Re: [Qemu-devel] [PATCH v6 8/8] tpm: Added support for TPM emulator

[Dr. David Alan Gilbert]

* Amarnath Valluri (address@hidden) wrote:
> On Tue, 2017-07-25 at 20:18 -0400, Stefan Berger wrote:
> > On 07/18/2017 04:49 AM, Amarnath Valluri wrote:
> > > 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..c90914c
> > > --- /dev/null
> > > +++ b/hw/tpm/tpm_emulator.c
> > > @@ -0,0 +1,973 @@
> > > +/*
> > > + *  emulator TPM driver
> > > + *
> > > + *  Copyright (c) 2017 Intel Corporation
> > > + *  Author: Amarnath Valluri <address@hidden>
> > > + *
> > > + *  Copyright (c) 2010 - 2013 IBM Corporation
> > > + *  Authors:
> > > + *    Stefan Berger <address@hidden>
> > > + *
> > > + *  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/migration.h"
> > > +#include "qapi/error.h"
> > > +
> > > +#include <fcntl.h>
> > > +#include <sys/types.h>
> > > +#include <sys/stat.h>
> > > +#include <stdio.h>
> > > +
> > > +#define DEBUG_TPM 0
> > > +
> > > +#define DPRINT(fmt, ...) do { \
> > > +    if (DEBUG_TPM) { \
> > > +        fprintf(stderr, fmt, ## __VA_ARGS__); \
> > > +    } \
> > > +} while (0);
> > > +
> > > +#define DPRINTF(fmt, ...) DPRINT("tpm-emulator: "fmt"\n", __VA_ARGS__)
> > > +
> > > +#define TYPE_TPM_EMULATOR "tpm-emulator"
> > > +#define TPM_EMULATOR(obj) \
> > > +    OBJECT_CHECK(TPMEmulator, (obj), TYPE_TPM_EMULATOR)
> > > +
> > > +static const TPMDriverOps tpm_emulator_driver;
> > > +
> > > +/* data structures */
> > > +typedef struct TPMEmulator {
> > > +    TPMBackend parent;
> > > +
> > > +    TPMEmulatorOptions *ops;
> > > +    QIOChannel *data_ioc;
> > > +    QIOChannel *ctrl_ioc;
> > > +    bool op_executing;
> > > +    bool op_canceled;
> > > +    bool child_running;
> > > +    TPMVersion tpm_version;
> > > +    ptm_cap caps; /* capabilities of the TPM */
> > > +    uint8_t cur_locty_number; /* last set locality */
> > > +    QemuMutex state_lock;
> > > +    Error *migration_blocker;
> > > +} TPMEmulator;
> > > +
> > > +#define TPM_DEFAULT_EMULATOR "swtpm"
> > > +#define TPM_DEFAULT_LOGLEVEL 5
> > > +#define TPM_EMULATOR_PIDFILE "/tmp/qemu-tpm.pid"
> > 
> > swtpm will write this file and remove it when it terminates. You may run 
> > into concurrency problems as well. I would extend this name with the pid 
> > of the QEMU process starting swtpm.
> Stefan, there was some issue in my reabasing and sent wrong version of
> patchset, but i made all the changes you suggested including the pid
> file.
> 
> But i did not sent the next version as Marc-André Lureau objected the
> the idea of spawning swtpm from Qemu. I started exploring his suggestion
> of 'chardev'.
> 
> I feel like we are back to square one :).

I agree with Marc-Andre that it's best not to spawn it from qemu; the
way we do pretty much all other external tools is to get something else
to start them up and wire them back in with a chardev.

Dave

> - Amarnath
> 
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK