On Tue, Sep 11, 2018 at 09:36:51AM -0700, Andy Lutomirski wrote:
> > save_pgd = efi_call_phys_prolog();
> > local_irq_save(flags);
> > status = efi_call_phys(...);
> > local_irq_restore(flags);
> >
> > efi_call_phys_epilog(save_pgd);
> >
> > So, yes, interrupts are very much enabled.
>
> Does fixing that solve the problem? It seems more robust.
The problem is still that in efi_call_phys_prolog() we load the gdt with
its physical address, and when we reload the %cr3 in _epilog from
initial_page_table to swapper_pg_dir again the gdt is no longer mapped.
Blocking interrupts is more robust, but we can't block NMIs that way
that would also trigger the issue, no?
So I am in favor of changing the order in efi_call_phys_epilog() too.
Regards,
Joerg
