Re: [PATCH v3 6/9] hw/i386/pc: Initialize ram_memory variable directly

[Bernhard Beschow]

Am 4. Februar 2023 15:26:13 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Sat, 4 Feb 2023, Bernhard Beschow wrote:
>> Going through pc_memory_init() seems quite complicated for a simple
>> assignment.
>> 
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>> include/hw/i386/pc.h | 1 -
>> hw/i386/pc.c         | 2 --
>> hw/i386/pc_piix.c    | 4 ++--
>> hw/i386/pc_q35.c     | 5 ++---
>> 4 files changed, 4 insertions(+), 8 deletions(-)
>> 
>> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
>> index 66e3d059ef..b60b95921b 100644
>> --- a/include/hw/i386/pc.h
>> +++ b/include/hw/i386/pc.h
>> @@ -162,7 +162,6 @@ void xen_load_linux(PCMachineState *pcms);
>> void pc_memory_init(PCMachineState *pcms,
>>                     MemoryRegion *system_memory,
>>                     MemoryRegion *rom_memory,
>> -                    MemoryRegion **ram_memory,
>>                     uint64_t pci_hole64_size);
>> uint64_t pc_pci_hole64_start(void);
>> DeviceState *pc_vga_init(ISABus *isa_bus, PCIBus *pci_bus);
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 6e592bd969..8898cc9961 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -936,7 +936,6 @@ static hwaddr pc_max_used_gpa(PCMachineState *pcms, 
>> uint64_t pci_hole64_size)
>> void pc_memory_init(PCMachineState *pcms,
>>                     MemoryRegion *system_memory,
>>                     MemoryRegion *rom_memory,
>> -                    MemoryRegion **ram_memory,
>>                     uint64_t pci_hole64_size)
>> {
>>     int linux_boot, i;
>> @@ -994,7 +993,6 @@ void pc_memory_init(PCMachineState *pcms,
>>      * Split single memory region and use aliases to address portions of it,
>>      * done for backwards compatibility with older qemus.
>>      */
>> -    *ram_memory = machine->ram;
>>     ram_below_4g = g_malloc(sizeof(*ram_below_4g));
>>     memory_region_init_alias(ram_below_4g, NULL, "ram-below-4g", 
>> machine->ram,
>>                              0, x86ms->below_4g_mem_size);
>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> index 5bde4533cc..00ba725656 100644
>> --- a/hw/i386/pc_piix.c
>> +++ b/hw/i386/pc_piix.c
>> @@ -143,6 +143,7 @@ static void pc_init1(MachineState *machine,
>>     if (xen_enabled()) {
>>         xen_hvm_init_pc(pcms, &ram_memory);
>>     } else {
>> +        ram_memory = machine->ram;
>
>Maybe you could just replace the few places it's used with machine->ram 
>directly and get rid of the local variable. There seems to be no advantage 
>storing it in a local just to use it once (in q35 below) or twice in pc-piix. 
>The local name is not even that much shorter so I don't see a reason to have 
>it in the first place,

Possible with q35 but not with piix which needs to get the RAM from Xen if 
running in this mode. I'll adjust q35 then.

Best regards,
Bernhard
>
>Regards,
>BALATON Zoltan
>
>>         if (!pcms->max_ram_below_4g) {
>>             pcms->max_ram_below_4g = 0xe0000000; /* default: 3.5G */
>>         }
>> @@ -205,8 +206,7 @@ static void pc_init1(MachineState *machine,
>> 
>>     /* allocate ram and load rom/bios */
>>     if (!xen_enabled()) {
>> -        pc_memory_init(pcms, system_memory,
>> -                       rom_memory, &ram_memory, hole64_size);
>> +        pc_memory_init(pcms, system_memory, rom_memory, hole64_size);
>>     } else {
>>         pc_system_flash_cleanup_unused(pcms);
>>         if (machine->kernel_filename != NULL) {
>> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
>> index 8253b49296..88f0981f50 100644
>> --- a/hw/i386/pc_q35.c
>> +++ b/hw/i386/pc_q35.c
>> @@ -129,7 +129,7 @@ static void pc_q35_init(MachineState *machine)
>>     MemoryRegion *system_io = get_system_io();
>>     MemoryRegion *pci_memory;
>>     MemoryRegion *rom_memory;
>> -    MemoryRegion *ram_memory;
>> +    MemoryRegion *ram_memory = machine->ram;
>>     GSIState *gsi_state;
>>     ISABus *isa_bus;
>>     int i;
>> @@ -216,8 +216,7 @@ static void pc_q35_init(MachineState *machine)
>>     }
>> 
>>     /* allocate ram and load rom/bios */
>> -    pc_memory_init(pcms, system_memory, rom_memory, &ram_memory,
>> -                   pci_hole64_size);
>> +    pc_memory_init(pcms, system_memory, rom_memory, pci_hole64_size);
>> 
>>     object_property_add_child(OBJECT(machine), "q35", OBJECT(q35_host));
>>     object_property_set_link(OBJECT(q35_host), MCH_HOST_PROP_RAM_MEM,
>>