Re: [Qemu-devel] [PATCH 1/5] tpm: Move getting TPM buffer size to backends

[Stefan Berger]

On 11/08/2017 11:21 AM, Marc-André Lureau wrote:
> On Mon, Nov 06, 2017 at 07:58:52PM -0500, Stefan Berger wrote:
> > Rather than setting the size of the TPM buffer in the front-end,
> > query the backend for the size of the buffer. In this patch we
> > just move the hard-coded buffer size of 4096 to the backends.
> >
> > Signed-off-by: Stefan Berger <address@hidden>
> > ---
> >   backends/tpm.c               |  9 +++++++++
> >   hw/tpm/tpm_emulator.c        |  6 ++++++
> >   hw/tpm/tpm_passthrough.c     |  6 ++++++
> >   hw/tpm/tpm_tis.c             | 12 +++++++-----
> >   include/sysemu/tpm_backend.h | 11 +++++++++++
> >   5 files changed, 39 insertions(+), 5 deletions(-)
> >
> > diff --git a/backends/tpm.c b/backends/tpm.c
> > index 7777467..e7d0f9a 100644
> > --- a/backends/tpm.c
> > +++ b/backends/tpm.c
> > @@ -139,6 +139,15 @@ TPMVersion tpm_backend_get_tpm_version(TPMBackend *s)
> >       return k->get_tpm_version(s);
> >   }
> >   
> > +uint32_t tpm_backend_get_buffer_size(TPMBackend *s)
> We have a slight preference for size_t in qemu (even if underlying
> protocol uses u32)

I changed this now throughout the series. I'll collect the Reviewed-by's 
next time.

> > +{
> > +    TPMBackendClass *k = TPM_BACKEND_GET_CLASS(s);
> > +
> > +    assert(k->get_buffer_size);
>
> No need to have assert here to be consitent with qemu code, however it
> is nice to have a comment on the interface declaration instead.
>
> (I considered all function pointers mandatory unless explicitely
> marked optional, as in "tpm-be: update optional function pointers")

Removed the assert.

