On 9/14/23 17:33, andrew.cooper3@xxxxxxxxxx wrote:
It's an assumption about what "definitely won't" be paravirt in the future. XenPV stack handling is almost-FRED-like and has been for the better part of two decades. You frequently complain that there's too much black magic holding XenPV together. A paravirt-FRED will reduce the differences vs native substantially.
Call it "paravirtualized exception handling." In that sense, the refactoring of the exception handling to benefit FRED is definitely useful for reducing paravirtualization. The FRED-specific code is largely trivial, and presumably what you would do is to replace the FRED wrapper with a Xen wrapper and call the common handler routines.
-hpa