答复: [Qemu-devel] [PATCH] QEMU: ARM: boot: Load kernel at an Image friendly address

[lig.fnst at cn.fujitsu.com]

> -----邮件原件-----
> 发件人: qemu-devel-bounces+lig.fnst=cn.fujitsu.com at nongnu.org
> [mailto:qemu-devel-bounces+lig.fnst=cn.fujitsu.com at nongnu.org] 代表 Peter
> Crosthwaite
> 发送时间: 2014年4月23日 10:20
> 收件人: Christopher Covington
> 抄送: Joel Fernandes; Peter Maydell; QEMU Developers; Linux ARM Kernel List
> 主题: Re: [Qemu-devel] [PATCH] QEMU: ARM: boot: Load kernel at an Image
> friendly address
> 
> On Thu, Apr 17, 2014 at 11:34 PM, Christopher Covington
> <cov at codeaurora.org> wrote:
> > On 04/17/2014 06:02 AM, Peter Maydell wrote:
> >> On 2 April 2014 13:47, Peter Maydell <peter.maydell at linaro.org> wrote:
> >>> On 2 April 2014 13:11, Peter Crosthwaite <peter.crosthwaite at xilinx.com>
> wrote:
> >>>> Like others, I have been carrying this change locally. Good to see it up!
> >>>
> >>> Why are you all booting raw Images anyway (just out of curiosity)?
> >>
> >> Given the recent feedback from the kernel mailing list (viz "don't
> >> boot Image unless you really know what you're doing, the correct load
> >> image may change randomly depending what other board support is in a
> >> multikernel image, etc") maybe we should just remove the Image
> >> booting support instead? Clearly nobody who hasn't locally patched
> >> QEMU is using it at the moment...
> >
> > An opportunity for a fresh start at low-level loading facilities,
> > should anyone be inclined to pursue it, sounds good to me.
> >
> 
> FWIW, im already using my own bootloader out of tree that cuts in on this
> lower level. I'm getting close to be able to throw away -kernel and friends
> completely. 

Me too :-)

To implement I have it as a QOMified device so you just add it on
> the command line:
> 
> qemu-system-foo -device
> loader,image=/path/to/file[,addr=0xdeadbeef][,cpunr=X] 
> To load a particular image to a particular CPU (and it is repeatable).

Why in to a particular CPU?
The motivation is ?

Thanks!

> 
> You can:
> 
> 1: Load elfs and uImages (addr= is ignored)
> 2: Load raw or zImages
> 3: Load data files at arbitrary addresses (cpunr= is ignored)
> 
> With this, you can BYO secondary bootloops or even run multiple guests of
> different CPUs. You can also boot on a non-zeroth CPU. You can place raw
> images wherever you want (the issue in this thread). You can also load in
> firmware to ROMs.
> 
> I then have a tiny hack to make -kernel optional for all ARM.
> Bootloader works for at least ARM and Microblaze, haven't tested for others
> yet.
> 
> Regards,
> Peter
> 
> > Christopher
> >
> > --
> > Employee of Qualcomm Innovation Center, Inc.
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> > hosted by the Linux Foundation.
> >