[SLOF] [PATCH v3 12/17] Add TPM firmware API call get-maximum-cmd-size

[Stefan Berger]

From: Stefan Berger <stefanb at linux.vnet.ibm.com>

This patch adds support for the firmware API call get-maximum-cmd-size.

Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
---
 board-qemu/slof/vio-vtpm-cdriver.fs |  7 ++++++
 board-qemu/slof/vtpm-sml.fs         | 10 +++++++++
 lib/libtpm/tcgbios.c                | 44 +++++++++++++++++++++++++++++++++++++
 lib/libtpm/tcgbios.h                |  1 +
 lib/libtpm/tcgbios_int.h            |  6 +++++
 lib/libtpm/tpm.code                 | 10 +++++++++
 lib/libtpm/tpm.in                   |  1 +
 7 files changed, 79 insertions(+)

diff --git a/board-qemu/slof/vio-vtpm-cdriver.fs b/board-qemu/slof/vio-vtpm-cdriver.fs
index ac4b196..77d6e81 100644
--- a/board-qemu/slof/vio-vtpm-cdriver.fs
+++ b/board-qemu/slof/vio-vtpm-cdriver.fs
@@ -122,6 +122,13 @@ false VALUE vtpm-debug?
     THEN
 ;
 
+\ firmware API call
+: get-maximum-cmd-size ( -- maximum-size )
+    " get-maximum-cmd-size" vtpm-call-forward IF
+        0
+    THEN
+;
+
 : open ( )
     vtpm-debug? IF ." VTPM: vTPM open()" cr THEN
     true
diff --git a/board-qemu/slof/vtpm-sml.fs b/board-qemu/slof/vtpm-sml.fs
index 3b64454..ead68bf 100644
--- a/board-qemu/slof/vtpm-sml.fs
+++ b/board-qemu/slof/vtpm-sml.fs
@@ -84,6 +84,16 @@ log-base LOG-SIZE tpm-set-log-parameters
     THEN
 ;
 
+: get-maximum-cmd-size ( -- max-size )
+    vtpm-debug? IF
+        ." Call to get-maximum-cmd-size" cr
+    THEN
+    tpm-get-maximum-cmd-size                       ( -- max-size )
+    dup 0= IF     \ Display if return value is 0
+        ." VTPM: Return value from tpm-get-maximum-cmd-size: " dup . cr
+    THEN
+;
+
 \
 \ internal API calls
 \
diff --git a/lib/libtpm/tcgbios.c b/lib/libtpm/tcgbios.c
index 81ae443..27601e9 100644
--- a/lib/libtpm/tcgbios.c
+++ b/lib/libtpm/tcgbios.c
@@ -38,6 +38,8 @@
 #define dprintf(_x ...)
 #endif
 
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
 static const uint8_t startup_st_clear[] = { 0x00, TPM_ST_CLEAR };
 static const uint8_t startup_st_state[] = { 0x00, TPM_ST_STATE };
 
@@ -74,6 +76,11 @@ static const uint8_t get_capability_durations[] = {
 	0x00, 0x00, 0x01, 0x20
 };
 
+static const uint8_t get_capability_buffer_size[] = {
+	0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x04,
+	0x00, 0x00, 0x01, 0x24
+};
+
 static uint8_t evt_separator[] = {0xff,0xff,0xff,0xff};
 
 struct tpm_state {
@@ -1151,3 +1158,40 @@ int tpm_get_state(void)
 
 	return state;
 }
+
+/*
+ * tpm_get_maximum_cmd_size: Function for interfacing with the firmware API
+ *
+ * This function returns the maximum size a TPM command (or response) may have.
+ */
+uint32_t tpm_get_maximum_cmd_size(void)
+{
+	uint32_t rc;
+	uint32_t return_code;
+	struct tpm_rsp_getcap_buffersize buffersize;
+	uint32_t result;
+
+	if (!has_working_tpm())
+		return 0;
+
+	rc = build_and_send_cmd(TPM_ORD_GET_CAPABILITY,
+				get_capability_buffer_size,
+				sizeof(get_capability_buffer_size),
+				(uint8_t *)&buffersize, sizeof(buffersize),
+				&return_code, TPM_DURATION_TYPE_SHORT);
+
+	if (rc || return_code)
+		goto err_exit;
+
+	result = MIN(cpu_to_be32(buffersize.buffersize),
+	             spapr_vtpm_get_buffersize());
+
+	return result;
+
+err_exit:
+	dprintf("TPM malfunctioning (line %d).\n", __LINE__);
+
+	tpm_set_failure();
+
+	return 0;
+}
diff --git a/lib/libtpm/tcgbios.h b/lib/libtpm/tcgbios.h
index b08e12f..6eb6751 100644
--- a/lib/libtpm/tcgbios.h
+++ b/lib/libtpm/tcgbios.h
@@ -34,6 +34,7 @@ uint32_t tpm_measure_bcv_mbr(uint32_t bootdrv, const uint8_t *addr,
                              uint32_t length);
 uint32_t tpm_add_event_separators(uint32_t start_pcr, uint32_t end_pcr);
 uint32_t tpm_process_opcode(uint8_t op, bool verbose);
+uint32_t tpm_get_maximum_cmd_size(void);
 
 /* flags returned by tpm_get_state */
 #define TPM_STATE_ENABLED        1
diff --git a/lib/libtpm/tcgbios_int.h b/lib/libtpm/tcgbios_int.h
index d6090d6..5c5a887 100644
--- a/lib/libtpm/tcgbios_int.h
+++ b/lib/libtpm/tcgbios_int.h
@@ -161,6 +161,12 @@ struct tpm_rsp_getcap_durations {
 	uint32_t durations[TPM_NUM_DURATIONS];
 } __attribute__((packed));
 
+struct tpm_rsp_getcap_buffersize {
+	struct tpm_rsp_header hdr;
+	uint32_t size;
+	uint32_t buffersize;
+} __attribute__((packed));
+
 #define TPM_PPI_OP_NOOP 0
 #define TPM_PPI_OP_ENABLE 1
 #define TPM_PPI_OP_DISABLE 2
diff --git a/lib/libtpm/tpm.code b/lib/libtpm/tpm.code
index 010a961..c5a93bb 100644
--- a/lib/libtpm/tpm.code
+++ b/lib/libtpm/tpm.code
@@ -162,3 +162,13 @@ PRIM(tpm_X2d_measure_X2d_scrtm)
 	PUSH;
 	TOS.n = tpm_measure_scrtm();
 MIRP
+
+/****************************************************/
+/* Firmware API                                     */
+/* SLOF:   tpm-get-maximum-cmd-size ( -- max-size)  */
+/* LIBTPM: maxsize = tpm_get_maximum_cmd_size()     */
+/****************************************************/
+PRIM(tpm_X2d_get_X2d_maximum_X2d_cmd_X2d_size)
+	PUSH;
+	TOS.n = tpm_get_maximum_cmd_size();
+MIRP
diff --git a/lib/libtpm/tpm.in b/lib/libtpm/tpm.in
index 59a4ba6..1bd393e 100644
--- a/lib/libtpm/tpm.in
+++ b/lib/libtpm/tpm.in
@@ -27,3 +27,4 @@ cod(tpm-process-opcode)
 cod(tpm-get-state)
 cod(tpm-is-working)
 cod(tpm-measure-scrtm)
+cod(tpm-get-maximum-cmd-size)
-- 
2.4.3