pc: Unbreak ROM mapping for ISA machine

This is based on the original fix by Hervé Poussineau: pc_memory_init
actually takes a memory region for mapping BIOS and extension ROMs. That
equals the PCI memory region if PCI is available, but must be system
memory in the ISA case.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/pc.c

@@ -965,7 +965,7 @@ void pc_memory_init(MemoryRegion *system_memory,
                     const char *initrd_filename,
                     ram_addr_t below_4g_mem_size,
                     ram_addr_t above_4g_mem_size,
-                    MemoryRegion *pci_memory,
+                    MemoryRegion *rom_memory,
                     MemoryRegion **ram_memory)
 {
     char *filename;
@@ -1029,7 +1029,7 @@ void pc_memory_init(MemoryRegion *system_memory,
     isa_bios = g_malloc(sizeof(*isa_bios));
     memory_region_init_alias(isa_bios, "isa-bios", bios,
                              bios_size - isa_bios_size, isa_bios_size);
-    memory_region_add_subregion_overlap(pci_memory,
+    memory_region_add_subregion_overlap(rom_memory,
                                         0x100000 - isa_bios_size,
                                         isa_bios,
                                         1);
@@ -1037,13 +1037,13 @@ void pc_memory_init(MemoryRegion *system_memory,
 
     option_rom_mr = g_malloc(sizeof(*option_rom_mr));
     memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE);
-    memory_region_add_subregion_overlap(pci_memory,
+    memory_region_add_subregion_overlap(rom_memory,
                                         PC_ROM_MIN_VGA,
                                         option_rom_mr,
                                         1);
 
     /* map all the bios at the top of memory */
-    memory_region_add_subregion(pci_memory,
+    memory_region_add_subregion(rom_memory,
                                 (uint32_t)(-bios_size),
                                 bios);
 

hw/pc.h

@@ -137,7 +137,7 @@ void pc_memory_init(MemoryRegion *system_memory,
                     const char *initrd_filename,
                     ram_addr_t below_4g_mem_size,
                     ram_addr_t above_4g_mem_size,
-                    MemoryRegion *pci_memory,
+                    MemoryRegion *rom_memory,
                     MemoryRegion **ram_memory);
 qemu_irq *pc_allocate_cpu_irq(void);
 void pc_vga_init(PCIBus *pci_bus);

hw/pc_piix.c

@@ -97,6 +97,7 @@ static void pc_init1(MemoryRegion *system_memory,
     ISADevice *rtc_state;
     MemoryRegion *ram_memory;
     MemoryRegion *pci_memory;
+    MemoryRegion *rom_memory;
 
     pc_cpus_init(cpu_model);
 
@@ -112,15 +113,21 @@ static void pc_init1(MemoryRegion *system_memory,
         below_4g_mem_size = ram_size;
     }
 
-    pci_memory = g_new(MemoryRegion, 1);
-    memory_region_init(pci_memory, "pci", INT64_MAX);
+    if (pci_enabled) {
+        pci_memory = g_new(MemoryRegion, 1);
+        memory_region_init(pci_memory, "pci", INT64_MAX);
+        rom_memory = pci_memory;
+    } else {
+        pci_memory = NULL;
+        rom_memory = system_memory;
+    }
 
     /* allocate ram and load rom/bios */
     if (!xen_enabled()) {
         pc_memory_init(system_memory,
                        kernel_filename, kernel_cmdline, initrd_filename,
                        below_4g_mem_size, above_4g_mem_size,
-                       pci_memory, &ram_memory);
+                       rom_memory, &ram_memory);
     }
 
     if (!xen_enabled()) {