* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-02 9:26 ` Marc-André Lureau
@ 2018-03-02 10:14 ` Dr. David Alan Gilbert
2018-03-03 2:52 ` Stefan Berger
2018-03-02 13:19 ` Stefan Berger
` (2 subsequent siblings)
3 siblings, 1 reply; 18+ messages in thread
From: Dr. David Alan Gilbert @ 2018-03-02 10:14 UTC (permalink / raw)
To: Marc-André Lureau; +Cc: Stefan Berger, QEMU, Juan Quintela
* Marc-André Lureau (marcandre.lureau@gmail.com) wrote:
> Hi Stefan
>
> On Thu, Mar 1, 2018 at 8:59 PM, Stefan Berger
> <stefanb@linux.vnet.ibm.com> wrote:
> > Extend the TPM emulator backend device with state migration support.
> >
> > The external TPM emulator 'swtpm' provides a protocol over
> > its control channel to retrieve its state blobs. We implement
> > functions for getting and setting the different state blobs.
> > In case the setting of the state blobs fails, we return a
> > negative errno code to fail the start of the VM.
> >
> > Since we have an external TPM emulator, we need to make sure
> > that we do not migrate the state for as long as it is busy
> > processing a request. We need to wait for notification that
> > the request has completed processing.
>
> Because qemu will have to deal with an external state, managed by the
> tpm emulator (different from other storage/nvram):
>
> - the emulator statedir must be different between source and dest? Can
> it be the same?
> - what is the story regarding versionning? Can you migrate from/to any
> version, or only the same version?
> - can the host source and destination be of different endianess?
> - how is suspend and snapshot working?
>
> There are probably other complications that I can't think of
> immediately, but David or Juan help may help avoid mistakes.
Yes, I think that just about covers it.
> It probably deserves a few explanations in docs/specs/tpm.txt.
>
> >
> > Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
> > ---
> > hw/tpm/tpm_emulator.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++--
>
> It would be worth to add some basic tests. Either growing our own
> tests/tpm-emu.c test emulator
>
> or checking that swtpm is present (and of required version?) to
> run/skip the test a more complete test.
>
> > 1 file changed, 302 insertions(+), 10 deletions(-)
> >
> > diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
> > index b787aee..da877e5 100644
> > --- a/hw/tpm/tpm_emulator.c
> > +++ b/hw/tpm/tpm_emulator.c
> > @@ -55,6 +55,19 @@
> > #define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
> >
> > /* data structures */
> > +
> > +/* blobs from the TPM; part of VM state when migrating */
> > +typedef struct TPMBlobBuffers {
> > + uint32_t permanent_flags;
> > + TPMSizedBuffer permanent;
> > +
> > + uint32_t volatil_flags;
> > + TPMSizedBuffer volatil;
> > +
> > + uint32_t savestate_flags;
> > + TPMSizedBuffer savestate;
> > +} TPMBlobBuffers;
> > +
> > typedef struct TPMEmulator {
> > TPMBackend parent;
> >
> > @@ -70,6 +83,8 @@ typedef struct TPMEmulator {
> >
> > unsigned int established_flag:1;
> > unsigned int established_flag_cached:1;
> > +
> > + TPMBlobBuffers state_blobs;
>
> Suspicious addition, it shouldn't be necessary in running state. It
> could be allocated on demand? Even better if the field is removed, but
> this may not be possible with VMSTATE macros.
>
> > } TPMEmulator;
> >
> >
> > @@ -301,7 +316,8 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
> > return 0;
> > }
> >
> > -static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
> > +static int _tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize,
> > + bool is_resume)
>
> Using underscore-prefixed names is discouraged. Call it tpm_emulator_init?
>
> > {
> > TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > ptm_init init = {
> > @@ -309,12 +325,17 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
> > };
> > ptm_res res;
> >
> > + DPRINTF("%s is_resume: %d", __func__, is_resume);
> > +
>
> extra spaces, you may also add buffersize while at it.
Also it would be good to use trace_'s where possible rather than
DPRINTFs.
>
> > if (buffersize != 0 &&
> > tpm_emulator_set_buffer_size(tb, buffersize, NULL) < 0) {
> > goto err_exit;
> > }
> >
> > - DPRINTF("%s", __func__);
> > + if (is_resume) {
> > + init.u.req.init_flags = cpu_to_be32(PTM_INIT_FLAG_DELETE_VOLATILE);
> > + }
>
> Since it's a flags, and for future extensibility, I would suggest |=.
>
> > +
> > if (tpm_emulator_ctrlcmd(tpm_emu, CMD_INIT, &init, sizeof(init),
> > sizeof(init)) < 0) {
> > error_report("tpm-emulator: could not send INIT: %s",
> > @@ -333,6 +354,11 @@ err_exit:
> > return -1;
> > }
> >
> > +static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
> > +{
> > + return _tpm_emulator_startup_tpm(tb, buffersize, false);
> > +}
> > +
> > static bool tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
> > {
> > TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > @@ -431,16 +457,21 @@ static size_t tpm_emulator_get_buffer_size(TPMBackend *tb)
> > static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
> > {
> > Error *err = NULL;
> > + ptm_cap caps = PTM_CAP_GET_STATEBLOB | PTM_CAP_SET_STATEBLOB |
> > + PTM_CAP_STOP;
> >
> > - 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;
> > + if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, caps)) {
> > + error_setg(&tpm_emu->migration_blocker,
> > + "Migration disabled: TPM emulator does not support "
> > + "migration");
> > + 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 -1;
> > + }
> > }
> >
> > return 0;
> > @@ -569,6 +600,263 @@ static const QemuOptDesc tpm_emulator_cmdline_opts[] = {
> > { /* end of list */ },
> > };
> >
> > +/*
> > + * Transfer a TPM state blob from the TPM into a provided buffer.
> > + *
> > + * @tpm_emu: TPMEmulator
> > + * @type: the type of blob to transfer
> > + * @tsb: the TPMSizeBuffer to fill with the blob
> > + * @flags: the flags to return to the caller
> > + */
> > +static int tpm_emulator_get_state_blob(TPMEmulator *tpm_emu,
> > + uint8_t type,
> > + TPMSizedBuffer *tsb,
> > + uint32_t *flags)
> > +{
> > + ptm_getstate pgs;
> > + ptm_res res;
> > + ssize_t n;
> > + uint32_t totlength, length;
> > +
> > + tpm_sized_buffer_reset(tsb);
> > +
> > + pgs.u.req.state_flags = cpu_to_be32(PTM_STATE_FLAG_DECRYPTED);
> > + pgs.u.req.type = cpu_to_be32(type);
> > + pgs.u.req.offset = 0;
> > +
> > + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_GET_STATEBLOB,
> > + &pgs, sizeof(pgs.u.req),
> > + offsetof(ptm_getstate, u.resp.data)) < 0) {
> > + error_report("tpm-emulator: could not get state blob type %d : %s",
> > + type, strerror(errno));
> > + return -1;
>
> (I guess some day vmstate functions should have an Error ** argument)
>
> > + }
> > +
> > + res = be32_to_cpu(pgs.u.resp.tpm_result);
> > + if (res != 0 && (res & 0x800) == 0) {
> > + error_report("tpm-emulator: Getting the stateblob (type %d) failed "
> > + "with a TPM error 0x%x", type, res);
> > + return -1;
> > + }
> > +
> > + totlength = be32_to_cpu(pgs.u.resp.totlength);
> > + length = be32_to_cpu(pgs.u.resp.length);
> > + if (totlength != length) {
> > + error_report("tpm-emulator: Expecting to read %u bytes "
> > + "but would get %u", totlength, length);
> > + return -1;
> > + }
> > +
> > + *flags = be32_to_cpu(pgs.u.resp.state_flags);
> > +
> > + tsb->buffer = g_malloc(totlength);
>
> That TPMSizedBuffer is not really useful. Use GArray or qemu Buffer ?
> (and we could drop TPMSizedBuffer).
Also, given this is an arbitrary sized chunk, this should probably use
g_try_malloc and check the result rather than letting g_malloc assert on
failure (especially true on the source side).
> > + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr, tsb->buffer, totlength);
> > + if (n != totlength) {
> > + error_report("tpm-emulator: Could not read stateblob (type %d) : %s",
> > + type, strerror(errno));
> > + return -1;
> > + }
> > + tsb->size = totlength;
> > +
> > + DPRINTF("got state blob type %d, %d bytes, flags 0x%08x\n",
> > + type, tsb->size, *flags);
> > +
> > + return 0;
> > +}
> > +
> > +static int tpm_emulator_get_state_blobs(TPMEmulator *tpm_emu)
> > +{
> > + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
> > +
> > + if (tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
> > + &state_blobs->permanent,
> > + &state_blobs->permanent_flags) < 0 ||
> > + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
> > + &state_blobs->volatil,
> > + &state_blobs->volatil_flags) < 0 ||
> > + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
> > + &state_blobs->savestate,
> > + &state_blobs->savestate_flags) < 0) {
> > + goto err_exit;
> > + }
> > +
> > + return 0;
> > +
> > + err_exit:
> > + tpm_sized_buffer_reset(&state_blobs->volatil);
> > + tpm_sized_buffer_reset(&state_blobs->permanent);
> > + tpm_sized_buffer_reset(&state_blobs->savestate);
> > +
> > + return -1;
> > +}
> > +
> > +/*
> > + * Transfer a TPM state blob to the TPM emulator.
