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, 185 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu/0005-tpm-backend-Initialize-and-free-data-members-in-it-s.patch b/meta/recipes-devtools/qemu/qemu/0005-tpm-backend-Initialize-and-free-data-members-in-it-s.patch
new file mode 100644
index 0000000000..91dd542f45
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0005-tpm-backend-Initialize-and-free-data-members-in-it-s.patch
@@ -0,0 +1,185 @@
+From 83ef052c60de271a97abb7eb9b5a8aeee52659e6 Mon Sep 17 00:00:00 2001
+From: Amarnath Valluri <amarnath.valluri@intel.com>
+Date: Fri, 31 Mar 2017 10:58:11 +0300
+Subject: [PATCH 05/12] tpm-backend: Initialize and free data members in it's
+ own methods
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Initialize and free TPMBackend data members in it's own instance_init() and
+instance_finalize methods.
+
+Took the opportunity to remove unneeded destroy() method from TpmDriverOps
+interface as TPMBackend is a Qemu Object, we can use object_unref() inplace of
+tpm_backend_destroy() to free the backend object, hence removed destroy() from
+TPMDriverOps interface.
+
+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 [f35fe5cb97bbdaa6a6967f2fefc3fc1f79680601]
+---
+ backends/tpm.c               | 16 ++++++----------
+ hw/tpm/tpm_passthrough.c     | 31 ++++++++++++-------------------
+ include/sysemu/tpm_backend.h |  7 -------
+ tpm.c                        |  2 +-
+ 4 files changed, 19 insertions(+), 37 deletions(-)
+
+diff --git a/backends/tpm.c b/backends/tpm.c
+index ce56c3b74d..cf5abf1582 100644
+--- a/backends/tpm.c
++++ b/backends/tpm.c
+@@ -51,15 +51,6 @@ const char *tpm_backend_get_desc(TPMBackend *s)
+     return k->ops->desc();
+ }
+ 
+-void tpm_backend_destroy(TPMBackend *s)
+-{
+-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+-
+-    k->ops->destroy(s);
+-
+-    tpm_backend_thread_end(s);
+-}
+-
+ int tpm_backend_init(TPMBackend *s, TPMState *state,
+                      TPMRecvDataCB *datacb)
+ {
+@@ -182,17 +173,22 @@ static void tpm_backend_prop_set_opened(Object *obj, bool value, Error **errp)
+ 
+ static void tpm_backend_instance_init(Object *obj)
+ {
++    TPMBackend *s = TPM_BACKEND(obj);
++
+     object_property_add_bool(obj, "opened",
+                              tpm_backend_prop_get_opened,
+                              tpm_backend_prop_set_opened,
+                              NULL);
+-
++    s->fe_model = -1;
+ }
+ 
+ static void tpm_backend_instance_finalize(Object *obj)
+ {
+     TPMBackend *s = TPM_BACKEND(obj);
+ 
++    g_free(s->id);
++    g_free(s->path);
++    g_free(s->cancel_path);
+     tpm_backend_thread_end(s);
+ }
+ 
+diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
+index f50d9cffd7..815a72ef9a 100644
+--- a/hw/tpm/tpm_passthrough.c
++++ b/hw/tpm/tpm_passthrough.c
+@@ -417,8 +417,6 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
+     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+ 
+     tb->id = g_strdup(id);
+-    /* let frontend set the fe_model to proper value */
+-    tb->fe_model = -1;
+ 
+     if (tpm_passthrough_handle_device_opts(opts, tb)) {
+         goto err_exit;
+@@ -432,26 +430,11 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
+     return tb;
+ 
+ err_exit:
+-    g_free(tb->id);
++    object_unref(obj);
+ 
+     return NULL;
+ }
+ 
+-static void tpm_passthrough_destroy(TPMBackend *tb)
+-{
+-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+-
+-    tpm_passthrough_cancel_cmd(tb);
+-
+-    qemu_close(tpm_pt->tpm_fd);
+-    qemu_close(tpm_pt->cancel_fd);
+-
+-    g_free(tb->id);
+-    g_free(tb->path);
+-    g_free(tb->cancel_path);
+-    g_free(tpm_pt->tpm_dev);
+-}
+-
+ static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
+     TPM_STANDARD_CMDLINE_OPTS,
+     {
+@@ -472,7 +455,6 @@ static const TPMDriverOps tpm_passthrough_driver = {
+     .opts                     = tpm_passthrough_cmdline_opts,
+     .desc                     = tpm_passthrough_create_desc,
+     .create                   = tpm_passthrough_create,
+-    .destroy                  = tpm_passthrough_destroy,
+     .init                     = tpm_passthrough_init,
+     .startup_tpm              = tpm_passthrough_startup_tpm,
+     .realloc_buffer           = tpm_passthrough_realloc_buffer,
+@@ -486,10 +468,21 @@ static const TPMDriverOps tpm_passthrough_driver = {
+ 
+ static void tpm_passthrough_inst_init(Object *obj)
+ {
++    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
++
++    tpm_pt->tpm_fd = -1;
++    tpm_pt->cancel_fd = -1;
+ }
+ 
+ static void tpm_passthrough_inst_finalize(Object *obj)
+ {
++    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
++
++    tpm_passthrough_cancel_cmd(TPM_BACKEND(obj));
++
++    qemu_close(tpm_pt->tpm_fd);
++    qemu_close(tpm_pt->cancel_fd);
++    g_free(tpm_pt->tpm_dev);
+ }
+ 
+ static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
+diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
+index 58308b3687..202ec8d5a2 100644
+--- a/include/sysemu/tpm_backend.h
++++ b/include/sysemu/tpm_backend.h
+@@ -78,7 +78,6 @@ struct TPMDriverOps {
+     const char *(*desc)(void);
+ 
+     TPMBackend *(*create)(QemuOpts *opts, const char *id);
+-    void (*destroy)(TPMBackend *t);
+ 
+     /* initialize the backend */
+     int (*init)(TPMBackend *t);
+@@ -118,12 +117,6 @@ enum TpmType tpm_backend_get_type(TPMBackend *s);
+ const char *tpm_backend_get_desc(TPMBackend *s);
+ 
+ /**
+- * tpm_backend_destroy:
+- * @s: the backend to destroy
+- */
+-void tpm_backend_destroy(TPMBackend *s);
+-
+-/**
+  * tpm_backend_init:
+  * @s: the backend to initialized
+  * @state: TPMState
+diff --git a/tpm.c b/tpm.c
+index b7166ca200..7feb3b43c9 100644
+--- a/tpm.c
++++ b/tpm.c
+@@ -158,7 +158,7 @@ void tpm_cleanup(void)
+ 
+     QLIST_FOREACH_SAFE(drv, &tpm_backends, list, next) {
+         QLIST_REMOVE(drv, list);
+-        tpm_backend_destroy(drv);
++        object_unref(OBJECT(drv));
+     }
+ }
+ 
+-- 
+2.11.0
+