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

[Peter Crosthwaite]

On Wed, Apr 23, 2014 at 12:47 PM, address@hidden
<address@hidden> wrote:
>> -----邮件原件-----
>> 发件人: address@hidden
>> [mailto:address@hidden 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
>> <address@hidden> wrote:
>> > On 04/17/2014 06:02 AM, Peter Maydell wrote:
>> >> On 2 April 2014 13:47, Peter Maydell <address@hidden> wrote:
>> >>> On 2 April 2014 13:11, Peter Crosthwaite <address@hidden>
>> 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 ?

Multiple different guests on different CPUs.

BTW, I used your blob loader as the starting point of development, so
I have merely extended it with these image and cpu features.

Regards,
Peter

>
> 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.
>> >
>