On Mon, 15 Mar 2021 19:52:46 +0000 Slava Ovsiienko <viachesl...@nvidia.com> wrote:
> Hi, Jan > > > -----Original Message----- > > From: Jan Viktorin <vikto...@cesnet.cz> > > Sent: Monday, March 15, 2021 21:49 > > To: Slava Ovsiienko <viachesl...@nvidia.com> > > Cc: dev@dpdk.org; Asaf Penso <as...@nvidia.com>; Shahaf Shuler > > <shah...@nvidia.com>; Matan Azrad <ma...@nvidia.com> > > Subject: Re: [PATCH 2/2] net/mlx5: avoid unbind step to enable switchdev > > mode > > > > On Mon, 15 Mar 2021 19:31:25 +0000 > > Slava Ovsiienko <viachesl...@nvidia.com> wrote: > > > > > Hi, Jan > > > > Hello Salva, > > > > I am sorry, but I didn't get the point of your response. For me, there was > > 1 PF > > 0000:05:00.1, SRIOV disabled. So, I followed the guide [1]. > > > > 1. Enable SRIOV via mlxconfig. Done. > > > > 2. Configure max number of VFs. Done. > > > > 3. Reset firmware. Done. > > > > In fact, I had to reboot the machine here so I am not convinced the reset of > > firmware is the thing. But I can image that there is some other use case > > for it. > > After reboot, I configured 2 VFs: 0000:05:00.4, 0000:05:00.5. > > > > 4. Unbind the PF 0000:05:00.1. Done. > No, it is the second physical port. You should unbind your VFs instead - > 0000:05:00.4, 0000:05:00.5. > > Please, see: > > > 3. Then, we should unbind VFs ONLY, PF should be kept untouched. OK. Now I understand. Thus, the guide should read "Unbind the VF devices (can be rebind after the switchdev mode)". I will post v2 with this change. Thanks for clarification. Jan > > With best regards, > Slava > > > > > 5. Fail, no way how to configure switchdev because of previous step. > > Thus, I strongly believe that the guide is misleading here. > > > > When I bound the PF 0000:05:00.1 back, I could configure the switchdev > > mode and everything was just OK and seemed to be working. So **after** > > the bind I configured the switchdev mode properly. > > > > [1] https://doc.dpdk.org/guides/nics/mlx5.html#enable-switchdev-mode > > > > Jan > > > > > > > > 1. Let's suppose we have the one port NIC, PCI BDF 08:00.0, SR-IOV > > > enabled, 0 VFs is configured, netdev name is ens1f0 (depends on distro > > and kernel version). > > > > > > 2. Then, we configure 3 VFs with SR-IOV, we get : > > > - 08:00.0 - PF, ens1f0 > > > - 08:00.1 - VF0, ens1f1 > > > - 08:00.2 - VF1, ens1f2 > > > - 08:00.3 - VF2, ens1f3 > > > > > > 3. Then, we should unbind VFs ONLY, PF should be kept untouched. > > > - 08:00.0 - PF, ens1f0 > > > - 08:00.1 - VF0, - > > > - 08:00.2 - VF1, - > > > - 08:00.3 - VF2, - > > > > > > 4. Then, configure switchdev mode > > > - 08:00.0 - PF, ens1f0 > > > - 08:00.1 - VF0, - > > > - 08:00.2 - VF1, - > > > - 08:00.3 - VF2, - > > > + we get 3 representor netdevs: > > > ens1f0_0 (no dedicated PCI device) > > > ens1f0_1 (no dedicated PCI device) > > > ens1f0_2 (no dedicated PCI device) > > > > > > 5. Then, bind VFs back (assume we are no going to map them to VMs) > > > - 08:00.0 - PF, ens1f0 > > > - 08:00.1 - VF0, ens1f1 > > > - 08:00.2 - VF1, ens1f2 > > > - 08:00.3 - VF2, ens1f3 > > > - ens1f0_0 (no dedicated PCI device) > > > - ens1f0_1 (no dedicated PCI device) > > > - ens1f0_2 (no dedicated PCI device) > > > > > > 6. As result we should get 7 netdevs - 1 PF (Uplink representor), 3 > > > VFs, 3 representors (no PCI device, pure netdev) > > > > > > With best regards, Slava > > > > > > > -----Original Message----- > > > > From: Jan Viktorin <vikto...@cesnet.cz> > > > > Sent: Monday, March 15, 2021 18:11 > > > > To: Slava Ovsiienko <viachesl...@nvidia.com> > > > > Cc: dev@dpdk.org; Asaf Penso <as...@nvidia.com>; Shahaf Shuler > > > > <shah...@nvidia.com>; Matan Azrad <ma...