Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2017-10-04-3' into staging

Merge tpm 2017/10/04 v3

# gpg: Signature made Fri 13 Oct 2017 12:37:07 BST
# gpg:                using RSA key 0x75AD65802A0B4211
# gpg: Good signature from "Stefan Berger <stefanb@linux.vnet.ibm.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: B818 B9CA DF90 89C2 D5CE  C66B 75AD 6580 2A0B 4211

* remotes/stefanberger/tags/pull-tpm-2017-10-04-3:
  specs: Describe the TPM support in QEMU
  tpm: Move tpm_cleanup() to right place
  tpm: Added support for TPM emulator
  tpm-passthrough: move reusable code to utils
  tpm-backend: Move realloc_buffer() implementation to tpm-tis model
  tpm-backend: Add new API to read backend TpmInfo
  tpm-backend: Made few interface methods optional
  tpm-backend: Initialize and free data members in it's own methods
  tpm-backend: Move thread handling inside TPMBackend
  tpm-backend: Remove unneeded member variable from backend class
  tpm: Use EMSGSIZE instead of EBADMSG to compile on OpenBSD

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

17 files changed, 1216 insertions, 371 deletions

diff --git a/backends/tpm.c b/backends/tpm.c
index 536f262bb7..37c84b7c66 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -18,27 +18,30 @@
 #include "qapi/qmp/qerror.h"
 #include "sysemu/tpm.h"
 #include "qemu/thread.h"
-#include "sysemu/tpm_backend_int.h"
 
-enum TpmType tpm_backend_get_type(TPMBackend *s)
+static void tpm_backend_worker_thread(gpointer data, gpointer user_data)
 {
-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+    TPMBackend *s = TPM_BACKEND(user_data);
+    TPMBackendClass *k  = TPM_BACKEND_GET_CLASS(s);
 
-    return k->ops->type;
+    assert(k->handle_request != NULL);
+    k->handle_request(s, (TPMBackendCmd)data);
 }
 
-const char *tpm_backend_get_desc(TPMBackend *s)
+static void tpm_backend_thread_end(TPMBackend *s)
 {
-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
-
-    return k->ops->desc();
+    if (s->thread_pool) {
+        g_thread_pool_push(s->thread_pool, (gpointer)TPM_BACKEND_CMD_END, NULL);
+        g_thread_pool_free(s->thread_pool, FALSE, TRUE);
+        s->thread_pool = NULL;
+    }
 }
 
-void tpm_backend_destroy(TPMBackend *s)
+enum TpmType tpm_backend_get_type(TPMBackend *s)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    k->ops->destroy(s);
+    return k->ops->type;
 }
 
 int tpm_backend_init(TPMBackend *s, TPMState *state,
@@ -46,48 +49,62 @@ int tpm_backend_init(TPMBackend *s, TPMState *state,
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    return k->ops->init(s, state, datacb);
+    s->tpm_state = state;
+    s->recv_data_callback = datacb;
+    s->had_startup_error = false;
+
+    return k->ops->init ? k->ops->init(s) : 0;
 }
 
 int tpm_backend_startup_tpm(TPMBackend *s)
 {
+    int res = 0;
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    return k->ops->startup_tpm(s);
-}
+    /* terminate a running TPM */
+    tpm_backend_thread_end(s);
 
-bool tpm_backend_had_startup_error(TPMBackend *s)
-{
-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+    s->thread_pool = g_thread_pool_new(tpm_backend_worker_thread, s, 1, TRUE,
+                                       NULL);
+    g_thread_pool_push(s->thread_pool, (gpointer)TPM_BACKEND_CMD_INIT, NULL);
+
+    res = k->ops->startup_tpm ? k->ops->startup_tpm(s) : 0;
 
-    return k->ops->had_startup_error(s);
+    s->had_startup_error = (res != 0);
+
+    return res;
 }
 
-size_t tpm_backend_realloc_buffer(TPMBackend *s, TPMSizedBuffer *sb)
+bool tpm_backend_had_startup_error(TPMBackend *s)
 {
-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
-
-    return k->ops->realloc_buffer(sb);
+    return s->had_startup_error;
 }
 
 void tpm_backend_deliver_request(TPMBackend *s)
 {
-    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
-
-    k->ops->deliver_request(s);
+    g_thread_pool_push(s->thread_pool, (gpointer)TPM_BACKEND_CMD_PROCESS_CMD,
+                       NULL);
 }
 
 void tpm_backend_reset(TPMBackend *s)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    k->ops->reset(s);
+    if (k->ops->reset) {
+        k->ops->reset(s);
+    }
+
+    tpm_backend_thread_end(s);
+
+    s->had_startup_error = false;
 }
 
 void tpm_backend_cancel_cmd(TPMBackend *s)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
+    assert(k->ops->cancel_cmd);
+
     k->ops->cancel_cmd(s);
 }
 
@@ -95,23 +112,40 @@ bool tpm_backend_get_tpm_established_flag(TPMBackend *s)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    return k->ops->get_tpm_established_flag(s);
+    return k->ops->get_tpm_established_flag ?
+           k->ops->get_tpm_established_flag(s) : false;
 }
 
 int tpm_backend_reset_tpm_established_flag(TPMBackend *s, uint8_t locty)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
-    return k->ops->reset_tpm_established_flag(s, locty);
+    return k->ops->reset_tpm_established_flag ?
+           k->ops->reset_tpm_established_flag(s, locty) : 0;
 }
 
 TPMVersion tpm_backend_get_tpm_version(TPMBackend *s)
 {
     TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
 
+    assert(k->ops->get_tpm_version);
+
     return k->ops->get_tpm_version(s);
 }
 
+TPMInfo *tpm_backend_query_tpm(TPMBackend *s)
+{
+    TPMInfo *info = g_new0(TPMInfo, 1);
+    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
+
+    info->id = g_strdup(s->id);
+    info->model = s->fe_model;
+    info->options = k->ops->get_tpm_options ?
+                    k->ops->get_tpm_options(s) : NULL;
+
+    return info;
+}
+
 static bool tpm_backend_prop_get_opened(Object *obj, Error **errp)
 {
     TPMBackend *s = TPM_BACKEND(obj);
@@ -152,33 +186,21 @@ 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;
 }
 
-void tpm_backend_thread_deliver_request(TPMBackendThread *tbt)
-{
-   g_thread_pool_push(tbt->pool, (gpointer)TPM_BACKEND_CMD_PROCESS_CMD, NULL);
-}
-
-void tpm_backend_thread_create(TPMBackendThread *tbt,
-                               GFunc func, gpointer user_data)
+static void tpm_backend_instance_finalize(Object *obj)
 {
-    if (!tbt->pool) {
-        tbt->pool = g_thread_pool_new(func, user_data, 1, TRUE, NULL);
-        g_thread_pool_push(tbt->pool, (gpointer)TPM_BACKEND_CMD_INIT, NULL);
-    }
-}
+    TPMBackend *s = TPM_BACKEND(obj);
 
-void tpm_backend_thread_end(TPMBackendThread *tbt)
-{
-    if (tbt->pool) {
-        g_thread_pool_push(tbt->pool, (gpointer)TPM_BACKEND_CMD_END, NULL);
-        g_thread_pool_free(tbt->pool, FALSE, TRUE);
-        tbt->pool = NULL;
-    }
+    g_free(s->id);
+    tpm_backend_thread_end(s);
 }
 
 static const TypeInfo tpm_backend_info = {
@@ -186,6 +208,7 @@ static const TypeInfo tpm_backend_info = {
     .parent = TYPE_OBJECT,
     .instance_size = sizeof(TPMBackend),
     .instance_init = tpm_backend_instance_init,
+    .instance_finalize = tpm_backend_instance_finalize,
     .class_size = sizeof(TPMBackendClass),
     .abstract = true,
 };
diff --git a/configure b/configure
index 6587e8014b..3c733f1a53 100755
--- a/configure
+++ b/configure
@@ -3495,6 +3495,12 @@ else
   tpm_passthrough=no
 fi
 
+# TPM emulator is for all posix systems
+if test "$mingw32" != "yes"; then
+  tpm_emulator=$tpm
+else
+  tpm_emulator=no
+fi
 ##########################################
 # attr probe
 
@@ -5412,6 +5418,7 @@ echo "gcov enabled      $gcov"
 echo "TPM support       $tpm"
 echo "libssh2 support   $libssh2"
 echo "TPM passthrough   $tpm_passthrough"
+echo "TPM emulator      $tpm_emulator"
 echo "QOM debugging     $qom_cast_debug"
 echo "Live block migration $live_block_migration"
 echo "lzo support       $lzo"
@@ -6011,12 +6018,16 @@ if test "$live_block_migration" = "yes" ; then
   echo "CONFIG_LIVE_BLOCK_MIGRATION=y" >> $config_host_mak
 fi
 
