diff --git a/svvptc.adoc b/svvptc.adoc index 3450e9f..c92ef7f 100644 --- a/svvptc.adoc +++ b/svvptc.adoc @@ -73,17 +73,17 @@ accesses by that hart to such PTEs. [NOTE] ==== Typically, PTEs are marked as Valid by the operating system following a -page-fault exception or during system calls for memory mapping. In cases like -these, the trap handler usually employs an `SRET` instruction to return from the -trap. The stores it executes to change the Valid bit of the PTEs from 0 to 1 -then become visible to implicit references to such PTEs within a bounded -timeframe. This is applicable for instructions like the one causing the -page-fault or those accessing new memory regions. A memory-management fence can -be used to force immediate visibility of these PTE updates to all implicit -references associated with instructions following the memory-management fence. -But when Svvptc is implemented, visibility (in a bounded amount of time) is -guaranteed and use of a memory-management fence is not required in these -scenarios. While this approach might lead to an occasional gratuitous page-fault, -the performance benefit of omitting the memory-management fence instructions -outweighs the occasional cost of a gratuitous page-fault. +page-fault exception or during system calls for memory mapping. In such cases, +the trap handler commonly employs an `SRET` instruction to return from the trap. +When Svvptc is implemented, the stores it executes to change the Valid bit +of the PTEs from 0 to 1 then become visible to implicit references to those PTEs +within a bounded timeframe. This visibility pertains to the instructions like +the one causing the page-fault or those accessing new memory regions. A +memory-management fence can be used to force immediate visibility of these PTE +updates to all implicit references associated with instructions following the +memory-management fence. However, when Svvptc is implemented, visibility (in a +bounded amount of time) is guaranteed and use of a memory-management fence is +not required in these scenarios. While this approach might lead to an occasional +gratuitous page-fault, the performance benefit of omitting the memory-management +fence instructions outweighs the occasional cost of a gratuitous page-fault. ====