> > + *
> > + * @tpm_emu: TPMEmulator
> > + * @type: the type of TPM state blob to transfer
> > + * @tsb: TPMSizeBuffer containing the TPM state blob
> > + * @flags: Flags describing the (encryption) state of the TPM state blob
> > + */
> > +static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
> > + uint32_t type,
> > + TPMSizedBuffer *tsb,
> > + uint32_t flags)
> > +{
> > + uint32_t offset = 0;
> > + ssize_t n;
> > + ptm_setstate pss;
> > + ptm_res tpm_result;
> > +
> > + if (tsb->size == 0) {
> > + return 0;
> > + }
> > +
> > + pss = (ptm_setstate) {
> > + .u.req.state_flags = cpu_to_be32(flags),
> > + .u.req.type = cpu_to_be32(type),
> > + .u.req.length = cpu_to_be32(tsb->size),
> > + };
> > +
> > + /* write the header only */
> > + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
> > + offsetof(ptm_setstate, u.req.data), 0) < 0) {
> > + error_report("tpm-emulator: could not set state blob type %d : %s",
> > + type, strerror(errno));
> > + return -1;
> > + }
> > +
> > + /* now the body */
> > + n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr,
> > + &tsb->buffer[offset], tsb->size);
> > + if (n != tsb->size) {
> > + error_report("tpm-emulator: Writing the stateblob (type %d) "
> > + "failed: %s", type, strerror(errno));
> > + return -1;
> > + }
> > +
> > + /* now get the result */
> > + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
> > + (uint8_t *)&pss, sizeof(pss.u.resp));
> > + if (n != sizeof(pss.u.resp)) {
> > + error_report("tpm-emulator: Reading response from writing stateblob "
> > + "(type %d) failed: %s", type, strerror(errno));
> > + return -1;
> > + }
> > +
> > + tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
> > + if (tpm_result != 0) {
> > + error_report("tpm-emulator: Setting the stateblob (type %d) failed "
> > + "with a TPM error 0x%x", type, tpm_result);
> > + return -1;
> > + }
> > +
> > + DPRINTF("set the state blob type %d, %d bytes, flags 0x%08x\n",
> > + type, tsb->size, flags);
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Set all the TPM state blobs.
> > + *
> > + * Returns a negative errno code in case of error.
> > + */
> > +static int tpm_emulator_set_state_blobs(TPMBackend *tb)
> > +{
> > + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
> > +
> > + DPRINTF("%s: %d", __func__, __LINE__);
> > +
> > + if (tpm_emulator_stop_tpm(tb) < 0) {
> > + return -EIO;
> > + }
> > +
> > + if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
> > + &state_blobs->permanent,
> > + state_blobs->permanent_flags) < 0 ||
> > + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
> > + &state_blobs->volatil,
> > + state_blobs->volatil_flags) < 0 ||
> > + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
> > + &state_blobs->savestate,
> > + state_blobs->savestate_flags) < 0) {
> > + return -EBADMSG;
> > + }
> > +
> > + DPRINTF("DONE SETTING STATEBLOBS");
>
> UPPERCASES!
>
> > +
> > + return 0;
> > +}
> > +
> > +static int tpm_emulator_pre_save(void *opaque)
> > +{
> > + TPMBackend *tb = opaque;
> > + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > +
> > + DPRINTF("%s", __func__);
> > +
> > + tpm_backend_finish_sync(tb);
> > +
> > + /* get the state blobs from the TPM */
> > + return tpm_emulator_get_state_blobs(tpm_emu);
> > +}
> > +
> > +/*
> > + * Load the TPM state blobs into the TPM.
> > + *
> > + * Returns negative errno codes in case of error.
> > + */
> > +static int tpm_emulator_post_load(void *opaque,
> > + int version_id __attribute__((unused)))
>
> unnecessary attribute
>
> > +{
> > + TPMBackend *tb = opaque;
> > + int ret;
> > +
> > + ret = tpm_emulator_set_state_blobs(tb);
> > + if (ret < 0) {
> > + return ret;
> > + }
> > +
> > + if (_tpm_emulator_startup_tpm(tb, 0, true) < 0) {
> > + return -EIO;
> > + }
> > +
>
> I dislike the mix of functions returning errno and others, and the
> lack of Error **, but it's not specific to this patch. Ok. :)
>
> > + return 0;
> > +}
> > +
> > +static const VMStateDescription vmstate_tpm_emulator = {
> > + .name = "tpm-emulator",
> > + .version_id = 1,
> > + .minimum_version_id = 0,
>
> version_id = 1 & minimum_version_id = 0 ?
>
> It's the first version, let's have version_id = 0 (and you could
> remove minimum_version).
>
> > + .minimum_version_id_old = 0,
>
> No need to specify that, no load_state_old() either
>
> > + .pre_save = tpm_emulator_pre_save,
> > + .post_load = tpm_emulator_post_load,
> > + .fields = (VMStateField[]) {
> > + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
> > + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
> > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
> > + TPMEmulator, 1, 0,
> > + state_blobs.permanent.size),
> > +
> > + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
> > + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
> > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
> > + TPMEmulator, 1, 0,
> > + state_blobs.volatil.size),
> > +
> > + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
> > + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
> > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
> > + TPMEmulator, 1, 0,
> > + state_blobs.savestate.size),
> > +
> > + VMSTATE_END_OF_LIST()
> > + }
> > +};
> > +
> > static void tpm_emulator_inst_init(Object *obj)
> > {
> > TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
> > @@ -577,6 +865,8 @@ static void tpm_emulator_inst_init(Object *obj)
> > tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
> > tpm_emu->cur_locty_number = ~0;
> > qemu_mutex_init(&tpm_emu->mutex);
> > +
> > + vmstate_register(NULL, -1, &vmstate_tpm_emulator, obj);
> > }
> >
> > /*
> > @@ -613,6 +903,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
> > }
> >
> > qemu_mutex_destroy(&tpm_emu->mutex);
> > +
> > + vmstate_unregister(NULL, &vmstate_tpm_emulator, obj);
It's best to avoid the vmstate_register/unregister and just set the
dc->vmsd pointer during class_init; see hw/virtio/virtio-balloon.c
virtio_balloon_class_init for an example.
Dave
> > }
> >
> > static void tpm_emulator_class_init(ObjectClass *klass, void *data)
> > --
> > 2.5.5
> >
> >
>
> looks good to me overall
>
> --
> Marc-André Lureau
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 18+ messages in thread* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-02 10:14 ` Dr. David Alan Gilbert
@ 2018-03-03 2:52 ` Stefan Berger
2018-03-05 12:43 ` Dr. David Alan Gilbert
0 siblings, 1 reply; 18+ messages in thread
From: Stefan Berger @ 2018-03-03 2:52 UTC (permalink / raw)
To: Dr. David Alan Gilbert, Marc-André Lureau; +Cc: Juan Quintela, QEMU
On 03/02/2018 05:14 AM, Dr. David Alan Gilbert wrote:
> * Marc-André Lureau (marcandre.lureau@gmail.com) wrote:
>> Hi Stefan
>>
>> On Thu, Mar 1, 2018 at 8:59 PM, Stefan Berger
>> <stefanb@linux.vnet.ibm.com> wrote:
>>> Extend the TPM emulator backend device with state migration support.
>>>
>>> The external TPM emulator 'swtpm' provides a protocol over
>>> its control channel to retrieve its state blobs. We implement
>>> functions for getting and setting the different state blobs.
>>> In case the setting of the state blobs fails, we return a
>>> negative errno code to fail the start of the VM.
>>>
>>> Since we have an external TPM emulator, we need to make sure
>>> that we do not migrate the state for as long as it is busy
>>> processing a request. We need to wait for notification that
>>> the request has completed processing.
>> Because qemu will have to deal with an external state, managed by the
>> tpm emulator (different from other storage/nvram):
>>
>> - the emulator statedir must be different between source and dest? Can
>> it be the same?
>> - what is the story regarding versionning? Can you migrate from/to any
>> version, or only the same version?
>> - can the host source and destination be of different endianess?
>> - how is suspend and snapshot working?
>>
>> There are probably other complications that I can't think of
>> immediately, but David or Juan help may help avoid mistakes.
> Yes, I think that just about covers it.
>
>> It probably deserves a few explanations in docs/specs/tpm.txt.
>>
>>> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
>>> ---
>>> hw/tpm/tpm_emulator.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++--
>> It would be worth to add some basic tests. Either growing our own
>> tests/tpm-emu.c test emulator
>>
>> or checking that swtpm is present (and of required version?) to
>> run/skip the test a more complete test.
>>
>>> 1 file changed, 302 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
>>> index b787aee..da877e5 100644
>>> --- a/hw/tpm/tpm_emulator.c
>>> +++ b/hw/tpm/tpm_emulator.c
>>> @@ -55,6 +55,19 @@
>>> #define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
>>>
>>> /* data structures */
>>> +
>>> +/* blobs from the TPM; part of VM state when migrating */
>>> +typedef struct TPMBlobBuffers {
>>> + uint32_t permanent_flags;
>>> + TPMSizedBuffer permanent;
>>> +
>>> + uint32_t volatil_flags;
>>> + TPMSizedBuffer volatil;
>>> +
>>> + uint32_t savestate_flags;
>>> + TPMSizedBuffer savestate;
>>> +} TPMBlobBuffers;
>>> +
>>> typedef struct TPMEmulator {
>>> TPMBackend parent;
>>>
>>> @@ -70,6 +83,8 @@ typedef struct TPMEmulator {
>>>
>>> unsigned int established_flag:1;
>>> unsigned int established_flag_cached:1;
>>> +
>>> + TPMBlobBuffers state_blobs;
>> Suspicious addition, it shouldn't be necessary in running state. It
>> could be allocated on demand? Even better if the field is removed, but
>> this may not be possible with VMSTATE macros.
>>
>>> } TPMEmulator;
>>>
>>>
>>> @@ -301,7 +316,8 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
>>> return 0;
>>> }
>>>
>>> -static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>>> +static int _tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize,
>>> + bool is_resume)
>> Using underscore-prefixed names is discouraged. Call it tpm_emulator_init?
