Hi, when I use early microcode loading with the microcode update with the BTI mitigations, resuming from suspend to RAM is broken.
Based on added logging to enter_state() (from power.c) it doesn't survive the local_irq_restore(flags) call (at least a printk() after the call doesn't output anything on the serial console). I guess that some irq handler tries to use IBRS/IBPB. But the microcode is only loaded later. If I simply move the microcode_resume_cpu(0) directly before the local_irq_restore(flags) everything seems to work fine. But I'm not sure if this has unintended consequences. I tested the above with Xen 4.8.3 from Qubes which includes the BTI and microcode patches from staging-4.8. AFAICS there are no commits which changes the affected code or other commits which sound relevant so this probably affected also all the newer branches. Simon
Description: OpenPGP digital signature
_______________________________________________ Xen-devel mailing list Xenfirstname.lastname@example.org https://lists.xenproject.org/mailman/listinfo/xen-devel