On Mon, Sep 30, 2024, Xin Li (Intel) wrote: > From: Xin Li <xin3.li@xxxxxxxxx> > > Allow WRMSRNS to be advertised to guests. The shortlog and this sentence are incorrect. Assuming there are no controls for WRMSRNS, then KVM isn't allowing anything. Userspace can advertise WRMSRNS support whenever it wants, and the guest can cleanly execute WRMSRNS regardless of whether or not it's advertised in CPUID. KVM is simply advertising support to userspace. > WRMSRNS behaves exactly like WRMSR with the only difference being Nope, not the only difference. WRMSR and WRMSRNS use the same basic exit reason (see Appendix C). For WRMSR, the exit qualification is 0, while for WRMSRNS it is 1. And the whole reaosn I went spelunking was to verify that WRMSRNS honors all MSR exiting controls and generates the same exits. That information needs to be explicitly stated. I'll rewrite the shortlog and changelog when applying.
