lkml.org 
[lkml]   [2023]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH v2] tpm: Don't make vendor check required for probe
    From
    On Tue Aug 22, 2023 at 5:05 PM EEST, Mario Limonciello wrote:
    > On 8/22/2023 08:22, Jarkko Sakkinen wrote:
    > > On Mon Aug 21, 2023 at 5:02 PM EEST, Mario Limonciello wrote:
    > >> The vendor check introduced by commit 554b841d4703 ("tpm: Disable RNG for
    > >> all AMD fTPMs") doesn't work properly on a number of Intel fTPMs. On the
    > >> reported systems the TPM doesn't reply at bootup and returns back the
    > >> command code. This makes the TPM fail probe.
    > >>
    > >> As this isn't crucial for anything but AMD fTPM and AMD fTPM works, check
    > >> the chip vendor and if it's not AMD don't run the checks.
    > >>
    > >> Cc: stable@vger.kernel.org
    > >> Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
    > >> Reported-by: Todd Brandt <todd.e.brandt@intel.com>
    > >> Reported-by: Patrick Steinhardt <ps@pks.im>
    > >> Reported-by: Ronan Pigott <ronan@rjp.ie>
    > >> Reported-by: Raymond Jay Golo <rjgolo@gmail.com>
    > >> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217804
    > >> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
    > >> ---
    > >> v1->v2:
    > >> * Check x86 vendor for AMD
    > >> ---
    > >> drivers/char/tpm/tpm_crb.c | 7 ++++++-
    > >> 1 file changed, 6 insertions(+), 1 deletion(-)
    > >>
    > >> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
    > >> index 9eb1a18590123..7faf670201ccc 100644
    > >> --- a/drivers/char/tpm/tpm_crb.c
    > >> +++ b/drivers/char/tpm/tpm_crb.c
    > >> @@ -465,8 +465,12 @@ static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
    > >>
    > >> static int crb_check_flags(struct tpm_chip *chip)
    > >> {
    > >> + int ret = 0;
    > >> +#ifdef CONFIG_X86
    > >> u32 val;
    > >> - int ret;
    > >> +
    > >> + if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
    > >> + return ret;
    > >>
    > >> ret = crb_request_locality(chip, 0);
    > >> if (ret)
    > >> @@ -481,6 +485,7 @@ static int crb_check_flags(struct tpm_chip *chip)
    > >>
    > >> release:
    > >> crb_relinquish_locality(chip, 0);
    > >> +#endif
    > >
    > > Looks much better but the main question here is that is this combination
    > > possible:
    > >
    > > 1. AMD CPU
    > > 2. Non-AMD fTPM (i.e. manufacturer property differs)
    > >
    > > BR, Jarkko
    >
    > Yes that combination is possible.
    >
    > Pluton TPM uses the tpm_crb driver.

    Then I guess we'll go with this for now. Thanks for the effort.

    Tested-by: Jarkko Sakkinen <jarkko@kernel.org> # QEMU + swtpm
    Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

    I'm planning to send a pull request right after this with the fix so it
    will land to v6.6-rc1 or v6.6-rc2:
    https://lore.kernel.org/linux-integrity/20230817201935.31399-1-jarkko@kernel.org/

    BR, Jarkko

    \
     
     \ /
      Last update: 2023-08-22 16:56    [W:3.905 / U:0.000 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site