On 01/08/2018 07:28 AM, Yves-Alexis Perez wrote: > On Mon, 2018-01-08 at 15:19 +0000, Ben Hutchings wrote: >>> I tried this on a ThinkPad X230 (Ivy Bridge CPU, i7 3520M, so pcid but not >>> invpcid) on full UEFI mode and it doesn't boot at all. grub-efi loads the >>> kernel and initrd, but I don't have any message after “Loading initial >>> ramdisk” (even with debug earlyprintk=vga). >> If you boot with EFI you need to use earlyprintk=efi. > Thanks! With that, I can see the last few log lines before it hangs: > > Kernel/User page tables isolation: enabled > […] > bootconsole [earlyefi0] disabled Does "earlyprintk=efi,keep" help get more out to the console? > Also I must have done something wrong earlier today, because when booting with > 'nopcid' it does work (which is consistent with other people tests, afaict). If I had to guess, I'd say we're probably putting a PCID value into the low bits of CR3 before we've _enabled_ PCID support in the CPU.