Re: [Qemu-devel] TPM does not seem to work under QEMU with TPM patches

[Kent Yoder <key@linux.vnet.ibm.com>]

Hi Jordi,

On Mon, Aug 20, 2012 at 06:12:44PM -0400, Jordi Cucurull Juan wrote:
> Dear all,
> 
> I am testing the TPM patches of Stefan Berger to provide TPM support
> to QEMU. Nevertheless I have not managed to run them successfully.
> During the compilation of QEMU with his patches (V18 for revision
> 563987d) I have not had any issue. But, I have a virtual machine
> based on CentOS 6.2 and the TPM does not seem to be present. I run
> the machine with the following command line (as a root user):
> 
> # /usr/local/bin/qemu-system-x86_64 -hda qemu-disk-centos.img -m
> 1024 -boot d -enable-kvm -usbdevice tablet -k es -tpmdev
> passthrough,id=tpm0,path=/dev/tpm0 -device tpm-tis,tpmdev=tpm0
> 
> My real machine has an Infineon TPM v1.2. When I try to load the TSS
> library (Trousers) inside the client machine (the CentOS 6.2) it
> throws the following error:
> 
> insmod: error inserting '/lib/modules/2.6.32-279.5.1.el6.x86_64/kernel/drivers/char/tpm/tpm_atmel.ko':
> -1 no such device

  This should be fine - the tpm_tis driver should be driving the vtpm.

> 
> Apart from this, QEMU does not throw any error. Should I enable
> something else to have access to the TPM? In addition, I do not see
> any /dev/vtpm0 device in my real machine.

  As I understand them, the qemu patches allow direct writing from the
guest to the host's /dev/tpm0, so you wouldn't see a new device node.

Kent

> 
> Best regards,
> Jordi.
> 
> 
> -- 
> Jordi Cucurull Juan
> Researcher
> Scytl Secure Electronic Voting
> Plaça Gal·la Placidia, 1-3, 1st floor · 08006 Barcelona
> Phone:     + 34 934 230 324
> Fax        + 34 933 251 028
> jordi.cucurull@scytl.com
> http://www.scytl.com
> 
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