On 28.08.19 16:44, Richard Henderson wrote: > On 8/28/19 4:10 AM, David Hildenbrand wrote: >> + * If the access is permitted, returns the host address similar to >> + * tlb_vaddr_to_host(). Returns NULL in case direct access to the host page >> + * is not allowed or if the size is 0. > > Maybe we can find some better language -- "not allowed" sounds like a > permissions check, and we longjmp out on permission check failures. > > Perhaps "if the page requires i/o access"?
Yeah, and NOTDIRTY, emulated via i/o access. I will rephrase. > > Why are you returning NULL for size 0? Just because the caller hasn't > committed to a size and thus we haven't checked watchpoints? Yes, I think it's the right thing to do. Watchpoints are one part of the story, the other part is TLB_RECHECK (a.k.a. TLB_INVALID_MASK or "subpage protection"). Allowing access could lead to hidden BUGs. I consider somebody wanting to get access to a host page with an access size of zero an interface violation. -- Thanks, David / dhildenb
