Re: [PATCH v5.1 01/12] mini-os/tpm{back, front}: Change shared page ABI

[Daniel De Graaf <dgdegra@tycho.nsa.gov>]

On 04/11/2013 10:00 AM, Ian Campbell wrote:
> Is this in the wrong thread and should be in "[PATCH v5 00/12] vTPM
> updates for 4.3" as an update to
> <1363896689-11086-2-git-send-email-dgdegra@tycho.nsa.gov> ?
>

Yes, this is an update to that patch and should have also been sent in
reply to that thread.

> On Fri, 2013-03-22 at 22:30 +0000, Daniel De Graaf wrote:
>> 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>
>>
>> ---
>>
>> Changes from v5: handle xenbus states properly, and keep the old header
>> contents intact.
>>
>> Changes from v4: use feature-protocol-v2 nodes instead of changing the
>> device name; add command cancellation support to the protocol.
>>