On Mon, 27 Nov 2023, Nicholas Piggin wrote:
On Sun Nov 26, 2023 at 2:34 AM AEST, BALATON Zoltan wrote:
The machine uses a modified U-Boot under GPL license but the sources
of it are lost with only a binary available so it cannot be included
in QEMU. Allow running without the firmware image with -bios none
which can be used when calling a boot loader directly and thus
simplifying booting guests. We need a small routine that AmigaOS calls
from ROM which is added in this case to allow booting AmigaOS without
external firmware image.
Signed-off-by: BALATON Zoltan <bala...@eik.bme.hu>
---
v2: Unfortunately AmigaOS needs some additional ROM part which is added
Please merge for 8.2 as it allows booting AmigaOS simpler without
having to download separate firmware.
How to test this?
You can check with -M amigaone -bios none then from QEMU monitor
(qemu) xp/10i 0xfff7ff80
hw/ppc/amigaone.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/hw/ppc/amigaone.c b/hw/ppc/amigaone.c
index 992a55e632..a11d2d5556 100644
--- a/hw/ppc/amigaone.c
+++ b/hw/ppc/amigaone.c
@@ -40,6 +40,16 @@
#define PROM_ADDR 0xfff00000
#define PROM_SIZE (512 * KiB)
+/* AmigaOS calls this routine from ROM, use this if -bios none */
+static const char dummy_fw[] = {
+ 0x38, 0x00, 0x00, 0x08, /* li r0,8 */
+ 0x7c, 0x09, 0x03, 0xa6, /* mtctr r0 */
+ 0x54, 0x63, 0xf8, 0x7e, /* srwi r3,r3,1 */
+ 0x42, 0x00, 0xff, 0xfc, /* bdnz 0x8 */
+ 0x7c, 0x63, 0x18, 0xf8, /* not r3,r3 */
+ 0x4e, 0x80, 0x00, 0x20, /* blr */
+};
This is clever, but does anything else create blobs like this?
There are some examples in hw/mips/{loongson3_virt.c, malta.c} at least
and maybe others that put code in guest memory. If this was longer than
this few instructions I'd consider putting it in a binary but this seems
simpler for such small code.
It could be put into a .S in pc-bios, which might be a bit more
consistent.
We might make a ppc/ subdirectory under there, but that's for
another time.
Maybe later we could reorganise these unless it's really necessary to
change this for 8.2 now. (The mips boards and some arm and riscv machines
seem to use rom_add_blob_fixed() which sould show up in info roms under
monitor so maybe I could look at changing to use that now if you think it
would be better that way.)
Regards,
BALATON Zoltan
Thanks,
Nick
+
static void amigaone_cpu_reset(void *opaque)
{
PowerPCCPU *cpu = opaque;
@@ -94,17 +104,21 @@ static void amigaone_init(MachineState *machine)
}
/* allocate and load firmware */
+ rom = g_new(MemoryRegion, 1);
+ memory_region_init_rom(rom, NULL, "rom", PROM_SIZE, &error_fatal);
+ memory_region_add_subregion(get_system_memory(), PROM_ADDR, rom);
filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, fwname);
if (filename) {
- rom = g_new(MemoryRegion, 1);
- memory_region_init_rom(rom, NULL, "rom", PROM_SIZE, &error_fatal);
- memory_region_add_subregion(get_system_memory(), PROM_ADDR, rom);
sz = load_image_targphys(filename, PROM_ADDR, PROM_SIZE);
if (sz <= 0 || sz > PROM_SIZE) {
error_report("Could not load firmware '%s'", filename);
exit(1);
}
g_free(filename);
+ } else if (!strcmp(fwname, "none")) {
+ address_space_write_rom(&address_space_memory, 0xfff7ff80,
+ MEMTXATTRS_UNSPECIFIED, dummy_fw,
+ ARRAY_SIZE(dummy_fw));
} else if (!qtest_enabled()) {
error_report("Could not find firmware '%s'", fwname);
exit(1);