From: Matthew Garrett <mjg59@google.com>
To: "Safford, David (GE Global Research, US)" <david.safford@ge.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"jarkko.sakkinen@linux.intel.com"
<jarkko.sakkinen@linux.intel.com>,
"Wiseman, Monty (GE Global Research, US)" <monty.wiseman@ge.com>
Subject: Re: [PATCH] tpm_crb - workaround broken ACPI tables
Date: Thu, 11 Jul 2019 13:33:14 -0700 [thread overview]
Message-ID: <CACdnJutS4-N0GgtYPy9GGJ8dVf48VZGF5AFL2raB55bSPKUpNw@mail.gmail.com> (raw)
In-Reply-To: <BCA04D5D9A3B764C9B7405BBA4D4A3C035EF7CFE@ALPMBAPA12.e2k.ad.ge.com>
On Thu, Jul 11, 2019 at 12:32 PM Safford, David (GE Global Research,
US) <david.safford@ge.com> wrote:
> As far as I can tell, some OEMs simply are putting bad data in the tables.
> I have seen at least one report where a BIOS update did fix the problem.
The issue is that the CRB region is mapped into a region marked as
ACPI NVS. drivers/acpi/nvs.c claims this region and as a result a
resource conflict is generated. Since Windows is clearly fine with
other drivers using ACPI NVS regions, the correct fix involves
figuring out a way to either share these resources or allow tpm_crb to
reclaim the region from the NVS driver. Note that the NVS driver's
behaviour is to save and restore NVS regions over suspend/resume, so
simply forcibly allocating the resource will result in two separate
codepaths touching the region on resume - this seems like a bad
outcome. Ideally this could be solved generically, but practically
(given we've only seen this around TPMs, as far as I can tell) adding
a hook to nvs.c that allowed drivers aware of the issue to have the
space handed off to them might be easier.
Have you seen this on any non-AMD systems?
next prev parent reply other threads:[~2019-07-11 20:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 12:29 [PATCH] tpm_crb - workaround broken ACPI tables Safford, David (GE Global Research, US)
2019-07-11 14:10 ` Jarkko Sakkinen
2019-07-11 14:58 ` Jason Gunthorpe
2019-07-11 16:44 ` Safford, David (GE Global Research, US)
2019-07-11 18:50 ` Jason Gunthorpe
2019-07-11 19:31 ` Safford, David (GE Global Research, US)
2019-07-11 20:33 ` Matthew Garrett [this message]
2019-07-12 12:41 ` Safford, David (GE Global Research, US)
2019-07-12 15:06 ` Jason Gunthorpe
2019-07-12 15:48 ` Jarkko Sakkinen
2019-07-12 18:24 ` Matthew Garrett
2019-07-12 19:05 ` Safford, David (GE Global Research, US)
2019-07-12 20:36 ` Matthew Garrett
2019-07-14 19:28 ` Safford, David (GE Global Research, US)
2019-07-14 23:48 ` Matthew Garrett
2019-07-15 19:44 ` Matthew Garrett
2019-07-11 19:16 ` Jarkko Sakkinen
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