-# TPM passthrough support?
 if test "$tpm" = "yes"; then
   echo 'CONFIG_TPM=$(CONFIG_SOFTMMU)' >> $config_host_mak
+  # TPM passthrough support?
   if test "$tpm_passthrough" = "yes"; then
     echo "CONFIG_TPM_PASSTHROUGH=y" >> $config_host_mak
   fi
+  # TPM emulator support?
+  if test "$tpm_emulator" = "yes"; then
+    echo "CONFIG_TPM_EMULATOR=y" >> $config_host_mak
+  fi
 fi
 
 echo "TRACE_BACKENDS=$trace_backends" >> $config_host_mak
diff --git a/docs/specs/tpm.txt b/docs/specs/tpm.txt
new file mode 100644
index 0000000000..914daaceea
--- /dev/null
+++ b/docs/specs/tpm.txt
@@ -0,0 +1,123 @@
+QEMU TPM Device
+===============
+
+= Guest-side Hardware Interface =
+
+The QEMU TPM emulation implements a TPM TIS hardware interface following the
+Trusted Computing Group's specification "TCG PC Client Specific TPM Interface
+Specification (TIS)", Specification Version 1.3, 21 March 2013. This
+specification, or a later version of it, can be accessed from the following
+URL:
+
+https://trustedcomputinggroup.org/pc-client-work-group-pc-client-specific-tpm-interface-specification-tis/
+
+The TIS interface makes a memory mapped IO region in the area 0xfed40000 -
+0xfed44fff available to the guest operating system.
+
+
+QEMU files related to TPM TIS interface:
+ - hw/tpm/tpm_tis.c
+ - hw/tpm/tpm_tis.h
+
+
+= ACPI Interface =
+
+The TPM device is defined with ACPI ID "PNP0C31". QEMU builds a SSDT and passes
+it into the guest through the fw_cfg device. The device description contains
+the base address of the TIS interface 0xfed40000 and the size of the MMIO area
+(0x5000). In case a TPM2 is used by QEMU, a TPM2 ACPI table is also provided.
+The device is described to be used in polling mode rather than interrupt mode
+primarily because no unused IRQ could be found.
+
+To support measurement logs to be written by the firmware, e.g. SeaBIOS, a TCPA
+table is implemented. This table provides a 64kb buffer where the firmware can
+write its log into. For TPM 2 only a more recent version of the TPM2 table
+provides support for measurements logs and a TCPA table does not need to be
+created.
+
+The TCPA and TPM2 ACPI tables follow the Trusted Computing Group specification
+"TCG ACPI Specification" Family "1.2" and "2.0", Level 00 Revision 00.37. This
+specification, or a later version of it, can be accessed from the following
+URL:
+
+https://trustedcomputinggroup.org/tcg-acpi-specification/
+
+
+QEMU files related to TPM ACPI tables:
+ - hw/i386/acpi-build.c
+ - include/hw/acpi/tpm.h
+
+
+= TPM backend devices =
+
+The TPM implementation is split into two parts, frontend and backend. The
+frontend part is the hardware interface, such as the TPM TIS interface
+described earlier, and the other part is the TPM backend interface. The backend
+interfaces implement the interaction with a TPM device, which may be a physical
+or an emulated device. The split between the front- and backend devices allows
+a frontend to be connected with any available backend. This enables the TIS
+interface to be used with the passthrough backend or the (future) swtpm backend.
+
+
+QEMU files related to TPM backends:
+ - backends/tpm.c
+ - include/sysemu/tpm_backend.h
+ - include/sysemu/tpm_backend_int.h
+
+
+== The QEMU TPM passthrough device ==
+
+In case QEMU is run on Linux as the host operating system it is possible to
+make the hardware TPM device available to a single QEMU guest. In this case the
+user must make sure that no other program is using the device, e.g., /dev/tpm0,
+before trying to start QEMU with it.
+
+The passthrough driver uses the host's TPM device for sending TPM commands
+and receiving responses from. Besides that it accesses the TPM device's sysfs
+entry for support of command cancellation. Since none of the state of a
+hardware TPM can be migrated between hosts, virtual machine migration is
+disabled when the TPM passthrough driver is used.
+
+Since the host's TPM device will already be initialized by the host's firmware,
+certain commands, e.g. TPM_Startup(), sent by the virtual firmware for device
+initialization, will fail. In this case the firmware should not use the TPM.
+
+Sharing the device with the host is generally not a recommended usage scenario
+for a TPM device. The primary reason for this is that two operating systems can
+then access the device's single set of resources, such as platform configuration
+registers (PCRs). Applications or kernel security subsystems, such as the
+Linux Integrity Measurement Architecture (IMA), are not expecting to share PCRs.
+
+
+QEMU files related to the TPM passthrough device:
+ - hw/tpm/tpm_passthrough.c
+ - hw/tpm/tpm_util.c
+ - hw/tpm/tpm_util.h
+
+
+Command line to start QEMU with the TPM passthrough device using the host's
+hardware TPM /dev/tpm0:
+
+qemu-system-x86_64 -display sdl -enable-kvm \
+  -m 1024 -boot d -bios bios-256k.bin -boot menu=on \
+  -tpmdev passthrough,id=tpm0,path=/dev/tpm0 \
+  -device tpm-tis,tpmdev=tpm0 test.img
+
+The following commands should result in similar output inside the VM with a
+Linux kernel that either has the TPM TIS driver built-in or available as a
+module:
+
+#> dmesg | grep -i tpm
+[    0.711310] tpm_tis 00:06: 1.2 TPM (device=id 0x1, rev-id 1)
+
+#> dmesg | grep TCPA
+[    0.000000] ACPI: TCPA 0x0000000003FFD191C 000032 (v02 BOCHS  \
+    BXPCTCPA 0000001 BXPC 00000001)
+
+#> ls -l /dev/tpm*
+crw-------. 1 root root 10, 224 Jul 11 10:11 /dev/tpm0
+
+#> find /sys/devices/ | grep pcrs$ | xargs cat
+PCR-00: 35 4E 3B CE 23 9F 38 59 ...
+...
+PCR-23: 00 00 00 00 00 00 00 00 ...
diff --git a/hmp.c b/hmp.c
index 739d330f4e..ec61329ebb 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1000,6 +1000,7 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
     Error *err = NULL;
     unsigned int c = 0;
     TPMPassthroughOptions *tpo;
+    TPMEmulatorOptions *teo;
 
