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>
---
 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

On 5/4/21 8:48 AM, Jason Andryuk 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>
> ---

Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.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
> 

On 04/05/2021 13:48, Jason Andryuk 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>

This is definitely the kind of health warning needed for people playing
this area.