qemu: use upstream swtpm support

Upstream finally accepted and merged a different approach for
connecting QEMU to swtpm: instead of a custom cuse-tpm device, a
normal chardev connects to swtpm, and that chardev then is used by the
TPM device. For now we have to backport those patches, but the next
major QEMU update will have them.

However, the chardev-connect-socket-to-a-spawned-command.patch is
something that OE will have to carry permanently. It simplifies
starting and stopping swtpm when invoking QEMU through runqemu without
having to teach that script about the additional process. Upstream
rejected the patch because they want to keep the complexity of
starting additional processes out of QEMU.

A recent enough swtpm is needed. The one currently used by
meta-security fails to communicate properly with QEMU, leading to this
failure:

  qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm0: tpm-emulator: Failed to send CMD_SET_DATAFD: Input/output error
  qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm0: tpm-emulator: Could not cleanly shutdown the TPM: Invalid argument

With a recent enough swtpm, one can create a TPM device like this:

  - bitbake swtpm-native
  - create a TPM instance and initialize it with:

       $ mkdir -p my-machine/myvtpm0
       $ tmp*/work/*/swtpm-wrappers-native/*/swtpm_setup_oe.sh --tpm-state my-machine/myvtpm0 --createek
       Starting vTPM manufacturing as root:root @ Wed 06 Dec 2017 10:03:14 AM CET
       TPM is listening on TCP port 34613.
       Successfully created EK.
       Successfully authored TPM state.
       Ending vTPM manufacturing @ Wed 06 Dec 2017 10:03:14 AM CET

  - runqemu "qemuparams=-chardev 'socket,id=chrtpm0,cmd=exec
    swtpm_oe.sh socket --terminate --ctrl type=unixio,,clientfd=0
    --tpmstate dir=... --log level=10,,file=.../swtpm.log --tpm2'
    -tpmdev emulator,id=tpm0,chardev=chrtpm0 -device
    tpm-tis,tpmdev=tpm0" ...

Beware that the double commas are intentional. They are needed to
embed commas in the "cmd" value.

swtpm_oe.sh is from swtpm-wrappers-native. In the example it is
invoked without the full path for the sake of brevity. In practice,
one has to use the full
path (tmp*/work/*/swtpm-wrappers-native/*/swtpm_oe.sh).

With the TPM2-preview version of swtpm, the same works for TPM2 by
adding the --tpm2 parameter when invoking swtpm_setup_oe.sh and
swtpm_oe.sh.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 75 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu/0003-tpm-backend-Remove-unneeded-member-variable-from-bac.patch b/meta/recipes-devtools/qemu/qemu/0003-tpm-backend-Remove-unneeded-member-variable-from-bac.patch
new file mode 100644
index 0000000000..6b94eba720
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0003-tpm-backend-Remove-unneeded-member-variable-from-bac.patch
@@ -0,0 +1,75 @@
+From cac845f55b8f27e5c90e0f2e3dcbeea7013df67c Mon Sep 17 00:00:00 2001
+From: Amarnath Valluri <amarnath.valluri@intel.com>
+Date: Thu, 30 Mar 2017 15:55:17 +0300
+Subject: [PATCH 03/12] tpm-backend: Remove unneeded member variable from
+ backend class
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+TPMDriverOps inside TPMBackend is not required, as it is supposed to be a class
+member. The only possible reason for keeping in TPMBackend was, to get the
+backend type in tpm.c where dedicated backend api, tpm_backend_get_type() is
+present.
+
+Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com>
+Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
+
+Upstream-Status: Backport [fb4b0c6765471dad2363875989e7661ca5f9a608]
+---
+ hw/tpm/tpm_passthrough.c     | 4 ----
+ include/sysemu/tpm_backend.h | 1 -
+ tpm.c                        | 2 +-
+ 3 files changed, 1 insertion(+), 6 deletions(-)
+
+diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
+index 9234eb3459..a0baf5f080 100644
+--- a/hw/tpm/tpm_passthrough.c
++++ b/hw/tpm/tpm_passthrough.c
+@@ -46,8 +46,6 @@
+ #define TPM_PASSTHROUGH(obj) \
+     OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
+ 
+-static const TPMDriverOps tpm_passthrough_driver;
+-
+ /* data structures */
+ typedef struct TPMPassthruThreadParams {
+     TPMState *tpm_state;
+@@ -462,8 +460,6 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
+     /* let frontend set the fe_model to proper value */
+     tb->fe_model = -1;
+ 
+-    tb->ops = &tpm_passthrough_driver;
+-
+     if (tpm_passthrough_handle_device_opts(opts, tb)) {
+         goto err_exit;
+     }
+diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
+index b0a9731aee..3708413035 100644
+--- a/include/sysemu/tpm_backend.h
++++ b/include/sysemu/tpm_backend.h
+@@ -50,7 +50,6 @@ struct TPMBackend {
+     enum TpmModel fe_model;
+     char *path;
+     char *cancel_path;
+-    const TPMDriverOps *ops;
+ 
+     QLIST_ENTRY(TPMBackend) list;
+ };
+diff --git a/tpm.c b/tpm.c
+index 2dbea70645..b7166ca200 100644
+--- a/tpm.c
++++ b/tpm.c
+@@ -212,7 +212,7 @@ static TPMInfo *qmp_query_tpm_inst(TPMBackend *drv)
+     res->model = drv->fe_model;
+     res->options = g_new0(TpmTypeOptions, 1);
+ 
+-    switch (drv->ops->type) {
++    switch (tpm_backend_get_type(drv)) {
+     case TPM_TYPE_PASSTHROUGH:
+         res->options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
+         tpo = g_new0(TPMPassthroughOptions, 1);
+-- 
+2.11.0
+