     info_list = qmp_query_tpm(&err);
     if (err) {
@@ -1029,6 +1030,10 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
                            tpo->has_cancel_path ? ",cancel-path=" : "",
                            tpo->has_cancel_path ? tpo->cancel_path : "");
             break;
+        case TPM_TYPE_OPTIONS_KIND_EMULATOR:
+            teo = ti->options->u.emulator.data;
+            monitor_printf(mon, ",chardev=%s", teo->chardev);
+            break;
         case TPM_TYPE_OPTIONS_KIND__MAX:
             break;
         }
diff --git a/hw/tpm/Makefile.objs b/hw/tpm/Makefile.objs
index 64cecc3b67..41f0b7a590 100644
--- a/hw/tpm/Makefile.objs
+++ b/hw/tpm/Makefile.objs
@@ -1,2 +1,3 @@
 common-obj-$(CONFIG_TPM_TIS) += tpm_tis.o
 common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o tpm_util.o
+common-obj-$(CONFIG_TPM_EMULATOR) += tpm_emulator.o tpm_util.o
diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
new file mode 100644
index 0000000000..95e1e041cf
--- /dev/null
+++ b/hw/tpm/tpm_emulator.c
@@ -0,0 +1,587 @@
+/*
+ *  Emulator TPM driver
+ *
+ *  Copyright (c) 2017 Intel Corporation
+ *  Author: Amarnath Valluri <amarnath.valluri@intel.com>
+ *
+ *  Copyright (c) 2010 - 2013 IBM Corporation
+ *  Authors:
+ *    Stefan Berger <stefanb@us.ibm.com>
+ *
+ *  Copyright (C) 2011 IAIK, Graz University of Technology
+ *    Author: Andreas Niederl
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "qemu/sockets.h"
+#include "io/channel-socket.h"
+#include "sysemu/tpm_backend.h"
+#include "tpm_int.h"
+#include "hw/hw.h"
+#include "hw/i386/pc.h"
+#include "tpm_util.h"
+#include "tpm_ioctl.h"
+#include "migration/blocker.h"
+#include "qapi/error.h"
+#include "qapi/clone-visitor.h"
+#include "chardev/char-fe.h"
+
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+
+#define DEBUG_TPM 0
+
+#define DPRINTF(fmt, ...) do { \
+    if (DEBUG_TPM) { \
+        fprintf(stderr, "tpm-emulator:"fmt"\n", ## __VA_ARGS__); \
+    } \
+} while (0)
+
+#define TYPE_TPM_EMULATOR "tpm-emulator"
+#define TPM_EMULATOR(obj) \
+    OBJECT_CHECK(TPMEmulator, (obj), TYPE_TPM_EMULATOR)
+
+#define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
+
+static const TPMDriverOps tpm_emulator_driver;
+
+/* data structures */
+typedef struct TPMEmulator {
+    TPMBackend parent;
+
+    TPMEmulatorOptions *options;
+    CharBackend ctrl_chr;
+    QIOChannel *data_ioc;
+    TPMVersion tpm_version;
+    ptm_cap caps; /* capabilities of the TPM */
+    uint8_t cur_locty_number; /* last set locality */
+    Error *migration_blocker;
+} TPMEmulator;
+
+
+static int tpm_emulator_ctrlcmd(CharBackend *dev, unsigned long cmd, void *msg,
+                                size_t msg_len_in, size_t msg_len_out)
+{
+    uint32_t cmd_no = cpu_to_be32(cmd);
+    ssize_t n = sizeof(uint32_t) + msg_len_in;
+    uint8_t *buf = NULL;
+
+    buf = g_alloca(n);
+    memcpy(buf, &cmd_no, sizeof(cmd_no));
+    memcpy(buf + sizeof(cmd_no), msg, msg_len_in);
+
+    n = qemu_chr_fe_write_all(dev, buf, n);
+    if (n <= 0) {
+        return -1;
+    }
+
+    if (msg_len_out != 0) {
+        n = qemu_chr_fe_read_all(dev, msg, msg_len_out);
+        if (n <= 0) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,
+                                     const uint8_t *in, uint32_t in_len,
+                                     uint8_t *out, uint32_t out_len,
+                                     bool *selftest_done,
+                                     Error **err)
+{
+    ssize_t ret;
+    bool is_selftest = false;
+    const struct tpm_resp_hdr *hdr = NULL;
+
+    if (selftest_done) {
+        *selftest_done = false;
+        is_selftest = tpm_util_is_selftest(in, in_len);
+    }
+
+    ret = qio_channel_write_all(tpm_emu->data_ioc, (char *)in, in_len, err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    ret = qio_channel_read_all(tpm_emu->data_ioc, (char *)out, sizeof(*hdr),
+                               err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    hdr = (struct tpm_resp_hdr *)out;
+    out += sizeof(*hdr);
+    ret = qio_channel_read_all(tpm_emu->data_ioc, (char *)out,
+                               be32_to_cpu(hdr->len) - sizeof(*hdr) , err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    if (is_selftest) {
+        *selftest_done = (be32_to_cpu(hdr->errcode) == 0);
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_set_locality(TPMEmulator *tpm_emu, uint8_t locty_number)
+{
+    ptm_loc loc;
+
+    DPRINTF("%s : locality: 0x%x", __func__, locty_number);
+
+    if (tpm_emu->cur_locty_number == locty_number) {
+        return 0;
+    }
+
+    DPRINTF("setting locality : 0x%x", locty_number);
+    loc.u.req.loc = locty_number;
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_LOCALITY, &loc,
+                             sizeof(loc), sizeof(loc)) < 0) {
+        error_report("tpm-emulator: could not set locality : %s",
+                     strerror(errno));
+        return -1;
+    }
+
+    loc.u.resp.tpm_result = be32_to_cpu(loc.u.resp.tpm_result);
+    if (loc.u.resp.tpm_result != 0) {
+        error_report("tpm-emulator: TPM result for set locality : 0x%x",
+                     loc.u.resp.tpm_result);
+        return -1;
+    }
+
+    tpm_emu->cur_locty_number = locty_number;
+
+    return 0;
+}
+
+static void tpm_emulator_handle_request(TPMBackend *tb, TPMBackendCmd cmd)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    TPMLocality *locty = NULL;
+    bool selftest_done = false;
+    Error *err = NULL;
+
+    DPRINTF("processing command type %d", cmd);
+
+    switch (cmd) {
+    case TPM_BACKEND_CMD_PROCESS_CMD:
+        locty = tb->tpm_state->locty_data;
+        if (tpm_emulator_set_locality(tpm_emu,
+                                      tb->tpm_state->locty_number) < 0 ||
+            tpm_emulator_unix_tx_bufs(tpm_emu, locty->w_buffer.buffer,
+                                      locty->w_offset, locty->r_buffer.buffer,
+                                      locty->r_buffer.size, &selftest_done,
+                                      &err) < 0) {
+            tpm_util_write_fatal_error_response(locty->r_buffer.buffer,
+                                                locty->r_buffer.size);
+            error_report_err(err);
+        }
+
+        tb->recv_data_callback(tb->tpm_state, tb->tpm_state->locty_number,
+                               selftest_done);
+
+        break;
+    case TPM_BACKEND_CMD_INIT:
+    case TPM_BACKEND_CMD_END:
+    case TPM_BACKEND_CMD_TPM_RESET:
+        /* nothing to do */
+        break;
+    }
+}
+
+static int tpm_emulator_probe_caps(TPMEmulator *tpm_emu)
+{
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_CAPABILITY,
+                         &tpm_emu->caps, 0, sizeof(tpm_emu->caps)) < 0) {
+        error_report("tpm-emulator: probing failed : %s", strerror(errno));
+        return -1;
+    }
+
+    tpm_emu->caps = be64_to_cpu(tpm_emu->caps);
+
+    DPRINTF("capabilities : 0x%"PRIx64, tpm_emu->caps);
+
+    return 0;
+}
+
+static int tpm_emulator_check_caps(TPMEmulator *tpm_emu)
+{
+    ptm_cap caps = 0;
+    const char *tpm = NULL;
+
+    /* check for min. required capabilities */
+    switch (tpm_emu->tpm_version) {
+    case TPM_VERSION_1_2:
+        caps = PTM_CAP_INIT | PTM_CAP_SHUTDOWN | PTM_CAP_GET_TPMESTABLISHED |
+               PTM_CAP_SET_LOCALITY | PTM_CAP_SET_DATAFD;
+        tpm = "1.2";
+        break;
+    case TPM_VERSION_2_0:
+        caps = PTM_CAP_INIT | PTM_CAP_SHUTDOWN | PTM_CAP_GET_TPMESTABLISHED |
+               PTM_CAP_SET_LOCALITY | PTM_CAP_RESET_TPMESTABLISHED |
+               PTM_CAP_SET_DATAFD;
+        tpm = "2";
+        break;
+    case TPM_VERSION_UNSPEC:
+        error_report("tpm-emulator: TPM version has not been set");
+        return -1;
+    }
+
+    if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, caps)) {
+        error_report("tpm-emulator: TPM does not implement minimum set of "
+                     "required capabilities for TPM %s (0x%x)", tpm, (int)caps);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_startup_tpm(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_init init;
+    ptm_res res;
+
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_INIT, &init, sizeof(init),
+                         sizeof(init)) < 0) {
+        error_report("tpm-emulator: could not send INIT: %s",
+                     strerror(errno));
+        goto err_exit;
+    }
+
+    res = be32_to_cpu(init.u.resp.tpm_result);
+    if (res) {
+        error_report("tpm-emulator: TPM result for CMD_INIT: 0x%x", res);
+        goto err_exit;
