Re: [PATCH] tpm_crb - workaround broken ACPI tables

[Matthew Garrett <mjg59@google.com>]

On Fri, Jul 12, 2019 at 5:42 AM Safford, David (GE Global Research,
US) <david.safford@ge.com> wrote:
> Thanks - that was very helpful.
> All of my misbehaving systems are AMD - mostly Ryzen and Threadripper towers,
> of various motherboard OEMs. One system is a 3rd gen Ryzen laptop (Asus FX505dy).

I suspect the issue comes from AMD's reference code rather than
multiple vendors all having made the same mistake. Unfortunate.

> But the laptop shows a new layout:
> [    2.069539] tpm_crb MSFT0101:00: can't request region for resource
> [mem 0xbd11f000-0xbd122fff]
> [    2.069543] tpm_crb: probe of MSFT0101:00 failed with error -16
> [    2.177663] ima: No TPM chip found, activating TPM-bypass!
>
> bbc64000-bd14afff : Reserved
>   bd11f000-bd11ffff : MSFT0101:00
>   bd123000-bd123fff : MSFT0101:00
> bd14b000-bd179fff : ACPI Tables
> bd17a000-bd328fff : ACPI Non-volatile Storage

Hmm, that's interesting. Is this a UEFI or BIOS system? Can you
provide the e820 data from dmesg?

> Have you looked at the sequencing during suspend/restore?
> If ACPI is the last to save, and first to restore, the TPM's use may
> still be safe. I'll try to run some tests along those lines, and look
> at the nvs driver.

The NVS stuff was largely implemented by attempting to identify what
Windows was doing and duplicating that, so it's kind of dangerous to
rely on its ordering - there's a risk it might end up changing
suddenly in order to mimic Windows' behaviour more closely.