qemu/acpi-build: cross migration fixes

index a711145..ac62454 100644
@@ -542,6 +542,7 @@ struct Rom {
     size_t datasize;
 
     uint8_t *data;
+    MemoryRegion *mr;
     int isrom;
     char *fw_dir;
     char *fw_file;

@@ -641,7 +642,7 @@ err:
 }
 
 int rom_add_blob(const char *name, const void *blob, size_t len,
-                 hwaddr addr)
+                 hwaddr addr, MemoryRegion *mr)
 {
     Rom *rom;
 

@@ -651,6 +652,11 @@ int rom_add_blob(const char *name, const void *blob, size_t len,
     rom->romsize  = len;
     rom->datasize = len;
     rom->data     = g_malloc0(rom->datasize);
+    rom->mr       = mr;
+    if (mr) {
+        assert(memory_region_is_ram(mr));
+        rom->isrom = memory_region_is_rom(mr);
+    }
     memcpy(rom->data, blob, len);
     rom_insert(rom);
     return 0;

@@ -697,7 +703,12 @@ static void rom_reset(void *unused)
         if (rom->data == NULL) {
             continue;
         }
-        cpu_physical_memory_write_rom(rom->addr, rom->data, rom->datasize);
+        if (rom->mr) {
+            void *host = memory_region_get_ram_ptr(rom->mr);
+            memcpy(host, rom->data, rom->datasize);
+        } else {
+            cpu_physical_memory_write_rom(rom->addr, rom->data, rom->datasize);
+        }
         if (rom->isrom) {
             /* rom needs to be written only once */
             g_free(rom->data);

@@ -713,6 +724,9 @@ int rom_load_all(void)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
+        if (rom->mr) {
+            continue;
+        }
         if (rom->fw_file) {
             continue;
         }

@@ -746,6 +760,9 @@ static Rom *find_rom(hwaddr addr)
         if (rom->fw_file) {
             continue;
         }
+        if (rom->mr) {
+            continue;
+        }
         if (rom->addr > addr) {
             continue;
         }

@@ -773,6 +790,9 @@ int rom_copy(uint8_t *dest, hwaddr addr, size_t size)
         if (rom->fw_file) {
             continue;
         }
+        if (rom->mr) {
+            continue;
+        }
         if (rom->addr + rom->romsize < addr) {
             continue;
         }

@@ -832,7 +852,13 @@ void do_info_roms(Monitor *mon, const QDict *qdict)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (!rom->fw_file) {
+        if (rom->mr) {
+            monitor_printf(mon, "%s"
+                           " size=0x%06zx name=\"%s\"\n",
+                           rom->mr->name,
+                           rom->romsize,
+                           rom->name);
+        } else if (!rom->fw_file) {
             monitor_printf(mon, "addr=" TARGET_FMT_plx
                            " size=0x%06zx mem=%s name=\"%s\"\n",
                            rom->addr, rom->romsize,

index 3449bd8..d6914d6 100644
@@ -73,7 +73,7 @@ static inline void hwsetup_free(HWSetup *hw)
 static inline void hwsetup_create_rom(HWSetup *hw,
         hwaddr base)
 {
-    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base);
+    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base, NULL);
 }
 
 static inline void hwsetup_add_u8(HWSetup *hw, uint8_t u)

index 15d4cc9..b39e7d1 100644
@@ -27,7 +27,7 @@ void pstrcpy_targphys(const char *name,
 int rom_add_file(const char *file, const char *fw_dir,
                  hwaddr addr, int32_t bootindex);
 int rom_add_blob(const char *name, const void *blob, size_t len,
-                 hwaddr addr);
+                 hwaddr addr, MemoryRegion *mr);
 int rom_add_elf_program(const char *name, void *data, size_t datasize,
                         size_t romsize, hwaddr addr);
 int rom_load_all(void);

@@ -39,7 +39,7 @@ void do_info_roms(Monitor *mon, const QDict *qdict);
 #define rom_add_file_fixed(_f, _a, _i)          \
     rom_add_file(_f, NULL, _a, _i)
 #define rom_add_blob_fixed(_f, _b, _l, _a)      \
-    rom_add_blob(_f, _b, _l, _a)
+    rom_add_blob(_f, _b, _l, _a, NULL)
 
 #define PC_ROM_MIN_VGA     0xc0000
 #define PC_ROM_MIN_OPTION  0xc8000

index 43e4988..911c913 100644
@@ -35,6 +35,7 @@
 #include "hw/nvram/fw_cfg.h"
 #include "hw/i386/bios-linker-loader.h"
 #include "hw/pci/pci_bus.h"
+#include "hw/loader.h"
 
 #define ACPI_BUILD_APPNAME  "Bochs"
 #define ACPI_BUILD_APPNAME6 "BOCHS "

@@ -933,6 +934,28 @@ build_rsdp(GArray *linker, unsigned rsdt)
     return rsdp_table;
 }
 
+static void acpi_add_rom_blob(PcGuestInfo *guest_info, GArray *blob,
+                              const char *name, unsigned align)
+{
+    MemoryRegion *mr = g_malloc(sizeof(*mr));
+
+    /* Align size to multiple of given size. This reduces the chance
+     * we need to change size in the future (breaking cross version migration).
+     */
+    g_array_set_size(blob, (ROUND_UP(acpi_data_len(blob), align) +
+                            g_array_get_element_size(blob) - 1) /
+                             g_array_get_element_size(blob));
+    memory_region_init_ram_ptr(mr, "etc/blob-script",
+                               acpi_data_len(blob), blob->data);
+    memory_region_set_readonly(mr, true);
+    vmstate_register_ram_global(mr);
+    rom_add_blob(ACPI_BUILD_TABLE_FILE, blob->data, acpi_data_len(blob),
+                 -1, mr);
+
+    fw_cfg_add_file(guest_info->fw_cfg, name,
+                    blob->data, acpi_data_len(blob));
+}
+
 #define ACPI_MAX_ACPI_TABLES 20
 void acpi_setup(PcGuestInfo *guest_info)
 {