+    }
+    return 0;
+
+err_exit:
+    return -1;
+}
+
+static bool tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_est est;
+
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_TPMESTABLISHED, &est,
+                             0, sizeof(est)) < 0) {
+        error_report("tpm-emulator: Could not get the TPM established flag: %s",
+                     strerror(errno));
+        return false;
+    }
+    DPRINTF("established flag: %0x", est.u.resp.bit);
+
+    return (est.u.resp.bit != 0);
+}
+
+static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
+                                                   uint8_t locty)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_reset_est reset_est;
+    ptm_res res;
+
+    /* only a TPM 2.0 will support this */
+    if (tpm_emu->tpm_version != TPM_VERSION_2_0) {
+        return 0;
+    }
+
+    reset_est.u.req.loc = tpm_emu->cur_locty_number;
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_RESET_TPMESTABLISHED,
+                             &reset_est, sizeof(reset_est),
+                             sizeof(reset_est)) < 0) {
+        error_report("tpm-emulator: Could not reset the establishment bit: %s",
+                     strerror(errno));
+        return -1;
+    }
+
+    res = be32_to_cpu(reset_est.u.resp.tpm_result);
+    if (res) {
+        error_report("tpm-emulator: TPM result for rest establixhed flag: 0x%x",
+                     res);
+        return -1;
+    }
+
+    return 0;
+}
+
+static void tpm_emulator_cancel_cmd(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_res res;
+
+    if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, PTM_CAP_CANCEL_TPM_CMD)) {
+        DPRINTF("Backend does not support CANCEL_TPM_CMD");
+        return;
+    }
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_CANCEL_TPM_CMD, &res, 0,
+                             sizeof(res)) < 0) {
+        error_report("tpm-emulator: Could not cancel command: %s",
+                     strerror(errno));
+    } else if (res != 0) {
+        error_report("tpm-emulator: Failed to cancel TPM: 0x%x",
+                     be32_to_cpu(res));
+    }
+}
+
+static TPMVersion tpm_emulator_get_tpm_version(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+
+    return tpm_emu->tpm_version;
+}
+
+static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
+{
+    Error *err = NULL;
+
+    error_setg(&tpm_emu->migration_blocker,
+               "Migration disabled: TPM emulator not yet migratable");
+    migrate_add_blocker(tpm_emu->migration_blocker, &err);
+    if (err) {
+        error_report_err(err);
+        error_free(tpm_emu->migration_blocker);
+        tpm_emu->migration_blocker = NULL;
+
+        return -1;
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_prepare_data_fd(TPMEmulator *tpm_emu)
+{
+    ptm_res res;
+    Error *err = NULL;
+    int fds[2] = { -1, -1 };
+
+    if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0) {
+        error_report("tpm-emulator: Failed to create socketpair");
+        return -1;
+    }
+
+    qemu_chr_fe_set_msgfds(&tpm_emu->ctrl_chr, fds + 1, 1);
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_DATAFD, &res, 0,
+                    sizeof(res)) || res != 0) {
+        error_report("tpm-emulator: Failed to send CMD_SET_DATAFD: %s",
+                     strerror(errno));
+        goto err_exit;
+    }
+
+    tpm_emu->data_ioc = QIO_CHANNEL(qio_channel_socket_new_fd(fds[0], &err));
+    if (err) {
+        error_prepend(&err, "tpm-emulator: Failed to create io channel: ");
+        error_report_err(err);
+        goto err_exit;
+    }
+
+    closesocket(fds[1]);
+
+    return 0;
+
+err_exit:
+    closesocket(fds[0]);
+    closesocket(fds[1]);
+    return -1;
+}
+
+static int tpm_emulator_handle_device_opts(TPMEmulator *tpm_emu, QemuOpts *opts)
+{
+    const char *value;
+
+    value = qemu_opt_get(opts, "chardev");
+    if (value) {
+        Error *err = NULL;
+        Chardev *dev = qemu_chr_find(value);
+
+        if (!dev) {
+            error_report("tpm-emulator: tpm chardev '%s' not found.", value);
+            goto err;
+        }
+
+        if (!qemu_chr_fe_init(&tpm_emu->ctrl_chr, dev, &err)) {
+            error_prepend(&err, "tpm-emulator: No valid chardev found at '%s':",
+                          value);
+            error_report_err(err);
+            goto err;
+        }
+
+        tpm_emu->options->chardev = g_strdup(value);
+    }
+
+    if (tpm_emulator_prepare_data_fd(tpm_emu) < 0) {
+        goto err;
+    }
+
+    /* FIXME: tpm_util_test_tpmdev() accepts only on socket fd, as it also used
+     * by passthrough driver, which not yet using GIOChannel.
+     */
+    if (tpm_util_test_tpmdev(QIO_CHANNEL_SOCKET(tpm_emu->data_ioc)->fd,
+                             &tpm_emu->tpm_version)) {
+        error_report("'%s' is not emulating TPM device. Error: %s",
+                      tpm_emu->options->chardev, strerror(errno));
+        goto err;
+    }
+
+    DPRINTF("TPM Version %s", tpm_emu->tpm_version == TPM_VERSION_1_2 ? "1.2" :
+            (tpm_emu->tpm_version == TPM_VERSION_2_0 ?  "2.0" : "Unspecified"));
+
+    if (tpm_emulator_probe_caps(tpm_emu) ||
+        tpm_emulator_check_caps(tpm_emu)) {
+        goto err;
+    }
+
+    return tpm_emulator_block_migration(tpm_emu);
+
+err:
+    DPRINTF("Startup error");
+    return -1;
+}
+
+static TPMBackend *tpm_emulator_create(QemuOpts *opts, const char *id)
+{
+    TPMBackend *tb = TPM_BACKEND(object_new(TYPE_TPM_EMULATOR));
+
+    tb->id = g_strdup(id);
+
+    if (tpm_emulator_handle_device_opts(TPM_EMULATOR(tb), opts)) {
+        goto err_exit;
+    }
+
+    return tb;
+
+err_exit:
+    object_unref(OBJECT(tb));
+
+    return NULL;
+}
+
+static TpmTypeOptions *tpm_emulator_get_tpm_options(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
+
+    options->type = TPM_TYPE_OPTIONS_KIND_EMULATOR;
+    options->u.emulator.data = QAPI_CLONE(TPMEmulatorOptions, tpm_emu->options);
+
+    return options;
+}
+
+static const QemuOptDesc tpm_emulator_cmdline_opts[] = {
+    TPM_STANDARD_CMDLINE_OPTS,
+    {
+        .name = "chardev",
+        .type = QEMU_OPT_STRING,
+        .help = "Character device to use for out-of-band control messages",
+    },
+    { /* end of list */ },
+};
+
+static const TPMDriverOps tpm_emulator_driver = {
+    .type                     = TPM_TYPE_EMULATOR,
+    .opts                     = tpm_emulator_cmdline_opts,
+    .desc                     = "TPM emulator backend driver",
+
+    .create                   = tpm_emulator_create,
+    .startup_tpm              = tpm_emulator_startup_tpm,
+    .cancel_cmd               = tpm_emulator_cancel_cmd,
+    .get_tpm_established_flag = tpm_emulator_get_tpm_established_flag,
+    .reset_tpm_established_flag = tpm_emulator_reset_tpm_established_flag,
+    .get_tpm_version          = tpm_emulator_get_tpm_version,
+    .get_tpm_options          = tpm_emulator_get_tpm_options,
+};
+
+static void tpm_emulator_inst_init(Object *obj)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
+
+    DPRINTF("%s", __func__);
+    tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
+    tpm_emu->cur_locty_number = ~0;
+}
+
+/*
+ * Gracefully shut down the external TPM
+ */
+static void tpm_emulator_shutdown(TPMEmulator *tpm_emu)
+{
+    ptm_res res;
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SHUTDOWN, &res, 0,
+                             sizeof(res)) < 0) {
+        error_report("tpm-emulator: Could not cleanly shutdown the TPM: %s",
+                     strerror(errno));
+    } else if (res != 0) {
+        error_report("tpm-emulator: TPM result for sutdown: 0x%x",
+                     be32_to_cpu(res));
+    }
+}
+
+static void tpm_emulator_inst_finalize(Object *obj)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
+
+    tpm_emulator_shutdown(tpm_emu);
+
+    object_unref(OBJECT(tpm_emu->data_ioc));
+
+    qemu_chr_fe_deinit(&tpm_emu->ctrl_chr, false);
+
+    qapi_free_TPMEmulatorOptions(tpm_emu->options);
+
+    if (tpm_emu->migration_blocker) {
+        migrate_del_blocker(tpm_emu->migration_blocker);
+        error_free(tpm_emu->migration_blocker);
+    }
+}
+
+static void tpm_emulator_class_init(ObjectClass *klass, void *data)
+{
+    TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
+    tbc->ops = &tpm_emulator_driver;
+    tbc->handle_request = tpm_emulator_handle_request;
+}
+
+static const TypeInfo tpm_emulator_info = {
+    .name = TYPE_TPM_EMULATOR,
+    .parent = TYPE_TPM_BACKEND,
+    .instance_size = sizeof(TPMEmulator),
+    .class_init = tpm_emulator_class_init,
