Re: [PATCH v4 10/27] hw/i386/pc: Remove linuxboot.bin

[Igor Mammedov <imammedo@redhat.com>]

On Thu,  8 May 2025 15:35:33 +0200
Philippe Mathieu-Daudé <philmd@linaro.org> wrote:

> All PC machines now use the linuxboot_dma.bin binary,
> we can remove the non-DMA version (linuxboot.bin).
> 
> Suggested-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  hw/i386/pc.c                  |   3 +-


linuxboot.bin is referenced in a few more files:

hw/i386/x86-common.c:    option_rom[nb_option_roms].name = "linuxboot.bin";
hw/nvram/fw_cfg.c:    { "genroms/linuxboot.bin", 60 },

are you sure we should keep it there?

>  pc-bios/meson.build           |   1 -
>  pc-bios/optionrom/Makefile    |   2 +-
>  pc-bios/optionrom/linuxboot.S | 195 ----------------------------------
>  4 files changed, 2 insertions(+), 199 deletions(-)
>  delete mode 100644 pc-bios/optionrom/linuxboot.S
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 524d2fd98e8..4e6fe68e2e0 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -654,8 +654,7 @@ void xen_load_linux(PCMachineState *pcms)
>  
>      x86_load_linux(x86ms, fw_cfg, PC_FW_DATA, pcmc->pvh_enabled);
>      for (i = 0; i < nb_option_roms; i++) {
> -        assert(!strcmp(option_rom[i].name, "linuxboot.bin") ||
> -               !strcmp(option_rom[i].name, "linuxboot_dma.bin") ||
> +        assert(!strcmp(option_rom[i].name, "linuxboot_dma.bin") ||
>                 !strcmp(option_rom[i].name, "pvh.bin") ||
>                 !strcmp(option_rom[i].name, "multiboot_dma.bin"));
>          rom_add_option(option_rom[i].name, option_rom[i].bootindex);
> diff --git a/pc-bios/meson.build b/pc-bios/meson.build
> index f2d4dc416a4..39a7fea332e 100644
> --- a/pc-bios/meson.build
> +++ b/pc-bios/meson.build
> @@ -63,7 +63,6 @@ blobs = [
>    'efi-vmxnet3.rom',
>    'qemu-nsis.bmp',
>    'multiboot_dma.bin',
> -  'linuxboot.bin',
>    'linuxboot_dma.bin',
>    'kvmvapic.bin',
>    'pvh.bin',
> diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
> index 1183ef88922..e694c7aac00 100644
> --- a/pc-bios/optionrom/Makefile
> +++ b/pc-bios/optionrom/Makefile
> @@ -2,7 +2,7 @@ include config.mak
>  SRC_DIR := $(TOPSRC_DIR)/pc-bios/optionrom
>  VPATH = $(SRC_DIR)
>  
> -all: multiboot_dma.bin linuxboot.bin linuxboot_dma.bin kvmvapic.bin pvh.bin
> +all: multiboot_dma.bin linuxboot_dma.bin kvmvapic.bin pvh.bin
>  # Dummy command so that make thinks it has done something
>  	@true
>  
> diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
> deleted file mode 100644
> index ba821ab922d..00000000000
> --- a/pc-bios/optionrom/linuxboot.S
> +++ /dev/null
> @@ -1,195 +0,0 @@
> -/*
> - * Linux Boot Option ROM
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License as published by
> - * the Free Software Foundation; either version 2 of the License, or
> - * (at your option) any later version.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> - * GNU General Public License for more details.
> - *
> - * You should have received a copy of the GNU General Public License
> - * along with this program; if not, see <http://www.gnu.org/licenses/>.
> - *
> - * Copyright Novell Inc, 2009
> - *   Authors: Alexander Graf <agraf@suse.de>
> - *
> - * Based on code in hw/pc.c.
> - */
> -
> -#include "optionrom.h"
> -
> -#define BOOT_ROM_PRODUCT "Linux loader"
> -
> -BOOT_ROM_START
> -
> -run_linuxboot:
> -
> -	cli
> -	cld
> -
> -	jmp		copy_kernel
> -boot_kernel:
> -
> -	read_fw		FW_CFG_SETUP_ADDR
> -
> -	mov		%eax, %ebx
> -	shr		$4, %ebx
> -
> -	/* All segments contain real_addr */
> -	mov		%bx, %ds
> -	mov		%bx, %es
> -	mov		%bx, %fs
> -	mov		%bx, %gs
> -	mov		%bx, %ss
> -
> -	/* CX = CS we want to jump to */
> -	add		$0x20, %bx
> -	mov		%bx, %cx
> -
> -	/* SP = cmdline_addr-real_addr-16 */
