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

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@xxxxxxxxxxxxx> ?

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@xxxxxxxxxxxxx>
Cc: Jan Beulich <JBeulich@xxxxxxxx>


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.

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