On Sun, 18 Sep, at 11:09:08PM, Waiman Long wrote: > > I have finally finished bisecting the problem. I was wrong in saying that > the 4.7.3 kernel had no problem. It did have. There were some slight > differences between the 4.8 and 4.7 kernel config files that I used. After > some further testing, it was found that the bootup problem only happened > when the following kernel config option was defined: > > CONFIG_EFI_MIXED=y > > Bisecting reviewed that the following 4.6 patch was the first patch that had > this problem: > > c9f2a9a65e4855b74d92cdad688f6ee4a1a323ff > [PATCH] x86/efi: Hoist page table switching code into efi_call_virt() > > I did testing on my test system with three different partition sizes: > 1) 16-socket Broadwell-EX with 12TB memory > 2) 8-socket Broadwell-EX with 6TB memory > 3) 4-socket Broadwell-EX with 3TB memory > > Only the 16-socket and 8-socket configurations had this problem. I am not > sure if over 4TB of main memory is a factor or not.
Yes, I think it's a safe bet that the amount of main memory is a major factor here. Thanks for the report. The only real difference when CONFIG_EFI_MIXED is enabled for 64-bit kernel and 64-bit firmware is that main memory will be mapped into the EFI page tables at its physical addresses. I'll go stare at the code and get back to you.
