acpi: build_hmat: 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 offsets magic from API user.

Also since acpi_table_begin() reserves space only for standard header
while previous acpi_data_push() reserved the header + 4 bytes field,
add 4 bytes 'Reserved' field into hmat_build_table_structs()
which didn have it.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20210924122802.1455362-10-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/hw/acpi/hmat.c b/hw/acpi/hmat.c
index edb3fd9..6913ebf 100644
--- a/hw/acpi/hmat.c
+++ b/hw/acpi/hmat.c
@@ -200,6 +200,8 @@ static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
     HMAT_LB_Info *hmat_lb;
     NumaHmatCacheOptions *hmat_cache;
 
+    build_append_int_noprefix(table_data, 0, 4); /* Reserved */
+
     for (i = 0; i < numa_state->num_nodes; i++) {
         flags = 0;
 
@@ -256,14 +258,10 @@ static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
 void build_hmat(GArray *table_data, BIOSLinker *linker, NumaState *numa_state,
                 const char *oem_id, const char *oem_table_id)
 {
-    int hmat_start = table_data->len;
-
-    /* reserve space for HMAT header  */
-    acpi_data_push(table_data, 40);
+    AcpiTable table = { .sig = "HMAT", .rev = 2,
+                        .oem_id = oem_id, .oem_table_id = oem_table_id };
 
+    acpi_table_begin(&table, table_data);
     hmat_build_table_structs(table_data, numa_state);
-
-    build_header(linker, table_data,
-                 (void *)(table_data->data + hmat_start),
-                 "HMAT", table_data->len - hmat_start, 2, oem_id, oem_table_id);
+    acpi_table_end(linker, &table);
 }