Add a TPM Passthrough backend driver implementation

This patch is based of off version 9 of Stefan Berger's patch series
  "QEMU Trusted Platform Module (TPM) integration"
and adds a new backend driver for it.

This patch adds a passthrough backend driver for passing commands sent to the
emulated TPM device directly to a TPM device opened on the host machine.
Thus it is possible to use a hardware TPM device in a system running on QEMU,
providing the ability to access a TPM in a special state (e.g. after a Trusted
Boot).

This functionality is being used in the acTvSM Trusted Virtualization Platform
which is available on [1].

Usage example:
  qemu-system-x86_64 -tpmdev passthrough,id=tpm0,path=/dev/tpm0 \
                     -device tpm-tis,tpmdev=tpm0 \
                     -cdrom test.iso -boot d

Some notes about the host TPM:
The TPM needs to be enabled and activated. If that's not the case one
has to go through the BIOS/UEFI and enable and activate that TPM for TPM
commands to work as expected.
It may be necessary to boot the kernel using tpm_tis.force=1 in the boot
command line or 'modprobe tpm_tis force=1' in case of using it as a module.

Regards,
Andreas Niederl, Stefan Berger

[1] http://trustedjava.sourceforge.net/

Signed-off-by: Andreas Niederl <andreas.niederl@iaik.tugraz.at>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
Reviewed-by: Joel Schopp <jschopp@linux.vnet.ibm.com>
Message-id: 1361987275-26289-6-git-send-email-stefanb@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/tpm/tpm_int.h b/tpm/tpm_int.h
index d5358adf83..f7056436cc 100644
--- a/tpm/tpm_int.h
+++ b/tpm/tpm_int.h
@@ -18,6 +18,8 @@
 struct TPMDriverOps;
 typedef struct TPMDriverOps TPMDriverOps;
 
+typedef struct TPMPassthruState TPMPassthruState;
+
 typedef struct TPMBackend {
     char *id;
     enum TpmModel fe_model;
@@ -25,6 +27,10 @@ typedef struct TPMBackend {
     char *cancel_path;
     const TPMDriverOps *ops;
 
+    union {
+        TPMPassthruState *tpm_pt;
+    } s;
+
     QLIST_ENTRY(TPMBackend) list;
 } TPMBackend;
 
@@ -74,10 +80,37 @@ struct TPMDriverOps {
     bool (*get_tpm_established_flag)(TPMBackend *t);
 };
 
+struct tpm_req_hdr {
+    uint16_t tag;
+    uint32_t len;
+    uint32_t ordinal;
+} QEMU_PACKED;
+
+struct tpm_resp_hdr {
+    uint16_t tag;
+    uint32_t len;
+    uint32_t errcode;
+} QEMU_PACKED;
+
+#define TPM_TAG_RQU_COMMAND       0xc1
+#define TPM_TAG_RQU_AUTH1_COMMAND 0xc2
+#define TPM_TAG_RQU_AUTH2_COMMAND 0xc3
+
+#define TPM_TAG_RSP_COMMAND       0xc4
+#define TPM_TAG_RSP_AUTH1_COMMAND 0xc5
+#define TPM_TAG_RSP_AUTH2_COMMAND 0xc6
+
+#define TPM_FAIL                  9
+
+#define TPM_ORD_GetTicks          0xf1
+
 TPMBackend *qemu_find_tpm(const char *id);
 int tpm_register_model(enum TpmModel model);
 int tpm_register_driver(const TPMDriverOps *tdo);
 void tpm_display_backend_drivers(void);
 const TPMDriverOps *tpm_get_backend_driver(const char *type);
+void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len);
+
+extern const TPMDriverOps tpm_passthrough_driver;
 
 #endif /* TPM_TPM_INT_H */