[PATCH v6 1/3] acpi: Some build_tpm2() code reshape

[Eric Auger <eric.auger@redhat.com>]

Remove any reference to Acpi20TPM2 and adopt an implementation
similar to build_ghes_v2().

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Igor Mammedov <imammedo@redhat.com>

---

v5 -> v6:
- add reference to the spec + comment about LAML and LASA fields
- also moved LASA intro comment above build_append_int_noprefix()
  as requested by Igor
---
 hw/acpi/aml-build.c | 54 +++++++++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 19 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 2cb7b991ef..1cc08a3eb9 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1878,48 +1878,64 @@ build_hdr:
                  "FACP", tbl->len - fadt_start, f->rev, oem_id, oem_table_id);
 }
 
+/*
+ * build_tpm2 - Build the TPM2 table as specified in table 7 of
+ * "TCG ACPI Specification; Family 1.2 and 2.0;
+ * Level 00 Revision 00.37, December 19, 2014"
+ * Note: the LASA and LAML fields are optional for TPM-2.0 (the above
+ * table does not mention them) but are needed at least for SeaBIOS.
+ * See the Acpi20TPM2 struct for the corresponding layout.
+ */
 void build_tpm2(GArray *table_data, BIOSLinker *linker, GArray *tcpalog)
 {
-    Acpi20TPM2 *tpm2_ptr = acpi_data_push(table_data, sizeof(AcpiTableHeader));
-    unsigned log_addr_size = sizeof(tpm2_ptr->log_area_start_address);
-    unsigned log_addr_offset =
-        (char *)&tpm2_ptr->log_area_start_address - table_data->data;
     uint8_t start_method_params[12] = {};
+    unsigned log_addr_offset, tpm2_start;
+    uint64_t control_area_start_address;
     TPMIf *tpmif = tpm_find();
+    uint32_t start_method;
+    void *tpm2_ptr;
 
-    /* platform class */
+    tpm2_start = table_data->len;
+    tpm2_ptr = acpi_data_push(table_data, sizeof(AcpiTableHeader));
+
+    /* Platform Class */
     build_append_int_noprefix(table_data, TPM2_ACPI_CLASS_CLIENT, 2);
-    /* reserved */
+    /* Reserved */
     build_append_int_noprefix(table_data, 0, 2);
     if (TPM_IS_TIS_ISA(tpmif) || TPM_IS_TIS_SYSBUS(tpmif)) {
-        /* address of control area */
-        build_append_int_noprefix(table_data, 0, 8);
-        /* start method */
-        build_append_int_noprefix(table_data, TPM2_START_METHOD_MMIO, 4);
+        control_area_start_address = 0;
+        start_method = TPM2_START_METHOD_MMIO;
     } else if (TPM_IS_CRB(tpmif)) {
-        build_append_int_noprefix(table_data, TPM_CRB_ADDR_CTRL, 8);
-        build_append_int_noprefix(table_data, TPM2_START_METHOD_CRB, 4);
+        control_area_start_address = TPM_CRB_ADDR_CTRL;
+        start_method = TPM2_START_METHOD_CRB;
     } else {
-        g_warn_if_reached();
+        g_assert_not_reached();
     }
+    /* Address of Control Area */
+    build_append_int_noprefix(table_data, control_area_start_address, 8);
+    /* Start Method */
+    build_append_int_noprefix(table_data, start_method, 4);
 
-    /* platform specific parameters */
-    g_array_append_vals(table_data, &start_method_params, 12);
+    /* Platform Specific Parameters */
+    g_array_append_vals(table_data, &start_method_params,
+                        ARRAY_SIZE(start_method_params));
 
-    /* log area minimum length */
+    /* Log Area Minimum Length */
     build_append_int_noprefix(table_data, TPM_LOG_AREA_MINIMUM_SIZE, 4);
 
     acpi_data_push(tcpalog, TPM_LOG_AREA_MINIMUM_SIZE);
     bios_linker_loader_alloc(linker, ACPI_BUILD_TPMLOG_FILE, tcpalog, 1,
                              false);
 
-    /* log area start address to be filled by Guest linker */
+    log_addr_offset = table_data->len;
+
+    /* Log Area Start Address to be filled by Guest linker */
     build_append_int_noprefix(table_data, 0, 8);
     bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
-                                   log_addr_offset, log_addr_size,
+                                   log_addr_offset, 8,
                                    ACPI_BUILD_TPMLOG_FILE, 0);
     build_header(linker, table_data,
-                 (void *)tpm2_ptr, "TPM2", sizeof(*tpm2_ptr), 4, NULL, NULL);
+                 tpm2_ptr, "TPM2", table_data->len - tpm2_start, 4, NULL, NULL);
 }
 
 /* ACPI 5.0: 6.4.3.8.2 Serial Bus Connection Descriptors */
-- 
2.20.1