From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45808) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1edyFV-00046M-9x for qemu-devel@nongnu.org; Tue, 23 Jan 2018 08:04:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1edyFQ-0004YC-LP for qemu-devel@nongnu.org; Tue, 23 Jan 2018 08:04:25 -0500 Received: from mga01.intel.com ([192.55.52.88]:49137) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1edyFQ-0004XP-Bw for qemu-devel@nongnu.org; Tue, 23 Jan 2018 08:04:20 -0500 Message-ID: <5A673369.6050408@intel.com> Date: Tue, 23 Jan 2018 21:06:49 +0800 From: Wei Wang MIME-Version: 1.0 References: <20180119130653.24044-1-stefanha@redhat.com> <5A65C652.6080307@intel.com> <20180123111238.GC6565@stefanha-x1.localdomain> In-Reply-To: <20180123111238.GC6565@stefanha-x1.localdomain> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC 0/2] virtio-vhost-user: add virtio-vhost-user device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, mst@redhat.com, zhiyong.yang@intel.com, Maxime Coquelin , jasowang@redhat.com On 01/23/2018 07:12 PM, Stefan Hajnoczi wrote: > On Mon, Jan 22, 2018 at 07:09:06PM +0800, Wei Wang wrote: >> On 01/19/2018 09:06 PM, Stefan Hajnoczi wrote: >> >> >> - Suppose in the future there is also a kernel virtio-vhost-user driver as >> other PCI devices, can we unbind the kernel driver first, and then bind the >> device to the dpdk driver? A normal PCI device should be able to smoothly >> switch between the kernel driver and dpdk driver. > It depends what you mean by "smoothly switch". > > If you mean whether it's possible to go from a kernel driver to > vfio-pci, then the answer is yes. > > But if the kernel driver has an established vhost-user connection then > it will be closed. This is the same as reconnecting with AF_UNIX > vhost-user. > Actually not only the case of switching to testpmd after kernel establishes the connection, but also for several runs of testpmd. That is, if we run testpmd, then exit testpmd. I think the second run of testpmd won't work. I'm thinking about caching the received master msgs in QEMU when virtio_vhost_user_parse_m2s(). Btw, I'm trying to run the code, but couldn't bind the virito-vhost-user device to vfio-pci (reports Unknown device), not sure if it is because the device type is "Unclassified device". Best, Wei