Hi folks, I see there has been some previous discussion [1] about 1.5 years ago around the fact that AArch64 SVE instructions do not emit any memory operations via the plugin interface, as one might expect them to.
I am interested in being able to more accurately trace the memory operations of SVE instructions using the plugin interface - has there been any further discussion or work on this topic off-list (or that escaped my searching)? In the previous discussion [1], Richard raised some interesting questions: > The plugin interface needs extension for this. How should I signal that 256 > consecutive byte loads have occurred? How should I signal that the > controlling > predicate was not all true, so only 250 of those 256 were actually active? > How > should I signal 59 non-consecutive (gather) loads have occurred? > > If the answer is simply that you want 256 or 250 or 59 plugin callbacks > respectively, then we might be able to force the memory operations into the > slow path, and hook the operation there. As if it were an i/o operation. My initial reaction is that simply sending individual callbacks for each access (only the ones which were active, in the case of predication) seems to fit reasonably well with the existing plugin interface. For instance, I think we already receive two callbacks for each AArch64 `LDP` instruction, right? If this is an agreeable solution that wouldn't take too much effort to implement (and no one else is doing it), would someone mind pointing me in the right direction to get started? Thanks! -Aaron [1] https://lists.nongnu.org/archive/html/qemu-discuss/2020-12/msg00015.html
