On Wed, Aug 28, 2019 at 11:53:12AM -0400, Mimi Zohar wrote: > On Mon, 2019-08-26 at 22:05 -0300, Jason Gunthorpe wrote: > > The sysfs is not done, fundamentally, because the sysfs structure of > > the existing TPM1 stuff is grandfathered in, and doing anything like > > it for TPM2 is a complete NAK for not following the normal sysfs > > interface design rules, particularly of one value per file. This is a > > big part of why it was dropped for TPM2. > > The original TPM 2.0 support was missing a lot of TPM 1.2 > functionality, including exporting the TPM event log. So it wasn't > clear that leaving out the sysfs support was intentional or simply a > question of someone needing to implement it. It was intentional. > > So exposing PCRs and things through sysfs is not going to happen. > > > > If you had some very narrowly defined things like version, then > > *maybe* but I think a well defined use case is needed for why this > > needs to be sysfs and can't be done in C as Jarkko explained. > > Piotr's request for a sysfs file to differentiate between TPM 1.2 and > TPM 2.0 is a reasonable request and probably could be implemented on > TPM registration. > > If exposing the PCRs through sysfs is not acceptable, then perhaps > suggest an alternative. Use the char dev, this is exactly what is is for. Jason