@nvidia.com> > > > > Subject: Re: [PATCH 2/2] net/mlx5: avoid unbind step to enable > > > > switchdev mode > > > > > > > > Hello Salva, > > > > > > > > On Mon, 15 Mar 2021 15:53:51 +0000 > > > > Slava Ovsiienko <viachesl...@nvidia.com> wrote: > > > > > > > > > Hi, Jan > > > > > > > > > > Yes, bullet [4] explicitly requires to unbind VFs, and detach the > > > > > netdevs > > > > from the mlx5_core driver. > > > > > Otherwise, kernel driver refuses to be configured with switchdev > > > > > mode in > > > > [5]. So, [4] can't be skipped. > > > > > After setting swithdev mode, VFs can be bound back (if it is > > > > > needed, and > > > > these ones are not mapped to VMs): > > > > > > > > OK, but I believe that it is **not possible** to follow the rule [5]. > > > > The guide explicitly says in [4] "can be rebind **after** the > > > > switchdev mode". > > > > Just, if you unbind the device, there is no way how to configure the > > > > switchdev mode, this is the contradiction I mentioned in the commit. > > > > You cannot configure switchdev mode because the interface is gone > > > > and the path /sys/class/net/<net device>/compat/devlink/mode no > > longer exists. > > > > > > > > So, maybe, just the formulation is wrong. So, what is the **exact > > > > right** way how to do it? I would change the commit accordingly. > > > > Just, let's make it right. Would it work this way? > > > > > > > > # echo -n "<device pci address>" > > > > > /sys/bus/pci/drivers/mlx5_core/unbind > > > > # echo -n "<device pci address>" > > > > > /sys/bus/pci/drivers/mlx5_core/bind > > > > # echo switchdev > /sys/class/net/<net device>/compat/devlink/mode > > > > > > > > It is good to mention that after the rebind, the <net device> can > > > > change. > > > > > > > > Regards, > > > > Jan > > > > > > > > > > > > > > echo -n "<device pci address>" > > > > > > > /sys/bus/pci/drivers/mlx5_core/bind > > > > > > > > > > With best regards, > > > > > Slava > > > > > > > > > > > -----Original Message----- > > > > > > From: Jan Viktorin <ivikto...@fit.vutbr.cz> > > > > > > Sent: Monday, March 15, 2021 17:34 > > > > > > To: dev@dpdk.org > > > > > > Cc: Jan Viktorin <vikto...@cesnet.cz>; Asaf Penso > > > > > > <as...@nvidia.com>; Shahaf Shuler <shah...@nvidia.com>; Slava > > > > > > Ovsiienko <viachesl...@nvidia.com>; Matan Azrad > > > > <ma...@nvidia.com> > > > > > > Subject: [PATCH 2/2] net/mlx5: avoid unbind step to enable > > > > > > switchdev mode > > > > > > > > > > > > From: Jan Viktorin <vikto...@cesnet.cz> > > > > > > > > > > > > The step 4 is a contradiction. It advices to unbind the device > > > > > > from the mlx5_core which removes the associated system network > > > > > > interface > > > > (e.g. > > > > > > eth0). In the step 5, the same system network interface (e.g. > > > > > > eth0) is required to exist. > > > > > > > > > > > > Signed-off-by: Jan Viktorin <vikto...@cesnet.cz> > > > > > > --- > > > > > > doc/guides/nics/mlx5.rst | 6 +----- > > > > > > 1 file changed, 1 insertion(+), 5 deletions(-) > > > > > > > > > > > > diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst > > > > > > index 0a2dc3dee..122d8e0fc 100644 > > > > > > --- a/doc/guides/nics/mlx5.rst > > > > > > +++ b/doc/guides/nics/mlx5.rst > > > > > > @@ -1370,11 +1370,7 @@ the DPDK application. > > > > > > > > > > > > echo <num of vfs > /sys/class/net/<net > > > > > > device>/device/sriov_numvfs > > > > > > > > > > > > -4. Unbind the device (can be rebind after the switchdev mode):: > > > > > > - > > > > > > - echo -n "<device pci address>" > > > > > > > /sys/bus/pci/drivers/mlx5_core/unbind > > > > > > - > > > > > > -5. Enable switchdev mode:: > > > > > > +4. Enable switchdev mode:: > > > > > > > > > > > > echo switchdev > /sys/class/net/<net > > > > > > device>/compat/devlink/mode > > > > > > > > > > > > -- > > > > > > 2.30.1 > > > > > > > > >
