Re: [PATCH v10 03/38] x86/msr: Add the WRMSRNS instruction support

[H. Peter Anvin]

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