On Fri, Sep 19, 2025 at 10:05:58AM +0300, Jarkko Sakkinen wrote: > On Thu, Sep 18, 2025 at 10:49:28PM -0500, Serge E. Hallyn wrote: > > On Thu, Sep 18, 2025 at 10:30:18PM +0300, Jarkko Sakkinen wrote: > > > The current shenanigans for duration calculation introduce too much > > > complexity for a trivial problem, and further the code is hard to patch > > > and > > > maintain. > > > > > > Address these issues with a flat look-up table, which is easy to > > > understand > > > and patch. If leaf driver specific patching is required in future, it is > > > easy enough to make a copy of this table during driver initialization and > > > add the chip parameter back. > > > > > > 'chip->duration' is retained for TPM 1.x. > > > > > > As the first entry for this new behavior address TCG spec update mentioned > > > in this issue: > > > > > > https://github.com/raspberrypi/linux/issues/7054 > > > > > > Therefore, for TPM_SelfTest the duration is set to 3000 ms.
D'oh! It *was* in the commit message all along, sorry. > > > This does not categorize a as bug, given that this is introduced to the > > > spec after the feature was originally made. > > > > > > Cc: Frédéric Jouen <[email protected]> > > > Signed-off-by: Jarkko Sakkinen <[email protected]> Looks good, thank you. Reviewed-by: Serge Hallyn <[email protected]> > > fwiw (which shouldn't be much) looks good to me, but two questions, > > one here and one below. > > > > First, it looks like in the existing code it is possible for a tpm2 > > chip to set its own timeouts and then set the TPM_CHIP_FLAG_HAVE_TIMEOUTS > > flag to avoid using the defaults, but I don't see anything using that > > in-tree. Is it possible that there are out of tree drivers that will be > > sabotaged here? Or am I misunderstanding that completely? > > Good questions, and I can brief a bit about the context of the > pre-existing art and this change. > > This complexity was formed in 2014 when I originally developed TPM2 > support and the only available testing plaform was early Intel PTT with > a flakky version of TPM2 support (e.g., no localities). > > Since then we haven't had per leaf-driver divergence. > > Further, I think that this type of layout is actually a better fit if > we ever need to quirks for command durations for a particular device, as > then we can migrate to "copy and patch" semantics i.e., have a copy of > this map in the chip structure. > > As per out-of-tree drivers, it's unfortunate reality of out-of-tree > drivers :-) However, this will definitely add some extra work, when > backporting fixes (not overwhelmingly much). > > BR, Jarkko
