>      libxl_domain_config *guest_config;
>>      libxl_domain_config guest_config_saved; /* vanilla config */
>>      int restore_fd;
>> +    libxl_domain_restore_params restore_params;
>>      libxl__domain_create_cb *callback;
>>      libxl_asyncprogress_how aop_console_how;
>>      /* private to domain_create */
>>      int guest_domid;
>> -    int checkpointed_stream;
> This has, in effect moved from "private to domain_create" to "filled in
> by user", I don't think the change here has actually changed its status,
> but I suspect it was wrong before (alternatively restore_fd is in the
> wrong place instead).

I think it was wrong before.  It was always a caller-provided parameter,
albeit implicit by virtue of essentially being a "remus" boolean.

~Andrew