[Intel-wired-lan] [PATCH S28 v2 1/9] ice: Reliably reset VFs

[Bowers, AndrewX <andrewx.bowers@intel.com>]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Tony Nguyen
> Sent: Tuesday, September 3, 2019 1:31 AM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [PATCH S28 v2 1/9] ice: Reliably reset VFs
> 
> From: Mitch Williams <mitch.a.williams@intel.com>
> 
> When a PFR (or bigger reset) occurs, the device clears the VF_MBX_ARQLEN
> register for all VFs. But if a VFR is triggered by a VF, the device does NOT clear
> this register, and the VF driver will never see the reset.
> 
> When this happens, the VF driver will eventually timeout and attempt
> recovery, and usually it will be successful. But this makes resets take a long
> time and there are occasional failures.
> 
> We cannot just blithely clear this register on every reset; this has been
> shown to cause synchronization problems when a PFR is triggered with a
> large number of VFs.
> 
> Fix this by clearing VF_MBX_ARQLEN when the reset source is not PFR.
> GlobR will trigger PFR, so this test catches that occurrence as well.
> 
> Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>