ping
On 12/6/18 10:32, Li Zhijian wrote:
> Long long ago, linux kernel has supported up to 4G initrd, but it's header
> still hard code to allow loading initrd below 2G only.
> cutting from arch/x86/head.S:
> # (Header version 0x0203 or later) the highest safe address for the contents
> # of an initrd. The current kernel allows up to 4 GB, but leave it at 2 GB to
> # avoid possible bootloader bugs.
>
> In order to support more than 2G initrd, qemu must allow loading initrd
> above 2G address. Luckly, recent kernel introduced a new field to linux header
> named xloadflags:XLF_CAN_BE_LOADED_ABOVE_4G which tells bootload an optional
> and safe address to load initrd.
>
> Current QEMU/BIOS always loads initrd below below_4g_mem_size which always
> less than 4G, so here limiting initrd_max to 4G - 1 simply is enough if
> this bit is set.
>
> Default roms(Seabios + optionrom(linuxboot_dma)) works as expected with this
> patchset.
>
> changes:
> V4:
> - add Reviwed-by tag to 1/4 and 2/4
> - use scripts/update-linux-headers.sh to import bootparam.h
> - minor fix at commit log
> V3:
> - rebase code basing on http://patchwork.ozlabs.org/cover/1005990 and
> https://patchew.org/QEMU/20181122133507.30950-1-peter.maydell@linaro.org
> - add new patch 3/4 to import header bootparam.h (Michael S. Tsirkin)
>
> V2: add 2 patches(3/5, 4/5) to fix potential loading issue.
>
> Li Zhijian (4):
> unify len and addr type for memory/address APIs
> refactor load_image_size
> i386: import & use bootparam.h
> i386: allow to load initrd below 4G for recent linux
>
> exec.c | 47 ++++++++++++++--------------
> hw/core/loader.c | 11 +++----
> hw/i386/pc.c | 18 ++++++-----
> include/exec/cpu-all.h | 2 +-
> include/exec/cpu-common.h | 8 ++---
> include/exec/memory.h | 22 ++++++-------
> include/standard-headers/asm-x86/bootparam.h | 34 ++++++++++++++++++++
> scripts/update-linux-headers.sh | 4 +++
> 8 files changed, 92 insertions(+), 54 deletions(-)
> create mode 100644 include/standard-headers/asm-x86/bootparam.h
>