On 08/11/2022 11:38, Roger Pau Monne wrote: > Like on the Arm side, return -EINVAL when attempting to do a p2m > operation on dying domains.
Honestly, I'd drop the comment about ARM. "the Arm side" has existed for of all of a couple of weeks. A far better justification is because almost all other DOMCTLs are rejected with -EINVAL against dying domains. > The current logic returns 0 and leaves the domctl parameter > uninitialized for any parameter fetching operations (like the > GET_ALLOCATION operation), which is not helpful from a toolstack point > of view, because there's no indication that the data hasn't been > fetched. > > Reported-by: Edwin Török <[email protected]> > Signed-off-by: Roger Pau Monné <[email protected]> Reviewed-by: Andrew Cooper <[email protected]>, ideally with a modified commit message. Xen's behaviour is definitely bogus, whatever the perceived intention behind this change was originally. System-wide memory handling is unusably broken for known reasons, let alone unexpected surprises like this, it is not credible to suggest that unspecified obsolete code might be broken by such a change; it's definitely broken, and what we risk is exposing a previously hidden error. Not that this is relevant, because Xend only makes this hypercall bounded by domctls which do yield -EINVAL for dying domains. ~Andrew