> -	read_fw		FW_CFG_CMDLINE_ADDR
> -	mov		%eax, %ebx
> -	read_fw		FW_CFG_SETUP_ADDR
> -	sub		%eax, %ebx
> -	sub		$16, %ebx
> -	mov		%ebx, %esp
> -
> -	/* Build indirect lret descriptor */
> -	pushw		%cx		/* CS */
> -	xor		%ax, %ax
> -	pushw		%ax		/* IP = 0 */
> -
> -	/* Clear registers */
> -	xor		%eax, %eax
> -	xor		%ebx, %ebx
> -	xor		%ecx, %ecx
> -	xor		%edx, %edx
> -	xor		%edi, %edi
> -	xor		%ebp, %ebp
> -
> -	/* Jump to Linux */
> -	lret
> -
> -
> -copy_kernel:
> -	/* Read info block in low memory (0x10000 or 0x90000) */
> -	read_fw		FW_CFG_SETUP_ADDR
> -	shr		$4, %eax
> -	mov		%eax, %es
> -	xor		%edi, %edi
> -	read_fw_blob_addr32_edi(FW_CFG_SETUP)
> -
> -	cmpw            $0x203, %es:0x206      // if protocol >= 0x203
> -	jae             1f                     // have initrd_max
> -	movl            $0x37ffffff, %es:0x22c // else assume 0x37ffffff
> -1:
> -
> -	/* Check if using kernel-specified initrd address */
> -	read_fw		FW_CFG_INITRD_ADDR
> -	mov		%eax, %edi             // (load_kernel wants it in %edi)
> -	read_fw		FW_CFG_INITRD_SIZE     // find end of initrd
> -	add		%edi, %eax
> -	xor		%es:0x22c, %eax        // if it matches es:0x22c
> -	and		$-4096, %eax           // (apart from padding for page)
> -	jz		load_kernel            // then initrd is not at top
> -					       // of memory
> -
> -	/* pc.c placed the initrd at end of memory.  Compute a better
> -	 * initrd address based on e801 data.
> -	 */
> -	mov		$0xe801, %ax
> -	xor		%cx, %cx
> -	xor		%dx, %dx
> -	int		$0x15
> -
> -	/* Output could be in AX/BX or CX/DX */
> -	or		%cx, %cx
> -	jnz		1f
> -	or		%dx, %dx
> -	jnz		1f
> -	mov		%ax, %cx
> -	mov		%bx, %dx
> -1:
> -
> -	or		%dx, %dx
> -	jnz		2f
> -	addw		$1024, %cx            /* add 1 MB */
> -	movzwl		%cx, %edi
> -	shll		$10, %edi             /* convert to bytes */
> -	jmp		3f
> -
> -2:
> -	addw		$16777216 >> 16, %dx  /* add 16 MB */
> -	movzwl		%dx, %edi
> -	shll		$16, %edi             /* convert to bytes */
> -
> -3:
> -	read_fw         FW_CFG_INITRD_SIZE
> -	subl            %eax, %edi
> -	andl            $-4096, %edi          /* EDI = start of initrd */
> -	movl		%edi, %es:0x218       /* put it in the header */
> -
> -load_kernel:
> -	/* We need to load the kernel into memory we can't access in 16 bit
> -	   mode, so let's get into 32 bit mode, write the kernel and jump
> -	   back again. */
> -
> -	/* Reserve space on the stack for our GDT descriptor. */
> -	mov             %esp, %ebp
> -	sub             $16, %esp
> -
> -	/* Now create the GDT descriptor */
> -	movw		$((3 * 8) - 1), -16(%bp)
> -	mov		%cs, %eax
> -	movzwl		%ax, %eax
> -	shl		$4, %eax
> -	addl		$gdt, %eax
> -	movl		%eax, -14(%bp)
> -
> -	/* And load the GDT */
> -	data32 lgdt	-16(%bp)
> -	mov		%ebp, %esp
> -
> -	/* Get us to protected mode now */
> -	mov		$1, %eax
> -	mov		%eax, %cr0
> -
> -	/* So we can set ES to a 32-bit segment */
> -	mov		$0x10, %eax
> -	mov		%eax, %es
> -
> -	/* We're now running in 16-bit CS, but 32-bit ES! */
> -
> -	/* Load kernel and initrd */
> -	read_fw_blob_addr32_edi(FW_CFG_INITRD)
> -	read_fw_blob_addr32(FW_CFG_KERNEL)
> -	read_fw_blob_addr32(FW_CFG_CMDLINE)
> -
> -	/* And now jump into Linux! */
> -	mov		$0, %eax
> -	mov		%eax, %cr0
> -
> -	/* ES = CS */
> -	mov		%cs, %ax
> -	mov		%ax, %es
> -
> -	jmp		boot_kernel
> -
> -/* Variables */
> -
> -.align 4, 0
> -gdt:
> -	/* 0x00 */
> -.byte	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
> -
> -	/* 0x08: code segment (base=0, limit=0xfffff, type=32bit code exec/read, DPL=0, 4k) */
> -.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00
> -
> -	/* 0x10: data segment (base=0, limit=0xfffff, type=32bit data read/write, DPL=0, 4k) */
> -.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00
> -
> -BOOT_ROM_END