From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:47267) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1glZZi-0005Gl-29 for qemu-devel@nongnu.org; Mon, 21 Jan 2019 08:25:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1glZZf-0002Zv-Sk for qemu-devel@nongnu.org; Mon, 21 Jan 2019 08:25:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35864) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1glZZf-0002Yb-Hw for qemu-devel@nongnu.org; Mon, 21 Jan 2019 08:25:11 -0500 References: <1547729344-3895-1-git-send-email-lizhijian@cn.fujitsu.com> From: Paolo Bonzini Message-ID: <80181877-275e-64d0-c23e-47fc9001db35@redhat.com> Date: Mon, 21 Jan 2019 14:24:54 +0100 MIME-Version: 1.0 In-Reply-To: <1547729344-3895-1-git-send-email-lizhijian@cn.fujitsu.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 0/4] allow to load initrd below 4G for recent kernel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Li Zhijian , qemu-devel@nongnu.org, mst@redhat.com, peter.maydell@linaro.org Cc: philmd@redhat.com, zhijianx.li@intel.com, philip.li@intel.com, Richard Henderson , Eduardo Habkost , Marcel Apfelbaum , Stefano Garzarella , Peter Crosthwaite On 17/01/19 13:49, 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/boot/x86/header.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 bootloader an optional > and safe address to load initrd. > > It's believed that if XLF_CAN_BE_LOADED_ABOVE_4G is set, initrd can > be loaded into any address. > > Default roms(Seabios + optionrom(linuxboot_dma)) works as expected with this > patchset. > > I stole some comments from yours, fell free to let me know if you don't like this. > > changes: > V6: no functional changes > - Patch 3/4: Fix line over 80 characters && use double quates for all pathes (Stefano Garzarella) > - Patch 4/4: update comments > > V5: add a few reviewed-tag and update 4/4 changelog and comments > 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. > > > CC: Paolo Bonzini > CC: Richard Henderson > CC: Eduardo Habkost > CC: "Michael S. Tsirkin" > CC: Marcel Apfelbaum > CC: Stefano Garzarella > CC: Peter Crosthwaite > CC: Peter Maydell > > Li Zhijian (4): > unify len and addr type for memory/address APIs > hw/core/loader.c: Read as long as possible in load_image_size() > i386: import & use bootparam.h > i386: allow to load initrd below 4 GB for recent linux > > exec.c | 47 ++++++++++++++-------------- > hw/core/loader.c | 11 +++---- > hw/i386/pc.c | 29 ++++++++++++----- > 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 | 6 ++++ > 8 files changed, 105 insertions(+), 54 deletions(-) > create mode 100644 include/standard-headers/asm-x86/bootparam.h > Queued, thanks. Paolo