On 3/11/24 16:56, Nadav Amit wrote: > So you can look on the dirty-bit, which is not being set > speculatively and save yourself one problem. Define "set speculatively". :) > If software on one logical processor writes to a page while software > on another logical processor concurrently clears the R/W flag in the > paging-structure entry that maps the page, execution on some > processors may result in the entry’s dirty flag being set (due to the > write on the first logical processor) and the entry’s R/W flag being > clear (due to the update to the entry on the second logical > processor). In other words, you'll see both a fault *AND* the dirty bit. The write never retired and the dirty bit is set. Does that count as being set speculatively? That's just the behavior that the SDM explicitly admits to.
