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

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

On 10/17/20 6:31 PM, BALATON Zoltan via wrote:
> On Sat, 17 Oct 2020, Philippe Mathieu-Daudé wrote:
>> +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);
> 
> Please don't come up with any more great ideas for this patch unless you 
> also propose a replacement and test it. This one works and we could just 
> get this in as it is until the real problem with load_elf is fixed at 
> which point all this can be removed so no need to be more sophisticated 
> as the simple cast I have.

Zoltan, I'm not trying to block your patch to get merged,
I'm asking because I'm trying to understand how this API
is expected to be used.

> As you can see in the original discussion:
> 
> http://patchwork.ozlabs.org/project/qemu-devel/patch/c69a791c7cad1246f3f34b3993dee4f549b75aa2.1593456926.git.balaton@eik.bme.hu/ 
> 
> 
> problem is really in include/hw/elf_ops.h this is just a work around for 
> that as I did not want to break anything I can't test so I'd rather fix 
> it up here and let you fix load_elf then drop this cast. But unless you 
> can do that before the freeze please don't hold up this patch any more.
> 
> Regards,
> BALATON Zoltan
> 
>>> +        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);
>>>       }
>>>
>>
>>
>>