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Date: Tue, 26 Nov 2013 15:14:32 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 08/17] add unix_msgfd_lookup() to callback
 get_buffer
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To: Lei Li <lilei@linux.vnet.ibm.com>
Cc: aarcange@redhat.com, quintela@redhat.com, qemu-devel@nongnu.org, mrhines@linux.vnet.ibm.com, mdroth@linux.vnet.ibm.com, aliguori@amazon.com, lagarcia@br.ibm.com, rcj@linux.vnet.ibm.com

Il 26/11/2013 15:00, Lei Li ha scritto:
>>>
>> I think adding a byte in the middle of the stream is not reliable.
>>
>> Rather, you should transmit the socket always at the same place, for
>> example in the first call of qemu_local_save_ram, after it has written
>> the 64-bit field.
> 
> I guess 'transmit the socket' you mean transmit the fd?

Yes.

> Sorry that I am quite understand your suggestion here.. Do you
> mean that send_pipefd in the first call of qemu_local_save_ram
> after it has written the 64-bit field? In this way, get rid of
> qemu_local_send_pipefd?

Yes.  This way you know exactly where to "eat" the byte that's written
with sendmsg.

Paolo

> Currently, the fd control message is sent at the end of the stream
> in ram_save_setup stage, followed by the ram page. The control
> message of fd is always at the same place.