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Date:   Sat, 19 Jun 2021 09:53:58 +0200
From:   Lukas Wunner <lukas@wunner.de>
To:     Pali =?iso-8859-1?Q?Roh=E1r?= <pali@kernel.org>
Cc:     David Laight <David.Laight@ACULAB.COM>,
        Greg KH <gregkh@linuxfoundation.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Marek =?iso-8859-1?Q?Beh=FAn?= <kabel@kernel.org>
Subject: Re: xhci_pci & PCIe hotplug crash
Message-ID: <20210619075358.GA31639@wunner.de>
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On Wed, May 05, 2021 at 05:39:42PM +0200, Pali Roh?r wrote:
> On Wednesday 05 May 2021 15:20:11 David Laight wrote:
> > From: Pali Roh?r
> > Sent: 05 May 2021 14:03
> > > So seems that PCIe controller HW triggers these external aborts when
> > > device on PCIe bus is not accessible anymore.
> > > 
> > > If this issue is really caused by MMIO access from xhci driver when
> > > device is not accessible on the bus anymore, can we do something to
> > > prevent this kernel crash? Somehow mask that external abort in kernel
> > > for a time during MMIO access?
> > 
> > If it is a cycle abort then the interrupted address is probably
> > that of the MMIO instruction.
> > So you need to catch the abort, emulate the instruction and
> > then return to the next one.
> 
> Has kernel API & infrastructure for catching these aborts and executing
> own driver handler when abort happens?

Yes, see here for an example:

https://lore.kernel.org/linux-pci/20210615191405.21878-4-jim2101024@gmail.com/