On May 6, 2021, at 10:00, Jason Andryuk <jandryuk@gmail.com> wrote:
> The vtpmmgr TPM 2.0 support is incomplete.  Add a warning about that to
> the documentation so others don't have to work through discovering it is
> broken.
> 
> Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> docs/man/xen-vtpmmgr.7.pod | 11 +++++++++++
> 1 file changed, 11 insertions(+)
> 
> diff --git a/docs/man/xen-vtpmmgr.7.pod b/docs/man/xen-vtpmmgr.7.pod
> index af825a7ffe..875dcce508 100644
> --- a/docs/man/xen-vtpmmgr.7.pod
> +++ b/docs/man/xen-vtpmmgr.7.pod
> @@ -222,6 +222,17 @@ XSM label, not the kernel.
> 
> =head1 Appendix B: vtpmmgr on TPM 2.0
> 
> +=head2 WARNING: Incomplete - cannot persist data
> +
> +TPM 2.0 support for vTPM manager is incomplete.  There is no support for
> +persisting an encryption key, so vTPM manager regenerates primary and secondary
> +key handles each boot.
> +
> +Also, the vTPM manger group command implementation hardcodes TPM 1.2 commands.
> +This means running manage-vtpmmgr.pl fails when the TPM 2.0 hardware rejects
> +the TPM 1.2 commands.  vTPM manager with TPM 2.0 cannot create groups and
> +therefore cannot persist vTPM contents.
> +
> =head2 Manager disk image setup:
> 
> The vTPM Manager requires a disk image to store its encrypted data. The image
> -- 
> 2.30.2

Should SUPPORT.md also be updated?

https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=SUPPORT.md;hb=refs/heads/master

Rich