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Date:   Thu, 8 Nov 2018 14:49:00 -0700
From:   Keith Busch <keith.busch@intel.com>
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Alexandru Gagniuc <mr.nuke.me@gmail.com>,
        linux-pci@vger.kernel.org, alex_gagniuc@dellteam.com,
        austin_bolen@dell.com, shyam_iyer@dell.com,
        linux-kernel@vger.kernel.org,
        Jonathan Derrick <jonathan.derrick@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Lukas Wunner <lukas@wunner.de>,
        Russell Currey <ruscur@russell.cc>,
        Sam Bobroff <sbobroff@linux.ibm.com>,
        Oliver O'Halloran <oohall@gmail.com>,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is
 disconnected
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References: <20180918221501.13112-1-mr.nuke.me@gmail.com>
 <20181107234257.GC41183@google.com>
 <20181108200855.GE41183@google.com>
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On Thu, Nov 08, 2018 at 02:09:17PM -0600, Bjorn Helgaas wrote:
> 
> I'm having second thoughts about this.  One thing I'm uncomfortable
> with is that sprinkling pci_dev_is_disconnected() around feels ad hoc
> instead of systematic, in the sense that I don't know how we convince
> ourselves that this (and only this) is the correct place to put it.

You know how the kernel provides ZERO_PAGE, wouldn't it be cool if we
also had a ONES_PAGE and could remap all virtual addresses from a memory
mapped device to that page on an ungraceful disconnect? I do not know
how to accomplish that, so might just be crazy talk... But if it is
possible, that would be a pretty nifty way to solve this problem.