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Re: [Qemu-devel] [PATCH V8 07/14] Implementation of the libtpms-based ba
Michael S. Tsirkin
Re: [Qemu-devel] [PATCH V8 07/14] Implementation of the libtpms-based backend
Thu, 1 Sep 2011 20:27:27 +0300
On Wed, Aug 31, 2011 at 10:35:58AM -0400, Stefan Berger wrote:
> This patch provides the glue for the TPM TIS interface (frontend) to
> the libtpms that provides the actual TPM functionality.
> Some details:
> This part of the patch provides support for the spawning of a thread
> that will interact with the libtpms-based TPM. It expects a signal
> from the frontend to wake and pick up the TPM command that is supposed
> to be processed and delivers the response packet using a callback
> function provided by the frontend.
> The backend connects itself to the frontend by filling out an interface
> structure with pointers to the function implementing support for various
> In this part a structure with callback functions is registered with
> libtpms. Those callback functions are invoked by libtpms for example to
> store the TPM's state.
> The libtpms-based backend implements functionality to write into a
> Qemu block storage device rather than to plain files. With that we
> can support VM snapshotting and we also get the possibility to use
> encrypted QCoW2 for free. Thanks to Anthony for pointing this out.
> The storage part of the driver has been split off into its own patch.
> - cache a copy of the last permanent state blob
> - move some functions into tpm_builtin.h
> - reworked parts of the error path handling where the TPM is
> now used to process commands under error conditions and the callbacks
> make the TPM aware of the error conditions. Only as the last resort
> fault messages are sent by the backend driver circumventing the TPM.
> - add out_len variable used in the thread
> - check access() to TPM's state file and report error if file is not
> - temporarily deactivate the building of the tpm_builtin.c until
> subsequent patch completely converts it to the libtpms based driver
> - fixes to adhere to the qemu coding style
> Signed-off-by: Stefan Berger <address@hidden>
> configure | 1
> hw/tpm_builtin.c | 450
> hw/tpm_builtin.h | 56 ++++++
> 3 files changed, 482 insertions(+), 25 deletions(-)
> Index: qemu-git/hw/tpm_builtin.c
> --- qemu-git.orig/hw/tpm_builtin.c
> +++ qemu-git/hw/tpm_builtin.c
> @@ -1,5 +1,5 @@
> - * builtin 'null' TPM driver
> + * builtin TPM driver based on libtpms
Just wondering - might a stub driver be useful for
basic testing on systems without TPM hardware?
The namespace comment applies to this and all other patches.
- Re: [Qemu-devel] [PATCH V8 07/14] Implementation of the libtpms-based backend,
Michael S. Tsirkin <=