[docs][syscalls] Add note about VMAR address space deallocation
This deallocation issue did not seem to be explained in the docs
before.
Bug: ZX-2642
Test: check formatting via Gitiles
Change-Id: I227290afdd48ffb20f7c54ddd1c87c48eb78274a
diff --git a/docs/syscalls/vmar_allocate.md b/docs/syscalls/vmar_allocate.md
index d977732..90160bc 100644
--- a/docs/syscalls/vmar_allocate.md
+++ b/docs/syscalls/vmar_allocate.md
@@ -70,6 +70,14 @@
## NOTES
+### Deallocation
+
+The address space occupied by a VMAR will remain allocated (within its
+parent VMAR) until the VMAR is destroyed by calling **vmar_destroy**().
+
+Note that just closing the VMAR's handle does not deallocate the address
+space occupied by the VMAR.
+
### The COMPACT flag
The kernel interprets this flag as a request to reduce sprawl in allocations.
