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

[BALATON Zoltan]

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. 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);
> >       }