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Re: [Qemu-devel] [PATCH] fix multiboot loading if load_end_addr == 0 (fw
From: |
Serge E. Hallyn |
Subject: |
Re: [Qemu-devel] [PATCH] fix multiboot loading if load_end_addr == 0 (fwd) |
Date: |
Tue, 20 Mar 2012 15:04:09 +0000 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
Quoting Scott Moser (address@hidden):
> Re-sending to qemu-devel. I'd originally sent this to kvm mailing list.
>
>
> ---------- Forwarded message ----------
> Date: Sat, 17 Mar 2012 00:08:06
> From: Scott Moser <address@hidden>
> To: address@hidden
> Subject: [PATCH] fix multiboot loading if load_end_addr == 0
>
> The previous code did not treat the case where load_end_addr was 0
> specially. The multiboot specification says the following:
> * load_end_addr
> Contains the physical address of the end of the data segment.
> (load_end_addr - load_addr) specifies how much data to load. This
> implies that the text and data segments must be consecutive in the
> OS image; this is true for existing a.out executable formats. If
> this field is zero, the boot loader assumes that the text and data
> segments occupy the whole OS image file.
>
> This was raised initially as launchpad bug
> https://bugs.launchpad.net/qemu/+bug/957622
>
Tested-by: Serge Hallyn <address@hidden>
> diff --git a/hw/multiboot.c b/hw/multiboot.c
> index b4484a3..b1e04c5 100644
> --- a/hw/multiboot.c
> +++ b/hw/multiboot.c
> @@ -202,10 +202,16 @@ int load_multiboot(void *fw_cfg,
> uint32_t mh_bss_end_addr = ldl_p(header+i+24);
> mh_load_addr = ldl_p(header+i+16);
> uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
> - uint32_t mb_load_size = mh_load_end_addr - mh_load_addr;
> -
> + uint32_t mb_load_size = 0;
> mh_entry_addr = ldl_p(header+i+28);
> - mb_kernel_size = mh_bss_end_addr - mh_load_addr;
> +
> + if (mh_load_end_addr) {
> + mb_kernel_size = mh_bss_end_addr - mh_load_addr;
> + mb_load_size = mh_load_end_addr - mh_load_addr;
> + } else {
> + mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
> + mb_load_size = mb_kernel_size;
> + }
>
> /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
> uint32_t mh_mode_type = ldl_p(header+i+32);