On Thu, Feb 13, 2020 at 02:45:49PM -0500, Stefan Berger wrote: > > Any driver that knows the TPM must be started prior to Linux > > booting should not use the flag. vtpm drivers in general would seem > > to be the case where we can make this statement. > > Wouldn't this statement apply to all systems, including embedded ones? > Basically all firmwares should implement the CRTM and do the TPM > initialization. It is not mandatory that systems with TPMs start it in the firmware. That is only required if the TPM PCR feature is going to be used. A TPM can quite happily be used for key storage without FW support. Arguably this is sort of done wrong. eg if the platform has provided TPM information through uEFI or something then we shouldn't try to auto start the system TPM. At least for TPM1 detecting a non-started TPM was harmless, so nobody really cared. I wonder if TPM2 is much different.. But certainly auto startup should *not* be required to have a working TPM driver, that is just fundamentally wrong. Jason
