On Fri, Sep 15, 2023, Tom Lendacky wrote: > On 9/14/23 16:13, Sean Christopherson wrote: > This toggling possibility raises a question related to the second patch in > this series that eliminates the use of the user return MSR for TSC_AUX. > Depending on when the interfaces are called (set CPUID, host-initiated WRMSR > of TSC_AUX, set CPUID again), I think we could end up in a state where the > host TSC_AUX may not get restored properly, not 100% sure at the moment, > though. Give me a few minutes to respond to patch 2, I think it can be much simpler, more performant, and avoid any races. > Let me drop that patch from the series for now and just send the fix(es). > I'll work through the other scenarios and code paths and send the user > return MSR optimization as a separate series later.
