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

[Tom Lendacky]

On 6/22/2017 5:56 AM, Borislav Petkov wrote:
> 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 at amd.com>
>> ---
>>   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 at suse.de>
> 
> 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.

Correct.

Thanks,
Tom

>