Re: [Qemu-devel] [PATCH for-2.3] arm: memory: Replace memory_region_init_ram with memory_region_allocate_system_memory

[Paolo Bonzini <pbonzini@redhat.com>]

On 24/03/2015 22:24, Dirk Müller wrote:
> +++ b/hw/arm/exynos4210.c
> @@ -283,16 +283,16 @@ Exynos4210State *exynos4210_init(MemoryRegion *system_mem,
>      /* DRAM */
>      mem_size = ram_size;
>      if (mem_size > EXYNOS4210_DRAM_MAX_SIZE) {
> -        memory_region_init_ram(&s->dram1_mem, NULL, "exynos4210.dram1",
> -                mem_size - EXYNOS4210_DRAM_MAX_SIZE, &error_abort);
> -        vmstate_register_ram_global(&s->dram1_mem);
> +        unsigned long dram1_size = mem_size - EXYNOS4210_DRAM_MAX_SIZE;
> +        memory_region_allocate_system_memory(&s->dram1_mem, NULL,
> +                                             "exynos4210.dram1",
> +                                             dram1_size);
>          memory_region_add_subregion(system_mem, EXYNOS4210_DRAM1_BASE_ADDR,
>                  &s->dram1_mem);
>          mem_size = EXYNOS4210_DRAM_MAX_SIZE;
>      }
> -    memory_region_init_ram(&s->dram0_mem, NULL, "exynos4210.dram0", mem_size,
> -                           &error_abort);
> -    vmstate_register_ram_global(&s->dram0_mem);
> +    memory_region_allocate_system_memory(&s->dram0_mem, NULL,
> +                                         "exynos4210.dram0", mem_size);
>      memory_region_add_subregion(system_mem, EXYNOS4210_DRAM0_BASE_ADDR,
>              &s->dram0_mem);

You cannot call memory_region_allocate_system_memory twice.  For cases
like this one, the right thing to do is to create a region with
memory_region_allocate_system_memory, and then replace
memory_region_init_ram with memory_region_init_alias.  This "slices" the
region created by memory_region_allocate_system_memory.

Paolo