@@ -993,12 +1016,18 @@ void acpi_setup(PcGuestInfo *guest_info)
     rsdp = build_rsdp(linker, rsdt);
 
     /* Now expose it all to Guest */
-    fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_TABLE_FILE,
-                    table_data->data, table_data->len);
+    acpi_add_rom_blob(guest_info, table_data,
+                      ACPI_BUILD_TABLE_FILE, 1 << 20);
+
+    acpi_add_rom_blob(guest_info, linker,
+                      "etc/linker-script", TARGET_PAGE_SIZE);
+
+    /*
+     * RSDP is small so it's easy to keep it immutable, no need to
+     * bother with ROM blobs.
+     */
     fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
                     rsdp->data, acpi_data_len(rsdp));
-    fw_cfg_add_file(guest_info->fw_cfg, "etc/linker-script",
-                    linker->data, acpi_data_len(linker));
 
     /* Cleanup GArray wrappers and memory if no longer used. */
     bios_linker_cleanup(linker);

index 911c913..7e52457 100644
@@ -966,6 +966,10 @@ void acpi_setup(PcGuestInfo *guest_info)
         ACPI_BUILD_DPRINTF(3, "No fw cfg. Boiling out.\n");
     }
 
+    if (!guest_info->has_acpi_build) {
+        ACPI_BUILD_DPRINTF(3, "ACPI build disabled. Boiling out.\n");
+    }
+
     table_data = g_array_new(false, true /* clear */, 1);
     table_offsets = g_array_new(false, true /* clear */,
                                         sizeof(uint32_t));

index e46f19a..eb11456 100644
@@ -59,6 +59,7 @@ static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 0x376 };
 static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 
 static bool has_pvpanic = true;
+static bool has_acpi_build = true;
 
 /* PC hardware initialisation */
 static void pc_init1(MemoryRegion *system_memory,

@@ -124,6 +125,7 @@ static void pc_init1(MemoryRegion *system_memory,
 
     guest_info = pc_guest_info_init(below_4g_mem_size, above_4g_mem_size);
 
+    guest_info->has_acpi_build = has_acpi_build;
     guest_info->dsdt_code = AcpiDsdtAmlCode;
     guest_info->dsdt_size = sizeof AcpiDsdtAmlCode;
 

@@ -266,12 +268,18 @@ static void pc_init_pci(QEMUMachineInitArgs *args)
              initrd_filename, cpu_model, 1, 1);
 }
 
+static void pc_init_pci_1_5(QEMUMachineInitArgs *args)
+{
+    has_acpi_build = false;
+    pc_init_pci(args);
+}
+
 static void pc_init_pci_1_4(QEMUMachineInitArgs *args)
 {
     pc_sysfw_flash_vs_rom_bug_compatible = true;
     has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
-    pc_init_pci(args);
+    pc_init_pci_1_5(args);
 }
 
 static void pc_init_pci_1_3(QEMUMachineInitArgs *args)

@@ -365,7 +373,7 @@ static QEMUMachine pc_i440fx_machine_v1_6 = {
 static QEMUMachine pc_i440fx_machine_v1_5 = {
     .name = "pc-i440fx-1.5",
     .desc = "Standard PC (i440FX + PIIX, 1996)",
-    .init = pc_init_pci,
+    .init = pc_init_pci_1_5,
     .hot_add_cpu = pc_hot_add_cpu,
     .max_cpus = 255,
     .compat_props = (GlobalProperty[]) {

index c11118a..e101112 100644
@@ -49,6 +49,7 @@
 #define MAX_SATA_PORTS     6
 
 static bool has_pvpanic = true;
+static bool has_acpi_build = true;
 
 /* PC hardware initialisation */
 static void pc_q35_init(QEMUMachineInitArgs *args)

@@ -109,6 +110,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     }
 
     guest_info = pc_guest_info_init(below_4g_mem_size, above_4g_mem_size);
+    guest_info->has_acpi_build = has_acpi_build;
     guest_info->dsdt_code = Q35AcpiDsdtAmlCode;
     guest_info->dsdt_size = sizeof Q35AcpiDsdtAmlCode;
 

@@ -216,12 +218,18 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     }
 }
 
+static void pc_q35_init_1_5(QEMUMachineInitArgs *args)
+{
+    has_acpi_build = false;
+    pc_q35_init(args);
+}
+
 static void pc_q35_init_1_4(QEMUMachineInitArgs *args)
 {
     pc_sysfw_flash_vs_rom_bug_compatible = true;
     has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
-    pc_q35_init(args);
+    pc_q35_init_1_5(args);
 }
 
 static QEMUMachine pc_q35_machine_v1_6 = {

@@ -237,7 +245,7 @@ static QEMUMachine pc_q35_machine_v1_6 = {
 static QEMUMachine pc_q35_machine_v1_5 = {
     .name = "pc-q35-1.5",
     .desc = "Standard PC (Q35 + ICH9, 2009)",
-    .init = pc_q35_init,
+    .init = pc_q35_init_1_5,
     .hot_add_cpu = pc_hot_add_cpu,
     .max_cpus = 255,
     .compat_props = (GlobalProperty[]) {

index 80c9e71..722d7d0 100644
@@ -51,6 +51,7 @@ struct PcGuestInfo {
     uint64_t mcfg_base;
     const unsigned char *dsdt_code;
     unsigned dsdt_size;
+    bool has_acpi_build;
     FWCfgState *fw_cfg;
 };