[Qemu-devel] Re: [RFC PATCH 14/20] Upgrade QEMU_FILE_VERSION from 3 to 4, and introduce qemu_savevm_state_all().

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 04/21/2010 12:57 AM, Yoshiaki Tamura wrote:
> Make a 32bit entry after QEMU_VM_FILE_VERSION to recognize whether the
> transfered data is QEMU_VM_FT_MODE or QEMU_VM_LIVE_MIGRATION_MODE.
>    

I'd rather you encapsulate the current protocol as opposed to extending 
it with a new version.

You could also do this by just having a new -incoming option, right?  
All you really need is to indicate that this is for high frequency 
checkpointing, right?

Regards,

Anthony Liguori

> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
> ---
>   savevm.c |   76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>   sysemu.h |    1 +
>   2 files changed, 75 insertions(+), 2 deletions(-)
>
> diff --git a/savevm.c b/savevm.c
> index 292ae32..19b3efb 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1402,8 +1402,10 @@ static void vmstate_save(QEMUFile *f, SaveStateEntry *se)
>   }
>
>   #define QEMU_VM_FILE_MAGIC           0x5145564d
> -#define QEMU_VM_FILE_VERSION_COMPAT  0x00000002
> -#define QEMU_VM_FILE_VERSION         0x00000003
> +#define QEMU_VM_FILE_VERSION_COMPAT  0x00000003
> +#define QEMU_VM_FILE_VERSION         0x00000004
> +#define QEMU_VM_LIVE_MIGRATION_MODE  0x00000005
> +#define QEMU_VM_FT_MODE              0x00000006
>
>   #define QEMU_VM_EOF                  0x00
>   #define QEMU_VM_SECTION_START        0x01
> @@ -1425,6 +1427,12 @@ int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
>
>       qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
>       qemu_put_be32(f, QEMU_VM_FILE_VERSION);
> +
> +    if (ft_mode) {
> +        qemu_put_be32(f, QEMU_VM_FT_MODE);
> +    } else {
> +        qemu_put_be32(f, QEMU_VM_LIVE_MIGRATION_MODE);
> +    }
>
>       QTAILQ_FOREACH(se,&savevm_handlers, entry) {
>           int len;
> @@ -1533,6 +1541,66 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
>       return 0;
>   }
>
> +int qemu_savevm_state_all(Monitor *mon, QEMUFile *f)
> +{
> +    SaveStateEntry *se;
> +
> +    QTAILQ_FOREACH(se,&savevm_handlers, entry) {
> +        int len;
> +
> +        if (se->save_live_state == NULL)
> +            continue;
> +
> +        /* Section type */
> +        qemu_put_byte(f, QEMU_VM_SECTION_START);
> +        qemu_put_be32(f, se->section_id);
> +
> +        /* ID string */
> +        len = strlen(se->idstr);
> +        qemu_put_byte(f, len);
> +        qemu_put_buffer(f, (uint8_t *)se->idstr, len);
> +
> +        qemu_put_be32(f, se->instance_id);
> +        qemu_put_be32(f, se->version_id);
> +        if (ft_mode == FT_INIT) {
> +            /* This is workaround. */
> +            se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
> +        } else {
> +            se->save_live_state(mon, f, QEMU_VM_SECTION_PART, se->opaque);
> +        }
> +    }
> +
> +    ft_mode = FT_TRANSACTION;
> +    QTAILQ_FOREACH(se,&savevm_handlers, entry) {
> +        int len;
> +
> +	if (se->save_state == NULL&&  se->vmsd == NULL)
> +	    continue;
> +
> +        /* Section type */
> +        qemu_put_byte(f, QEMU_VM_SECTION_FULL);
> +        qemu_put_be32(f, se->section_id);
> +
> +        /* ID string */
> +        len = strlen(se->idstr);
> +        qemu_put_byte(f, len);
> +        qemu_put_buffer(f, (uint8_t *)se->idstr, len);
> +
> +        qemu_put_be32(f, se->instance_id);
> +        qemu_put_be32(f, se->version_id);
> +
> +        vmstate_save(f, se);
> +    }
> +
> +    qemu_put_byte(f, QEMU_VM_EOF);
> +
> +    if (qemu_file_has_error(f))
> +        return -EIO;
> +
> +    return 0;
> +}
> +
> +
>   void qemu_savevm_state_cancel(Monitor *mon, QEMUFile *f)
>   {
>       SaveStateEntry *se;
> @@ -1617,6 +1685,10 @@ int qemu_loadvm_state(QEMUFile *f, int skip_header)
>           if (v != QEMU_VM_FILE_VERSION)
>               return -ENOTSUP;
>
> +        v = qemu_get_be32(f);
> +        if (v == QEMU_VM_FT_MODE) {
> +            ft_mode = FT_INIT;
> +        }
>       }
>
>       while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
> diff --git a/sysemu.h b/sysemu.h
> index 6c1441f..df314bb 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -67,6 +67,7 @@ int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
>                               int shared);
>   int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f);
>   int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f);
> +int qemu_savevm_state_all(Monitor *mon, QEMUFile *f);
>   void qemu_savevm_state_cancel(Monitor *mon, QEMUFile *f);
>   int qemu_loadvm_state(QEMUFile *f, int skip_header);
>
>