From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH net-next V0 19/21] mlx4_core: Modify driver initialization flow to accommodate SRIOV for Ethernet Date: Tue, 6 Dec 2011 17:41:40 +0000 Message-ID: <1323193300.2772.5.camel@bwh-desktop> References: <4ED8A636.40901@mellanox.co.il> <1323120413.2887.50.camel@bwh-desktop> <201112061035.54093.jackm@dev.mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Yevgeny Petrilin , , , , , To: Jack Morgenstein Return-path: In-Reply-To: <201112061035.54093.jackm-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Tue, 2011-12-06 at 10:35 +0200, Jack Morgenstein wrote: > On Monday 05 December 2011 23:26, Ben Hutchings wrote: > > The 'probe_vf' parameter is very odd. Why do you think it is necessary > > to make this a module parameter? It should be possible to bind and > > unbind the driver from each VF dynamically via sysfs but this parameter > > appears to restrict that. > > > The host which sees the PF will also see all the VFs once they come up. > As each VF appears (as seen by 'lspci'), the O/S will invoke the "probe" > method for that VF. Without the "probe_vf" parameter, this probe would > result in all the VFs being bound to the PF host (and thus unavailable for > guests). As I said, you can unbind it through sysfs. > The small section of code which makes use of the probe_vf parameter > (file net/ethernet/mellanox/mlx4_main.c): Yes, I get it. > /* Detect if this device is a virtual function */ > if (id && id->driver_data & MLX4_VF) { > /* When acting as pf, we normally skip vfs unless explicitly > * requested to probe them. */ > if (sr_iov && extended_func_num(pdev) > probe_vf) { > mlx4_warn(dev, "Skipping virtual function:%d\n", > extended_func_num(pdev)); > err = -ENODEV; > goto err_free_dev; > } > > If you invoke "dmesg" on the PF host, you will see a series of the > "Skipping... " messages, one per VF. If probe_vf > 0, the PF-host will > reserve some VFs for its own use, and not issue the "Skipping..." message > for those VFs. What if you want to change that later? You can't use those VFs in the PF-host without reloading the driver. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html