From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:44110)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1UF6Nq-0004xo-6i
	for qemu-devel@nongnu.org; Mon, 11 Mar 2013 13:19:44 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1UF6Nj-0007UZ-DP
	for qemu-devel@nongnu.org; Mon, 11 Mar 2013 13:19:34 -0400
Received: from mx1.redhat.com ([209.132.183.28]:63950)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1UF6Nj-0007UM-61
	for qemu-devel@nongnu.org; Mon, 11 Mar 2013 13:19:27 -0400
Date: Mon, 11 Mar 2013 19:19:45 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20130311171945.GA29167@redhat.com>
References: <1362976414-21396-1-git-send-email-mrhines@us.ibm.com>
	<1362976414-21396-4-git-send-email-mrhines@us.ibm.com>
	<20130311115140.GC23359@redhat.com>
	<513E0555.1060205@linux.vnet.ibm.com>
	<20130311170515.GB28930@redhat.com>
	<513E119F.1010203@linux.vnet.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <513E119F.1010203@linux.vnet.ibm.com>
Subject: Re: [Qemu-devel] [RFC PATCH RDMA support v3: 03/10] documentation
 of RDMA protocol in docs/rdma.txt
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: "Michael R. Hines" <mrhines@linux.vnet.ibm.com>
Cc: aliguori@us.ibm.com, michael.r.hines.mrhines@linux.vnet.ibm.com, qemu-devel@nongnu.org, owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com, gokul@us.ibm.com, pbonzini@redhat.com

On Mon, Mar 11, 2013 at 01:17:19PM -0400, Michael R. Hines wrote:
> On 03/11/2013 01:05 PM, Michael S. Tsirkin wrote:
> >Well that's exactly the question. As far as I remember the RDMA
> >memory model, you need to know a key and address to execute RDMA
> >writes. Remote memory also needs to be locked, so you need some
> >mechanism to lock chunks of memory, do RDMA write and unlock when
> >done.
> 
> Yes, memory is registered before the write occurs - that's is all
> taken care of in rdma.c (patch #04/10)
> 
> Same answer for the SEND messages: memory for each send must be
> registered before you send.
> 
> The pinning (mlock()) is already handled by libibverbs (by calling
> the function ibv_reg_mr()) - standard infiniband protocol
> initialization.
> 
> - Michael

Yes but the document should describe when is the destination
memory registered and how are keys/addresses passed back to
source.