On Fri, Feb 11, 2022, at 3:37 PM, Dave Hansen wrote: > On 1/30/22 13:18, Rick Edgecombe wrote: >> Add the user shadow stack MSRs to the xsave helpers, so they can be used >> to implement the functionality. > > Do these MSRs ever affect kernel-mode operation? > > If so, we might need to switch them more aggressively at context-switch > time like PKRU. > > If not, they can continue to be context-switched with the PASID state > which does not affect kernel-mode operation. PASID? PASID is all kinds of weird. I assume you mean switching it with all the normal state. > > Either way, it would be nice to have some changelog material to that effect.