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

[Ninad Palsule]

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