Re: [PATCH 09/29] [HACK] tools/libxc: save/restore v2 framework

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

On 11/09/14 11:34, Ian Campbell wrote:
> On Wed, 2014-09-10 at 18:10 +0100, Andrew Cooper wrote:
>> For testing purposes, the environmental variable "XG_MIGRATION_V2" allows the
>> two save/restore codepaths to coexist, and have a runtime switch.
>>
>> It is indended that once this series is less RFC, the v2 framework will
>> completely replace v1.
> I think we are now at the point where this hack needs to be dropped from
> the series.

One problem is remus.  My plan when dropping this patch was to drop all
of xc_domain_{save/restore}.c as well, but without remus migration-v2
support available, this will break existing set-ups.

One option might be to have legacy and v2 sitting properly side-by-side
in libxc for the transition period.

~Andrew

>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> ---
>>  tools/libxc/Makefile              |    1 +
>>  tools/libxc/saverestore/common.h  |   15 +++++++++++++++
>>  tools/libxc/saverestore/restore.c |   23 +++++++++++++++++++++++
>>  tools/libxc/saverestore/save.c    |   19 +++++++++++++++++++
>>  tools/libxc/xc_domain_restore.c   |    8 ++++++++
>>  tools/libxc/xc_domain_save.c      |    6 ++++++
>>  tools/libxc/xenguest.h            |   13 +++++++++++++
>>  7 files changed, 85 insertions(+)
>>  create mode 100644 tools/libxc/saverestore/common.h
>>  create mode 100644 tools/libxc/saverestore/restore.c
>>  create mode 100644 tools/libxc/saverestore/save.c
>>
>> diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
>> index 3b04027..564e805 100644
>> --- a/tools/libxc/Makefile
>> +++ b/tools/libxc/Makefile
>> @@ -45,6 +45,7 @@ GUEST_SRCS-y :=
>>  GUEST_SRCS-y += xg_private.c xc_suspend.c
>>  ifeq ($(CONFIG_MIGRATE),y)
>>  GUEST_SRCS-y += xc_domain_restore.c xc_domain_save.c
>> +GUEST_SRCS-y += $(wildcard saverestore/*.c)
>>  GUEST_SRCS-y += xc_offline_page.c xc_compression.c
>>  else
>>  GUEST_SRCS-y += xc_nomigrate.c
>> diff --git a/tools/libxc/saverestore/common.h b/tools/libxc/saverestore/common.h
>> new file mode 100644
>> index 0000000..f1aff44
>> --- /dev/null
>> +++ b/tools/libxc/saverestore/common.h
>> @@ -0,0 +1,15 @@
>> +#ifndef __COMMON__H
>> +#define __COMMON__H
>> +
>> +#include "../xg_private.h"
>> +
>> +#endif
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/tools/libxc/saverestore/restore.c b/tools/libxc/saverestore/restore.c
>> new file mode 100644
>> index 0000000..6624baa
>> --- /dev/null
>> +++ b/tools/libxc/saverestore/restore.c
>> @@ -0,0 +1,23 @@
>> +#include "common.h"
>> +
>> +int xc_domain_restore2(xc_interface *xch, int io_fd, uint32_t dom,
>> +                       unsigned int store_evtchn, unsigned long *store_mfn,
>> +                       domid_t store_domid, unsigned int console_evtchn,
>> +                       unsigned long *console_mfn, domid_t console_domid,
>> +                       unsigned int hvm, unsigned int pae, int superpages,
>> +                       int checkpointed_stream,
>> +                       struct restore_callbacks *callbacks)
>> +{
>> +    IPRINTF("In experimental %s", __func__);
>> +    return -1;
>> +}
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/tools/libxc/saverestore/save.c b/tools/libxc/saverestore/save.c
>> new file mode 100644
>> index 0000000..f6ad734
>> --- /dev/null
>> +++ b/tools/libxc/saverestore/save.c
>> @@ -0,0 +1,19 @@
>> +#include "common.h"
>> +
>> +int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
>> +                    uint32_t max_factor, uint32_t flags,
>> +                    struct save_callbacks* callbacks, int hvm)
>> +{
>> +    IPRINTF("In experimental %s", __func__);
>> +    return -1;
>> +}
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
>> index b411126..cec2dfc 100644
>> --- a/tools/libxc/xc_domain_restore.c
>> +++ b/tools/libxc/xc_domain_restore.c
>> @@ -1490,6 +1490,14 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
>>      struct restore_ctx *ctx = &_ctx;
>>      struct domain_info_context *dinfo = &ctx->dinfo;
>>  
>> +    if ( getenv("XG_MIGRATION_V2") )
>> +    {
>> +        return xc_domain_restore2(
>> +            xch, io_fd, dom, store_evtchn, store_mfn,
>> +            store_domid, console_evtchn, console_mfn, console_domid,
>> +            hvm,  pae,  superpages, checkpointed_stream, callbacks);
>> +    }
>> +
>>      DPRINTF("%s: starting restore of new domid %u", __func__, dom);
>>  
>>      pagebuf_init(&pagebuf);
>> diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
>> index 02544f8..a23ed68 100644
>> --- a/tools/libxc/xc_domain_save.c
>> +++ b/tools/libxc/xc_domain_save.c
>> @@ -894,6 +894,12 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
>>  
>>      int completed = 0;
>>  
>> +    if ( getenv("XG_MIGRATION_V2") )
>> +    {
>> +        return xc_domain_save2(xch, io_fd, dom, max_iters,
>> +                               max_factor, flags, callbacks, hvm);
>> +    }
>> +
>>      DPRINTF("%s: starting save of domid %u", __func__, dom);
>>  
>>      if ( hvm && !callbacks->switch_qemu_logdirty )
>> diff --git a/tools/libxc/xenguest.h b/tools/libxc/xenguest.h
>> index 40bbac8..55755cf 100644
>> --- a/tools/libxc/xenguest.h
>> +++ b/tools/libxc/xenguest.h
>> @@ -88,6 +88,10 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
>>                     uint32_t max_factor, uint32_t flags /* XCFLAGS_xxx */,
>>                     struct save_callbacks* callbacks, int hvm);
>>  
>> +/* Domain Save v2 */
>> +int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
>> +                    uint32_t max_factor, uint32_t flags,
>> +                    struct save_callbacks* callbacks, int hvm);
>>  
>>  /* callbacks provided by xc_domain_restore */
>>  struct restore_callbacks {
>> @@ -124,6 +128,15 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
>>                        unsigned int hvm, unsigned int pae, int superpages,
>>                        int checkpointed_stream,
>>                        struct restore_callbacks *callbacks);
>> +
>> +/* Domain Restore v2 */
>> +int xc_domain_restore2(xc_interface *xch, int io_fd, uint32_t dom,
>> +                       unsigned int store_evtchn, unsigned long *store_mfn,
>> +                       domid_t store_domid, unsigned int console_evtchn,
>> +                       unsigned long *console_mfn, domid_t console_domid,
>> +                       unsigned int hvm, unsigned int pae, int superpages,
>> +                       int checkpointed_stream,
>> +                       struct restore_callbacks *callbacks);
>>  /**
>>   * xc_domain_restore writes a file to disk that contains the device
>>   * model saved state.
>