mirror of
https://github.com/xen-project/xen.git
synced 2026-10-28 02:01:24 +01:00
Daniel De Graaf
f494d9f3c3
This changes the vTPM shared page ABI from a copy of the Xen network interface to a single-page interface that better reflects the expected behavior of a TPM: only a single request packet can be sent at any given time, and every packet sent generates a single response packet. This protocol change should also increase efficiency as it avoids mapping and unmapping grants when possible. The vtpm xenbus device now requires a feature-protocol-v2 node in xenstore to avoid conflicts with existing (xen-patched) kernels supporting the old interface. While the contents of the shared page have been defined to allow packets larger than a single page (actually 4088 bytes) by allowing the client to add extra grant references, the mapping of these extra references has not been implemented; a feature node in xenstore may be used in the future to indicate full support for the multi-page protocol. Most uses of the TPM should not require this feature. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Cc: Jan Beulich <JBeulich@suse.com>