Re: [PATCH rdma-next 00/13] Add RDMA inline crypto support

[Israel Rukshin <israelr@nvidia.com>]

Hi Sagi,

On 1/23/2023 1:27 PM, Sagi Grimberg wrote:
>
>>  From Israel,
>>
>> The purpose of this patchset is to add support for inline
>> encryption/decryption of the data at storage protocols like nvmf over
>> RDMA (at a similar way like integrity is used via unique mkey).
>>
>> This patchset adds support for plaintext keys. The patches were tested
>> on BF-3 HW with fscrypt tool to test this feature, which showed reduce
>> in CPU utilization when comparing at 64k or more IO size. The CPU 
>> utilization
>> was improved by more than 50% comparing to the SW only solution at 
>> this case.
>>
>> How to configure fscrypt to enable plaintext keys:
>>   # mkfs.ext4 -O encrypt /dev/nvme0n1
>>   # mount /dev/nvme0n1 /mnt/crypto -o inlinecrypt
>>   # head -c 64 /dev/urandom > /tmp/master_key
>>   # fscryptctl add_key /mnt/crypto/ < /tmp/master_key
>>   # mkdir /mnt/crypto/test1
>>   # fscryptctl set_policy 152c41b2ea39fa3d90ea06448456e7fb 
>> /mnt/crypto/test1
>>     ** “152c41b2ea39fa3d90ea06448456e7fb” is the output of the
>>        “fscryptctl add_key” command.
>>   # echo foo > /mnt/crypto/test1/foo
>>
>> Notes:
>>   - At plaintext mode only, the user set a master key and the fscrypt
>>     driver derived from it the DEK and the key identifier.
>>   - 152c41b2ea39fa3d90ea06448456e7fb is the derived key identifier
>>   - Only on the first IO, nvme-rdma gets a callback to load the 
>> derived DEK.
>>
>> There is no special configuration to support crypto at nvme modules.
>
> Hey, this looks sane to me in a very first glance.
>
> Few high level questions:
> - what happens with multipathing? when if not all devices are
> capable. SW fallback?
SW fallback happens every time the device doesn't support the specific 
crypto request (which include data-unit-size, mode and dun_bytes).
So with multipathing, one path uses the HW crypto offload and the other 
one uses the SW fallback.
> - Does the crypt stuff stay intact when bio is requeued?
Yes, the crypto ctx is copied when cloning the bio.
>
> I'm assuming you tested this with multipathing? This is not very
> useful if it is incompatible with it.
Yes, sure.
You can see the call to  blk_crypto_reprogram_all_keys(), which is 
called when the controller was reconnected after port toggling.

- Israel