Re: [Qemu-devel] [PATCH 0/5] tpm: Match frontend and backend buffer sizes (not 2.11)

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

On Mon, Nov 06, 2017 at 07:58:51PM -0500, Stefan Berger wrote:
> This patch series does away with the hard coded buffer size in the TIS
> frontend and instead retrieves the buffer size from the device that's
> being used. So it gets it from the host device or the external emulator.
> In case the frontend (CRB) cannot support the backend's current buffer size
> (typically 4k) it can adjust the buffer size the emulator is working with
> so that we will not run into the problem that the backend produces packets
> that the frontend cannot deliver to due mismatching buffer sizes.
> 

The approach looks ok to me. I don't have enough TPM/backend knowledge
to say how relevant that is in the long run. Modifying the CRB device
to set the buffer size to qemu CRB_CTRL_CMD_SIZE works. Windows 10 seems
happy at least.

Just a few remarks, I suppose you'll send a v2 soon,

thanks

>    Stefan
> 
> Stefan Berger (5):
>   tpm: Move getting TPM buffer size to backends
>   tpm: pull tpm_util_send() out of tpm_util_test()
>   tpm: tpm_passthrough: Read the buffer size from the host device
>   tpm: tpm_emulator: get and set buffer size of device
>   tpm: tpm_passthrough: Fail startup if FE buffer size < BE buffer size
> 
>  backends/tpm.c               |  13 +++-
>  hw/tpm/tpm_emulator.c        |  83 +++++++++++++++++++++++-
>  hw/tpm/tpm_int.h             |   9 +++
>  hw/tpm/tpm_ioctl.h           |  28 +++++++-
>  hw/tpm/tpm_passthrough.c     |  30 +++++++++
>  hw/tpm/tpm_tis.c             |  18 +++---
>  hw/tpm/tpm_util.c            | 149 +++++++++++++++++++++++++++++++++++++++++--
>  hw/tpm/tpm_util.h            |   3 +
>  include/sysemu/tpm_backend.h |  17 ++++-
>  9 files changed, 327 insertions(+), 23 deletions(-)
> 
> -- 
> 2.5.5
> 
>