Support for TPM command line options

This patch adds support for TPM command line options.
The command line options supported here are

./qemu-... -tpmdev passthrough,path=<path to TPM device>,id=<id>
           -device tpm-tis,tpmdev=<id>

and

./qemu-... -tpmdev ?

where the latter works similar to -soundhw ? and shows a list of
available TPM backends (for example 'passthrough').

Using the type parameter, the backend is chosen, i.e., 'passthrough' for the
passthrough driver. The interpretation of the other parameters along
with determining whether enough parameters were provided is pushed into
the backend driver, which needs to implement the interface function
'create' and return a TPMDriver structure if the VM can be started or 'NULL'
if not enough or bad parameters were provided.

Monitor support for 'info tpm' has been added. It for example prints the
following:

(qemu) info tpm
TPM devices:
 tpm0: model=tpm-tis
  \ tpm0: type=passthrough,path=/dev/tpm0

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add TPM (frontend) hardware interface (TPM TIS) to Qemu

This patch adds the main code of the TPM frontend driver, the TPM TIS
interface, to Qemu. The code is largely based on the previous implementation
for Xen but has been significantly extended to meet the standard's
requirements, such as the support for changing of localities and all the
functionality of the available flags.

Communication with the backend (i.e., for Xen or the libtpms-based one)
is cleanly separated through an interface which the backend driver needs
to implement.

The TPM TIS driver's backend was previously chosen in the code added
to arch_init. The frontend holds a pointer to the chosen backend (interface).

Communication with the backend is largely based on signals and conditions.
Whenever the frontend has collected a complete packet, it will signal
the backend, which then starts processing the command. Once the result
has been returned, the backend invokes a callback function
(tis_tpm_receive_cb()).

The one tricky part is support for VM suspend while the TPM is processing
a command. In this case the frontend driver is waiting for the backend
to return the result of the last command before shutting down. It waits
on a condition for a signal from the backend, which is delivered in
tis_tpm_receive_cb().

Testing the proper functioning of the different flags and localities
cannot be done from user space when running in Linux for example, since
access to the address space of the TPM TIS interface is not possible. Also
the Linux driver itself does not exercise all functionality. So, for
testing there is a fairly extensive test suite as part of the SeaBIOS patches
since from within the BIOS one can have full access to all the TPM's registers.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add a debug register

This patch uses the possibility to add a vendor-specific register and
adds a debug register useful for dumping the TIS's internal state. This
register is only active in a debug build (#define DEBUG_TIS).

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Build the TPM frontend code

Build the TPM frontend code that has been added so far.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add a TPM Passthrough backend driver implementation

This patch is based of off version 9 of Stefan Berger's patch series
  "Qemu Trusted Platform Module (TPM) integration"
and adds a new backend driver for it.

This patch adds a passthrough backend driver for passing commands sent to the
emulated TPM device directly to a TPM device opened on the host machine.

Thus it is possible to use a hardware TPM device in a system running on QEMU,
providing the ability to access a TPM in a special state (e.g. after a Trusted
Boot).

This functionality is being used in the acTvSM Trusted Virtualization Platform
which is available on [1].

Usage example:
  qemu-system-x86_64 -tpmdev passthrough,id=tpm0,path=/dev/tpm0 \
                     -device tpm-tis,tpmdev=tpm0 \
                     -cdrom test.iso -boot d

Some notes about the host TPM:
The TPM needs to be enabled and activated. If that's not the case one
has to go through the BIOS/UEFI and enable and activate that TPM for TPM
commands to work as expected.
It may be necessary to boot the kernel using tpm_tis.force=1 in the boot
command line or 'modprobe tpm_tis force=1' in case of using it as a module.

Regards,
Andreas Niederl, Stefan Berger

[1] http://trustedjava.sourceforge.net/

Signed-off-by: Andreas Niederl <andreas.niederl@iaik.tugraz.at>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Introduce --enable-tpm-passthrough configure option

Introduce --enable-tpm-passthrough configure option.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add fd parameter for TPM passthrough driver

Enable the passing of a file descriptor via fd=<..> to access the host's
TPM device using the TPM passthrough driver.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>