Re: [Qemu-devel] [PATCH v4 2/8] acpi: add vmcoreinfo device

[Michael S. Tsirkin]

On Fri, Jul 14, 2017 at 10:04:31PM +0200, Laszlo Ersek wrote:
> > It worries me that the format of this seems completely undefined
> > except in the patchset cover letter.
> > I don't think we should merge this before it is.
> 
> I'm not sure what you mean, this patch adds "docs/specs/vmcoreinfo.txt".
> That file is the first level contract between the guest firmware
> (generally, via the linker/loader), the guest kernel driver
> (specifically), and QEMU (also specifically).
> 
> The second level contract is the guest kernel's vmcoreinfo ELF note
> (which is pointed-to by the first level contract). The layout of that is
> specified elsewhere indeed (I don't think it belongs here).
> 
> We've taken care not to trust anything coming from the guest kernel.
> 
> Can you clarify please?
> 
> Thanks
> Laszlo

All there is is this:

+Version 0 content:
+
+ uint64 paddr:
+  Physical address of the Linux vmcoreinfo ELF note.
+ uint32 size:
+  Size of the vmcoreinfo ELF note.

It isn't defined here what is the Linux vmcoreinfo ELF note.
You want a bit more info so people trying to use it know where to start
and what they can get out of it.

-- 
MST