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

Wed, 08 Nov 2017 10:31:53 -0800 

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 <stef...@linux.vnet.ibm.com>
---
  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 <marcandre.lur...@redhat.com>

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