   Stefan

> > +
> > +    return k->get_buffer_size(s);
> > +}
> > +
> >   TPMInfo *tpm_backend_query_tpm(TPMBackend *s)
> >   {
> >       TPMInfo *info = g_new0(TPMInfo, 1);
> > diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
> > index 24cb611..5a6107e 100644
> > --- a/hw/tpm/tpm_emulator.c
> > +++ b/hw/tpm/tpm_emulator.c
> > @@ -356,6 +356,11 @@ static TPMVersion tpm_emulator_get_tpm_version(TPMBackend 
> > *tb)
> >       return tpm_emu->tpm_version;
> >   }
> >   
> > +static uint32_t tpm_emulator_get_buffer_size(TPMBackend *tb)
> > +{
> > +    return 4096;
> > +}
> > +
> >   static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
> >   {
> >       Error *err = NULL;
> > @@ -556,6 +561,7 @@ static void tpm_emulator_class_init(ObjectClass *klass, 
> > void *data)
> >       tbc->get_tpm_established_flag = tpm_emulator_get_tpm_established_flag;
> >       tbc->reset_tpm_established_flag = tpm_emulator_reset_tpm_established_flag;
> >       tbc->get_tpm_version = tpm_emulator_get_tpm_version;
> > +    tbc->get_buffer_size = tpm_emulator_get_buffer_size;
> >       tbc->get_tpm_options = tpm_emulator_get_tpm_options;
> >   
> >       tbc->handle_request = tpm_emulator_handle_request;
> > diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
> > index 73554aa..7ff9249 100644
> > --- a/hw/tpm/tpm_passthrough.c
> > +++ b/hw/tpm/tpm_passthrough.c
> > @@ -199,6 +199,11 @@ static TPMVersion 
> > tpm_passthrough_get_tpm_version(TPMBackend *tb)
> >       return tpm_pt->tpm_version;
> >   }
> >   
> > +static uint32_t tpm_passthrough_get_buffer_size(TPMBackend *tb)
> > +{
> > +    return 4096;
> > +}
> > +
> >   /*
> >    * Unless path or file descriptor set has been provided by user,
> >    * determine the sysfs cancel file following kernel documentation
> > @@ -354,6 +359,7 @@ static void tpm_passthrough_class_init(ObjectClass *klass, 
> > void *data)
> >       tbc->reset_tpm_established_flag =
> >           tpm_passthrough_reset_tpm_established_flag;
> >       tbc->get_tpm_version = tpm_passthrough_get_tpm_version;
> > +    tbc->get_buffer_size = tpm_passthrough_get_buffer_size;
> >       tbc->get_tpm_options = tpm_passthrough_get_tpm_options;
> >       tbc->handle_request = tpm_passthrough_handle_request;
> >   }
> > diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
> > index cc32fcd..a3df40f 100644
> > --- a/hw/tpm/tpm_tis.c
> > +++ b/hw/tpm/tpm_tis.c
> > @@ -88,6 +88,8 @@ typedef struct TPMState {
> >   
> >       TPMBackend *be_driver;
> >       TPMVersion be_tpm_version;
> > +
> > +    uint32_t be_buffer_size;
> >   } TPMState;
> >   
> >   #define TPM(obj) OBJECT_CHECK(TPMState, (obj), TYPE_TPM_TIS)
> > @@ -977,10 +979,9 @@ 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)
> > +static void tpm_tis_realloc_buffer(TPMSizedBuffer *sb,
> > +                                   uint32_t wanted_size)
> >   {
> > -    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;
> > @@ -1007,6 +1008,7 @@ static void tpm_tis_reset(DeviceState *dev)
> >       int c;
> >   
> >       s->be_tpm_version = tpm_backend_get_tpm_version(s->be_driver);
> > +    s->be_buffer_size = tpm_backend_get_buffer_size(s->be_driver);
> >   
> >       tpm_backend_reset(s->be_driver);
> >   
> > @@ -1033,9 +1035,9 @@ static void tpm_tis_reset(DeviceState *dev)
> >           s->loc[c].state = TPM_TIS_STATE_IDLE;
> >   
> >           s->loc[c].w_offset = 0;
> > -        tpm_tis_realloc_buffer(&s->loc[c].w_buffer);
> > +        tpm_tis_realloc_buffer(&s->loc[c].w_buffer, s->be_buffer_size);
> >           s->loc[c].r_offset = 0;
> > -        tpm_tis_realloc_buffer(&s->loc[c].r_buffer);
> > +        tpm_tis_realloc_buffer(&s->loc[c].r_buffer, s->be_buffer_size);
> >       }
> >   
> >       tpm_tis_do_startup_tpm(s);
> > diff --git a/include/sysemu/tpm_backend.h b/include/sysemu/tpm_backend.h
> > index 590e8b4..d23cef2 100644
> > --- a/include/sysemu/tpm_backend.h
> > +++ b/include/sysemu/tpm_backend.h
> > @@ -80,6 +80,7 @@ struct TPMBackendClass {
> >       int (*reset_tpm_established_flag)(TPMBackend *t, uint8_t locty);
> >   
> >       TPMVersion (*get_tpm_version)(TPMBackend *t);
> > +    uint32_t (*get_buffer_size)(TPMBackend *t);
> >   
> >       TpmTypeOptions *(*get_tpm_options)(TPMBackend *t);
> >   
> > @@ -183,6 +184,16 @@ int tpm_backend_reset_tpm_established_flag(TPMBackend *s, uint8_t locty);
> >   TPMVersion tpm_backend_get_tpm_version(TPMBackend *s);
> >   
> >   /**
> > + * tpm_backend_get_buffer_size:
> > + * @s: the backend to call into
> > + *
> > + * Get the TPM's buffer size.
> > + *
> > + * Returns buffer size.
> > + */
> > +uint32_t tpm_backend_get_buffer_size(TPMBackend *s);
> > +
> > +/**
> >    * tpm_backend_query_tpm:
> >    * @s: the backend
> >    *
> > --
> > 2.5.5
> Looks good to me otherwise,
>
> Reviewed-by: Marc-André Lureau <address@hidden>