feat: switch to a per-device metrics model for vsock and rng devices

to allow for running vmm tests in parallel

Signed-off-by: aerosouund <aerosound161@gmail.com>

Author: aerosouund

Cargo.lock

@@ -40,6 +40,7 @@ log = { version = "0.4.29", features = ["std", "serde"] }
 log-instrument = { path = "../log-instrument", optional = true }
 memfd = "0.6.5"
 micro_http = { git = "https://github.com/firecracker-microvm/micro-http" }
+regex = "1"
 pci = { path = "../pci" }
 semver = { version = "1.0.27", features = ["serde"] }
 serde = { version = "1.0.228", features = ["derive", "rc"] }

src/vmm/Cargo.toml

@@ -221,7 +221,10 @@ pub mod tests {
 
     use std::os::unix::ffi::OsStrExt;
 
+    use regex::Regex;
+
     use super::*;
+
     use crate::devices::virtio::net::generated;
     use crate::devices::virtio::net::test_utils::{TapTrafficSimulator, enable, if_index};
 
@@ -241,10 +244,16 @@ pub mod tests {
             generated::ifreq__bindgen_ty_1::default().ifrn_name.len()
         });
 
-        // Empty name - The tap should be named "tap0" by default
+        // Empty name - The tap should be named by the kernel (e.g., "tap0", "tap1", etc.)
         let tap = Tap::open_named("").unwrap();
-        assert_eq!(b"tap0\0\0\0\0\0\0\0\0\0\0\0\0", &tap.if_name);
-        assert_eq!("tap0", tap.if_name_as_str());
+        let tap_name_str = tap.if_name_as_str();
+
+        // Check that it starts with "tap" and the remainder is numeric.
+        assert!(
+            Regex::new(r"^tap\d+$").unwrap().is_match(tap_name_str),
+            "Generated tap name '{}' does not match expected pattern",
+            tap_name_str
+        );
 
         // Test using '%d' to have the kernel assign an unused name,
         // and that we correctly copy back that generated name