On Sat Aug 5, 2023 at 2:21 AM EEST, Mario Limonciello wrote:
> On 8/4/23 17:54, Jarkko Sakkinen wrote:
> > On Thu Aug 3, 2023 at 9:24 PM EEST, Mario Limonciello wrote:
> >> The TPM RNG functionality is not necessary for entropy when the CPU
> >> already supports the RDRAND instruction. The TPM RNG functionality
> >> was previously disabled on a subset of AMD fTPM series, but reports
> >> continue to show problems on some systems causing stutter root caused
> >> to TPM RNG functionality.
> >>
> >> Expand disabling TPM RNG use for all AMD fTPMs whether they have versions
> >> that claim to have fixed or not. To accomplish this, move the detection
> >> into part of the TPM CRB registration and add a flag indicating that
> >> the TPM should opt-out of registration to hwrng.
> >>
> >> Cc: stable@xxxxxxxxxxxxxxx # 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@xxxxxxxxxx
> >> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217719
> >> Reported-by: bitlord0xff@xxxxxxxxx
> >> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217212
> >> Reviewed-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> >> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> >
> > I will skip rc5 and send this for rc6 on Monday.
> >
> > Has anyone with suitable AMD system tested this?
>
> Probably obvious; but I tested with a system that can support both dTPM
> and fTPM and swapped between the two before I sent it.
Ok, great. I've tested that with non-AMD system things continue to
work so I guess that is sufficient enough for:
Tested-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
