Re: [PATCH v2 2/3] hw/mips/boston: Allow loading elf kernel and dtb

[BALATON Zoltan]

On Wed, 29 Sep 2021, Jiaxun Yang wrote:

> ELF kernel allows us debugging much easier with DWARF symbols.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> --
> v2: Use g_autofree
> ---
> hw/mips/boston.c | 36 ++++++++++++++++++++++++++++++++----
> 1 file changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/hw/mips/boston.c b/hw/mips/boston.c
> index 5c720440fb..5d3f054a3e 100644
> --- a/hw/mips/boston.c
> +++ b/hw/mips/boston.c
> @@ -20,6 +20,7 @@
> #include "qemu/osdep.h"
> #include "qemu/units.h"
>
> +#include "elf.h"
> #include "hw/boards.h"
> #include "hw/char/serial.h"
> #include "hw/ide/pci.h"
> @@ -546,10 +547,37 @@ static void boston_mach_init(MachineState *machine)
>             exit(1);
>         }
>     } else if (machine->kernel_filename) {
> -        fit_err = load_fit(&boston_fit_loader, machine->kernel_filename, s);
> -        if (fit_err) {
> -            error_report("unable to load FIT image");
> -            exit(1);
> +        uint64_t kernel_entry, kernel_low, kernel_high, kernel_size;
> +
> +        kernel_size = load_elf(machine->kernel_filename, NULL,
> +                           cpu_mips_kseg0_to_phys, NULL,
> +                           (uint64_t *)&kernel_entry,
> +                           (uint64_t *)&kernel_low, (uint64_t *)&kernel_high,

These (uint64_t *) casts should not be needed and kernel_low seems to be 
unused so you could just pass NULL for it (see commit 617160c9e1f8).

Regards,
BALATON Zoltan

> +                           NULL, 0, EM_MIPS, 1, 0);
> +
> +        if (kernel_size) {
> +            hwaddr dtb_paddr = QEMU_ALIGN_UP(kernel_high, 64 * KiB);
> +            hwaddr dtb_vaddr = cpu_mips_phys_to_kseg0(NULL, dtb_paddr);
> +
> +            s->kernel_entry = kernel_entry;
> +            if (machine->dtb) {
> +                int dt_size;
> +                g_autofree const void *dtb_file_data, *dtb_load_data;
> +
> +                dtb_file_data = load_device_tree(machine->dtb, &dt_size);
> +                dtb_load_data = boston_fdt_filter(s, dtb_file_data, NULL, 
> &dtb_vaddr);
> +
> +                /* Calculate real fdt size after filter */
> +                dt_size = fdt_totalsize(dtb_load_data);
> +                rom_add_blob_fixed("dtb", dtb_load_data, dt_size, dtb_paddr);
> +            }
> +        } else {
> +            /* Try to load file as FIT */
> +            fit_err = load_fit(&boston_fit_loader, machine->kernel_filename, 
> s);
> +            if (fit_err) {
> +                error_report("unable to load kernel image");
> +                exit(1);
> +            }
>         }
>
>         gen_firmware(memory_region_get_ram_ptr(flash) + 0x7c00000,