Re: [Qemu-devel] [PATCH v3 6/7] loader: Implement .hex file loader

[Stefan Hajnoczi]

On Thu, Aug 02, 2018 at 11:04:46PM +0100, Peter Maydell wrote:
> On 2 August 2018 at 13:43, Stefan Hajnoczi <address@hidden> wrote:
> > On Mon, Jul 30, 2018 at 07:01:53PM +0100, Peter Maydell wrote:
> >> I'm still not convinced we want to add another random
> >> special case only-works-on-one-architecture-and-some-boards
> >> feature to the -kernel command line option.
> >>
> >> Adding it to the "generic loader" device might be more plausible?
> >
> > I'm not sure I understand the purpose of the generic loader.
> >
> > As a user -kernel <myfile> is easier than -device
> > loader,file=<myfile>,cpu-num=1.
> >
> > Can you explain the advantage to moving hex file loading to the generic
> > loader?
> 
> It means we have a command line option for loading hex files
> that works for every board and every CPU architecture.
> (Similarly, if you want a way to load an ELF file that
> works the same way for all boards and CPUs, the generic
> loader is it -- -kernel will not reliably do the job.
> You can also use it to load more than one ELF file or
> to load different ELF files for different CPUs, neither
> of which you can do with -kernel.)
> 
> -kernel, like all our legacy short options, is, yes,
> easier to use; it's also a twisted mess of different
> "do what I mean" functionality that varies depending
> on the guest CPU architecture and subtype, the machine
> being emulated, and other random things like "did the
> user also tell us to start a BIOS image". It mostly means
> "run a Linux kernel", with some extras wedged in on the
> side where we thought we could do it without breaking the
> kernel case. Oh, and we don't document anywhere what
> it actually does. I'm reluctant to add yet another layer of
> "do what I mean" to it that only has an effect on a subset
> of Arm boards.

Okay, I understand better now.  Thanks!

I'll resend with the generic loader instead of -kernel.

Stefan

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