feature(xen): dynamic platform architecture (#194)

* wip hvm

* feat: move platform stuff all into it's own thing

* hvm work

* more hvm work

* more hvm work

* feat: rework to support multiple platforms

* hvm nonredist

* more hvm work

* more hvm work

* pvh work

* work on loading cmdline

* implement initrd loading for pvh

* partially working pvh support

* fix merge issues

* pvh works!

* swap over to pv support

* remove old kernel stuff

* fix support for pv

* pvh is gone for now

* fix(runtime): debug should be respected

* fix(xen): arm64 is currently unsupported, treat it as such at runtime

* fix(examples): use architecture cfg for boot example

* fix(x86): use IOMMU only when needed for passthrough

* chore(build): print kernel architecture during fetch

crates/build/bin/fetch_kernel.rs

@@ -26,6 +26,7 @@ async fn main() -> Result<()> {
     fs::create_dir_all("target/kernel").await?;
 
     let arch = env::var("TARGET_ARCH").map_err(|_| anyhow!("missing TARGET_ARCH env var"))?;
+    println!("kernel architecture: {}", arch);
     let platform = OciPlatform::new(
         Os::Linux,
         match arch.as_str() {