Re: [Qemu-devel] [PATCH v9 03/10] Add save_block_hdr function

[Juan Quintela]

Anthony Liguori <address@hidden> wrote:
> On 04/11/2012 01:49 PM, Orit Wasserman wrote:
>> Signed-off-by: Orit Wasserman<address@hidden>
>> Signed-off-by: Benoit Hudzia<address@hidden>
>> Signed-off-by: Petter Svard<address@hidden>
>> Signed-off-by: Aidan Shribman<address@hidden>
>> ---
>>   arch_init.c |   26 ++++++++++++++------------
>>   1 files changed, 14 insertions(+), 12 deletions(-)
>>
>> diff --git a/arch_init.c b/arch_init.c
>> index 2e534f1..47b9fef 100644
>> --- a/arch_init.c
>> +++ b/arch_init.c
>> @@ -347,6 +347,18 @@ void cache_resize(int64_t new_size)
>>       g_free(old_page_cache);
>>   }
>>
>> +static void save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t offset,
>> +        int cont, int flag)
>> +{
>> +        qemu_put_be64(f, offset | cont | flag);
>> +        if (!cont) {
>> +                qemu_put_byte(f, strlen(block->idstr));
>> +                qemu_put_buffer(f, (uint8_t *)block->idstr,
>> +                                strlen(block->idstr));
>> +        }
>> +
>> +}
>
>
> Any time we're changing protocols/formats, we need to document it.  We
> need a docs/xbzrle.txt (and it should be before this patch).

Agreed.

> It's not clear to me how we preserve compatibility here either.
> You're potentially passing garbage to an older QEMU.

I think not.  Only if you are migrating with the -x option.  And then,
you get what you asked for.

> I thought I had previously asked for a monitor command to negotiate
> extensions for migration?

I think it is in another patch.

Later, Juan