>>
>>> {
>>> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>>> ptm_init init = {
>>> @@ -309,12 +325,17 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>>> };
>>> ptm_res res;
>>>
>>> + DPRINTF("%s is_resume: %d", __func__, is_resume);
>>> +
>> extra spaces, you may also add buffersize while at it.
> Also it would be good to use trace_'s where possible rather than
> DPRINTFs.
Here's a branch where I am doing that now:
https://github.com/stefanberger/qemu-tpm/commits/tracing
I would leave a DEBUG_TIS in the tpm_tis.c, though.
>> That TPMSizedBuffer is not really useful. Use GArray or qemu Buffer ?
>> (and we could drop TPMSizedBuffer).
> Also, given this is an arbitrary sized chunk, this should probably use
> g_try_malloc and check the result rather than letting g_malloc assert on
> failure (especially true on the source side).
Will fix. Thanks.
>
>>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr, tsb->buffer, totlength);
>>> + if (n != totlength) {
>>> + error_report("tpm-emulator: Could not read stateblob (type %d) : %s",
>>> + type, strerror(errno));
>>> + return -1;
>>> + }
>>> + tsb->size = totlength;
>>> +
>>> + DPRINTF("got state blob type %d, %d bytes, flags 0x%08x\n",
>>> + type, tsb->size, *flags);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int tpm_emulator_get_state_blobs(TPMEmulator *tpm_emu)
>>> +{
>>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>>> +
>>> + if (tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>>> + &state_blobs->permanent,
>>> + &state_blobs->permanent_flags) < 0 ||
>>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>>> + &state_blobs->volatil,
>>> + &state_blobs->volatil_flags) < 0 ||
>>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>>> + &state_blobs->savestate,
>>> + &state_blobs->savestate_flags) < 0) {
>>> + goto err_exit;
>>> + }
>>> +
>>> + return 0;
>>> +
>>> + err_exit:
>>> + tpm_sized_buffer_reset(&state_blobs->volatil);
>>> + tpm_sized_buffer_reset(&state_blobs->permanent);
>>> + tpm_sized_buffer_reset(&state_blobs->savestate);
>>> +
>>> + return -1;
>>> +}
>>> +
>>> +/*
>>> + * Transfer a TPM state blob to the TPM emulator.
>>> + *
>>> + * @tpm_emu: TPMEmulator
>>> + * @type: the type of TPM state blob to transfer
>>> + * @tsb: TPMSizeBuffer containing the TPM state blob
>>> + * @flags: Flags describing the (encryption) state of the TPM state blob
>>> + */
>>> +static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
>>> + uint32_t type,
>>> + TPMSizedBuffer *tsb,
>>> + uint32_t flags)
>>> +{
>>> + uint32_t offset = 0;
>>> + ssize_t n;
>>> + ptm_setstate pss;
>>> + ptm_res tpm_result;
>>> +
>>> + if (tsb->size == 0) {
>>> + return 0;
>>> + }
>>> +
>>> + pss = (ptm_setstate) {
>>> + .u.req.state_flags = cpu_to_be32(flags),
>>> + .u.req.type = cpu_to_be32(type),
>>> + .u.req.length = cpu_to_be32(tsb->size),
>>> + };
>>> +
>>> + /* write the header only */
>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
>>> + offsetof(ptm_setstate, u.req.data), 0) < 0) {
>>> + error_report("tpm-emulator: could not set state blob type %d : %s",
>>> + type, strerror(errno));
>>> + return -1;
>>> + }
>>> +
>>> + /* now the body */
>>> + n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr,
>>> + &tsb->buffer[offset], tsb->size);
>>> + if (n != tsb->size) {
>>> + error_report("tpm-emulator: Writing the stateblob (type %d) "
>>> + "failed: %s", type, strerror(errno));
>>> + return -1;
>>> + }
>>> +
>>> + /* now get the result */
>>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
>>> + (uint8_t *)&pss, sizeof(pss.u.resp));
>>> + if (n != sizeof(pss.u.resp)) {
>>> + error_report("tpm-emulator: Reading response from writing stateblob "
>>> + "(type %d) failed: %s", type, strerror(errno));
>>> + return -1;
>>> + }
>>> +
>>> + tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
>>> + if (tpm_result != 0) {
>>> + error_report("tpm-emulator: Setting the stateblob (type %d) failed "
>>> + "with a TPM error 0x%x", type, tpm_result);
>>> + return -1;
>>> + }
>>> +
>>> + DPRINTF("set the state blob type %d, %d bytes, flags 0x%08x\n",
>>> + type, tsb->size, flags);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +/*
>>> + * Set all the TPM state blobs.
>>> + *
>>> + * Returns a negative errno code in case of error.
>>> + */
>>> +static int tpm_emulator_set_state_blobs(TPMBackend *tb)
>>> +{
>>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>>> +
>>> + DPRINTF("%s: %d", __func__, __LINE__);
>>> +
>>> + if (tpm_emulator_stop_tpm(tb) < 0) {
>>> + return -EIO;
>>> + }
>>> +
>>> + if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>>> + &state_blobs->permanent,
>>> + state_blobs->permanent_flags) < 0 ||
>>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>>> + &state_blobs->volatil,
>>> + state_blobs->volatil_flags) < 0 ||
>>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>>> + &state_blobs->savestate,
>>> + state_blobs->savestate_flags) < 0) {
>>> + return -EBADMSG;
>>> + }
>>> +
>>> + DPRINTF("DONE SETTING STATEBLOBS");
>> UPPERCASES!
>>
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int tpm_emulator_pre_save(void *opaque)
>>> +{
>>> + TPMBackend *tb = opaque;
>>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>>> +
>>> + DPRINTF("%s", __func__);
>>> +
>>> + tpm_backend_finish_sync(tb);
>>> +
>>> + /* get the state blobs from the TPM */
>>> + return tpm_emulator_get_state_blobs(tpm_emu);
>>> +}
>>> +
>>> +/*
>>> + * Load the TPM state blobs into the TPM.
>>> + *
>>> + * Returns negative errno codes in case of error.
>>> + */
>>> +static int tpm_emulator_post_load(void *opaque,
>>> + int version_id __attribute__((unused)))
>> unnecessary attribute
>>
>>> +{
>>> + TPMBackend *tb = opaque;
>>> + int ret;
>>> +
>>> + ret = tpm_emulator_set_state_blobs(tb);
>>> + if (ret < 0) {
>>> + return ret;
>>> + }
>>> +
>>> + if (_tpm_emulator_startup_tpm(tb, 0, true) < 0) {
>>> + return -EIO;
>>> + }
>>> +
>> I dislike the mix of functions returning errno and others, and the
>> lack of Error **, but it's not specific to this patch. Ok. :)
>>
>>> + return 0;
>>> +}
>>> +
>>> +static const VMStateDescription vmstate_tpm_emulator = {
>>> + .name = "tpm-emulator",
>>> + .version_id = 1,
>>> + .minimum_version_id = 0,
>> version_id = 1 & minimum_version_id = 0 ?
>>
>> It's the first version, let's have version_id = 0 (and you could
>> remove minimum_version).
>>
>>> + .minimum_version_id_old = 0,
>> No need to specify that, no load_state_old() either
>>
>>> + .pre_save = tpm_emulator_pre_save,
>>> + .post_load = tpm_emulator_post_load,
>>> + .fields = (VMStateField[]) {
>>> + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
>>> + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
>>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
>>> + TPMEmulator, 1, 0,
>>> + state_blobs.permanent.size),
>>> +
>>> + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
>>> + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
>>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
>>> + TPMEmulator, 1, 0,
>>> + state_blobs.volatil.size),
>>> +
>>> + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
>>> + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
>>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
>>> + TPMEmulator, 1, 0,
>>> + state_blobs.savestate.size),
>>> +
>>> + VMSTATE_END_OF_LIST()
>>> + }
>>> +};
>>> +
>>> static void tpm_emulator_inst_init(Object *obj)
>>> {
>>> TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
>>> @@ -577,6 +865,8 @@ static void tpm_emulator_inst_init(Object *obj)
>>> tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
>>> tpm_emu->cur_locty_number = ~0;
>>> qemu_mutex_init(&tpm_emu->mutex);
>>> +
>>> + vmstate_register(NULL, -1, &vmstate_tpm_emulator, obj);
>>> }
>>>
>>> /*
>>> @@ -613,6 +903,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
>>> }
>>>
>>> qemu_mutex_destroy(&tpm_emu->mutex);
>>> +
>>> + vmstate_unregister(NULL, &vmstate_tpm_emulator, obj);
> It's best to avoid the vmstate_register/unregister and just set the
> dc->vmsd pointer during class_init; see hw/virtio/virtio-balloon.c
> virtio_balloon_class_init for an example.
hw/tpm/tpm_emulator.c:909:tpm_emulator_class_init: Object 0x55f4cbc72680
is not an instance of type device
Aborted
Can we leave it as it is ?
Thanks for the review.
Stefan
^ permalink raw reply [flat|nested] 18+ messages in thread* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-03 2:52 ` Stefan Berger
@ 2018-03-05 12:43 ` Dr. David Alan Gilbert
2018-03-05 13:52 ` Stefan Berger
0 siblings, 1 reply; 18+ messages in thread
From: Dr. David Alan Gilbert @ 2018-03-05 12:43 UTC (permalink / raw)
To: Stefan Berger; +Cc: Marc-André Lureau, Juan Quintela, QEMU
* Stefan Berger (stefanb@linux.vnet.ibm.com) wrote:
> On 03/02/2018 05:14 AM, Dr. David Alan Gilbert wrote:
> > * Marc-André Lureau (marcandre.lureau@gmail.com) wrote:
> > > Hi Stefan
> > >
> > > On Thu, Mar 1, 2018 at 8:59 PM, Stefan Berger
> > > <stefanb@linux.vnet.ibm.com> wrote:
> > > > Extend the TPM emulator backend device with state migration support.
