Re: [PATCH v4 2/3] s390/crypto: Rework protected key AES for true asynch support

Herbert Xu
2025-05-13T08:07:25Z

On Fri, May 09, 2025 at 12:24:01PM +0200, Harald Freudenberger wrote:
> This is a complete rework of the protected key AES (PAES) implementation.
> The goal of this rework is to implement the 4 modes (ecb, cbc, ctr, xts)
> in a real asynchronous fashion:
> - init(), exit() and setkey() are synchronous and don't allocate any memory.
> - the encrypt/decrypt functions first try to do the job in a synchronous
> manner. If this fails, for example the protected key got invalid caused
> by a guest suspend/resume or guest migration action, the encrypt/decrypt
> is transferred to an instance of the crypto engine (see below) for
> asynchronous processing.
> These postponed requests are then handled by the crypto engine by
> invoking the do_one_request() callback but may of course again run into
> a still not converted key or the key is getting invalid. If the key is
> still not converted, the first thread does the conversion and updates
> the key status in the transformation context. The conversion is
> invoked via pkey API with a new flag PKEY_XFLAG_NOMEMALLOC.
> Note that once there is an active requests enqueued to get async
> processed via crypto engine, further requests also need to go via
> crypto engine to keep the request sequence.
>
> This patch together with the pkey/zcrypt/AP extensions to support
> the new PKEY_XFLAG_NOMEMMALOC should toughen the paes crypto algorithms
> to truly meet the requirements for in-kernel skcipher implementations
> and the usage patterns for the dm-crypt and dm-integrity layers.
>
> Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
> ---
> arch/s390/crypto/paes_s390.c | 1812 ++++++++++++++++++++++++----------
> 1 file changed, 1270 insertions(+), 542 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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