+    .instance_init = tpm_emulator_inst_init,
+    .instance_finalize = tpm_emulator_inst_finalize,
+};
+
+static void tpm_emulator_register(void)
+{
+    type_register_static(&tpm_emulator_info);
+    tpm_register_driver(&tpm_emulator_driver);
+}
+
+type_init(tpm_emulator_register)
diff --git a/hw/tpm/tpm_ioctl.h b/hw/tpm/tpm_ioctl.h
new file mode 100644
index 0000000000..33564b11de
--- /dev/null
+++ b/hw/tpm/tpm_ioctl.h
@@ -0,0 +1,246 @@
+/*
+ * tpm_ioctl.h
+ *
+ * (c) Copyright IBM Corporation 2014, 2015.
+ *
+ * This file is licensed under the terms of the 3-clause BSD license
+ */
+#ifndef _TPM_IOCTL_H_
+#define _TPM_IOCTL_H_
+
+#include <stdint.h>
+#include <sys/uio.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+
+/*
+ * Every response from a command involving a TPM command execution must hold
+ * the ptm_res as the first element.
+ * ptm_res corresponds to the error code of a command executed by the TPM.
+ */
+
+typedef uint32_t ptm_res;
+
+/* PTM_GET_TPMESTABLISHED: get the establishment bit */
+struct ptm_est {
+    union {
+        struct {
+            ptm_res tpm_result;
+            unsigned char bit; /* TPM established bit */
+        } resp; /* response */
+    } u;
+};
+
+/* PTM_RESET_TPMESTABLISHED: reset establishment bit */
+struct ptm_reset_est {
+    union {
+        struct {
+            uint8_t loc; /* locality to use */
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+        } resp; /* response */
+    } u;
+};
+
+/* PTM_INIT */
+struct ptm_init {
+    union {
+        struct {
+            uint32_t init_flags; /* see definitions below */
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+        } resp; /* response */
+    } u;
+};
+
+/* above init_flags */
+#define PTM_INIT_FLAG_DELETE_VOLATILE (1 << 0)
+    /* delete volatile state file after reading it */
+
+/* PTM_SET_LOCALITY */
+struct ptm_loc {
+    union {
+        struct {
+            uint8_t loc; /* locality to set */
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+        } resp; /* response */
+    } u;
+};
+
+/* PTM_HASH_DATA: hash given data */
+struct ptm_hdata {
+    union {
+        struct {
+            uint32_t length;
+            uint8_t data[4096];
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+        } resp; /* response */
+    } u;
+};
+
+/*
+ * size of the TPM state blob to transfer; x86_64 can handle 8k,
+ * ppc64le only ~7k; keep the response below a 4k page size
+ */
+#define PTM_STATE_BLOB_SIZE (3 * 1024)
+
+/*
+ * The following is the data structure to get state blobs from the TPM.
+ * If the size of the state blob exceeds the PTM_STATE_BLOB_SIZE, multiple reads
+ * with this ioctl and with adjusted offset are necessary. All bytes
+ * must be transferred and the transfer is done once the last byte has been
+ * returned.
+ * It is possible to use the read() interface for reading the data; however, the
+ * first bytes of the state blob will be part of the response to the ioctl(); a
+ * subsequent read() is only necessary if the total length (totlength) exceeds
+ * the number of received bytes. seek() is not supported.
+ */
+struct ptm_getstate {
+    union {
+        struct {
+            uint32_t state_flags; /* may be: PTM_STATE_FLAG_DECRYPTED */
+            uint32_t type;        /* which blob to pull */
+            uint32_t offset;      /* offset from where to read */
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+            uint32_t state_flags; /* may be: PTM_STATE_FLAG_ENCRYPTED */
+            uint32_t totlength;   /* total length that will be transferred */
+            uint32_t length;      /* number of bytes in following buffer */
+            uint8_t  data[PTM_STATE_BLOB_SIZE];
+        } resp; /* response */
+    } u;
+};
+
+/* TPM state blob types */
+#define PTM_BLOB_TYPE_PERMANENT  1
+#define PTM_BLOB_TYPE_VOLATILE   2
+#define PTM_BLOB_TYPE_SAVESTATE  3
+
+/* state_flags above : */
+#define PTM_STATE_FLAG_DECRYPTED     1 /* on input:  get decrypted state */
+#define PTM_STATE_FLAG_ENCRYPTED     2 /* on output: state is encrypted */
+
+/*
+ * The following is the data structure to set state blobs in the TPM.
+ * If the size of the state blob exceeds the PTM_STATE_BLOB_SIZE, multiple
+ * 'writes' using this ioctl are necessary. The last packet is indicated
+ * by the length being smaller than the PTM_STATE_BLOB_SIZE.
+ * The very first packet may have a length indicator of '0' enabling
+ * a write() with all the bytes from a buffer. If the write() interface
+ * is used, a final ioctl with a non-full buffer must be made to indicate
+ * that all data were transferred (a write with 0 bytes would not work).
+ */
+struct ptm_setstate {
+    union {
+        struct {
+            uint32_t state_flags; /* may be PTM_STATE_FLAG_ENCRYPTED */
+            uint32_t type;        /* which blob to set */
+            uint32_t length;      /* length of the data;
+                                     use 0 on the first packet to
+                                     transfer using write() */
+            uint8_t data[PTM_STATE_BLOB_SIZE];
+        } req; /* request */
+        struct {
+            ptm_res tpm_result;
+        } resp; /* response */
+    } u;
+};
+
+/*
+ * PTM_GET_CONFIG: Data structure to get runtime configuration information
+ * such as which keys are applied.
+ */
+struct ptm_getconfig {
+    union {
+        struct {
+            ptm_res tpm_result;
+            uint32_t flags;
+        } resp; /* response */
+    } u;
+};
+
+#define PTM_CONFIG_FLAG_FILE_KEY        0x1
+#define PTM_CONFIG_FLAG_MIGRATION_KEY   0x2
+
+
+typedef uint64_t ptm_cap;
+typedef struct ptm_est ptm_est;
+typedef struct ptm_reset_est ptm_reset_est;
+typedef struct ptm_loc ptm_loc;
+typedef struct ptm_hdata ptm_hdata;
+typedef struct ptm_init ptm_init;
+typedef struct ptm_getstate ptm_getstate;
+typedef struct ptm_setstate ptm_setstate;
+typedef struct ptm_getconfig ptm_getconfig;
+
+/* capability flags returned by PTM_GET_CAPABILITY */
+#define PTM_CAP_INIT               (1)
+#define PTM_CAP_SHUTDOWN           (1 << 1)
+#define PTM_CAP_GET_TPMESTABLISHED (1 << 2)
+#define PTM_CAP_SET_LOCALITY       (1 << 3)
+#define PTM_CAP_HASHING            (1 << 4)
+#define PTM_CAP_CANCEL_TPM_CMD     (1 << 5)
+#define PTM_CAP_STORE_VOLATILE     (1 << 6)
+#define PTM_CAP_RESET_TPMESTABLISHED (1 << 7)
+#define PTM_CAP_GET_STATEBLOB      (1 << 8)
+#define PTM_CAP_SET_STATEBLOB      (1 << 9)
+#define PTM_CAP_STOP               (1 << 10)
+#define PTM_CAP_GET_CONFIG         (1 << 11)
+#define PTM_CAP_SET_DATAFD         (1 << 12)
+
+enum {
+    PTM_GET_CAPABILITY     = _IOR('P', 0, ptm_cap),
+    PTM_INIT               = _IOWR('P', 1, ptm_init),
+    PTM_SHUTDOWN           = _IOR('P', 2, ptm_res),
+    PTM_GET_TPMESTABLISHED = _IOR('P', 3, ptm_est),
+    PTM_SET_LOCALITY       = _IOWR('P', 4, ptm_loc),
+    PTM_HASH_START         = _IOR('P', 5, ptm_res),
+    PTM_HASH_DATA          = _IOWR('P', 6, ptm_hdata),
+    PTM_HASH_END           = _IOR('P', 7, ptm_res),
+    PTM_CANCEL_TPM_CMD     = _IOR('P', 8, ptm_res),
+    PTM_STORE_VOLATILE     = _IOR('P', 9, ptm_res),
+    PTM_RESET_TPMESTABLISHED = _IOWR('P', 10, ptm_reset_est),
+    PTM_GET_STATEBLOB      = _IOWR('P', 11, ptm_getstate),
+    PTM_SET_STATEBLOB      = _IOWR('P', 12, ptm_setstate),
+    PTM_STOP               = _IOR('P', 13, ptm_res),
+    PTM_GET_CONFIG         = _IOR('P', 14, ptm_getconfig),
+    PTM_SET_DATAFD         = _IOR('P', 15, ptm_res),
+};
+
+/*
+ * Commands used by the non-CUSE TPMs
+ *
+ * All messages container big-endian data.
+ *
+ * The return messages only contain the 'resp' part of the unions
+ * in the data structures above. Besides that the limits in the
+ * buffers above (ptm_hdata:u.req.data and ptm_get_state:u.resp.data
+ * and ptm_set_state:u.req.data) are 0xffffffff.
+ */
+enum {
+    CMD_GET_CAPABILITY = 1,
+    CMD_INIT,
+    CMD_SHUTDOWN,
+    CMD_GET_TPMESTABLISHED,
+    CMD_SET_LOCALITY,
+    CMD_HASH_START,
+    CMD_HASH_DATA,
+    CMD_HASH_END,
+    CMD_CANCEL_TPM_CMD,
+    CMD_STORE_VOLATILE,
+    CMD_RESET_TPMESTABLISHED,
+    CMD_GET_STATEBLOB,
+    CMD_SET_STATEBLOB,
+    CMD_STOP,
+    CMD_GET_CONFIG,
+    CMD_SET_DATAFD
+};
+
+#endif /* _TPM_IOCTL_H */
diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
index 9234eb3459..e6ace28b04 100644
--- a/hw/tpm/tpm_passthrough.c
+++ b/hw/tpm/tpm_passthrough.c
@@ -30,7 +30,7 @@
 #include "tpm_int.h"
 #include "hw/hw.h"
 #include "hw/i386/pc.h"
-#include "sysemu/tpm_backend_int.h"
+#include "qapi/clone-visitor.h"
 #include "tpm_tis.h"
 #include "tpm_util.h"
 
