Re: [Xen-devel] [PATCH] [HVM] [TPM] [1/3] Add TPM TIS type of device toACPI device list

[Stefan Berger <stefanb@xxxxxxxxxx>]

Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> wrote
on 10/27/2006 12:25:30 PM:

> What if the guest isn’t configured with a TPM device? It seems a
bit
> dodgy to advertise a non-existent device in the BIOS tables.

To solve this we would need one of the following
- a BIOS that probes for such devices and dynamically
appends the info to the (static) ACPI tables 
- a tool that builds and compiles the ACPI tables
according to the desired configuration of the HVM VM before the HVM is
started

A later version (2.6.18) of the corresponding Linux
driver allows you to modprobe the module with a '-force' parameter for
platforms where the correct ACPI information is not available. [In that
case if the vTPM facility is not available, the /dev/tpm0 won't become
available.]

I am not sure what the right solution is.


  Stefan

> 
>  -- Keir
> 
> On 24/10/06 7:48 pm, "Stefan Berger" <stefanb@xxxxxxxxxx>
wrote:

> This patch adds a TPM TIS type of device to the
ACPI device list which
> is supported for example by the Linux TPM TIS driver.
> The specification describing this entry can be found here:
> 
> https://www.trustedcomputinggroup.
> org/specs/PCClient/TCG_PCClientImplementationforBIOS_1-20_1-00.pdf
> 
> Section 9 in the document describes the device entry.
> 
> Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxx>
> 
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