Re: [Qemu-devel] [PATCH v2] register reset handler to write image into memory

[Alexander Graf]

On 26.09.2012, at 10:13, Yin Olivia-R63875 wrote:

> Hi Alex,
> 
> I checked all the rom_add_*() functions.
> Multiple platforms of different architectures use rom_add_* to save images.
>       hw/arm_boot.c
>       hw/exynos4210.
>       hw/highbank.
>       hw/mips_fulong2e.c
>       hw/mips_malta.c
>       hw/mips_r4k.c
>       hw/r2d.c
> 
> Even for PowerPC, it also use rom_add_blob() to write dtb in memory.
>       hw/ppc/e500.c:  rom_add_blob_fixed(BINARY_DEVICE_TREE_FILE, fdt, 
> fdt_size, addr);
>       hw/ppc440_bamboo.c
> 
> You also minder that ELF file.
>       hw/elf_ops.h:   rom_add_blob_fixed(label, data, mem_size, addr);
> 
> pstrcpy_targphys() does also call rom_add_blob_fixed() function, so we need 
> also verify
>       hw/alpha_dp264.c
>       hw/cris-boot.c
>       hw/lm32_boards.c
>       hw/microblaze_boot.c
>       hw/milkymist.c
>       hw/ppc.c
>       hw/ppc_newworld.c
>       hw/ppc_oldworld.c
>       hw/sun4m.c
>       hw/sun4m.c
> 
> Should we register reset handler for each above user?

I suppose we should decide on a case-by-case basis. If it's easy to reconstruct 
the binary, convert it to a reset handler. It it's too hard, leave it to 
whoever cares about the board.

> The callers of rom_ptr() function:
>       hw/s390-virtio.c
>       hw/sun4m.c
>       hw/sun4u.c
>       target-arm/cpu.c
> But I don't understand why rom_ptr should be changed.

Because rom_ptr works on roms. When we get rid of roms, rom_ptr won't work 
anymore, because there is no in-memory representation of the rom to work on.

So instead of calling rom_ptr, the respective code should have a reset handler 
that gets invoked after the rom restore handler (or a callback function?) which 
can restore the change to the rom that code wants to do.


Alex