@@ -46,29 +46,16 @@
 #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;
-
-    TPMRecvDataCB *recv_data_callback;
-    TPMBackend *tb;
-} TPMPassthruThreadParams;
-
 struct TPMPassthruState {
     TPMBackend parent;
 
-    TPMBackendThread tbt;
-
-    TPMPassthruThreadParams tpm_thread_params;
-
-    char *tpm_dev;
+    TPMPassthroughOptions *options;
+    const char *tpm_dev;
     int tpm_fd;
     bool tpm_executing;
     bool tpm_op_canceled;
     int cancel_fd;
-    bool had_startup_error;
 
     TPMVersion tpm_version;
 };
@@ -81,27 +68,6 @@ typedef struct TPMPassthruState TPMPassthruState;
 
 static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
 
-static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len)
-{
-    int ret, remain;
-
-    remain = len;
-    while (remain > 0) {
-        ret = write(fd, buf, remain);
-        if (ret < 0) {
-            if (errno != EINTR && errno != EAGAIN) {
-                return -1;
-            }
-        } else if (ret == 0) {
-            break;
-        } else {
-            buf += ret;
-            remain -= ret;
-        }
-    }
-    return len - remain;
-}
-
 static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
 {
     int ret;
@@ -115,45 +81,12 @@ static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
     }
     return ret;
 }
-
-static uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf)
-{
-    struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)buf;
-
-    return be32_to_cpu(resp->len);
-}
-
-/*
- * Write an error message in the given output buffer.
- */
-static void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len)
-{
-    if (out_len >= sizeof(struct tpm_resp_hdr)) {
-        struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
-
-        resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
-        resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
-        resp->errcode = cpu_to_be32(TPM_FAIL);
-    }
-}
-
-static bool tpm_passthrough_is_selftest(const uint8_t *in, uint32_t in_len)
-{
-    struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
-
-    if (in_len >= sizeof(*hdr)) {
-        return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
-    }
-
-    return false;
-}
-
 static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
                                         const uint8_t *in, uint32_t in_len,
                                         uint8_t *out, uint32_t out_len,
                                         bool *selftest_done)
 {
-    int ret;
+    ssize_t ret;
     bool is_selftest;
     const struct tpm_resp_hdr *hdr;
 
@@ -161,9 +94,9 @@ static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
     tpm_pt->tpm_executing = true;
     *selftest_done = false;
 
-    is_selftest = tpm_passthrough_is_selftest(in, in_len);
+    is_selftest = tpm_util_is_selftest(in, in_len);
 
-    ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
+    ret = qemu_write_full(tpm_pt->tpm_fd, (const void *)in, (size_t)in_len);
     if (ret != in_len) {
         if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
             error_report("tpm_passthrough: error while transmitting data "
@@ -183,7 +116,7 @@ static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
                          strerror(errno), errno);
         }
     } else if (ret < sizeof(struct tpm_resp_hdr) ||
-               tpm_passthrough_get_size_from_buffer(out) != ret) {
+               be32_to_cpu(((struct tpm_resp_hdr *)out)->len) != ret) {
         ret = -1;
         error_report("tpm_passthrough: received invalid response "
                      "packet from TPM");
@@ -196,7 +129,7 @@ static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
 
 err_exit:
     if (ret < 0) {
-        tpm_write_fatal_error_response(out, out_len);
+        tpm_util_write_fatal_error_response(out, out_len);
     }
 
     tpm_pt->tpm_executing = false;
@@ -216,12 +149,9 @@ static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
                                         selftest_done);
 }
 
-static void tpm_passthrough_worker_thread(gpointer data,
-                                          gpointer user_data)
+static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd cmd)
 {
-    TPMPassthruThreadParams *thr_parms = user_data;
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
-    TPMBackendCmd cmd = (TPMBackendCmd)data;
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
     bool selftest_done = false;
 
     DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
@@ -229,12 +159,12 @@ static void tpm_passthrough_worker_thread(gpointer data,
     switch (cmd) {
     case TPM_BACKEND_CMD_PROCESS_CMD:
         tpm_passthrough_unix_transfer(tpm_pt,
-                                      thr_parms->tpm_state->locty_data,
+                                      tb->tpm_state->locty_data,
                                       &selftest_done);
 
-        thr_parms->recv_data_callback(thr_parms->tpm_state,
-                                      thr_parms->tpm_state->locty_number,
-                                      selftest_done);
+        tb->recv_data_callback(tb->tpm_state,
+                               tb->tpm_state->locty_number,
+                               selftest_done);
         break;
     case TPM_BACKEND_CMD_INIT:
     case TPM_BACKEND_CMD_END:
@@ -244,47 +174,11 @@ static void tpm_passthrough_worker_thread(gpointer data,
     }
 }
 
-/*
- * Start the TPM (thread). If it had been started before, then terminate
- * and start it again.
- */
-static int tpm_passthrough_startup_tpm(TPMBackend *tb)
-{
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-
-    /* terminate a running TPM */
-    tpm_backend_thread_end(&tpm_pt->tbt);
-
-    tpm_backend_thread_create(&tpm_pt->tbt,
-                              tpm_passthrough_worker_thread,
-                              &tpm_pt->tpm_thread_params);
-
-    return 0;
-}
-
 static void tpm_passthrough_reset(TPMBackend *tb)
 {
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-
     DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
 
     tpm_passthrough_cancel_cmd(tb);
-
-    tpm_backend_thread_end(&tpm_pt->tbt);
-
-    tpm_pt->had_startup_error = false;
-}
-
-static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
-                                TPMRecvDataCB *recv_data_cb)
-{
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-
-    tpm_pt->tpm_thread_params.tpm_state = s;
-    tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
-    tpm_pt->tpm_thread_params.tb = tb;
-
-    return 0;
 }
 
 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
@@ -299,31 +193,6 @@ static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
     return 0;
 }
 
-static bool tpm_passthrough_get_startup_error(TPMBackend *tb)
-{
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-
-    return tpm_pt->had_startup_error;
-}
-
-static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
-{
-    size_t wanted_size = 4096; /* Linux tpm.c buffer size */
-
-    if (sb->size != wanted_size) {
-        sb->buffer = g_realloc(sb->buffer, wanted_size);
-        sb->size = wanted_size;
-    }
-    return sb->size;
-}
-
-static void tpm_passthrough_deliver_request(TPMBackend *tb)
-{
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
-
-    tpm_backend_thread_deliver_request(&tpm_pt->tbt);
-}
-
 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
 {
     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
@@ -351,11 +220,6 @@ static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
     }
 }
 
-static const char *tpm_passthrough_create_desc(void)
-{
-    return "Passthrough TPM backend driver";
-}
-
 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
 {
     TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
@@ -369,15 +233,14 @@ static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
  * in Documentation/ABI/stable/sysfs-class-tpm.
  * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel
  */
-static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
+static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt)
 {
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
     int fd = -1;
     char *dev;
     char path[PATH_MAX];
 
-    if (tb->cancel_path) {
-        fd = qemu_open(tb->cancel_path, O_WRONLY);
+    if (tpm_pt->options->cancel_path) {
+        fd = qemu_open(tpm_pt->options->cancel_path, O_WRONLY);
         if (fd < 0) {
             error_report("Could not open TPM cancel path : %s",
                          strerror(errno));
@@ -392,7 +255,7 @@ static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
                      dev) < sizeof(path)) {
             fd = qemu_open(path, O_WRONLY);
             if (fd >= 0) {
-                tb->cancel_path = g_strdup(path);
+                tpm_pt->options->cancel_path = g_strdup(path);
             } else {
                 error_report("tpm_passthrough: Could not open TPM cancel "
                              "path %s : %s", path, strerror(errno));
@@ -412,17 +275,18 @@ static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
     const char *value;
 
     value = qemu_opt_get(opts, "cancel-path");
-    tb->cancel_path = g_strdup(value);
+    if (value) {
+        tpm_pt->options->cancel_path = g_strdup(value);
+        tpm_pt->options->has_cancel_path = true;
+    }
 
     value = qemu_opt_get(opts, "path");
-    if (!value) {
-        value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
+    if (value) {
+        tpm_pt->options->has_path = true;
+        tpm_pt->options->path = g_strdup(value);
     }
 
-    tpm_pt->tpm_dev = g_strdup(value);
-
-    tb->path = g_strdup(tpm_pt->tpm_dev);
-
+    tpm_pt->tpm_dev = value ? value : TPM_PASSTHROUGH_DEFAULT_DEVICE;
     tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
     if (tpm_pt->tpm_fd < 0) {
         error_report("Cannot access TPM device using '%s': %s",
@@ -443,10 +307,8 @@ static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
     tpm_pt->tpm_fd = -1;
 
  err_free_parameters:
-    g_free(tb->path);
-    tb->path = NULL;
-
-    g_free(tpm_pt->tpm_dev);
+    qapi_free_TPMPassthroughOptions(tpm_pt->options);
+    tpm_pt->options = NULL;
     tpm_pt->tpm_dev = NULL;
 
     return 1;
@@ -459,16 +321,12 @@ 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;
-
-    tb->ops = &tpm_passthrough_driver;
 
     if (tpm_passthrough_handle_device_opts(opts, tb)) {
         goto err_exit;
     }
 
-    tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
+    tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt);
     if (tpm_pt->cancel_fd < 0) {
         goto err_exit;
     }
@@ -476,26 +334,20 @@ 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)
+static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
 {
-    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+    TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
 
-    tpm_passthrough_cancel_cmd(tb);
-
-    tpm_backend_thread_end(&tpm_pt->tbt);
-
-    qemu_close(tpm_pt->tpm_fd);
-    qemu_close(tpm_pt->cancel_fd);
+    options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
+    options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions,
+                                             TPM_PASSTHROUGH(tb)->options);
 
