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

[Philippe Mathieu-Daudé]

On 7/29/21 5:39 AM, Jiaxun Yang wrote:
> ELF kernel allows us debugging much easier with DWARF symbols.

You can load the symbols using the 'loader' device:
docs/system/generic-loader.rst.

> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
>  hw/mips/boston.c | 38 ++++++++++++++++++++++++++++++++++----
>  1 file changed, 34 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/mips/boston.c b/hw/mips/boston.c
> index a5746ede65..42b31a1ce4 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 +547,39 @@ 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,
> +                           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;
> +                const void *dtb_file_data, *dtb_load_data;

g_autofree is preferred.

Otherwise:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +
> +                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);
> +                g_free((void *) dtb_file_data);
> +                g_free((void *) dtb_load_data);
> +            }
> +        } 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,
>