> > > >
> > > > The external TPM emulator 'swtpm' provides a protocol over
> > > > its control channel to retrieve its state blobs. We implement
> > > > functions for getting and setting the different state blobs.
> > > > In case the setting of the state blobs fails, we return a
> > > > negative errno code to fail the start of the VM.
> > > >
> > > > Since we have an external TPM emulator, we need to make sure
> > > > that we do not migrate the state for as long as it is busy
> > > > processing a request. We need to wait for notification that
> > > > the request has completed processing.
> > > Because qemu will have to deal with an external state, managed by the
> > > tpm emulator (different from other storage/nvram):
> > >
> > > - the emulator statedir must be different between source and dest? Can
> > > it be the same?
> > > - what is the story regarding versionning? Can you migrate from/to any
> > > version, or only the same version?
> > > - can the host source and destination be of different endianess?
> > > - how is suspend and snapshot working?
> > >
> > > There are probably other complications that I can't think of
> > > immediately, but David or Juan help may help avoid mistakes.
> > Yes, I think that just about covers it.
> >
> > > It probably deserves a few explanations in docs/specs/tpm.txt.
> > >
> > > > Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
> > > > ---
> > > > hw/tpm/tpm_emulator.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++--
> > > It would be worth to add some basic tests. Either growing our own
> > > tests/tpm-emu.c test emulator
> > >
> > > or checking that swtpm is present (and of required version?) to
> > > run/skip the test a more complete test.
> > >
> > > > 1 file changed, 302 insertions(+), 10 deletions(-)
> > > >
> > > > diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
> > > > index b787aee..da877e5 100644
> > > > --- a/hw/tpm/tpm_emulator.c
> > > > +++ b/hw/tpm/tpm_emulator.c
> > > > @@ -55,6 +55,19 @@
> > > > #define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
> > > >
> > > > /* data structures */
> > > > +
> > > > +/* blobs from the TPM; part of VM state when migrating */
> > > > +typedef struct TPMBlobBuffers {
> > > > + uint32_t permanent_flags;
> > > > + TPMSizedBuffer permanent;
> > > > +
> > > > + uint32_t volatil_flags;
> > > > + TPMSizedBuffer volatil;
> > > > +
> > > > + uint32_t savestate_flags;
> > > > + TPMSizedBuffer savestate;
> > > > +} TPMBlobBuffers;
> > > > +
> > > > typedef struct TPMEmulator {
> > > > TPMBackend parent;
> > > >
> > > > @@ -70,6 +83,8 @@ typedef struct TPMEmulator {
> > > >
> > > > unsigned int established_flag:1;
> > > > unsigned int established_flag_cached:1;
> > > > +
> > > > + TPMBlobBuffers state_blobs;
> > > Suspicious addition, it shouldn't be necessary in running state. It
> > > could be allocated on demand? Even better if the field is removed, but
> > > this may not be possible with VMSTATE macros.
> > >
> > > > } TPMEmulator;
> > > >
> > > >
> > > > @@ -301,7 +316,8 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
> > > > return 0;
> > > > }
> > > >
> > > > -static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
> > > > +static int _tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize,
> > > > + bool is_resume)
> > > Using underscore-prefixed names is discouraged. Call it tpm_emulator_init?
> > >
> > > > {
> > > > TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > > > ptm_init init = {
> > > > @@ -309,12 +325,17 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
> > > > };
> > > > ptm_res res;
> > > >
> > > > + DPRINTF("%s is_resume: %d", __func__, is_resume);
> > > > +
> > > extra spaces, you may also add buffersize while at it.
> > Also it would be good to use trace_'s where possible rather than
> > DPRINTFs.
>
> Here's a branch where I am doing that now:
>
> https://github.com/stefanberger/qemu-tpm/commits/tracing
>
> I would leave a DEBUG_TIS in the tpm_tis.c, though.
>
> > > That TPMSizedBuffer is not really useful. Use GArray or qemu Buffer ?
> > > (and we could drop TPMSizedBuffer).
> > Also, given this is an arbitrary sized chunk, this should probably use
> > g_try_malloc and check the result rather than letting g_malloc assert on
> > failure (especially true on the source side).
>
> Will fix. Thanks.
>
>
> >
> > > > + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr, tsb->buffer, totlength);
> > > > + if (n != totlength) {
> > > > + error_report("tpm-emulator: Could not read stateblob (type %d) : %s",
> > > > + type, strerror(errno));
> > > > + return -1;
> > > > + }
> > > > + tsb->size = totlength;
> > > > +
> > > > + DPRINTF("got state blob type %d, %d bytes, flags 0x%08x\n",
> > > > + type, tsb->size, *flags);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int tpm_emulator_get_state_blobs(TPMEmulator *tpm_emu)
> > > > +{
> > > > + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
> > > > +
> > > > + if (tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
> > > > + &state_blobs->permanent,
> > > > + &state_blobs->permanent_flags) < 0 ||
> > > > + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
> > > > + &state_blobs->volatil,
> > > > + &state_blobs->volatil_flags) < 0 ||
> > > > + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
> > > > + &state_blobs->savestate,
> > > > + &state_blobs->savestate_flags) < 0) {
> > > > + goto err_exit;
> > > > + }
> > > > +
> > > > + return 0;
> > > > +
> > > > + err_exit:
> > > > + tpm_sized_buffer_reset(&state_blobs->volatil);
> > > > + tpm_sized_buffer_reset(&state_blobs->permanent);
> > > > + tpm_sized_buffer_reset(&state_blobs->savestate);
> > > > +
> > > > + return -1;
> > > > +}
> > > > +
> > > > +/*
> > > > + * Transfer a TPM state blob to the TPM emulator.
> > > > + *
> > > > + * @tpm_emu: TPMEmulator
> > > > + * @type: the type of TPM state blob to transfer
> > > > + * @tsb: TPMSizeBuffer containing the TPM state blob
> > > > + * @flags: Flags describing the (encryption) state of the TPM state blob
> > > > + */
> > > > +static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
> > > > + uint32_t type,
> > > > + TPMSizedBuffer *tsb,
> > > > + uint32_t flags)
> > > > +{
> > > > + uint32_t offset = 0;
> > > > + ssize_t n;
> > > > + ptm_setstate pss;
> > > > + ptm_res tpm_result;
> > > > +
> > > > + if (tsb->size == 0) {
> > > > + return 0;
> > > > + }
> > > > +
> > > > + pss = (ptm_setstate) {
> > > > + .u.req.state_flags = cpu_to_be32(flags),
> > > > + .u.req.type = cpu_to_be32(type),
> > > > + .u.req.length = cpu_to_be32(tsb->size),
> > > > + };
> > > > +
> > > > + /* write the header only */
> > > > + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
> > > > + offsetof(ptm_setstate, u.req.data), 0) < 0) {
> > > > + error_report("tpm-emulator: could not set state blob type %d : %s",
> > > > + type, strerror(errno));
> > > > + return -1;
> > > > + }
> > > > +
> > > > + /* now the body */
> > > > + n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr,
> > > > + &tsb->buffer[offset], tsb->size);
> > > > + if (n != tsb->size) {
> > > > + error_report("tpm-emulator: Writing the stateblob (type %d) "
> > > > + "failed: %s", type, strerror(errno));
> > > > + return -1;
> > > > + }
> > > > +
> > > > + /* now get the result */
> > > > + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
> > > > + (uint8_t *)&pss, sizeof(pss.u.resp));
> > > > + if (n != sizeof(pss.u.resp)) {
> > > > + error_report("tpm-emulator: Reading response from writing stateblob "
> > > > + "(type %d) failed: %s", type, strerror(errno));
> > > > + return -1;
> > > > + }
> > > > +
> > > > + tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
> > > > + if (tpm_result != 0) {
> > > > + error_report("tpm-emulator: Setting the stateblob (type %d) failed "
> > > > + "with a TPM error 0x%x", type, tpm_result);
> > > > + return -1;
> > > > + }
> > > > +
> > > > + DPRINTF("set the state blob type %d, %d bytes, flags 0x%08x\n",
> > > > + type, tsb->size, flags);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/*
> > > > + * Set all the TPM state blobs.
> > > > + *
> > > > + * Returns a negative errno code in case of error.
> > > > + */
> > > > +static int tpm_emulator_set_state_blobs(TPMBackend *tb)
> > > > +{
> > > > + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > > > + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
> > > > +
> > > > + DPRINTF("%s: %d", __func__, __LINE__);
> > > > +
> > > > + if (tpm_emulator_stop_tpm(tb) < 0) {
> > > > + return -EIO;
> > > > + }
> > > > +
> > > > + if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
> > > > + &state_blobs->permanent,
> > > > + state_blobs->permanent_flags) < 0 ||
> > > > + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
> > > > + &state_blobs->volatil,
> > > > + state_blobs->volatil_flags) < 0 ||
> > > > + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
> > > > + &state_blobs->savestate,
> > > > + state_blobs->savestate_flags) < 0) {
> > > > + return -EBADMSG;
> > > > + }
> > > > +
> > > > + DPRINTF("DONE SETTING STATEBLOBS");
> > > UPPERCASES!
> > >
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int tpm_emulator_pre_save(void *opaque)
> > > > +{
> > > > + TPMBackend *tb = opaque;
> > > > + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> > > > +
> > > > + DPRINTF("%s", __func__);
> > > > +
> > > > + tpm_backend_finish_sync(tb);
> > > > +
> > > > + /* get the state blobs from the TPM */
> > > > + return tpm_emulator_get_state_blobs(tpm_emu);
> > > > +}
> > > > +
> > > > +/*
> > > > + * Load the TPM state blobs into the TPM.
