Make the BIOS linker optional in acpi_table_end() and calculate the ACPI
table checksum directly if no linker is provided.

This makes it possible to call for example
acpi_build_madt() from outside the ACPI table builder context.

Signed-off-by: Oliver Steffen <osteffen@redhat.com>
---
 hw/acpi/aml-build.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index dad4cfcc7d..ea1c415b21 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -22,6 +22,7 @@
 #include "qemu/osdep.h"
 #include <glib/gprintf.h>
 #include "hw/acpi/aml-build.h"
+#include "hw/acpi/acpi.h"
 #include "qemu/bswap.h"
 #include "qemu/bitops.h"
 #include "system/numa.h"
@@ -1741,6 +1742,7 @@ void acpi_table_end(BIOSLinker *linker, AcpiTable *desc)
     uint32_t table_len = desc->array->len - desc->table_offset;
     uint32_t table_len_le = cpu_to_le32(table_len);
     gchar *len_ptr = &desc->array->data[desc->table_offset + 4];
+    uint8_t *table;
 
     /* patch "Length" field that has been reserved by acpi_table_begin()
      * to the actual length, i.e. accumulated table length from
@@ -1748,8 +1750,14 @@ void acpi_table_end(BIOSLinker *linker, AcpiTable *desc)
      */
     memcpy(len_ptr, &table_len_le, sizeof table_len_le);
 
-    bios_linker_loader_add_checksum(linker, ACPI_BUILD_TABLE_FILE,
-        desc->table_offset, table_len, desc->table_offset + checksum_offset);
+    if (linker != NULL) {
+        bios_linker_loader_add_checksum(linker, ACPI_BUILD_TABLE_FILE,
+                                        desc->table_offset, table_len,
+                                        desc->table_offset + checksum_offset);
+    } else {
+        table = (uint8_t *) &desc->array->data[desc->table_offset];
+        table[checksum_offset] = acpi_checksum(table, table_len);
+    }
 }
 
 void *acpi_data_push(GArray *table_data, unsigned size)
-- 
2.52.0