Re: [PATCH v9] mac_oldworld: Allow loading binary ROM image

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

+Alistair for loader

On 10/17/20 5:47 PM, BALATON Zoltan via wrote:
> The beige G3 Power Macintosh has a 4MB firmware ROM. Fix the size of
> the rom region and fall back to loading a binary image with -bios if
> loading ELF image failed. This allows testing emulation with a ROM
> image from real hardware as well as using an ELF OpenBIOS image.
> 
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
> v9: Revert change from v8, back to the same as v7 rebased on latest
> 
>   hw/ppc/mac_oldworld.c | 29 ++++++++++++++++++++---------
>   1 file changed, 20 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/ppc/mac_oldworld.c b/hw/ppc/mac_oldworld.c
> index 05e46ee6fe..0117ae17f5 100644
> --- a/hw/ppc/mac_oldworld.c
> +++ b/hw/ppc/mac_oldworld.c
> @@ -59,6 +59,8 @@
>   #define NDRV_VGA_FILENAME "qemu_vga.ndrv"
>   
>   #define GRACKLE_BASE 0xfec00000
> +#define PROM_BASE 0xffc00000
> +#define PROM_SIZE (4 * MiB)
>   
>   static void fw_cfg_boot_set(void *opaque, const char *boot_device,
>                               Error **errp)
> @@ -100,6 +102,7 @@ static void ppc_heathrow_init(MachineState *machine)
>       SysBusDevice *s;
>       DeviceState *dev, *pic_dev;
>       BusState *adb_bus;
> +    uint64_t bios_addr;
>       int bios_size;
>       unsigned int smp_cpus = machine->smp.cpus;
>       uint16_t ppc_boot_device;
> @@ -128,24 +131,32 @@ static void ppc_heathrow_init(MachineState *machine)
>   
>       memory_region_add_subregion(sysmem, 0, machine->ram);
>   
> -    /* allocate and load BIOS */
> -    memory_region_init_rom(bios, NULL, "ppc_heathrow.bios", BIOS_SIZE,
> +    /* allocate and load firmware ROM */
> +    memory_region_init_rom(bios, NULL, "ppc_heathrow.bios", PROM_SIZE,
>                              &error_fatal);
> +    memory_region_add_subregion(sysmem, PROM_BASE, bios);
>   
> -    if (bios_name == NULL)
> +    if (!bios_name) {
>           bios_name = PROM_FILENAME;
> +    }
>       filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> -    memory_region_add_subregion(sysmem, PROM_ADDR, bios);
> -
> -    /* Load OpenBIOS (ELF) */
>       if (filename) {
> -        bios_size = load_elf(filename, NULL, 0, NULL, NULL, NULL, NULL, NULL,
> -                             1, PPC_ELF_MACHINE, 0, 0);
> +        /* Load OpenBIOS (ELF) */
> +        bios_size = load_elf(filename, NULL, NULL, NULL, NULL, &bios_addr,
> +                             NULL, NULL, 1, PPC_ELF_MACHINE, 0, 0);
> +        /* Unfortunately, load_elf sign-extends reading elf32 */

Maybe this is what translate_fn() is for?

uint64_t oldworld_phys(void *opaque, uint64_t addr)
{
     return addr & UINT32_MAX;
}

Using as (untested):

         bios_size = load_elf(filename, NULL, oldworld_phys, NULL,
                              NULL, &bios_addr, NULL,
                              NULL, 1, PPC_ELF_MACHINE, 0, 0);

> +        bios_addr = (uint32_t)bios_addr;
> +
> +        if (bios_size <= 0) {
> +            /* or load binary ROM image */
> +            bios_size = load_image_targphys(filename, PROM_BASE, PROM_SIZE);
> +            bios_addr = PROM_BASE;
> +        }
>           g_free(filename);
>       } else {
>           bios_size = -1;
>       }
> -    if (bios_size < 0 || bios_size > BIOS_SIZE) {
> +    if (bios_size < 0 || bios_addr - PROM_BASE + bios_size > PROM_SIZE) {
>           error_report("could not load PowerPC bios '%s'", bios_name);
>           exit(1);
>       }
>