netdev - Re: [PATCH net-next 2/2] net: hns3: add vf fault process in hns3 ras

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Message-ID: <Y8aEymyUf+WB8T8g@unreal>
Date:   Tue, 17 Jan 2023 13:21:46 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     "wangjie (L)" <wangjie125@...wei.com>
Cc:     Hao Lan <lanhao@...wei.com>, davem@...emloft.net, kuba@...nel.org,
        yisen.zhuang@...wei.com, salil.mehta@...wei.com,
        edumazet@...gle.com, pabeni@...hat.com, richardcochran@...il.com,
        shenjian15@...wei.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/2] net: hns3: add vf fault process in hns3 ras

On Tue, Jan 17, 2023 at 03:04:15PM +0800, wangjie (L) wrote:
> 
> 
> On 2023/1/13 14:51, Leon Romanovsky wrote:
> > On Fri, Jan 13, 2023 at 10:08:29AM +0800, Hao Lan wrote:
> > > From: Jie Wang <wangjie125@...wei.com>
> > > 
> > > Currently hns3 driver supports vf fault detect feature. Several ras caused
> > > by VF resources don't need to do PF function reset for recovery. The driver
> > > only needs to reset the specified VF.
> > > 
> > > So this patch adds process in ras module. New process will get detailed
> > > information about ras and do the most correct measures based on these
> > > accurate information.
> > > 
> > > Signed-off-by: Jie Wang <wangjie125@...wei.com>
> > > Signed-off-by: Hao Lan <lanhao@...wei.com>
> > > ---
> > >  drivers/net/ethernet/hisilicon/hns3/hnae3.h   |   1 +
> > >  .../hns3/hns3_common/hclge_comm_cmd.h         |   1 +
> > >  .../hisilicon/hns3/hns3pf/hclge_err.c         | 113 +++++++++++++++++-
> > >  .../hisilicon/hns3/hns3pf/hclge_err.h         |   2 +
> > >  .../hisilicon/hns3/hns3pf/hclge_main.c        |   3 +-
> > >  .../hisilicon/hns3/hns3pf/hclge_main.h        |   1 +
> > >  6 files changed, 115 insertions(+), 6 deletions(-)
> > 
> > Why is it good idea to reset VF from PF?
> > What will happen with driver bound to this VF?
> > Shouldn't PCI recovery handle it?
> > 
> > Thanks
> > .
> PF doesn't reset VF directly. These VF faults are detected by hardware,
> and only reported to PF. PF get the VF id from firmware, then notify the VF
> that it needs reset. VF will do reset after receive the request.

This description isn't aligned with the code. You are issuing
hclge_func_reset_cmd() command which will reset VF, while notification
are handled by hclge_func_reset_notify_vf().

It also doesn't make any sense to send notification event to VF through
FW while the goal is to recover from stuck FW in that VF.

> 
> These hardware faults are not standard PCI ras event, so we prefer to use
> MSIx path.

What is different here?

> >