Re: [Xen-devel] [PATCH v7 27/36] iommu/amd: Allow the AMD IOMMU to work with memory encryption

[Borislav Petkov <bp@xxxxxxxxx>]

On Fri, Jun 16, 2017 at 01:54:59PM -0500, Tom Lendacky wrote:
> The IOMMU is programmed with physical addresses for the various tables
> and buffers that are used to communicate between the device and the
> driver. When the driver allocates this memory it is encrypted. In order
> for the IOMMU to access the memory as encrypted the encryption mask needs
> to be included in these physical addresses during configuration.
> 
> The PTE entries created by the IOMMU should also include the encryption
> mask so that when the device behind the IOMMU performs a DMA, the DMA
> will be performed to encrypted memory.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>  drivers/iommu/amd_iommu.c       |   30 ++++++++++++++++--------------
>  drivers/iommu/amd_iommu_init.c  |   34 ++++++++++++++++++++++++++++------
>  drivers/iommu/amd_iommu_proto.h |   10 ++++++++++
>  drivers/iommu/amd_iommu_types.h |    2 +-
>  4 files changed, 55 insertions(+), 21 deletions(-)

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

Btw, I'm assuming the virt_to_phys() difference on SME systems is only
needed in a handful of places. Otherwise, I'd suggest changing the
virt_to_phys() function/macro directly. But I guess most of the places
need the real physical address without the enc bit.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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