From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 90E7CCE7 for ; Thu, 24 Dec 2015 04:28:56 +0100 (CET) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP; 23 Dec 2015 19:28:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,471,1444719600"; d="scan'208";a="868608742" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.66.49]) by fmsmga001.fm.intel.com with ESMTP; 23 Dec 2015 19:28:53 -0800 Date: Thu, 24 Dec 2015 11:30:27 +0800 From: Yuanhan Liu To: Thomas Monjalon Message-ID: <20151224033027.GY18863@yliu-dev.sh.intel.com> References: <20151222035041.GA7532@pxdev.xzpeter.org> <20151223015554.GC1694@pxdev.xzpeter.org> <20151223020949.GV18863@yliu-dev.sh.intel.com> <2150122.EUSmcjyJtA@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2150122.EUSmcjyJtA@xps13> User-Agent: Mutt/1.5.23 (2014-03-12) Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [Question] How pmd virtio works without UIO? X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Dec 2015 03:28:57 -0000 On Wed, Dec 23, 2015 at 11:26:17PM +0100, Thomas Monjalon wrote: > 2015-12-23 10:09, Yuanhan Liu: > > On Wed, Dec 23, 2015 at 09:55:54AM +0800, Peter Xu wrote: > > > On Tue, Dec 22, 2015 at 04:38:30PM +0000, Xie, Huawei wrote: > > > > On 12/22/2015 7:39 PM, Peter Xu wrote: > > > > > I tried to unbind one of the virtio net device, I see the PCI entry > > > > > still there. > > > > > > > > > > Before unbind: > > > > > > > > > > [root@vm proc]# lspci -k -s 00:03.0 > > > > > 00:03.0 Ethernet controller: Red Hat, Inc Virtio network device > > > > > Subsystem: Red Hat, Inc Device 0001 > > > > > Kernel driver in use: virtio-pci > > > > > [root@vm proc]# cat /proc/ioports | grep c060-c07f > > > > > c060-c07f : 0000:00:03.0 > > > > > c060-c07f : virtio-pci > > > > > > > > > > After unbind: > > > > > > > > > > [root@vm proc]# lspci -k -s 00:03.0 > > > > > 00:03.0 Ethernet controller: Red Hat, Inc Virtio network device > > > > > Subsystem: Red Hat, Inc Device 0001 > > > > > [root@vm proc]# cat /proc/ioports | grep c060-c07f > > > > > c060-c07f : 0000:00:03.0 > > > > > > > > > > So... does this means that it is an alternative to black list > > > > > solution? > > > > Oh, we could firstly check if this port is manipulated by kernel driver > > > > in virtio_resource_init/eth_virtio_dev_init, as long as it is not too late. > > > > Why can't we simply quit at pci_scan_one, once finding that it's not > > bond to uio (or similar stuff)? That would be generic enough, that we > > don't have to do similar checks for each new pmd driver. > > > > Or, am I missing something? > > UIO is not needed to make virtio works (without interrupt support). > Sometimes it may be required to avoid using kernel modules. While dig the git history, I found the commit: commit da978dfdc43b59e290a46d7ece5fd19ce79a1162 Author: Ouyang Changchun Date: Mon Feb 9 09:14:06 2015 +0800 virtio: use port IO to get PCI resource Make virtio not require UIO for some security reasons, this is to match 6WIND's virtio-net-pmd. Signed-off-by: Changchun Ouyang Acked-by: Huawei Xie The commit log is not well written, giving no explanation about the "some security reasons". Anyway, I see it now that it's kind of a design. Note that my first patch set about enabling virtio 1.0 [0] sets the RTE_PCI_DRV_NEED_MAPPING flag, which somehow implies that uio is a must, otherwise, eal init would fail at pci_map_device(). So that my pathset breaks the un-documented rule, and I need fix it. How about adding a wrapper, say rte_pci_map_device(), and exporting it, so that virtio pmd driver could map resources when necessary? [0]: http://dpdk.org/dev/patchwork/bundle/yliu/virtio-1.0-pmd/ > > > I guess there might be two problems? Which are: > > > > > > 1. How user avoid DPDK taking over virtio devices that they do not > > > want for IO (chooses which device to use) > > > > Isn't that what's the 'binding/unbinding' for? > > Binding is, sometimes, required. We may need fix the doc then. As the doc says it's a must: 3.6. Binding and Unbinding Network Ports to/from the Kernel Modules Instead, all ports that are to be used by an DPDK application ==> must be bound to the uio_pci_generic, igb_uio or vfio-pci module before the application is run. Any network ports under Linux* control will be ignored by the DPDK poll-mode drivers and cannot be used by the application. --yliu > But does it mean DPDK should use every available ports? > That's the default and may be configured with blacklist/whitelist. > > > > 2. Driver conflict between virtio PMD in DPDK, and virtio-pci in > > > kernel (happens on every virtio device that DPDK uses) > > > > If you unbinded the kernel driver first, which is the suggested (or > > must?) way to use DPDK, that will not happen.