Messages in this thread | | | Date | Sun, 26 Feb 2017 13:44:40 +0200 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v2 6/7] tpm: expose spaces via a device link /dev/tpms<n> |
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On Fri, Feb 24, 2017 at 08:02:08AM -0500, James Bottomley wrote: > On Thu, 2017-02-23 at 11:09 +0200, Jarkko Sakkinen wrote: > > On Thu, Feb 16, 2017 at 09:25:19PM +0200, Jarkko Sakkinen wrote: > > > From: James Bottomley <James.Bottomley@HansenPartnership.com> > > > > > > Currently the tpm spaces are not exposed to userspace. Make this > > > exposure via a separate device, which can now be opened multiple > > > times because each read/write transaction goes separately via the > > > space. > > > > > > Concurrency is protected by the chip->tpm_mutex for each read/write > > > transaction separately. The TPM is cleared of all transient > > > objects by the time the mutex is dropped, so there should be no > > > interference between the kernel and userspace. > > > Signed-off-by: James Bottomley < > > > > > > James.Bottomley@HansenPartnershp.com> > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com> > > Tested-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com> > > Thanks! > > > Nitpicking but I've been thinking about naming. What about calling > > the device as tpmrc0 as in resource context. I think that would be a > > better name than TPM space. > > Well the original name was tpmrm<n> for TPM with Resource Manager. You > wanted it to be tpms<n> for TPM with Spaces. > > I'm not entirely sold on the Resource Context name ... I think > Resource Manager (because it's what the TCG calls it) or Spaces > (because it's what all the code comments call it) are better. > Resource Context sounds like what TPM2_SaveContext() creates for you > rather than the interface. > > > You do not mix it up with namespaces and/or virtualization. With > > resource in front it cannot be easily mixed up with TPM contexts > > either. > > I'm a containers person. What this set of patches does is precisely OS > level virtualization in my book, so I don't think you need to pretend > it is't; and OS level virtualization is what a namespace does. The > only difference between this and the other kernel namespaces is that > you get a new namespace automatically when you open the device and you > can't enter an existing namespace. > > I think therefore that tpmns<n> for TPM Namespace would be very > appropriate.
Sorry for going back and forth with this but I turn it back to your original tpmrm. It's in the end of the day the least confusing option. I think this has been anyway useful to trip a bit around the options because it is hard to rollback API...
> > This does not equire any effort from your side. I could do the > > renaming. > > > > PS. Could you go through my commits and test and review them at some > > point so we would have the whole patch set peer tested? > > Already reviewed, just doing a test build (I'm travelling, so it > actually has to be on my physical laptop). > > James
There's now tabrm-v3 branch. I had to tweak error handling in your device adding patch because of b4e9d7561a70. I hope I didn't break anything.
/Jarkko
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