Provide a low-level interface to operating the new io_uring interface.
This is an unsafe interface with the basic operations of setting up the
ring, adding to it, removing from it, and polling it.
This will be followed by a safe interface layer on top of this code,
then by additions to the asynchronous executor that allow for
asynchronously doing multiple operations to files from one context.
Change-Id: I71f7ffb04ce8cb4da470deda9aee768ab95d3d98
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2124009
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
