Re: [PATCH 1/3] docs: Add support for TPM devices over I2C bus

[Cédric Le Goater]

On 3/23/23 04:01, Ninad Palsule wrote:
> This is a documentation change for I2C TPM device support.
>
> Qemu already supports devices attached to ISA and sysbus.
> This drop adds support for the I2C bus attached TPM devices.
>
> Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
>
> ---
> V2:
>
> Incorporated Stephen's review comments
> - Added example in the document.
> ---
>   docs/specs/tpm.rst | 20 +++++++++++++++++++-
>   1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/docs/specs/tpm.rst b/docs/specs/tpm.rst
> index 535912a92b..bf7249b09c 100644
> --- a/docs/specs/tpm.rst
> +++ b/docs/specs/tpm.rst
> @@ -21,11 +21,15 @@ QEMU files related to TPM TIS interface:
>    - ``hw/tpm/tpm_tis_common.c``
>    - ``hw/tpm/tpm_tis_isa.c``
>    - ``hw/tpm/tpm_tis_sysbus.c``
> + - ``hw/tpm/tpm_tis_i2c.c``
>    - ``hw/tpm/tpm_tis.h``
>   
>   Both an ISA device and a sysbus device are available. The former is
>   used with pc/q35 machine while the latter can be instantiated in the
> -Arm virt machine.
> +Arm virt machine. An I2C device support is also added which can be
> +instantiated in the arm based emulation machine. An I2C device is also
> +supported for the Arm virt machine. This device only supports the
> +TPM 2 protocol.
>   
>   CRB interface
>   -------------
> @@ -348,6 +352,20 @@ In case an Arm virt machine is emulated, use the following 
> command line:
>       -drive if=pflash,format=raw,file=flash0.img,readonly=on \
>       -drive if=pflash,format=raw,file=flash1.img
>   
> +In case a Rainier bmc machine is emulated, use the following command line:
> +
> +.. code-block:: console
> +
> +  qemu-system-arm -M rainier-bmc -nographic \
> +    -kernel ${IMAGEPATH}/fitImage-linux.bin \
> +    -dtb ${IMAGEPATH}/aspeed-bmc-ibm-rainier.dtb \
> +    -initrd ${IMAGEPATH}/obmc-phosphor-initramfs.rootfs.cpio.xz \
> +    -drive 
> file=${IMAGEPATH}/obmc-phosphor-image.rootfs.wic.qcow2,if=sd,index=2\
> +    -net nic -net 
> user,hostfwd=:127.0.0.1:2222-:22,hostfwd=:127.0.0.1:2443-:443\
> +    -chardev socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock \
> +    -tpmdev emulator,id=tpm0,chardev=chrtpm \
> +    -device tpm-tis-i2c,tpmdev=tpm0,bus=aspeed.i2c.bus.12,address=0x2e


The rainier images are not the easiest to find. Could we use an AST2600 EVB
machine instead and instantiate the device from user space ? see commit
3302184f7f or 7a7308eae0.

Thanks,

C.

>   In case SeaBIOS is used as firmware, it should show the TPM menu item
>   after entering the menu with 'ESC'.
>