Re: [PATCH 2/2] tpm: add backend for mssim

[Stefan Berger <stefanb@linux.ibm.com>]

On 12/15/22 13:01, James Bottomley wrote:
> From: James Bottomley <James.Bottomley@HansenPartnership.com>
> 
> The Microsoft Simulator (mssim) is the reference emulation platform
> for the TCG TPM 2.0 specification.
> 
> https://github.com/Microsoft/ms-tpm-20-ref.git
> 
> It exports a fairly simple network socket baset protocol on two
> sockets, one for command (default 2321) and one for control (default
> 2322).  This patch adds a simple backend that can speak the mssim
> protocol over the network.  It also allows the host, and two ports to
> be specified on the qemu command line.  The benefits are twofold:
> firstly it gives us a backend that actually speaks a standard TPM
> emulation protocol instead of the linux specific TPM driver format of
> the current emulated TPM backend and secondly, using the microsoft
> protocol, the end point of the emulator can be anywhere on the
> network, facilitating the cloud use case where a central TPM service
> can be used over a control network.
> 
> The implementation does basic control commands like power off/on, but
> doesn't implement cancellation or startup.  The former because
> cancellation is pretty much useless on a fast operating TPM emulator
> and the latter because this emulator is designed to be used with OVMF
> which itself does TPM startup and I wanted to validate that.
> 
> To run this, simply download an emulator based on the MS specification
> (package ibmswtpm2 on openSUSE) and run it, then add these two lines
> to the qemu command and it will use the emulator.
> 
>      -tpmdev mssim,id=tpm0 \
>      -device tpm-crb,tpmdev=tpm0 \
> 
> to use a remote emulator replace the first line with
> 
>      -tpmdev "{'type':'mssim','id':'tpm0','command':{'type':inet,'host':'remote','port':'2321'}}"
> 
> tpm-tis also works as the backend.

Since this device does not properly support migration you have to register a migration blocker.

    Stefan