feat: About

Add bao introduction to about section.

Signed-off-by: David Cerdeira <[email protected]>

source/bao_hyp/overview.rst

@@ -1,2 +1,21 @@
 Overview
 ========
+
+Bao (from Mandarin Chinese “bǎohù”, meaning “to protect”) is a lightweight,
+open-source embedded hypervisor which aims at providing strong isolation and
+real-time guarantees. Bao provides a minimal, from-scratch implementation of
+the partitioning hypervisor architecture. Designed mainly for targeting
+mixed-criticality systems, Bao strongly focuses on isolation for
+fault-containment and real-time behavior. Its implementation comprises only a
+minimal, thin-layer of privileged software leveraging ISA virtualization
+support to implement the static partitioning hypervisor architecture: resources
+are statically partitioned and assigned at VM instantiation time; memory is
+statically assigned using 2-stage translation; IO is pass-through only; virtual
+interrupts are directly mapped to physical ones; and it implements a 1-1
+mapping of virtual to physical CPUs, with no need for a scheduler. Bao has no
+external dependencies, such as on privileged VMs running untrustable, large
+monolithic general-purpose operating systems (e.g., Linux), and, as such,
+encompasses a much smaller TCB. Bao originally targets the Armv8-A
+architecture, but there is experimental support for the RISC-V architecture.
+
+