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My thinking is that RSPs and SSPs are per-task >> and are context-switched frequently, so we need to pass through them. But I am >> not sure if there is a reason for STKLVLS and CONFIG. > >There are VMCS fields, at which point intercepting and emulating is probably >more work than just letting the guest access directly. :-/ Just drop the MSR intercepting code and everything should work, right? KVM needs to handle userspace writes anyway. so, there is no "more work" to me. > >Ah, and there needs to be VMCS fields because presumably everything needs to be >switch atomically, e.g. an NMI that arrives shortly after VM-Exit presumbably >consumes STKLVLS and CONFIG. I assume CET's MSR_IA32_INT_SSP_TAB is in the same situation: it has a VMCS field and needs to be switched atomically. Either way, it's up to you.