Re: EFI stub kexec probelm

[Dave Young <dyoung@redhat.com>]

On 02/16/17 at 07:35pm, Eric W. Biederman wrote:
> Paweł Lenkow <p.lenkow@camlintechnologies.com> writes:
> 
> > Hi!
> >
> > I am trying to run EFI stub kernel using kexec and unfortunately 2nd kernel
> > crashes.
> 
> Adding the kexec list as there may be someone there who may be more
> knowledgeable about our problem.
> 
> > First kernel is loaded by UEFI, starts simple init with shell and then
> > I am loading the same image using kexec.
> >
> > It looks like a lack of correct mappings for EFI tables because it
> > calls address zero (RDI register) in efi_call.
> >
> > Does kernel support such configuration?
> >
> > If yes what could be wrong?
> 
> I don't know exactly where the support is, I haven't looked recently.
> 
> There is a major challenge with efi.  The call to place efi in virtual
> mode may be called exactly once.  There has been work on at least ia64
> to make it possible to capture the efi virtual address bass and pass it
> through to the kernel calling kexec.  I don't remember seeing the work
> to do that happen on other platforms.
> 
> I personally think we should just abandon running efi in virtual mode
> and always run efi in physicall mode, but the feedback when I suggested
> that was that efi didn't actually work if you did that.  *Shrug*
> 
> Given that efi_enter_virtual_mode is in your call trace I am guessing
> that the problem is the historical problem I have mentioned above.
> 
> Eric
> 
> 
> 
> > Using grub-efi all works fine, but it is not enough for me.
> >
> > See log below:
> >
> >
> > / # kexec -l /mnt/INSTALL/vmlinuz -s

What is the kexec-tools version? And does kexec -l works (without -s)?

A test with efi=debug parameters may help, also full logs of both
pre-kexec boot and post-kexec boot could also help to find something..

Thanks
Dave

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