-    g_free(tb->id);
-    g_free(tb->path);
-    g_free(tb->cancel_path);
-    g_free(tpm_pt->tpm_dev);
+    return options;
 }
 
 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
@@ -516,27 +368,34 @@ static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
 static const TPMDriverOps tpm_passthrough_driver = {
     .type                     = TPM_TYPE_PASSTHROUGH,
     .opts                     = tpm_passthrough_cmdline_opts,
-    .desc                     = tpm_passthrough_create_desc,
+    .desc                     = "Passthrough TPM backend driver",
     .create                   = tpm_passthrough_create,
-    .destroy                  = tpm_passthrough_destroy,
-    .init                     = tpm_passthrough_init,
-    .startup_tpm              = tpm_passthrough_startup_tpm,
-    .realloc_buffer           = tpm_passthrough_realloc_buffer,
     .reset                    = tpm_passthrough_reset,
-    .had_startup_error        = tpm_passthrough_get_startup_error,
-    .deliver_request          = tpm_passthrough_deliver_request,
     .cancel_cmd               = tpm_passthrough_cancel_cmd,
     .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
     .reset_tpm_established_flag = tpm_passthrough_reset_tpm_established_flag,
     .get_tpm_version          = tpm_passthrough_get_tpm_version,
+    .get_tpm_options          = tpm_passthrough_get_tpm_options,
 };
 
 static void tpm_passthrough_inst_init(Object *obj)
 {
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
+
+    tpm_pt->options = g_new0(TPMPassthroughOptions, 1);
+    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);
+    qapi_free_TPMPassthroughOptions(tpm_pt->options);
 }
 
 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
@@ -544,6 +403,7 @@ static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
     TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
 
     tbc->ops = &tpm_passthrough_driver;
+    tbc->handle_request = tpm_passthrough_handle_request;
 }
 
 static const TypeInfo tpm_passthrough_info = {
diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index a6440fef91..d5118e7f60 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -963,6 +963,16 @@ static int tpm_tis_do_startup_tpm(TPMState *s)
     return tpm_backend_startup_tpm(s->be_driver);
 }
 
+static void tpm_tis_realloc_buffer(TPMSizedBuffer *sb)
+{
+    size_t wanted_size = 4096; /* Linux tpm.c buffer size */
+
+    if (sb->size != wanted_size) {
+        sb->buffer = g_realloc(sb->buffer, wanted_size);
+        sb->size = wanted_size;
+    }
+}
+
 /*
  * Get the TPMVersion of the backend device being used
  */
@@ -1010,9 +1020,9 @@ static void tpm_tis_reset(DeviceState *dev)
         tis->loc[c].state = TPM_TIS_STATE_IDLE;
 
         tis->loc[c].w_offset = 0;
-        tpm_backend_realloc_buffer(s->be_driver, &tis->loc[c].w_buffer);
+        tpm_tis_realloc_buffer(&tis->loc[c].w_buffer);
         tis->loc[c].r_offset = 0;
-        tpm_backend_realloc_buffer(s->be_driver, &tis->loc[c].r_buffer);
+        tpm_tis_realloc_buffer(&tis->loc[c].r_buffer);
     }
 
     tpm_tis_do_startup_tpm(s);
diff --git a/hw/tpm/tpm_util.c b/hw/tpm/tpm_util.c
index 7b35429725..73d77965fd 100644
--- a/hw/tpm/tpm_util.c
+++ b/hw/tpm/tpm_util.c
@@ -24,6 +24,31 @@
 #include "tpm_int.h"
 
 /*
+ * Write an error message in the given output buffer.
+ */
+void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
+{
+    if (out_len >= sizeof(struct tpm_resp_hdr)) {
+        struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
+
+        resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
+        resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
+        resp->errcode = cpu_to_be32(TPM_FAIL);
+    }
+}
+
+bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
+{
+    struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in;
+
+    if (in_len >= sizeof(*hdr)) {
+        return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest);
+    }
+
+    return false;
+}
+
+/*
  * A basic test of a TPM device. We expect a well formatted response header
  * (error response is fine) within one second.
  */
@@ -43,10 +68,10 @@ static int tpm_util_test(int fd,
 
     n = write(fd, request, requestlen);
     if (n < 0) {
-        return errno;
+        return -errno;
     }
     if (n != requestlen) {
-        return EFAULT;
+        return -EFAULT;
     }
 
     FD_ZERO(&readfds);
@@ -55,18 +80,18 @@ static int tpm_util_test(int fd,
     /* wait for a second */
     n = select(fd + 1, &readfds, NULL, NULL, &tv);
     if (n != 1) {
-        return errno;
+        return -errno;
     }
 
     n = read(fd, &buf, sizeof(buf));
     if (n < sizeof(struct tpm_resp_hdr)) {
-        return EFAULT;
+        return -EFAULT;
     }
 
     resp = (struct tpm_resp_hdr *)buf;
     /* check the header */
     if (be32_to_cpu(resp->len) != n) {
-        return EBADMSG;
+        return -EMSGSIZE;
     }
 
     *return_tag = be16_to_cpu(resp->tag);
diff --git a/hw/tpm/tpm_util.h b/hw/tpm/tpm_util.h
index df76245e6e..2f7c96146d 100644
--- a/hw/tpm/tpm_util.h
+++ b/hw/tpm/tpm_util.h
@@ -24,6 +24,10 @@
 
 #include "sysemu/tpm_backend.h"
 
+void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len);
+
+bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len);
+
 int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version);
 
 #endif /* TPM_TPM_UTIL_H */
diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
index b0a9731aee..2c798a1eb4 100644
--- a/include/sysemu/tpm_backend.h
+++ b/include/sysemu/tpm_backend.h
@@ -29,33 +29,42 @@
 
 typedef struct TPMBackendClass TPMBackendClass;
 typedef struct TPMBackend TPMBackend;
-
 typedef struct TPMDriverOps TPMDriverOps;
+typedef void (TPMRecvDataCB)(TPMState *, uint8_t locty, bool selftest_done);
 
-struct TPMBackendClass {
-    ObjectClass parent_class;
-
-    const TPMDriverOps *ops;
-
-    void (*opened)(TPMBackend *s, Error **errp);
-};
+typedef enum TPMBackendCmd {
+    TPM_BACKEND_CMD_INIT = 1,
+    TPM_BACKEND_CMD_PROCESS_CMD,
+    TPM_BACKEND_CMD_END,
+    TPM_BACKEND_CMD_TPM_RESET,
+} TPMBackendCmd;
 
 struct TPMBackend {
     Object parent;
 
     /*< protected >*/
     bool opened;
+    TPMState *tpm_state;
+    GThreadPool *thread_pool;
+    TPMRecvDataCB *recv_data_callback;
+    bool had_startup_error;
 
+    /* <public> */
     char *id;
     enum TpmModel fe_model;
-    char *path;
-    char *cancel_path;
-    const TPMDriverOps *ops;
 
     QLIST_ENTRY(TPMBackend) list;
 };
 
-typedef void (TPMRecvDataCB)(TPMState *, uint8_t locty, bool selftest_done);
+struct TPMBackendClass {
+    ObjectClass parent_class;
+
+    const TPMDriverOps *ops;
+
+    void (*opened)(TPMBackend *s, Error **errp);
+
+    void (*handle_request)(TPMBackend *s, TPMBackendCmd cmd);
+};
 
 typedef struct TPMSizedBuffer {
     uint32_t size;
@@ -66,21 +75,14 @@ struct TPMDriverOps {
     enum TpmType type;
     const QemuOptDesc *opts;
     /* get a descriptive text of the backend to display to the user */
-    const char *(*desc)(void);
+    const char *desc;
 
     TPMBackend *(*create)(QemuOpts *opts, const char *id);
-    void (*destroy)(TPMBackend *t);
 
     /* initialize the backend */
-    int (*init)(TPMBackend *t, TPMState *s, TPMRecvDataCB *datacb);
+    int (*init)(TPMBackend *t);
     /* start up the TPM on the backend */
     int (*startup_tpm)(TPMBackend *t);
-    /* returns true if nothing will ever answer TPM requests */
-    bool (*had_startup_error)(TPMBackend *t);
-
-    size_t (*realloc_buffer)(TPMSizedBuffer *sb);
-
-    void (*deliver_request)(TPMBackend *t);
 
     void (*reset)(TPMBackend *t);
 
@@ -91,6 +93,8 @@ struct TPMDriverOps {
     int (*reset_tpm_established_flag)(TPMBackend *t, uint8_t locty);
 
     TPMVersion (*get_tpm_version)(TPMBackend *t);
+
+    TpmTypeOptions *(*get_tpm_options)(TPMBackend *t);
 };
 
 
@@ -103,20 +107,6 @@ struct TPMDriverOps {
 enum TpmType tpm_backend_get_type(TPMBackend *s);
 