> > > > + *
> > > > + * Returns negative errno codes in case of error.
> > > > + */
> > > > +static int tpm_emulator_post_load(void *opaque,
> > > > + int version_id __attribute__((unused)))
> > > unnecessary attribute
> > >
> > > > +{
> > > > + TPMBackend *tb = opaque;
> > > > + int ret;
> > > > +
> > > > + ret = tpm_emulator_set_state_blobs(tb);
> > > > + if (ret < 0) {
> > > > + return ret;
> > > > + }
> > > > +
> > > > + if (_tpm_emulator_startup_tpm(tb, 0, true) < 0) {
> > > > + return -EIO;
> > > > + }
> > > > +
> > > I dislike the mix of functions returning errno and others, and the
> > > lack of Error **, but it's not specific to this patch. Ok. :)
> > >
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static const VMStateDescription vmstate_tpm_emulator = {
> > > > + .name = "tpm-emulator",
> > > > + .version_id = 1,
> > > > + .minimum_version_id = 0,
> > > version_id = 1 & minimum_version_id = 0 ?
> > >
> > > It's the first version, let's have version_id = 0 (and you could
> > > remove minimum_version).
> > >
> > > > + .minimum_version_id_old = 0,
> > > No need to specify that, no load_state_old() either
> > >
> > > > + .pre_save = tpm_emulator_pre_save,
> > > > + .post_load = tpm_emulator_post_load,
> > > > + .fields = (VMStateField[]) {
> > > > + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
> > > > + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
> > > > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
> > > > + TPMEmulator, 1, 0,
> > > > + state_blobs.permanent.size),
> > > > +
> > > > + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
> > > > + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
> > > > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
> > > > + TPMEmulator, 1, 0,
> > > > + state_blobs.volatil.size),
> > > > +
> > > > + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
> > > > + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
> > > > + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
> > > > + TPMEmulator, 1, 0,
> > > > + state_blobs.savestate.size),
> > > > +
> > > > + VMSTATE_END_OF_LIST()
> > > > + }
> > > > +};
> > > > +
> > > > static void tpm_emulator_inst_init(Object *obj)
> > > > {
> > > > TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
> > > > @@ -577,6 +865,8 @@ static void tpm_emulator_inst_init(Object *obj)
> > > > tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
> > > > tpm_emu->cur_locty_number = ~0;
> > > > qemu_mutex_init(&tpm_emu->mutex);
> > > > +
> > > > + vmstate_register(NULL, -1, &vmstate_tpm_emulator, obj);
> > > > }
> > > >
> > > > /*
> > > > @@ -613,6 +903,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
> > > > }
> > > >
> > > > qemu_mutex_destroy(&tpm_emu->mutex);
> > > > +
> > > > + vmstate_unregister(NULL, &vmstate_tpm_emulator, obj);
> > It's best to avoid the vmstate_register/unregister and just set the
> > dc->vmsd pointer during class_init; see hw/virtio/virtio-balloon.c
> > virtio_balloon_class_init for an example.
>
> hw/tpm/tpm_emulator.c:909:tpm_emulator_class_init: Object 0x55f4cbc72680 is
> not an instance of type device
> Aborted
>
> Can we leave it as it is ?
Oh, not a device, hmmm that's odd; yeh probably best then.
Dave
>
> Thanks for the review.
>
> Stefan
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 18+ messages in thread* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-05 12:43 ` Dr. David Alan Gilbert
@ 2018-03-05 13:52 ` Stefan Berger
0 siblings, 0 replies; 18+ messages in thread
From: Stefan Berger @ 2018-03-05 13:52 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: Marc-André Lureau, Juan Quintela, QEMU
On 03/05/2018 07:43 AM, Dr. David Alan Gilbert wrote:
> * Stefan Berger (stefanb@linux.vnet.ibm.com) wrote:
>> On 03/02/2018 05:14 AM, Dr. David Alan Gilbert wrote:
>>
>> hw/tpm/tpm_emulator.c:909:tpm_emulator_class_init: Object 0x55f4cbc72680 is
>> not an instance of type device
>> Aborted
>>
>> Can we leave it as it is ?
> Oh, not a device, hmmm that's odd; yeh probably best then.
At least it doesn't *need* to be a device that an OS could talk to via
MMIO or so. That's the TIS or CRB hardware interfaces in this case. If
we have to convert this 'backend' to a device for some reason, I'd do
it, but rather leave it as it is if not.
Stefan
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-02 9:26 ` Marc-André Lureau
2018-03-02 10:14 ` Dr. David Alan Gilbert
@ 2018-03-02 13:19 ` Stefan Berger
2018-03-02 15:00 ` Stefan Berger
2018-03-05 20:33 ` Stefan Berger
3 siblings, 0 replies; 18+ messages in thread
From: Stefan Berger @ 2018-03-02 13:19 UTC (permalink / raw)
To: Marc-André Lureau; +Cc: QEMU, Dr. David Alan Gilbert, Juan Quintela
On 03/02/2018 04:26 AM, Marc-André Lureau wrote:
> Hi Stefan
>
> On Thu, Mar 1, 2018 at 8:59 PM, Stefan Berger
> <stefanb@linux.vnet.ibm.com> wrote:
>> Extend the TPM emulator backend device with state migration support.
>>
>> The external TPM emulator 'swtpm' provides a protocol over
>> its control channel to retrieve its state blobs. We implement
>> functions for getting and setting the different state blobs.
>> In case the setting of the state blobs fails, we return a
>> negative errno code to fail the start of the VM.
>>
>> Since we have an external TPM emulator, we need to make sure
>> that we do not migrate the state for as long as it is busy
>> processing a request. We need to wait for notification that
>> the request has completed processing.
> Because qemu will have to deal with an external state, managed by the
> tpm emulator (different from other storage/nvram):
>
> - the emulator statedir must be different between source and dest? Can
> it be the same?
You mean for local migration? I would suggest it be different
directories though it may work with the same. I haven't tried it like
that and the critical case here is local migration between different
versions of the swtpm and for example downgrading of state from v3 to v1
being refused.
> - what is the story regarding versionning? Can you migrate from/to any
> version, or only the same version?
I just redid the state marshalling/unmarshalling of the TPM 2
implementation. All structures that are written out are ID'ed and
versioned and accomodate compile-time optional parts. As for migration
between different versions, I am not sure what to promise about this
right now. So if you migrate a structure of the TPM 2 from v1 to v2 and
v2 has some new fields that v1 didn't have, we need default values to
assign to these new fields, which may or may not be possible depending
on circumstances and semantics of the fields. In the end it comes down
to upgradeability of the TPM 2 implementation. The current
implementation supports revision 146 of the TPM 2 specs. I cannot
predict the future and what future versions may add to the code and the
state of the device. Design/development of the TPM 2 is ongoing while
companies are producing TPM 2 chips following specs of a certain time.
They also have that problem of having to upgrade a device to a later
spec but could refuse to do so and tell you to buy a new machine. So in
our case it may actually be more difficult with the expected upgrade
path. If the state cannot be upgraded because default values cannot be
found, we would have to stop at a certain revision.
> - can the host source and destination be of different endianess?
Yes. All state is marshalled in big endian format. I have test cases in
swtpm that cover that. State produced on a x86_64 can be consumed on
ppc64 big endian.
> - how is suspend and snapshot working?
The tpm_emulator backend uses the same mechanisms to store state as all
the other devices do, except that we retrieve the state via .pre_save
from an external device where we fill buffers that are part of the
'normal' state of the device. You have come across the TPMSizedBuffers
that are being marshalled and those carry that state.
I have tried local migration to a file as well as local migration via
netcat. Both work.
>
> There are probably other complications that I can't think of
> immediately, but David or Juan help may help avoid mistakes.
>
> It probably deserves a few explanations in docs/specs/tpm.txt.
>
>> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
>> ---
>> hw/tpm/tpm_emulator.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++--
> It would be worth to add some basic tests. Either growing our own
> tests/tpm-emu.c test emulator
>
> or checking that swtpm is present (and of required version?) to
> run/skip the test a more complete test.
Ok, I'll have to look into that. I do have several test cases in swtpm
for that already.
>
>> 1 file changed, 302 insertions(+), 10 deletions(-)
>>
>> diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
>> index b787aee..da877e5 100644
>> --- a/hw/tpm/tpm_emulator.c
>> +++ b/hw/tpm/tpm_emulator.c
>> @@ -55,6 +55,19 @@
>> #define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
>>
>> /* data structures */
>> +
>> +/* blobs from the TPM; part of VM state when migrating */
>> +typedef struct TPMBlobBuffers {
>> + uint32_t permanent_flags;
>> + TPMSizedBuffer permanent;
>> +
>> + uint32_t volatil_flags;
>> + TPMSizedBuffer volatil;
>> +
>> + uint32_t savestate_flags;
>> + TPMSizedBuffer savestate;
>> +} TPMBlobBuffers;
>> +
>> typedef struct TPMEmulator {
>> TPMBackend parent;
>>
>> @@ -70,6 +83,8 @@ typedef struct TPMEmulator {
>>
>> unsigned int established_flag:1;
>> unsigned int established_flag_cached:1;
>> +
>> + TPMBlobBuffers state_blobs;
> Suspicious addition, it shouldn't be necessary in running state. It
> could be allocated on demand? Even better if the field is removed, but
> this may not be possible with VMSTATE macros.
This is the field that will carry the external devices' state blobs.
>> } TPMEmulator;
>>
>>
>> @@ -301,7 +316,8 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
>> return 0;
>> }
>>
>> -static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> +static int _tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize,
>> + bool is_resume)
> Using underscore-prefixed names is discouraged. Call it tpm_emulator_init?
