Re: [Qemu-devel] [PATCH v9 8/8] tpm: Added support for TPM emulator

["Valluri, Amarnath" <amarnath.valluri@intel.com>]

On Thu, 2017-09-28 at 13:53 +0200, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Sep 28, 2017 at 11:20 AM, Amarnath Valluri
> <amarnath.valluri@intel.com> wrote:
> > 
> > This change introduces a new TPM backend driver that can
> > communicate with
> > swtpm(software TPM emulator) using unix domain socket interface.
> > QEMU talks to
> > TPM emulator using QEMU's socket-based chardev backend device.
> > 
> > Swtpm uses two Unix sockets for communications, one for plain TPM
> > commands and
> > responses, and one for out-of-band control messages. QEMU passes
> > data socket to
> > be used over the control channel.
> > 
> > The swtpm and associated tools can be found here:
> >     https://github.com/stefanberger/swtpm
> > 
> > The swtpm's control channel protocol specification can be found
> > here:
> >     https://github.com/stefanberger/swtpm/wiki/Control-Channel-Spec
> > ification
> > 
> > Usage:
> >     # setup TPM state directory
> >     mkdir /tmp/mytpm
> >     chown -R tss:root /tmp/mytpm
> >     /usr/bin/swtpm_setup --tpm-state /tmp/mytpm --createek
> > 
> >     # Ask qemu to use TPM emulator with given tpm state directory
> >     qemu-system-x86_64 \
> >         [...] \
> >         -chardev socket,id=chrtpm,path=/tmp/swtpm-sock \
> >         -tpmdev emulator,id=tpm0,chardev=chrtpm \
> >         -device tpm-tis,tpmdev=tpm0 \
> >         [...]
> > 
> > Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com>
> > ---
> >  configure             |  13 +-
> >  hmp.c                 |   5 +
> >  hw/tpm/Makefile.objs  |   1 +
> >  hw/tpm/tpm_emulator.c | 599
> > ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  hw/tpm/tpm_ioctl.h    | 246 +++++++++++++++++++++
> >  qapi/tpm.json         |  21 +-
> >  qemu-options.hx       |  22 +-
> >  vl.c                  |   1 +
> >  8 files changed, 901 insertions(+), 7 deletions(-)
> >  create mode 100644 hw/tpm/tpm_emulator.c
> >  create mode 100644 hw/tpm/tpm_ioctl.h
> > 
> > diff --git a/configure b/configure
> > index cb0f7ed..a1b956e 100755
> > --- a/configure
> > +++ b/configure
> > @@ -3467,6 +3467,12 @@ 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
> > 
> > @@ -5359,6 +5365,7 @@ 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       $lzo"
> > @@ -5937,12 +5944,16 @@ if test "$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" >> $config_host_mak
> > diff --git a/hmp.c b/hmp.c
> > index 0fb2bc7..9cd8179 100644
> > --- a/hmp.c
> > +++ b/hmp.c
> > @@ -994,6 +994,7 @@ void hmp_info_tpm(Monitor *mon, const QDict
> > *qdict)
> >      Error *err = NULL;
> >      unsigned int c = 0;
> >      TPMPassthroughOptions *tpo;
> > +    TPMEmulatorOptions *teo;
> > 
> >      info_list = qmp_query_tpm(&err);
> >      if (err) {
> > @@ -1023,6 +1024,10 @@ void hmp_info_tpm(Monitor *mon, const QDict
> > *qdict)
> >                             tpo->has_cancel_path ? ",cancel-path="
> > : "",
> >                             tpo->has_cancel_path ? tpo->cancel_path 
> > : "");
> >              break;
> > +        case TPM_TYPE_OPTIONS_KIND_EMULATOR:
> > +            teo = ti->options->u.emulator.data;
> > +            monitor_printf(mon, ",chardev=%s", teo->chardev);
> > +            break;
> >          case TPM_TYPE_OPTIONS_KIND__MAX:
> >              break;
> >          }
> > diff --git a/hw/tpm/Makefile.objs b/hw/tpm/Makefile.objs
> > index 64cecc3..41f0b7a 100644
> > --- a/hw/tpm/Makefile.objs
> > +++ b/hw/tpm/Makefile.objs
> > @@ -1,2 +1,3 @@
> >  common-obj-$(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 0000000..0065b0a
> > --- /dev/null
> > +++ b/hw/tpm/tpm_emulator.c
> > @@ -0,0 +1,599 @@
> > +/*
> > + *  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.or
> > g/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 */
> > +    QemuMutex state_lock;
> The mutex isnt doing much with this code, as there should be no
> concurrent handle_request() (thread-pool has max-thread=1).
Yes I agree, I can remove this mutex in this case.
> 
> (I wonder if we could replace the thread-pool with a coroutine/bh
> doing IO instead to avoid potential thread races... or just do IO in
> the current context, like the ctrlcmd)
Yes we should. Can we do it as a separate PR?. As it touches both the
backends.

-Amarnath