Re: [PATCH v7 1/3] docs: Add support for TPM devices over I2C bus

[Ninad Palsule <ninad@linux.vnet.ibm.com>]

Hi Joel,


On 3/27/23 2:47 AM, Joel Stanley wrote:
> On Sun, 26 Mar 2023 at 22:44, Ninad Palsule <ninad@linux.ibm.com> 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.
>>
>> ---
>> V4:
>> Incorporate Cedric & Stefan's comments
>>
>> - Added example for ast2600-evb
>> - Corrected statement about arm virtual machine.
>>
>> ---
>> V6:
>> Incorporated review comments from Stefan.
>> ---
>>   docs/specs/tpm.rst | 32 ++++++++++++++++++++++++++++++++
>>   1 file changed, 32 insertions(+)
>>
>> diff --git a/docs/specs/tpm.rst b/docs/specs/tpm.rst
>> index 535912a92b..590e670a9a 100644
>> --- a/docs/specs/tpm.rst
>> +++ b/docs/specs/tpm.rst
>> @@ -21,12 +21,16 @@ 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.
>>
>> +An I2C device support is also provided which can be instantiated in the Arm
>> +based emulation machines. This device only supports the TPM 2 protocol.
>> +
>>   CRB interface
>>   -------------
>>
>> @@ -348,6 +352,34 @@ 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 ast2600-evb bmc machine is emulated and want to use TPM device
>> +attached to I2C bus, use the following command line:
>> +
>> +.. code-block:: console
>> +
>> +  qemu-system-arm -M ast2600-evb -nographic \
>> +    -kernel arch/arm/boot/zImage \
>> +    -dtb arch/arm/boot/dts/aspeed-ast2600-evb.dtb \
>> +    -initrd rootfs.cpio \
>> +    -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
> For testing, use this command to load the driver to the correct address:
>
> echo tpm_tis_i2c 0x2e > /sys/bus/i2c/devices/i2c-12/new_device
>
> (I don't know how specific we want to make the instructions, but
> adding a line like above would help others from having to re-discover
> the command).
Make sense. Added.
>
>> +
>> +In case a Rainier bmc machine is emulated and want to use TPM device
>> +attached to I2C bus, 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
>> +
> I'd drop this example, the above one is enough.
Removed.
>
>>   In case SeaBIOS is used as firmware, it should show the TPM menu item
>>   after entering the menu with 'ESC'.
>>
>> --
>> 2.37.2
>>