Update documentation to reflect that cache maintenance by set/way is blocked
Bug: 141600635
Change-Id: I5a6d1b361c19f33f41ef8a6d0f224b8a2f4dcf2f
diff --git a/docs/VmInterface.md b/docs/VmInterface.md
index 2464493..5678c8c 100644
--- a/docs/VmInterface.md
+++ b/docs/VmInterface.md
@@ -111,6 +111,12 @@
owning VM). Memory which has been donated or shared may not be forcefully
reclaimed, but the VM with which it was shared may choose to return it.
+## Cache
+
+VMs will be blocked from using cache maintenance instructions that operate by
+set/way. These operations are difficult to virtualize, and could expose the
+system to side-channel attacks.
+
## Logging
VMs may send a character to a shared log by means of a hypercall or SMC call.