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SubjectRe: [PATCH 1/1] vfio-pci: Add SR-IOV VF configuration via sysfs
From
I currently use it for early development/debugging work (SR-IOV
capable FPGA boards) where I test both PFs and VFs from userspace.
But I see your point that this may not be relevant for anything you
can buy off the shelf.

Cheers,
Andre

2014-10-01 16:03 GMT+02:00 Alex Williamson <alex.williamson@redhat.com>:
> On Wed, 2014-10-01 at 15:38 +0200, Andre Richter wrote:
>> If a PCIe device bound to vfio-pci happens to be SR-IOV capabale,
>> there is no possibility to bring up/shutdown the device's VFs.
>>
>> This patch adds a generic callback for the sysfs sriov_numvfs attribute.
>> The attribute will only show up for SR-IOV devices. Additionally,
>> each utilized pci_* function checks if the device is a PF.
>>
>> Signed-off-by: Andre Richter <andre.o.richter@gmail.com>
>> ---
>> drivers/vfio/pci/vfio_pci.c | 25 ++++++++++++++++++++-----
>> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> I don't understand why you'd want to do this. The PF is typically
> managed by a host driver. By allowing vfio-pci to manage SR-IOV, don't
> we potentially have assign-able PFs managing assign-able VFs? That
> seems like a bad idea. What use case do you have in mind? Thanks,
>
> Alex
>
>> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>> index f782533..2f6dfb3 100644
>> --- a/drivers/vfio/pci/vfio_pci.c
>> +++ b/drivers/vfio/pci/vfio_pci.c
>> @@ -919,12 +919,27 @@ static struct pci_error_handlers vfio_err_handlers = {
>> .error_detected = vfio_pci_aer_err_detected,
>> };
>>
>> +static int vfio_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
>> +{
>> + int ret = 0;
>> +
>> + if (num_vfs > 0) {
>> + ret = pci_enable_sriov(pdev, num_vfs);
>> + if (!ret)
>> + ret = pci_num_vf(pdev);
>> + } else
>> + pci_disable_sriov(pdev);
>> +
>> + return ret;
>> +}
>> +
>> static struct pci_driver vfio_pci_driver = {
>> - .name = "vfio-pci",
>> - .id_table = NULL, /* only dynamic ids */
>> - .probe = vfio_pci_probe,
>> - .remove = vfio_pci_remove,
>> - .err_handler = &vfio_err_handlers,
>> + .name = "vfio-pci",
>> + .id_table = NULL, /* only dynamic ids */
>> + .probe = vfio_pci_probe,
>> + .remove = vfio_pci_remove,
>> + .sriov_configure = vfio_pci_sriov_configure,
>> + .err_handler = &vfio_err_handlers,
>> };
>>
>> /*
>
>
>


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