 /**
- * tpm_backend_get_desc:
- * @s: the backend
- *
- * Returns a human readable description of the backend.
- */
-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
@@ -148,16 +138,6 @@ int tpm_backend_startup_tpm(TPMBackend *s);
 bool tpm_backend_had_startup_error(TPMBackend *s);
 
 /**
- * tpm_backend_realloc_buffer:
- * @s: the backend
- * @sb: the TPMSizedBuffer to re-allocated to the size suitable for the
- *      backend.
- *
- * This function returns the size of the allocated buffer
- */
-size_t tpm_backend_realloc_buffer(TPMBackend *s, TPMSizedBuffer *sb);
-
-/**
  * tpm_backend_deliver_request:
  * @s: the backend to send the request to
  *
@@ -223,6 +203,16 @@ void tpm_backend_open(TPMBackend *s, Error **errp);
  */
 TPMVersion tpm_backend_get_tpm_version(TPMBackend *s);
 
+/**
+ * tpm_backend_query_tpm:
+ * @s: the backend
+ *
+ * Query backend tpm info
+ *
+ * Returns newly allocated TPMInfo
+ */
+TPMInfo *tpm_backend_query_tpm(TPMBackend *s);
+
 TPMBackend *qemu_find_tpm(const char *id);
 
 const TPMDriverOps *tpm_get_backend_driver(const char *type);
diff --git a/include/sysemu/tpm_backend_int.h b/include/sysemu/tpm_backend_int.h
deleted file mode 100644
index 00639dd7de..0000000000
--- a/include/sysemu/tpm_backend_int.h
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- *  common TPM backend driver functions
- *
- *  Copyright (c) 2012-2013 IBM Corporation
- *  Authors:
- *    Stefan Berger <stefanb@us.ibm.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, see <http://www.gnu.org/licenses/>
- */
-
-#ifndef TPM_BACKEND_INT_H
-#define TPM_BACKEND_INT_H
-
-typedef struct TPMBackendThread {
-    GThreadPool *pool;
-} TPMBackendThread;
-
-void tpm_backend_thread_deliver_request(TPMBackendThread *tbt);
-void tpm_backend_thread_create(TPMBackendThread *tbt,
-                               GFunc func, gpointer user_data);
-void tpm_backend_thread_end(TPMBackendThread *tbt);
-
-typedef enum TPMBackendCmd {
-    TPM_BACKEND_CMD_INIT = 1,
-    TPM_BACKEND_CMD_PROCESS_CMD,
-    TPM_BACKEND_CMD_END,
-    TPM_BACKEND_CMD_TPM_RESET,
-} TPMBackendCmd;
-
-#endif /* TPM_BACKEND_INT_H */
diff --git a/qapi/tpm.json b/qapi/tpm.json
index e8b2d8dcb7..7093f268fb 100644
--- a/qapi/tpm.json
+++ b/qapi/tpm.json
@@ -39,10 +39,12 @@
 # An enumeration of TPM types
 #
 # @passthrough: TPM passthrough type
+# @emulator: Software Emulator TPM type
+#            Since: 2.11
 #
 # Since: 1.5
 ##
-{ 'enum': 'TpmType', 'data': [ 'passthrough' ] }
+{ 'enum': 'TpmType', 'data': [ 'passthrough', 'emulator' ] }
 
 ##
 # @query-tpm-types:
@@ -56,7 +58,7 @@
 # Example:
 #
 # -> { "execute": "query-tpm-types" }
-# <- { "return": [ "passthrough" ] }
+# <- { "return": [ "passthrough", "emulator" ] }
 #
 ##
 { 'command': 'query-tpm-types', 'returns': ['TpmType'] }
@@ -77,16 +79,29 @@
                                              '*cancel-path' : 'str'} }
 
 ##
+# @TPMEmulatorOptions:
+#
+# Information about the TPM emulator type
+#
+# @chardev: Name of a unix socket chardev
+#
+# Since: 2.11
+##
+{ 'struct': 'TPMEmulatorOptions', 'data': { 'chardev' : 'str' } }
+
+##
 # @TpmTypeOptions:
 #
 # A union referencing different TPM backend types' configuration options
 #
 # @type: 'passthrough' The configuration options for the TPM passthrough type
+#        'emulator' The configuration options for TPM emulator backend type
 #
 # Since: 1.5
 ##
 { 'union': 'TpmTypeOptions',
-   'data': { 'passthrough' : 'TPMPassthroughOptions' } }
+   'data': { 'passthrough' : 'TPMPassthroughOptions',
+             'emulator': 'TPMEmulatorOptions' } }
 
 ##
 # @TPMInfo:
diff --git a/qemu-options.hx b/qemu-options.hx
index 981742d191..3728e9b4dd 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3121,7 +3121,9 @@ DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
     "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
     "                use path to provide path to a character device; default is /dev/tpm0\n"
     "                use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
-    "                not provided it will be searched for in /sys/class/misc/tpm?/device\n",
+    "                not provided it will be searched for in /sys/class/misc/tpm?/device\n"
+    "-tpmdev emulator,id=id,chardev=dev\n"
+    "                configure the TPM device using chardev backend\n",
     QEMU_ARCH_ALL)
 STEXI
 
@@ -3130,8 +3132,8 @@ The general form of a TPM device option is:
 
 @item -tpmdev @var{backend} ,id=@var{id} [,@var{options}]
 @findex -tpmdev
-Backend type must be:
-@option{passthrough}.
+Backend type must be either one of the following:
+@option{passthrough}, @option{emulator}.
 
 The specific backend type will determine the applicable options.
 The @code{-tpmdev} option creates the TPM backend and requires a
@@ -3181,6 +3183,20 @@ To create a passthrough TPM use the following two options:
 Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
 @code{tpmdev=tpm0} in the device option.
 
+@item -tpmdev emulator, id=@var{id}, chardev=@var{dev}
+
+(Linux-host only) Enable access to a TPM emulator using Unix domain socket based
+chardev backend.
+
+@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
+
+To create a TPM emulator backend device with chardev socket backend:
+@example
+
+-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
+
+@end example
+
 @end table
 
 ETEXI
diff --git a/tpm.c b/tpm.c
index 2d830d072a..3122227156 100644
--- a/tpm.c
+++ b/tpm.c
@@ -62,7 +62,7 @@ static void tpm_display_backend_drivers(void)
             continue;
         }
         fprintf(stderr, "%12s   %s\n",
-                TpmType_str(i), be_drivers[i]->desc());
+                TpmType_str(i), be_drivers[i]->desc);
     }
     fprintf(stderr, "\n");
 }
@@ -157,7 +157,7 @@ void tpm_cleanup(void)
 
     QLIST_FOREACH_SAFE(drv, &tpm_backends, list, next) {
         QLIST_REMOVE(drv, list);
-        tpm_backend_destroy(drv);
+        object_unref(OBJECT(drv));
     }
 }
 
@@ -172,7 +172,6 @@ int tpm_init(void)
         return -1;
     }
 
-    atexit(tpm_cleanup);
     return 0;
 }
 
@@ -202,36 +201,6 @@ static const TPMDriverOps *tpm_driver_find_by_type(enum TpmType type)
     return be_drivers[type];
 }
 
-static TPMInfo *qmp_query_tpm_inst(TPMBackend *drv)
-{
-    TPMInfo *res = g_new0(TPMInfo, 1);
-    TPMPassthroughOptions *tpo;
-
-    res->id = g_strdup(drv->id);
-    res->model = drv->fe_model;
-    res->options = g_new0(TpmTypeOptions, 1);
-
-    switch (drv->ops->type) {
-    case TPM_TYPE_PASSTHROUGH:
-        res->options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
-        tpo = g_new0(TPMPassthroughOptions, 1);
-        res->options->u.passthrough.data = tpo;
-        if (drv->path) {
-            tpo->path = g_strdup(drv->path);
-            tpo->has_path = true;
-        }
-        if (drv->cancel_path) {
-            tpo->cancel_path = g_strdup(drv->cancel_path);
-            tpo->has_cancel_path = true;
-        }
-        break;
-    case TPM_TYPE__MAX:
-        break;
-    }
-
-    return res;
-}
-
 /*
  * Walk the list of active TPM backends and collect information about them
  * following the schema description in qapi-schema.json.
@@ -246,7 +215,7 @@ TPMInfoList *qmp_query_tpm(Error **errp)
             continue;
         }
         info = g_new0(TPMInfoList, 1);
-        info->value = qmp_query_tpm_inst(drv);
+        info->value = tpm_backend_query_tpm(drv);
 
         if (!cur_item) {
             head = cur_item = info;
diff --git a/vl.c b/vl.c
index d7c349233f..0723835bbf 100644
--- a/vl.c
+++ b/vl.c
@@ -4905,6 +4905,7 @@ int main(int argc, char **argv, char **envp)
     res_free();
 
     /* vhost-user must be cleaned up before chardevs.  */
+    tpm_cleanup();
     net_cleanup();
     audio_cleanup();
     monitor_cleanup();