feature(xen): implement power management operations (#215)

crates/xen/xencall/examples/power_management.rs

@@ -0,0 +1,19 @@
+use xencall::error::Result;
+use xencall::sys::CpuId;
+use xencall::XenCall;
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    env_logger::init();
+
+    let call = XenCall::open(0)?;
+    let physinfo = call.phys_info().await?;
+    println!("{:?}", physinfo);
+    let topology = call.cpu_topology().await?;
+    println!("{:?}", topology);
+    call.set_cpufreq_gov(CpuId::All, "performance").await?;
+    call.set_cpufreq_gov(CpuId::Single(0), "performance")
+        .await?;
+    call.set_turbo_mode(CpuId::All, true).await?;
+    Ok(())
+}