On 06/04/2018 12:55 PM, Jarkko Sakkinen wrote: > On Thu, May 31, 2018 at 04:29:09PM -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 driver supports only blocking calls, which >> doesn't allow asynchronous operation. This patch changes it and adds support >> for nonblocking write and a new poll function to enable applications using >> the API as designed by the spec. >> The new functionality can be tested using standard TPM tools implemented >> in [2], with modified TCTI from [3]. > > I would need some statistics before I have interest to take these > changes in any form eg use case where this matters in the end. The use cases motivating this feature are the same ones that motivated the non-blocking behavior of other kernel interfaces (files, sockets and other hardware) that has the potential to block threads in a process. By implementing this same behavior in the TPM driver our goal is to enable use of the TPM in programming languages / frameworks implementing an "event-driven" model. There are a lot of them out there but since the TSS2 APIs are currently limited to C our example code is in glib / GSource. Hopefully this is sufficient but if it isn't it would help us to get additional details on what you're looking for. Thanks, Philip
