Re: [Qemu-arm] Adding /dev/tpm0 to qemu-system-aarch64

[Lakshmi Ramasubramanian]

On 9/16/19 10:24 AM, Peter Maydell wrote:

Hi Peter,

> This is because QEMU only supports TPM device emulation on x86.
> To add it to aarch64 somebody would have to investigate what the
> hardware interface for TPM ought to be on aarch64 hardware, and
> then implement an emulation of it and add that to the 'virt'
> board. (It would probably share a lot of the implementation with
> the current x86 TPM, obviously.)
>
> thanks
> -- PMM

The TPM I am emulating is implemented in firmware (fTPM) that runs in 
the Trust Zone (emulated in QEMU). There is a kernel module that handles 
this fTPM.

If I add the following entry in the Device Tree that QEMU passes to the 
boot loader, the fTPM kernel module will load and it should be able to 
talk to the firmware device.

        tpm@0 {
            compatible = "myorg,ftpm"
        };

How do I add such a custom entry in the device tree in QEMU?

Is there a way to do that by, say, "-device" command line argument or 
such in qemu-system-aarch64?

Thanks,
 -lakshmi