acpi: build_rsdt: use acpi_table_begin()/acpi_table_end() instead of build_header()

it replaces error-prone pointer arithmetic for build_header() API,
with 2 calls to start and finish table creation,
which hides offests magic from API user.

While at it switch to build_append_int_noprefix() to build
entries to other tables (which also removes some manual offset
calculations).

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20210924122802.1455362-3-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 15 insertions, 16 deletions

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 229a3eb..616a292 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1884,33 +1884,32 @@ build_rsdp(GArray *tbl, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
                                     32);
 }
 
-/* Build rsdt table */
+/*
+ * ACPI 1.0 Root System Description Table (RSDT)
+ */
 void
 build_rsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets,
            const char *oem_id, const char *oem_table_id)
 {
     int i;
-    unsigned rsdt_entries_offset;
-    AcpiRsdtDescriptorRev1 *rsdt;
-    int rsdt_start = table_data->len;
-    const unsigned table_data_len = (sizeof(uint32_t) * table_offsets->len);
-    const unsigned rsdt_entry_size = sizeof(rsdt->table_offset_entry[0]);
-    const size_t rsdt_len = sizeof(*rsdt) + table_data_len;
-
-    rsdt = acpi_data_push(table_data, rsdt_len);
-    rsdt_entries_offset = (char *)rsdt->table_offset_entry - table_data->data;
+    AcpiTable table = { .sig = "RSDT", .rev = 1,
+                        .oem_id = oem_id, .oem_table_id = oem_table_id };
+
+    acpi_table_begin(&table, table_data);
     for (i = 0; i < table_offsets->len; ++i) {
         uint32_t ref_tbl_offset = g_array_index(table_offsets, uint32_t, i);
-        uint32_t rsdt_entry_offset = rsdt_entries_offset + rsdt_entry_size * i;
+        uint32_t rsdt_entry_offset = table.array->len;
 
-        /* rsdt->table_offset_entry to be filled by Guest linker */
+        /* reserve space for entry */
+        build_append_int_noprefix(table.array, 0, 4);
+
+        /* mark position of RSDT entry to be filled by Guest linker */
         bios_linker_loader_add_pointer(linker,
-            ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, rsdt_entry_size,
+            ACPI_BUILD_TABLE_FILE, rsdt_entry_offset, 4,
             ACPI_BUILD_TABLE_FILE, ref_tbl_offset);
+
     }
-    build_header(linker, table_data,
-                 (void *)(table_data->data + rsdt_start),
-                 "RSDT", rsdt_len, 1, oem_id, oem_table_id);
+    acpi_table_end(linker, &table);
 }
 
 /* Build xsdt table */