AMD fTPM patches for stable

AMD fTPM patches for stable

[Jason A. Donenfeld]

Hey Greg,

There was recently a bit of a snafoo with a maintainer taking the wrong
version of a patch and sending that up to Linus. That patch had
incorrect stable@ annotations and had a bug in it. That bug was fixed
with a follow up patch. But of course the metadata couldn't be changed
easily retroactively.

So I'm emailing to ask you to backport these two patches back to 5.5:

- 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
- cacc6e22932f ("tpm: Add a helper for checking hwrng enabled")

I know the stable@ tag says 6.1+, but the actual right tags from the
newer versioned patch that didn't get picked are:

Cc: stable@vger.kernel.org # 5.5+
Fixes: b006c439d58d ("hwrng: core - start hwrng kthread also for untrusted sources")
Fixes: f1324bbc4011 ("tpm: disable hwrng for fTPM on some AMD designs")
Fixes: 3ef193822b25 ("tpm_crb: fix fTPM on AMD Zen+ CPUs")
Reported-by: daniil.stas@posteo.net
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217719
Reported-by: bitlord0xff@gmail.com
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217212
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Let me know if you need any more info.

Thanks,
Jason

Re: AMD fTPM patches for stable

[Limonciello, Mario]

On 8/9/2023 4:33 PM, Jason A. Donenfeld wrote:
> Hey Greg,
> 
> There was recently a bit of a snafoo with a maintainer taking the wrong
> version of a patch and sending that up to Linus. That patch had
> incorrect stable@ annotations and had a bug in it. That bug was fixed
> with a follow up patch. But of course the metadata couldn't be changed
> easily retroactively.
> 
> So I'm emailing to ask you to backport these two patches back to 5.5:
> 
> - 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
> - cacc6e22932f ("tpm: Add a helper for checking hwrng enabled")
> 
> I know the stable@ tag says 6.1+, but the actual right tags from the
> newer versioned patch that didn't get picked are:
> 
> Cc: stable@vger.kernel.org # 5.5+
> Fixes: b006c439d58d ("hwrng: core - start hwrng kthread also for untrusted sources")
> Fixes: f1324bbc4011 ("tpm: disable hwrng for fTPM on some AMD designs")
> Fixes: 3ef193822b25 ("tpm_crb: fix fTPM on AMD Zen+ CPUs")
> Reported-by: daniil.stas@posteo.net
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217719
> Reported-by: bitlord0xff@gmail.com
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217212
> Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> 
> Let me know if you need any more info.
> 
> Thanks,
> Jason

So I had a quick try with the backports to see what happens.  6.1.y and 
6.4.y apply cleanly no problem.

However 5.15.y (and presumably 5.5.y) have a variety of issues that I 
think no longer make it a stable candidate.  I started going down the 
rabbit hole of dependencies and it's massive unless hand modifications 
are done.

Realistically the problem is most severe in 6.1.y because of 
b006c439d58d.  I don't know it's worth going back any further.

Re: AMD fTPM patches for stable

[Jason A. Donenfeld]

On Wed, Aug 09, 2023 at 05:22:02PM -0500, Limonciello, Mario wrote:
> 
> 
> On 8/9/2023 4:33 PM, Jason A. Donenfeld wrote:
> > Hey Greg,
> > 
> > There was recently a bit of a snafoo with a maintainer taking the wrong
> > version of a patch and sending that up to Linus. That patch had
> > incorrect stable@ annotations and had a bug in it. That bug was fixed
> > with a follow up patch. But of course the metadata couldn't be changed
> > easily retroactively.
> > 
> > So I'm emailing to ask you to backport these two patches back to 5.5:
> > 
> > - 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
> > - cacc6e22932f ("tpm: Add a helper for checking hwrng enabled")
> > 
> > I know the stable@ tag says 6.1+, but the actual right tags from the
> > newer versioned patch that didn't get picked are:
> > 
> > Cc: stable@vger.kernel.org # 5.5+
> > Fixes: b006c439d58d ("hwrng: core - start hwrng kthread also for untrusted sources")
> > Fixes: f1324bbc4011 ("tpm: disable hwrng for fTPM on some AMD designs")
> > Fixes: 3ef193822b25 ("tpm_crb: fix fTPM on AMD Zen+ CPUs")
> > Reported-by: daniil.stas@posteo.net
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217719
> > Reported-by: bitlord0xff@gmail.com
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217212
> > Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
> > Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> > 
> > Let me know if you need any more info.
> > 
> > Thanks,
> > Jason
> 
> So I had a quick try with the backports to see what happens.  6.1.y and 
> 6.4.y apply cleanly no problem.
> 
> However 5.15.y (and presumably 5.5.y) have a variety of issues that I 
> think no longer make it a stable candidate.  I started going down the 
> rabbit hole of dependencies and it's massive unless hand modifications 
> are done.
> 
> Realistically the problem is most severe in 6.1.y because of 
> b006c439d58d.  I don't know it's worth going back any further.

Okay. Your (AMD's) hardware, so I'm fine deferring to your judgement.

Jason