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SubjectRe: [RFC v5][PATCH 4/4] intel_txt: force IOMMU on for Intel(R) TXT launch
On Mon 2009-06-22 17:41:41, Joseph Cihula wrote:
> The tboot module will DMA protect all of memory in order to ensure the that
> kernel will be able to initialize without compromise (from DMA). Consequently,
> the kernel must enable Intel(R) Virtualization Technology for Directed I/O
> (VT-d or Intel IOMMU) in order to replace this broad protection with the
> appropriate page-granular protection. Otherwise DMA devices will be unable
> to read or write from memory and the kernel will eventually panic.
>
> Because runtime IOMMU support is configurable by command line options, this
> patch will force it to be enabled regardless of the options specified, and will
> log a message if it was required to force it on.
>
>
> dmar.c | 8 ++++++++
> intel-iommu.c | 28 ++++++++++++++++++++++++++--
> 2 files changed, 34 insertions(+), 2 deletions(-)

This needs documentation. And you probably should panic the kernel if
user passes unworkable options, not override his choices.

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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