Subject: Re: [v3] PCI: Add an option to control probing of VFs before enabling
 SR-IOV
To: Bjorn Helgaas <helgaas@kernel.org>
References: <1492037500-84654-1-git-send-email-bodong@mellanox.com>
 <20170414153718.GD29349@bhelgaas-glaptop.roam.corp.google.com>
CC: <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <saeedm@mellanox.com>, Eli Cohen <eli@mellanox.com>
From: Bodong Wang <bodong@mellanox.com>
Message-ID: <e11e080f-241e-7d6e-832d-7e5d819dfc57@mellanox.com>
Date: Fri, 14 Apr 2017 10:44:12 -0500
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On 4/14/2017 10:37 AM, Bjorn Helgaas wrote:
> On Thu, Apr 13, 2017 at 01:51:40AM +0300, bodong@mellanox.com wrote:
>> From: Bodong Wang <bodong@mellanox.com>
>>
>> Sometimes it is not desirable to probe the virtual functions after
>> SRIOV is enabled. This can save host side resource usage by VF
>> instances which would be eventually probed to VMs.
>>
>> Add a new PCI sysfs interface "sriov_drivers_autoprobe" to control
>> that from the PF, all current callers still retain the same
>> functionality. To modify it, echo 0/n/N (disable probe) or 1/y/Y
>> (enable probe) to:
>>
>> /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe
>>
>> Note that, the choice must be made before enabling VFs. The change
>> will not take effect if VFs are already enabled. Simply, one can set
>> sriov_numvfs to 0, choose whether to probe or not, and then resume
>> sriov_numvfs.
>>
>> Signed-off-by: Bodong Wang <bodong@mellanox.com>
>> Signed-off-by: Eli Cohen <eli@mellanox.com>
>> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>> Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
>> Reviewed-by: Bjorn Helgaas <helgaas@kernel.org>
> Applied to pci/virtualization for v4.12, thanks, Bodong!
Thank you! Bjorn/Alex/Gavin.