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[Qemu-devel] [PATCH for-4.0 v3 0/4] allow to load initrd below 4G for re
From: |
Li Zhijian |
Subject: |
[Qemu-devel] [PATCH for-4.0 v3 0/4] allow to load initrd below 4G for recent kernel |
Date: |
Mon, 3 Dec 2018 22:48:48 +0800 |
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:
V3:
- rebase code basing on http://patchwork.ozlabs.org/cover/1005990 and
https://patchew.org/QEMU/address@hidden
- 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 bootparam.h
i386: allow to load initrd below 4G for recent linux
exec.c | 47 +++++++++++++++++++++++------------------------
hw/core/loader.c | 11 +++++------
hw/i386/pc.c | 25 ++++++++++---------------
include/exec/cpu-all.h | 2 +-
include/exec/cpu-common.h | 8 ++++----
include/exec/memory.h | 22 +++++++++++-----------
6 files changed, 54 insertions(+), 61 deletions(-)
--
2.7.4
- [Qemu-devel] [PATCH for-4.0 v3 0/4] allow to load initrd below 4G for recent kernel,
Li Zhijian <=