Add RustyHermit changes for December 2021

Author: stlankes

content/this-month/2021-12/index.md

@@ -36,6 +36,14 @@ The `x86_64` crate provides various abstractions for `x86_64` systems, including
 
 In December, …
 
+### [`rusty-hermit`](https://crates.io/crates/rusty-hermit)
+
+RustyHermit is a unikernel targeting a scalable and predictable runtime for high-performance and cloud computing.
+This month, we integrate a [virtual i/o device driver](https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html), which based on memory mapped i/o and doesn't depend on  PCI device specification.
+For instance, micro VMs like [Firecracker](https://firecracker-microvm.github.io) and Qemu's [microvm machine type](https://qemu.readthedocs.io/en/latest/system/i386/microvm.html) doesn't support the PCI specification to accelerate the boot time and to improve the performance.
+With this device driver, `rusty-hermit` is able to run on Qemu's microvm platform.
+We are working to support Firecracker in the near future.
+
 ## Call for Participation
 
 Want to contribute to a Rust OSDev project, but don't know where to start? Pick up one of these outstanding