From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:60555 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753725AbaLHCcz (ORCPT ); Sun, 7 Dec 2014 21:32:55 -0500 Message-ID: <5484C77D.7060501@redhat.com> Date: Sun, 07 Dec 2014 16:32:45 -0500 From: Don Dutile MIME-Version: 1.0 To: Yuval Mintz , Eli Cohen , "bhelgaas@google.com" , David Miller CC: linux-pci , netdev , "ogerlitz@mellanox.com" , "yevgenyp@mellanox.com" , Eli Cohen Subject: Re: [PATCH RFC] pci: Control whether VFs are probed on pci_enable_sriov References: <1417957693-24979-1-git-send-email-eli@mellanox.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 12/07/2014 12:05 PM, Yuval Mintz wrote: > >> This can save host side resource usage by VF instances which would be >> eventually probed to VMs. > >> Use a parameter to pci_enable_sriov to control that policy, and modify >> all current callers such that they retain the same functionality. > > What's the end-game here? How eventually would this be controlled? > >> Use a one shot flag on struct pci_device which is cleared after the >> first probe is ignored so subsequent attempts go through. > > Does a one-shot flag suffice? E.g., consider assigning a VF to VM and > than shutting down the VM. Assuming this feature is disabled, > the VF didn't appear on the hypervisor prior to the assignment but > will appear after its shutdown. > +1 to this question. All I see is a one-shot savings in VF configuration time at pci_sriov_enable() time. Please explain why this is so important for mlx5 (sriov) operation? Can the vf driver probe be called & exit early the first time, and perform full (host) configuration thereafter? - Don