>
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> ptm_init init = {
>> @@ -309,12 +325,17 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> };
>> ptm_res res;
>>
>> + DPRINTF("%s is_resume: %d", __func__, is_resume);
>> +
> extra spaces, you may also add buffersize while at it.
>
>> if (buffersize != 0 &&
>> tpm_emulator_set_buffer_size(tb, buffersize, NULL) < 0) {
>> goto err_exit;
>> }
>>
>> - DPRINTF("%s", __func__);
>> + if (is_resume) {
>> + init.u.req.init_flags = cpu_to_be32(PTM_INIT_FLAG_DELETE_VOLATILE);
>> + }
> Since it's a flags, and for future extensibility, I would suggest |=.
>
>> +
>> if (tpm_emulator_ctrlcmd(tpm_emu, CMD_INIT, &init, sizeof(init),
>> sizeof(init)) < 0) {
>> error_report("tpm-emulator: could not send INIT: %s",
>> @@ -333,6 +354,11 @@ err_exit:
>> return -1;
>> }
>>
>> +static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> +{
>> + return _tpm_emulator_startup_tpm(tb, buffersize, false);
>> +}
>> +
>> static bool tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> @@ -431,16 +457,21 @@ static size_t tpm_emulator_get_buffer_size(TPMBackend *tb)
>> static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
>> {
>> Error *err = NULL;
>> + ptm_cap caps = PTM_CAP_GET_STATEBLOB | PTM_CAP_SET_STATEBLOB |
>> + PTM_CAP_STOP;
>>
>> - 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;
>> + if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, caps)) {
>> + error_setg(&tpm_emu->migration_blocker,
>> + "Migration disabled: TPM emulator does not support "
>> + "migration");
>> + 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 -1;
>> + }
>> }
>>
>> return 0;
>> @@ -569,6 +600,263 @@ static const QemuOptDesc tpm_emulator_cmdline_opts[] = {
>> { /* end of list */ },
>> };
>>
>> +/*
>> + * Transfer a TPM state blob from the TPM into a provided buffer.
>> + *
>> + * @tpm_emu: TPMEmulator
>> + * @type: the type of blob to transfer
>> + * @tsb: the TPMSizeBuffer to fill with the blob
>> + * @flags: the flags to return to the caller
>> + */
>> +static int tpm_emulator_get_state_blob(TPMEmulator *tpm_emu,
>> + uint8_t type,
>> + TPMSizedBuffer *tsb,
>> + uint32_t *flags)
>> +{
>> + ptm_getstate pgs;
>> + ptm_res res;
>> + ssize_t n;
>> + uint32_t totlength, length;
>> +
>> + tpm_sized_buffer_reset(tsb);
>> +
>> + pgs.u.req.state_flags = cpu_to_be32(PTM_STATE_FLAG_DECRYPTED);
>> + pgs.u.req.type = cpu_to_be32(type);
>> + pgs.u.req.offset = 0;
>> +
>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_GET_STATEBLOB,
>> + &pgs, sizeof(pgs.u.req),
>> + offsetof(ptm_getstate, u.resp.data)) < 0) {
>> + error_report("tpm-emulator: could not get state blob type %d : %s",
>> + type, strerror(errno));
>> + return -1;
> (I guess some day vmstate functions should have an Error ** argument)
>
>> + }
>> +
>> + res = be32_to_cpu(pgs.u.resp.tpm_result);
>> + if (res != 0 && (res & 0x800) == 0) {
>> + error_report("tpm-emulator: Getting the stateblob (type %d) failed "
>> + "with a TPM error 0x%x", type, res);
>> + return -1;
>> + }
>> +
>> + totlength = be32_to_cpu(pgs.u.resp.totlength);
>> + length = be32_to_cpu(pgs.u.resp.length);
>> + if (totlength != length) {
>> + error_report("tpm-emulator: Expecting to read %u bytes "
>> + "but would get %u", totlength, length);
>> + return -1;
>> + }
>> +
>> + *flags = be32_to_cpu(pgs.u.resp.state_flags);
>> +
>> + tsb->buffer = g_malloc(totlength);
> That TPMSizedBuffer is not really useful. Use GArray or qemu Buffer ?
> (and we could drop TPMSizedBuffer).
>
>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr, tsb->buffer, totlength);
>> + if (n != totlength) {
>> + error_report("tpm-emulator: Could not read stateblob (type %d) : %s",
>> + type, strerror(errno));
>> + return -1;
>> + }
>> + tsb->size = totlength;
>> +
>> + DPRINTF("got state blob type %d, %d bytes, flags 0x%08x\n",
>> + type, tsb->size, *flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int tpm_emulator_get_state_blobs(TPMEmulator *tpm_emu)
>> +{
>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>> +
>> + if (tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>> + &state_blobs->permanent,
>> + &state_blobs->permanent_flags) < 0 ||
>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>> + &state_blobs->volatil,
>> + &state_blobs->volatil_flags) < 0 ||
>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>> + &state_blobs->savestate,
>> + &state_blobs->savestate_flags) < 0) {
>> + goto err_exit;
>> + }
>> +
>> + return 0;
>> +
>> + err_exit:
>> + tpm_sized_buffer_reset(&state_blobs->volatil);
>> + tpm_sized_buffer_reset(&state_blobs->permanent);
>> + tpm_sized_buffer_reset(&state_blobs->savestate);
>> +
>> + return -1;
>> +}
>> +
>> +/*
>> + * Transfer a TPM state blob to the TPM emulator.
>> + *
>> + * @tpm_emu: TPMEmulator
>> + * @type: the type of TPM state blob to transfer
>> + * @tsb: TPMSizeBuffer containing the TPM state blob
>> + * @flags: Flags describing the (encryption) state of the TPM state blob
>> + */
>> +static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
>> + uint32_t type,
>> + TPMSizedBuffer *tsb,
>> + uint32_t flags)
>> +{
>> + uint32_t offset = 0;
>> + ssize_t n;
>> + ptm_setstate pss;
>> + ptm_res tpm_result;
>> +
>> + if (tsb->size == 0) {
>> + return 0;
>> + }
>> +
>> + pss = (ptm_setstate) {
>> + .u.req.state_flags = cpu_to_be32(flags),
>> + .u.req.type = cpu_to_be32(type),
>> + .u.req.length = cpu_to_be32(tsb->size),
>> + };
>> +
>> + /* write the header only */
>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
>> + offsetof(ptm_setstate, u.req.data), 0) < 0) {
>> + error_report("tpm-emulator: could not set state blob type %d : %s",
>> + type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + /* now the body */
>> + n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr,
>> + &tsb->buffer[offset], tsb->size);
>> + if (n != tsb->size) {
>> + error_report("tpm-emulator: Writing the stateblob (type %d) "
>> + "failed: %s", type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + /* now get the result */
>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
>> + (uint8_t *)&pss, sizeof(pss.u.resp));
>> + if (n != sizeof(pss.u.resp)) {
>> + error_report("tpm-emulator: Reading response from writing stateblob "
>> + "(type %d) failed: %s", type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
>> + if (tpm_result != 0) {
>> + error_report("tpm-emulator: Setting the stateblob (type %d) failed "
>> + "with a TPM error 0x%x", type, tpm_result);
>> + return -1;
>> + }
>> +
>> + DPRINTF("set the state blob type %d, %d bytes, flags 0x%08x\n",
>> + type, tsb->size, flags);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Set all the TPM state blobs.
>> + *
>> + * Returns a negative errno code in case of error.
>> + */
>> +static int tpm_emulator_set_state_blobs(TPMBackend *tb)
>> +{
>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>> +
>> + DPRINTF("%s: %d", __func__, __LINE__);
>> +
>> + if (tpm_emulator_stop_tpm(tb) < 0) {
>> + return -EIO;
>> + }
>> +
>> + if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>> + &state_blobs->permanent,
>> + state_blobs->permanent_flags) < 0 ||
>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>> + &state_blobs->volatil,
>> + state_blobs->volatil_flags) < 0 ||
>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>> + &state_blobs->savestate,
>> + state_blobs->savestate_flags) < 0) {
>> + return -EBADMSG;
>> + }
>> +
>> + DPRINTF("DONE SETTING STATEBLOBS");
> UPPERCASES!
>
>> +
>> + return 0;
>> +}
>> +
>> +static int tpm_emulator_pre_save(void *opaque)
>> +{
>> + TPMBackend *tb = opaque;
>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> +
>> + DPRINTF("%s", __func__);
>> +
>> + tpm_backend_finish_sync(tb);
>> +
>> + /* get the state blobs from the TPM */
>> + return tpm_emulator_get_state_blobs(tpm_emu);
>> +}
>> +
>> +/*
>> + * Load the TPM state blobs into the TPM.
>> + *
>> + * Returns negative errno codes in case of error.
>> + */
>> +static int tpm_emulator_post_load(void *opaque,
>> + int version_id __attribute__((unused)))
> unnecessary attribute
>
>> +{
>> + TPMBackend *tb = opaque;
>> + int ret;
>> +
>> + ret = tpm_emulator_set_state_blobs(tb);
>> + if (ret < 0) {
>> + return ret;
>> + }
>> +
>> + if (_tpm_emulator_startup_tpm(tb, 0, true) < 0) {
>> + return -EIO;
>> + }
>> +
> I dislike the mix of functions returning errno and others, and the
> lack of Error **, but it's not specific to this patch. Ok. :)
>
>> + return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_tpm_emulator = {
>> + .name = "tpm-emulator",
>> + .version_id = 1,
>> + .minimum_version_id = 0,
> version_id = 1 & minimum_version_id = 0 ?
>
> It's the first version, let's have version_id = 0 (and you could
> remove minimum_version).
