Messages in this thread | | | Date | Thu, 29 Mar 2018 10:48:24 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v7 0/5] Add Intel IOMMU debugfs support |
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[ Adding Gary from AMD to Cc ]
On Mon, Mar 19, 2018 at 09:37:14AM -0700, Jacob Pan wrote: > On Thu, 15 Mar 2018 14:18:54 +0100 > Joerg Roedel <joro@8bytes.org> wrote: > > > On Thu, Feb 15, 2018 at 08:38:11AM -0800, Jacob Pan wrote: > > > Just wondering if your concern is on the implementation or the > > > debugfs idea in general. Perhaps have some common IOMMU debugfs? > > > > My concern mainly is that we add interfaces which reveal > > potentially security relevant information > I don;t think security is any worse than existing kernel page table in > debugfs. i.e. /sys/kernel/debug/page_tables > This is a debug feature.
Okay, so here is the way to go: Please introduce a basic debugfs facility to the core iommu code. It should basically only create a 'iommu/' directory in debugfs where drivers can create their own sub-directories. This must be enabled by a new kconfig option (CONFIG_IOMMU_DEBUGFS) and the kernel should print a big fat warning at boot when it is enabled. This hopefully prevents anyone from enabling it for production kernels.
Then in the next cycle I will review again more closely what information about VT-d and AMD-Vi is revealed there and will probably apply what I can live with.
Thanks,
Joerg
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