vm-virtio: Initial crate

Copied from Firecracker 17a9089d for the queue implementation and from
crosvm 107edb3e for the device Trait. The device trait has some PCI
specific methods hence its crosvm origin.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vm-virtio/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "vm-virtio"
+version = "0.1.0"
+authors = ["Samuel Ortiz <sameo@linux.intel.com>"]
+edition = "2018"
+
+[dependencies]
+byteorder = "=1.2.1"
+devices = { path = "../devices" }
+epoll = "=4.0.1"
+libc = ">=0.2.39"
+log = "*"
+pci = { path = "../pci" }
+tempfile = ">=3.0.2"
+virtio-bindings = { path = "../virtio-bindings" }
+vm-allocator = { path = "../vm-allocator" }
+vmm-sys-util = { git = "https://github.com/sameo/vmm-sys-util" }
+
+[dependencies.vm-memory]
+git = "https://github.com/rust-vmm/vm-memory"
+features = ["backend-mmap"]