Re: [PATCH 5/6] x86/sev: Use configfs to re-enable RMP optimizations.

[Dave Hansen]

On 2/17/26 12:11, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
> 
> Use configfs as an interface to re-enable RMP optimizations at runtime
> 
> When SNP guests are launched, RMPUPDATE disables the corresponding
> RMPOPT optimizations. Therefore, an interface is required to manually
> re-enable RMP optimizations, as no mechanism currently exists to do so
> during SNP guest cleanup.

Is this like a proof-of-concept to poke the hardware and show it works?
Or, is this intended to be the way that folks actually interact with
SEV-SNP optimization in real production scenarios?

Shouldn't freeing SEV-SNP memory back to the system do this
automatically? Worst case, keep a 1-bit-per-GB bitmap of memory that's
been freed and schedule_work() to run in 1 or 10 or 100 seconds. That
should batch things up nicely enough. No?

I can't fathom that users don't want this to be done automatically for them.

Is the optimization scan really expensive or something? 1GB of memory
should have a small number of megabytes of metadata to scan.