Re: [Qemu-devel] [PATCH v5 1/4] Provide support for the CUSE TPM

[Stefan Berger]

"Michael S. Tsirkin" <address@hidden>
wrote on 01/20/2016 10:20:58 AM:

> From: "Michael S. Tsirkin" <address@hidden>

> > 
> > The CUSE TPM and associated tools can be found here:
> > 
> > https://github.com/stefanberger/swtpm
> > 
> > (please use the latest version)
> > 
> > To use the external CUSE TPM, the CUSE TPM should be started
as follows:
> > 
> > # terminate previously started CUSE TPM
> > /usr/bin/swtpm_ioctl -s /dev/vtpm-test
> > 
> > # start CUSE TPM
> > /usr/bin/swtpm_cuse -n vtpm-test
> > 
> > QEMU can then be started using the following parameters:
> > 
> > qemu-system-x86_64 \
> >    [...] \
> >         -tpmdev cuse-tpm,id=tpm0,cancel-path=/dev/null,path=/dev/vtpm-test
\
> >         -device tpm-tis,id=tpm0,tpmdev=tpm0
\
> >    [...]
> > 
> > 
> > Signed-off-by: Stefan Berger <address@hidden>
> > Cc: Eric Blake <address@hidden>
> 
> Before we add a dependency on this interface,
> I'd rather see this interface supported in kernel
> and not just in CUSE.

For using the single hardware TPM, we have the passthrough
type. It's usage is limited.

CUSE extends the TPM character device interface with
ioctl's. Behind the character device we can implement a TPM 1.2 and a TPM
2. Both TPM implementations require large amounts of code, which I don't
think should go into the Linux kernel itself. So I don't know who would
implement this interface inside the Linux kernel.

  Stefan