From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38726) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a6riL-0006XV-So for qemu-devel@nongnu.org; Wed, 09 Dec 2015 22:16:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a6riG-0002Ib-UP for qemu-devel@nongnu.org; Wed, 09 Dec 2015 22:16:17 -0500 Received: from mga11.intel.com ([192.55.52.93]:30152) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a6riG-0002HL-No for qemu-devel@nongnu.org; Wed, 09 Dec 2015 22:16:12 -0500 References: <1448372127-28115-1-git-send-email-tianyu.lan@intel.com> <20151207165039.GA20210@redhat.com> <56685631.50700@intel.com> From: "Lan, Tianyu" Message-ID: <5668EE6F.90200@intel.com> Date: Thu, 10 Dec 2015 11:15:59 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] live migration vs device assignment (motivation) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Duyck Cc: qemu-devel@nongnu.org, "Tantilov, Emil S" , kvm@vger.kernel.org, Ard Biesheuvel , aik@ozlabs.ru, "Skidmore, Donald C" , "Michael S. Tsirkin" , "Dong, Eddie" , "Jani, Nrupal" , quintela@redhat.com, Alexander Graf , Blue Swirl , cornelia.huck@de.ibm.com, Alex Williamson , kraxel@redhat.com, Anthony Liguori , amit.shah@redhat.com, Paolo Bonzini , "Rustad, Mark D" , lcapitulino@redhat.com, Or Gerlitz On 12/10/2015 1:14 AM, Alexander Duyck wrote: > On Wed, Dec 9, 2015 at 8:26 AM, Lan, Tianyu wrote: > >> For other kind of devices, it's hard to work. >> We are also adding migration support for QAT(QuickAssist Technology) device. >> >> QAT device user case introduction. >> Server, networking, big data, and storage applications use QuickAssist >> Technology to offload servers from handling compute-intensive operations, >> such as: >> 1) Symmetric cryptography functions including cipher operations and >> authentication operations >> 2) Public key functions including RSA, Diffie-Hellman, and elliptic curve >> cryptography >> 3) Compression and decompression functions including DEFLATE and LZS >> >> PCI hotplug will not work for such devices during migration and these >> operations will fail when unplug device. > > I assume the problem is that with a PCI hotplug event you are losing > the state information for the device, do I have that right? > > Looking over the QAT drivers it doesn't seem like any of them support > the suspend/resume PM calls. I would imagine it makes it difficult > for a system with a QAT card in it to be able to drop the system to a > low power state. You might want to try enabling suspend/resume > support for the devices on bare metal before you attempt to take on > migration as it would provide you with a good testing framework to see > what needs to be saved/restored within the device and in what order > before you attempt to do the same while migrating from one system to > another. Sure. The suspend/resume job is under way. Actually, we have enabled QAT work for migration internally. Doing more test and fixing bugs. > > - Alex >