Loading x86_64 images in multiboot was disabled on the ground that since multiboot actually boots 64bit kernels in 32bit mode, the binary would have to be 32bit.
https://lists.gnu.org/archive/html/qemu-devel/2010-08/msg00913.html But making the binary 32bit makes using debugging tools such as gdb unnecessarily complex since they don't understand what architecture the kernel actually is. Letting qemu load x86_64 images and boot them in 32bit mode is completely fine, works, and is what the multiboot standard actually expects. This notably fixes loading gnumach in x86_64 mode. Signed-off-by: Samuel Thibault <[email protected]> --- hw/i386/multiboot.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c index d544b62afb..004d5185fb 100644 --- a/hw/i386/multiboot.c +++ b/hw/i386/multiboot.c @@ -196,11 +196,6 @@ int load_multiboot(X86MachineState *x86ms, int kernel_size; fclose(f); - if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) { - error_report("Cannot load x86-64 image, give a 32bit one."); - exit(1); - } - kernel_size = load_elf(kernel_filename, NULL, NULL, NULL, &elf_entry, &elf_low, &elf_high, NULL, ELFDATA2LSB, I386_ELF_MACHINE, 0, 0); -- 2.53.0
