Re: [Qemu-devel] [PATCH] multiboot: Prevent loading of x86_64 images

[Alexander Graf]

On 19.08.2010, at 16:05, Avi Kivity wrote:

> On 08/19/2010 04:57 PM, Alexander Graf wrote:
>> 
>>> We rely on the existing behaviour in kvm-unit-tests.git.  Tests (.flat 
>>> files) are 64-bit elf binaries that are loaded in 32-bit more and switch 
>>> immediately to 64-bit.
>>> 
>>> We can easily wrap them in a 32-bit elf, but that's a needless complication.
>> Well, but if they wouldn't work in grub that doesn't help too much, right?
> 
> Since the processor vendors don't use kvm-unit-tests.git to test their 
> silicon, most people use qemu -kernel to run the unit tests, not grub.

It would potentially also help the unit tests, as running them in grub would 
allow for easy verification on real hardware too.

> 
>> I'm in full sympathy to stick to whatever grub does, as that's the reference 
>> implementation.
> 
> Copying reference implementations blindly is a bad idea as you just copy 
> their bugs.  In this case, however, the spec does agree with the 
> implementation, so I'm fine with the change.  I'm not so hot about the elf32 
> wrapper, but I accept it's the right thing.

:)


Alex