Re: [PATCH v2 0/2] hv_netvsc: associate VF and PV device by serial number

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Fri, Sep 14, 2018 at 12:54:55PM -0700, Stephen Hemminger wrote:
> The Hyper-V implementation of PCI controller has concept of 32 bit serial number
> (not to be confused with PCI-E serial number).  This value is sent in the protocol
> from the host to indicate SR-IOV VF device is attached to a synthetic NIC.
> 
> Using the serial number (instead of MAC address) to associate the two devices
> avoids lots of potential problems when there are duplicate MAC addresses from
> tunnels or layered devices.
> 
> The patch set is broken into two parts, one is for the PCI controller
> and the other is for the netvsc device. Normally, these go through different
> trees but sending them together here for better review. The PCI changes
> were submitted previously, but the main review comment was "why do you
> need this?". This is why.

The question was more whether we should convert this serial number into
a PCI slot number (that has user space visibility and that is what you are
after) to improve the current matching, I do not question why you need
it, just for the records.

Lorenzo

> v2 - slot name can be shorter.
>      remove locking when creating pci_slots; see comment for explaination
> 
> Stephen Hemminger (2):
>   PCI: hv: support reporting serial number as slot information
>   hv_netvsc: pair VF based on serial number
> 
>  drivers/net/hyperv/netvsc.c         |  3 ++
>  drivers/net/hyperv/netvsc_drv.c     | 58 ++++++++++++++++-------------
>  drivers/pci/controller/pci-hyperv.c | 37 ++++++++++++++++++
>  3 files changed, 73 insertions(+), 25 deletions(-)
> 
> -- 
> 2.18.0
>