Merge pull request #21 from keystone-enclave/docswork

Minor FAQ updates

docs/source/Getting-Started/FAQ.rst

@@ -1,8 +1,19 @@
 FAQ
 ===
 
+ Q: What can I run Keystone on?
+    - A: Keystone can be run on real RISC-V hardware, on FGPA, and in
+      simulation. See `Getting Started <#>`_
+
  Q: What is the difference between the SM and runtime?
     - A: The SM is part of the Keystone TCB, and is trusted by all
       components. The runtime is a (technically) optional part of the
       enclave itself. While the enclave app trusts it, it is not part
       of the trusted boot process and is not part of the Keystone TCB.
+
+ Q: Why are enclaves/SM/etc written in C? Why not Rust (or another modern language)?
+    - A: Rust RV64 support was unavailable when Keystone was
+      started. Few options for the security monitor besides C were
+      available. We are keeping a close eye on Rust support as it
+      matures for RV64, and expect to support it for enclaves at a
+      minimum.