>
>> + .minimum_version_id_old = 0,
> No need to specify that, no load_state_old() either
>
>> + .pre_save = tpm_emulator_pre_save,
>> + .post_load = tpm_emulator_post_load,
>> + .fields = (VMStateField[]) {
>> + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.permanent.size),
>> +
>> + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.volatil.size),
>> +
>> + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.savestate.size),
>> +
>> + VMSTATE_END_OF_LIST()
>> + }
>> +};
>> +
>> static void tpm_emulator_inst_init(Object *obj)
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
>> @@ -577,6 +865,8 @@ static void tpm_emulator_inst_init(Object *obj)
>> tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
>> tpm_emu->cur_locty_number = ~0;
>> qemu_mutex_init(&tpm_emu->mutex);
>> +
>> + vmstate_register(NULL, -1, &vmstate_tpm_emulator, obj);
>> }
>>
>> /*
>> @@ -613,6 +903,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
>> }
>>
>> qemu_mutex_destroy(&tpm_emu->mutex);
>> +
>> + vmstate_unregister(NULL, &vmstate_tpm_emulator, obj);
>> }
>>
>> static void tpm_emulator_class_init(ObjectClass *klass, void *data)
>> --
>> 2.5.5
>>
>>
> looks good to me overall
>
Thanks for the review. I'll fix your concerns.
Stefan4
^ permalink raw reply [flat|nested] 18+ messages in thread* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-02 9:26 ` Marc-André Lureau
2018-03-02 10:14 ` Dr. David Alan Gilbert
2018-03-02 13:19 ` Stefan Berger
@ 2018-03-02 15:00 ` Stefan Berger
2018-03-05 20:33 ` Stefan Berger
3 siblings, 0 replies; 18+ messages in thread
From: Stefan Berger @ 2018-03-02 15:00 UTC (permalink / raw)
To: Marc-André Lureau; +Cc: QEMU, Dr. David Alan Gilbert, Juan Quintela
On 03/02/2018 04:26 AM, Marc-André Lureau wrote:
> Hi Stefan
>
> On Thu, Mar 1, 2018 at 8:59 PM, Stefan Berger
> <stefanb@linux.vnet.ibm.com> wrote:
>> Extend the TPM emulator backend device with state migration support.
>>
>> The external TPM emulator 'swtpm' provides a protocol over
>> its control channel to retrieve its state blobs. We implement
>> functions for getting and setting the different state blobs.
>> In case the setting of the state blobs fails, we return a
>> negative errno code to fail the start of the VM.
>>
>> Since we have an external TPM emulator, we need to make sure
>> that we do not migrate the state for as long as it is busy
>> processing a request. We need to wait for notification that
>> the request has completed processing.
> Because qemu will have to deal with an external state, managed by the
> tpm emulator (different from other storage/nvram):
>
> - the emulator statedir must be different between source and dest? Can
> it be the same?
> - what is the story regarding versionning? Can you migrate from/to any
> version, or only the same version?
> - can the host source and destination be of different endianess?
> - how is suspend and snapshot working?
>
> There are probably other complications that I can't think of
> immediately, but David or Juan help may help avoid mistakes.
>
> It probably deserves a few explanations in docs/specs/tpm.txt.
>
>> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
>> ---
>> hw/tpm/tpm_emulator.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++--
> It would be worth to add some basic tests. Either growing our own
> tests/tpm-emu.c test emulator
>
> or checking that swtpm is present (and of required version?) to
> run/skip the test a more complete test.
>
>> 1 file changed, 302 insertions(+), 10 deletions(-)
>>
>> diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
>> index b787aee..da877e5 100644
>> --- a/hw/tpm/tpm_emulator.c
>> +++ b/hw/tpm/tpm_emulator.c
>> @@ -55,6 +55,19 @@
>> #define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
>>
>> /* data structures */
>> +
>> +/* blobs from the TPM; part of VM state when migrating */
>> +typedef struct TPMBlobBuffers {
>> + uint32_t permanent_flags;
>> + TPMSizedBuffer permanent;
>> +
>> + uint32_t volatil_flags;
>> + TPMSizedBuffer volatil;
>> +
>> + uint32_t savestate_flags;
>> + TPMSizedBuffer savestate;
>> +} TPMBlobBuffers;
>> +
>> typedef struct TPMEmulator {
>> TPMBackend parent;
>>
>> @@ -70,6 +83,8 @@ typedef struct TPMEmulator {
>>
>> unsigned int established_flag:1;
>> unsigned int established_flag_cached:1;
>> +
>> + TPMBlobBuffers state_blobs;
> Suspicious addition, it shouldn't be necessary in running state. It
> could be allocated on demand? Even better if the field is removed, but
> this may not be possible with VMSTATE macros.
I tried to use GArray *, but offsetof cannot be applied to it by the
VMSTATE macros (non-constant address).
Now I am trying to use Buffer (util/buffer.c) but here we're missing
VMSTATE macros. To support it, we would need a VMSTATE_SIZE_T() or so,
truncating size_t to 32 bits(?). This would be for storing the size
indicator 'size-t offset' of Buffer preceeding the actual buffer. Then
of course the VMSTATE_VBUFFER_ALLOC_UINT32 will not work anymore with
Buffer and we would need something like VMSTATE_QEMU_BUFFER_ALLOC().
Well, the TPMSizedBuffer fit the existing VMSTATE macros quite well and
was simple. Another approach would be to implement SimpleSizedBuffer,
which would basically be a renaming of TPMSizedBuffer with the existing
few TPMSizeBuffer functions wrapping it. Or we go with the plain size_t
length indicator and char *buffer without wrapping it in any structure -
but ... is that better?
> + .pre_save = tpm_emulator_pre_save,
> + .post_load = tpm_emulator_post_load,
> + .fields = (VMStateField[]) {
> + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
> + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
> + TPMEmulator, 1, 0,
> + state_blobs.permanent.size),
> +
> + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
> + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
> + TPMEmulator, 1, 0,
> + state_blobs.volatil.size),
> +
> + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
> + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
> + TPMEmulator, 1, 0,
> + state_blobs.savestate.size),
> +
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
Stefan
>> } TPMEmulator;
>>
>>
>> @@ -301,7 +316,8 @@ static int tpm_emulator_set_buffer_size(TPMBackend *tb,
>> return 0;
>> }
>>
>> -static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> +static int _tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize,
>> + bool is_resume)
> Using underscore-prefixed names is discouraged. Call it tpm_emulator_init?
>
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> ptm_init init = {
>> @@ -309,12 +325,17 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> };
>> ptm_res res;
>>
>> + DPRINTF("%s is_resume: %d", __func__, is_resume);
>> +
> extra spaces, you may also add buffersize while at it.
>
>> if (buffersize != 0 &&
>> tpm_emulator_set_buffer_size(tb, buffersize, NULL) < 0) {
>> goto err_exit;
>> }
>>
>> - DPRINTF("%s", __func__);
>> + if (is_resume) {
>> + init.u.req.init_flags = cpu_to_be32(PTM_INIT_FLAG_DELETE_VOLATILE);
>> + }
> Since it's a flags, and for future extensibility, I would suggest |=.
>
>> +
>> if (tpm_emulator_ctrlcmd(tpm_emu, CMD_INIT, &init, sizeof(init),
>> sizeof(init)) < 0) {
>> error_report("tpm-emulator: could not send INIT: %s",
>> @@ -333,6 +354,11 @@ err_exit:
>> return -1;
>> }
>>
>> +static int tpm_emulator_startup_tpm(TPMBackend *tb, size_t buffersize)
>> +{
>> + return _tpm_emulator_startup_tpm(tb, buffersize, false);
>> +}
>> +
>> static bool tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> @@ -431,16 +457,21 @@ static size_t tpm_emulator_get_buffer_size(TPMBackend *tb)
>> static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
>> {
>> Error *err = NULL;
>> + ptm_cap caps = PTM_CAP_GET_STATEBLOB | PTM_CAP_SET_STATEBLOB |
>> + PTM_CAP_STOP;
>>
>> - 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;
>> + if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, caps)) {
>> + error_setg(&tpm_emu->migration_blocker,
>> + "Migration disabled: TPM emulator does not support "
>> + "migration");
>> + 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 -1;
>> + }
>> }
>>
>> return 0;
>> @@ -569,6 +600,263 @@ static const QemuOptDesc tpm_emulator_cmdline_opts[] = {
>> { /* end of list */ },
>> };
>>
>> +/*
>> + * Transfer a TPM state blob from the TPM into a provided buffer.
>> + *
>> + * @tpm_emu: TPMEmulator
>> + * @type: the type of blob to transfer
>> + * @tsb: the TPMSizeBuffer to fill with the blob
>> + * @flags: the flags to return to the caller
>> + */
>> +static int tpm_emulator_get_state_blob(TPMEmulator *tpm_emu,
>> + uint8_t type,
>> + TPMSizedBuffer *tsb,
>> + uint32_t *flags)
>> +{
>> + ptm_getstate pgs;
>> + ptm_res res;
>> + ssize_t n;
>> + uint32_t totlength, length;
>> +
>> + tpm_sized_buffer_reset(tsb);
>> +
>> + pgs.u.req.state_flags = cpu_to_be32(PTM_STATE_FLAG_DECRYPTED);
>> + pgs.u.req.type = cpu_to_be32(type);
>> + pgs.u.req.offset = 0;
>> +
>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_GET_STATEBLOB,
>> + &pgs, sizeof(pgs.u.req),
>> + offsetof(ptm_getstate, u.resp.data)) < 0) {
>> + error_report("tpm-emulator: could not get state blob type %d : %s",
>> + type, strerror(errno));
>> + return -1;
> (I guess some day vmstate functions should have an Error ** argument)
>
>> + }
>> +
>> + res = be32_to_cpu(pgs.u.resp.tpm_result);
>> + if (res != 0 && (res & 0x800) == 0) {
>> + error_report("tpm-emulator: Getting the stateblob (type %d) failed "
>> + "with a TPM error 0x%x", type, res);
>> + return -1;
>> + }
>> +
>> + totlength = be32_to_cpu(pgs.u.resp.totlength);
>> + length = be32_to_cpu(pgs.u.resp.length);
>> + if (totlength != length) {
>> + error_report("tpm-emulator: Expecting to read %u bytes "
>> + "but would get %u", totlength, length);
>> + return -1;
>> + }
>> +
>> + *flags = be32_to_cpu(pgs.u.resp.state_flags);
>> +
>> + tsb->buffer = g_malloc(totlength);
> That TPMSizedBuffer is not really useful. Use GArray or qemu Buffer ?
