On Tue, Jun 12, 2018 at 10:58:26AM -0700, Tadeusz Struk wrote: > The TCG SAPI specification [1] defines a set of functions, which allows > applications to use the TPM device in either blocking or non-blocking fashion. > Each command defined by the specification has a corresponding > Tss2_Sys_<COMMAND>_Prepare() and Tss2_Sys_<COMMAND>_Complete() call, which > together with Tss2_Sys_ExecuteAsync() is designed to allow asynchronous > mode of operation. Currently the TPM driver supports only blocking calls, > which doesn't allow asynchronous IO operations. > This patch changes it and adds support for nonblocking write and a new poll > function to enable applications, which want to take advantage of this feature. > The new functionality can be tested using standard TPM tools implemented > in [2], together with modified TCTI from [3]. > > [1] https://trustedcomputinggroup.org/wp-content/uploads/TSS_SAPI_Version-1.1_Revision-22_review_030918.pdf > [2] https://github.com/tpm2-software/tpm2-tools > [3] https://github.com/tstruk/tpm2-tss/tree/async For me the value is still a bit questionable. The benchmark looks a bit flakky to give much figures how this would work with real world workloads. I read James response and I also have to question why not just a worker thread in user space? TPM does only one command at a time anyways. Cannot take this in before I know that user space will (1) adapt to this and (2) gain value compared to a worker thread. /Jarkko
