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

[BALATON Zoltan]

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,

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,