acpi: nvdimm_build_ssdt: use acpi_table_begin()/acpi_table_end() instead of build_hea...

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

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20210924122802.1455362-12-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 15f6ca82cab6f2f2cd6b6945929795a8c66badff..a7539cfe891d210172a5850c035af7fca26db1bb 100644 (file)
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -1274,14 +1274,15 @@ static void nvdimm_build_ssdt(GArray *table_offsets, GArray *table_data,
                               NVDIMMState *nvdimm_state,
                               uint32_t ram_slots, const char *oem_id)
 {
+    int mem_addr_offset;
     Aml *ssdt, *sb_scope, *dev;
-    int mem_addr_offset, nvdimm_ssdt;
+    AcpiTable table = { .sig = "SSDT", .rev = 1,
+                        .oem_id = oem_id, .oem_table_id = "NVDIMM" };
 
     acpi_add_table(table_offsets, table_data);
 
+    acpi_table_begin(&table, table_data);
     ssdt = init_aml_allocator();
-    acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
-
     sb_scope = aml_scope("\\_SB");
 
     dev = aml_device("NVDR");
@@ -1310,8 +1311,6 @@ static void nvdimm_build_ssdt(GArray *table_offsets, GArray *table_data,
     aml_append(sb_scope, dev);
     aml_append(ssdt, sb_scope);
 
-    nvdimm_ssdt = table_data->len;
-
     /* copy AML table into ACPI tables blob and patch header there */
     g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
     mem_addr_offset = build_append_named_dword(table_data,
@@ -1323,10 +1322,13 @@ static void nvdimm_build_ssdt(GArray *table_offsets, GArray *table_data,
     bios_linker_loader_add_pointer(linker,
         ACPI_BUILD_TABLE_FILE, mem_addr_offset, sizeof(uint32_t),
         NVDIMM_DSM_MEM_FILE, 0);
-    build_header(linker, table_data,
-        (void *)(table_data->data + nvdimm_ssdt),
-                 "SSDT", table_data->len - nvdimm_ssdt, 1, oem_id, "NVDIMM");
     free_aml_allocator();
+    /*
+     * must be executed as the last so that pointer patching command above
+     * would be executed by guest before it recalculated checksum which were
+     * scheduled by acpi_table_end()
+     */
+    acpi_table_end(linker, &table);
 }
 
 void nvdimm_build_srat(GArray *table_data)