Re: [PATCH v11 7/9] KVM: X86: Add userspace access interface for CET MSRs

[Paolo Bonzini]

On 26/04/20 17:23, Yang Weijiang wrote:
> What's the purpose of the selftest? Is it just for Shadow Stack SSP
> state transitions in various cases? e.g., L0 SSP<--->L3 SSP,
> L0 SSP1<--->L0 SSP2?

No, it checks that the whole state can be extracted and restored from a
running VM.  For example, it would have caught immediately that the
current SSP could not be saved and restored.

> We now have the KVM unit-test for CET functionalities,
> i.e., Shadow Stack and Indirect Branch Tracking for user-mode, I can put the
> state test app into the todo list as current patchset is mainly for user-mode
> protection, the supervisor-mode CET protection is the next step.

What are the limitations?  Or are you referring to the unit test?

Paolo