Anjali K [off-list ref] writes:

Hi Michael

On 18/06/24 12:41, Michael Ellerman wrote:

quoted

I guess there isn't a kmem_cache_create_user_readonly() ?

Thank you for your review.                                                    

My understanding of the question is whether there's a way to whitelist a   
region such that it can be copied to userspace, but not written to using   
copy_from_user().                                                             

 
Yes that's what I meant, and I pretty much worked that out from looking
at the implementation, but was hoping Kees would tell me it was there
somewhere, or implement it :)  Apologies for being cryptic.

No, we don't have a function to whitelist only for copy_to_user() and not  
copy_from_user().

Yep. I'll take this patch as-is, I think we've established that it's
pretty low risk to whitelist the whole cache.

cheers