smbios: don't check type4 structures in legacy mode

legacy mode doesn't support structures of type 2 and more,
and CLI has a check for '-smbios type' option, however it's
still possible to sneak in type4 as a blob with '-smbios file'
option. However doing the later makes SMBIOS tables broken
since SeaBIOS doesn't expect that.

Rather than trying to add support for type4 to legacy code
(both QEMU and SeaBIOS), simplify smbios_get_table_legacy()
by dropping not relevant check in legacy code and error out
on type4 blob.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>
Message-Id: <20240314152302.2324164-9-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/fw_cfg.c

@@ -71,8 +71,7 @@ void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg)
     smbios_set_cpuid(cpu->env.cpuid_version, cpu->env.features[FEAT_1_EDX]);
 
     if (pcmc->smbios_legacy_mode) {
-        smbios_tables = smbios_get_table_legacy(ms->smp.cpus,
-                                                &smbios_tables_len);
+        smbios_tables = smbios_get_table_legacy(&smbios_tables_len);
         fw_cfg_add_bytes(fw_cfg, FW_CFG_SMBIOS_ENTRIES,
                          smbios_tables, smbios_tables_len);
         return;

hw/smbios/smbios.c

@@ -545,14 +545,17 @@ opts_init(smbios_register_config);
  */
 #define SMBIOS_21_MAX_TABLES_LEN 0xffff
 
-static void smbios_validate_table(uint32_t expected_t4_count)
+static void smbios_check_type4_count(uint32_t expected_t4_count)
 {
     if (smbios_type4_count && smbios_type4_count != expected_t4_count) {
         error_report("Expected %d SMBIOS Type 4 tables, got %d instead",
                      expected_t4_count, smbios_type4_count);
         exit(1);
     }
+}
 
+static void smbios_validate_table(void)
+{
     if (smbios_ep_type == SMBIOS_ENTRY_POINT_TYPE_32 &&
         smbios_tables_len > SMBIOS_21_MAX_TABLES_LEN) {
         error_report("SMBIOS 2.1 table length %zu exceeds %d",
@@ -637,7 +640,7 @@ static void smbios_build_type_1_fields(void)
     }
 }
 
-uint8_t *smbios_get_table_legacy(uint32_t expected_t4_count, size_t *length)
+uint8_t *smbios_get_table_legacy(size_t *length)
 {
     int i;
     size_t usr_offset;
@@ -650,6 +653,12 @@ uint8_t *smbios_get_table_legacy(uint32_t expected_t4_count, size_t *length)
         exit(1);
     }
 
+    if (test_bit(4, have_binfile_bitmap)) {
+        error_report("can't process table for smbios "
+                     "type 4 on machine versions < 2.1!");
+        exit(1);
+    }
+
     g_free(smbios_entries);
     smbios_entries_len = sizeof(uint16_t);
     smbios_entries = g_malloc0(smbios_entries_len);
@@ -676,7 +685,7 @@ uint8_t *smbios_get_table_legacy(uint32_t expected_t4_count, size_t *length)
 
     smbios_build_type_0_fields();
     smbios_build_type_1_fields();
-    smbios_validate_table(expected_t4_count);
+    smbios_validate_table();
     *length = smbios_entries_len;
     return smbios_entries;
 }
@@ -1304,7 +1313,8 @@ void smbios_get_tables(MachineState *ms,
     smbios_build_type_41_table(errp);
     smbios_build_type_127_table();
 
-    smbios_validate_table(ms->smp.sockets);
+    smbios_check_type4_count(ms->smp.sockets);
+    smbios_validate_table();
     smbios_entry_point_setup();
 
     /* return tables blob and entry point (anchor), and their sizes */

include/hw/firmware/smbios.h

@@ -313,7 +313,7 @@ void smbios_set_defaults(const char *manufacturer, const char *product,
                          const char *version,
                          bool uuid_encoded, SmbiosEntryPointType ep_type);
 void smbios_set_default_processor_family(uint16_t processor_family);
-uint8_t *smbios_get_table_legacy(uint32_t expected_t4_count, size_t *length);
+uint8_t *smbios_get_table_legacy(size_t *length);
 void smbios_get_tables(MachineState *ms,
                        const struct smbios_phys_mem_area *mem_array,
                        const unsigned int mem_array_size,