| Message ID | 1544063533-10139-1-git-send-email-lizhijian@cn.fujitsu.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | allow to load initrd below 4G for recent kernel | expand |
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 >