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Date:   Tue, 20 Feb 2018 14:25:12 -0800
From:   Jacob Pan <jacob.jun.pan@linux.intel.com>
To:     Yves-Alexis Perez <corsac@debian.org>
Cc:     "Raj, Ashok" <ashok.raj@intel.com>, Joerg Roedel <joro@8bytes.org>,
        Sohil Mehta <sohil.mehta@intel.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        David Woodhouse <dwmw2@infradead.org>,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        Gayatri Kammela <gayatri.kammela@intel.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v7 0/5] Add Intel IOMMU debugfs support
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On Sun, 18 Feb 2018 23:15:32 +0100
Yves-Alexis Perez <corsac@debian.org> wrote:

> On Tue, 2018-02-13 at 13:40 -0800, Raj, Ashok wrote:
> > This version has only hw dumps for now, but we plan to add some
> > other things like walking 2nd level page-tables, or get some SVM
> > specific data from the driver in the future.   
> 
> Hi,
> 
> I'm not sure how much you know about chipsec [1], but with a oneliner
> [2] you can have it print a lot of data from Vt-d configuration,
> including page tables. As far as I remember, it doesn't need access
> to /dev/mem (but I gidn't dig to check how it does it).
> 
> It might still be useful to have everything from debugfs because
> it'll always be consistent with the current running kernel, but at
> least it might help users reporting bugs.
> 
> [1] https://github.com/chipsec/chipsec
> [2] http://paste.debian.net/1010105

I didn't know about chipsec but reading the code seems to rely on an
out-of-tree kernel module. I don't think it matches what we need here.