On Wed, Apr 10, 2019 at 12:04:32PM -0400, Sasha Levin wrote: > On Wed, Apr 10, 2019 at 02:29:27PM +0300, Jarkko Sakkinen wrote: > > On Sat, Apr 06, 2019 at 11:30:47AM -0400, Sasha Levin wrote: > > > On Wed, Apr 03, 2019 at 09:27:28PM +0300, Jarkko Sakkinen wrote: > > > > On Wed, Apr 03, 2019 at 09:18:27PM +0300, Jarkko Sakkinen wrote: > > > > > On Tue, Apr 02, 2019 at 03:33:16PM -0400, Sasha Levin wrote: > > > > > > This patch adds support for a software-only implementation of a TPM > > > > > > running in TEE. > > > > > > > > > > > > There is extensive documentation of the design here: > > > > > > https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ . > > > > > > > > > > > > As well as reference code for the firmware available here: > > > > > > https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM > > > > > > > > > > > > Signed-off-by: Thirupathaiah Annapureddy <thiruan@xxxxxxxxxxxxx> > > > > > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > > > > > > > > > What is the context anyway? I mean tpm_crb already supports fTPM running > > > > > in TZ. > > > > > > > > Might take 2-3 weeks before I have time to go through ftpm1.pdf with > > > > full concentration. I did search through the PDF for CRB and found > > > > zero hits. > > > > > > The fTPM as described in that paper and implemented in practice does not > > > use the CRB interface, thus we can't use tpm_crb to interface with the > > > firmware TPM. > > > > Obviously not but what is the reason of not implementing CRB but instead > > making yet another interface? I mean CRB supports SMC call. > > > > For me this is taking steps back as to the early days when there was > > proprietary intefaces to TPM before TCG came along and stardized. > > > > I'm sure that the TPM implementation itself could be reworked to > > inteface using CRB. It would also be good for ARM as a platform as now > > this new made up interface causes unwanted divergence. I thought that > > throwing ad hoc intefaces everywhere is something that ARM Linux > > community tries to reduce, not increase. > > I'm not sure what the original reasons were for not using the CRB > interface. Note that the paper is from a few years ago, and > implementations of this fTPM existed before the paper, so it's very > possible that it just predates CRB. > > Either way, there is existing hardware that runs this TPM and I'm trying > to get it out of Microsoft's tree and get it upstream. There's not much > I could do about existing hardware at this point. OK, the 2nd paragraph kind of is enough reason to pull it. Thanks for elaborating this. Just wanted to get a clearer picture where this sits in the universe. I'll do detailed review as soon as I have time. I don't need to have the hardware as long as *someone* could give tested-by for this. /Jarkko