> (and we could drop TPMSizedBuffer).
>
>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr, tsb->buffer, totlength);
>> + if (n != totlength) {
>> + error_report("tpm-emulator: Could not read stateblob (type %d) : %s",
>> + type, strerror(errno));
>> + return -1;
>> + }
>> + tsb->size = totlength;
>> +
>> + DPRINTF("got state blob type %d, %d bytes, flags 0x%08x\n",
>> + type, tsb->size, *flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int tpm_emulator_get_state_blobs(TPMEmulator *tpm_emu)
>> +{
>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>> +
>> + if (tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>> + &state_blobs->permanent,
>> + &state_blobs->permanent_flags) < 0 ||
>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>> + &state_blobs->volatil,
>> + &state_blobs->volatil_flags) < 0 ||
>> + tpm_emulator_get_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>> + &state_blobs->savestate,
>> + &state_blobs->savestate_flags) < 0) {
>> + goto err_exit;
>> + }
>> +
>> + return 0;
>> +
>> + err_exit:
>> + tpm_sized_buffer_reset(&state_blobs->volatil);
>> + tpm_sized_buffer_reset(&state_blobs->permanent);
>> + tpm_sized_buffer_reset(&state_blobs->savestate);
>> +
>> + return -1;
>> +}
>> +
>> +/*
>> + * Transfer a TPM state blob to the TPM emulator.
>> + *
>> + * @tpm_emu: TPMEmulator
>> + * @type: the type of TPM state blob to transfer
>> + * @tsb: TPMSizeBuffer containing the TPM state blob
>> + * @flags: Flags describing the (encryption) state of the TPM state blob
>> + */
>> +static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
>> + uint32_t type,
>> + TPMSizedBuffer *tsb,
>> + uint32_t flags)
>> +{
>> + uint32_t offset = 0;
>> + ssize_t n;
>> + ptm_setstate pss;
>> + ptm_res tpm_result;
>> +
>> + if (tsb->size == 0) {
>> + return 0;
>> + }
>> +
>> + pss = (ptm_setstate) {
>> + .u.req.state_flags = cpu_to_be32(flags),
>> + .u.req.type = cpu_to_be32(type),
>> + .u.req.length = cpu_to_be32(tsb->size),
>> + };
>> +
>> + /* write the header only */
>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
>> + offsetof(ptm_setstate, u.req.data), 0) < 0) {
>> + error_report("tpm-emulator: could not set state blob type %d : %s",
>> + type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + /* now the body */
>> + n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr,
>> + &tsb->buffer[offset], tsb->size);
>> + if (n != tsb->size) {
>> + error_report("tpm-emulator: Writing the stateblob (type %d) "
>> + "failed: %s", type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + /* now get the result */
>> + n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
>> + (uint8_t *)&pss, sizeof(pss.u.resp));
>> + if (n != sizeof(pss.u.resp)) {
>> + error_report("tpm-emulator: Reading response from writing stateblob "
>> + "(type %d) failed: %s", type, strerror(errno));
>> + return -1;
>> + }
>> +
>> + tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
>> + if (tpm_result != 0) {
>> + error_report("tpm-emulator: Setting the stateblob (type %d) failed "
>> + "with a TPM error 0x%x", type, tpm_result);
>> + return -1;
>> + }
>> +
>> + DPRINTF("set the state blob type %d, %d bytes, flags 0x%08x\n",
>> + type, tsb->size, flags);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Set all the TPM state blobs.
>> + *
>> + * Returns a negative errno code in case of error.
>> + */
>> +static int tpm_emulator_set_state_blobs(TPMBackend *tb)
>> +{
>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> + TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
>> +
>> + DPRINTF("%s: %d", __func__, __LINE__);
>> +
>> + if (tpm_emulator_stop_tpm(tb) < 0) {
>> + return -EIO;
>> + }
>> +
>> + if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
>> + &state_blobs->permanent,
>> + state_blobs->permanent_flags) < 0 ||
>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
>> + &state_blobs->volatil,
>> + state_blobs->volatil_flags) < 0 ||
>> + tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
>> + &state_blobs->savestate,
>> + state_blobs->savestate_flags) < 0) {
>> + return -EBADMSG;
>> + }
>> +
>> + DPRINTF("DONE SETTING STATEBLOBS");
> UPPERCASES!
>
>> +
>> + return 0;
>> +}
>> +
>> +static int tpm_emulator_pre_save(void *opaque)
>> +{
>> + TPMBackend *tb = opaque;
>> + TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
>> +
>> + DPRINTF("%s", __func__);
>> +
>> + tpm_backend_finish_sync(tb);
>> +
>> + /* get the state blobs from the TPM */
>> + return tpm_emulator_get_state_blobs(tpm_emu);
>> +}
>> +
>> +/*
>> + * Load the TPM state blobs into the TPM.
>> + *
>> + * Returns negative errno codes in case of error.
>> + */
>> +static int tpm_emulator_post_load(void *opaque,
>> + int version_id __attribute__((unused)))
> unnecessary attribute
>
>> +{
>> + TPMBackend *tb = opaque;
>> + int ret;
>> +
>> + ret = tpm_emulator_set_state_blobs(tb);
>> + if (ret < 0) {
>> + return ret;
>> + }
>> +
>> + if (_tpm_emulator_startup_tpm(tb, 0, true) < 0) {
>> + return -EIO;
>> + }
>> +
> I dislike the mix of functions returning errno and others, and the
> lack of Error **, but it's not specific to this patch. Ok. :)
>
>> + return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_tpm_emulator = {
>> + .name = "tpm-emulator",
>> + .version_id = 1,
>> + .minimum_version_id = 0,
> version_id = 1 & minimum_version_id = 0 ?
>
> It's the first version, let's have version_id = 0 (and you could
> remove minimum_version).
>
>> + .minimum_version_id_old = 0,
> No need to specify that, no load_state_old() either
>
>> + .pre_save = tpm_emulator_pre_save,
>> + .post_load = tpm_emulator_post_load,
>> + .fields = (VMStateField[]) {
>> + VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.permanent.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.permanent.size),
>> +
>> + VMSTATE_UINT32(state_blobs.volatil_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.volatil.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.volatil.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.volatil.size),
>> +
>> + VMSTATE_UINT32(state_blobs.savestate_flags, TPMEmulator),
>> + VMSTATE_UINT32(state_blobs.savestate.size, TPMEmulator),
>> + VMSTATE_VBUFFER_ALLOC_UINT32(state_blobs.savestate.buffer,
>> + TPMEmulator, 1, 0,
>> + state_blobs.savestate.size),
>> +
>> + VMSTATE_END_OF_LIST()
>> + }
>> +};
>> +
>> static void tpm_emulator_inst_init(Object *obj)
>> {
>> TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
>> @@ -577,6 +865,8 @@ static void tpm_emulator_inst_init(Object *obj)
>> tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
>> tpm_emu->cur_locty_number = ~0;
>> qemu_mutex_init(&tpm_emu->mutex);
>> +
>> + vmstate_register(NULL, -1, &vmstate_tpm_emulator, obj);
>> }
>>
>> /*
>> @@ -613,6 +903,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
>> }
>>
>> qemu_mutex_destroy(&tpm_emu->mutex);
>> +
>> + vmstate_unregister(NULL, &vmstate_tpm_emulator, obj);
>> }
>>
>> static void tpm_emulator_class_init(ObjectClass *klass, void *data)
>> --
>> 2.5.5
>>
>>
> looks good to me overall
>
^ permalink raw reply [flat|nested] 18+ messages in thread* Re: [Qemu-devel] [PATCH v4 1/2] tpm: extend TPM emulator with state migration support
2018-03-02 9:26 ` Marc-André Lureau
` (2 preceding siblings ...)
2018-03-02 15:00 ` Stefan Berger
@ 2018-03-05 20:33 ` Stefan Berger
3 siblings, 0 replies; 18+ messages in thread
From: Stefan Berger @ 2018-03-05 20:33 UTC (permalink / raw)
To: Marc-André Lureau; +Cc: QEMU, Dr. David Alan Gilbert, Juan Quintela
On 03/02/2018 04:26 AM, Marc-André Lureau wrote:
>
>> + return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_tpm_emulator = {
>> + .name = "tpm-emulator",
>> + .version_id = 1,
>> + .minimum_version_id = 0,
> version_id = 1 & minimum_version_id = 0 ?
>
> It's the first version, let's have version_id = 0 (and you could
> remove minimum_version).
It doesn't work... I cannot use version_id 0 in tpm_tis or in
tpm_emulator. For tpm_tis I get the error 'Missing section footer' upon
VM resume and for some weird reason it doesn't allocate the blob buffers
when reading them in tpm_emulator. I get a NULL pointer instead. So, we
are better off with version_id 1 here... The CRB seems to work as is.
Stefan
^ permalink raw reply [flat|nested] 18+ messages in thread