> > > > Hi Thomas and Ingo, > > > > > > > > I recently noticed that the below commits [1] and [2] are broken > > > > when kernel command line argument "efi=old_map" is passed. Sorry! > > > > I missed to test this condition prior to sending these patches to > > > > mailing list. > > > > I am working on a fix and will send it to mailing list as soon as it's > > > > ready. > > > > > > > > > > Could you elaborate on the problem please? > > > > Sure! My bad.. > > > > Little bit of history here: > > Boris with this patch set [1] introduced statically mapping EFI > > Runtime Services at -4G and also introduced "efi=old_map" to return to > > previous EFI functionality which used ioremap and __va(pa). > > > > [3] and [4] are links to old_map_region() > > > > The commit 08cfb38f3ef4 ("x86/efi: Unmap EFI boot services code/data > > regions from efi_pgd"), unmaps EFI boot services code/data regions > > *only* from efi_pgd but efi=old_map maps EFI boot services code/data > > regions into swapper_pgd. Also, efi=old_map uses either > > ioremap() or __va(md->phys_addr) to map EFI runtime/boot time services and > doesn't use kernel_map_pages_in_pgd(). > > > > So, we need a different unmapping routine to unmap EFI boot services > > code/data regions from swapper_pgd if they were mapped using efi=old_map. > > > > For the short term, could we simply make your changes dependent on efi != > old_map? That gives us some time to fix the old_map case properly.
Yes, I think we could and it should work but I hesitated to propose it because (as you already noted) it's a short term fix and not the right fix. Alternatively, we could also evaluate if we need to support efi=old_map case going further. I thought dropping it would be a bad idea because it changes kernel user visible interface (because it's a kernel command line argument) and never brought it up. Not sure what Thomas, Ingo or Linus might think about dropping a kernel command line argument. Regards, Sai