agent: create pci root Bus Path for arm64

port https://github.com/kata-containers/agent/pull/860 here.

Fixes: #1059
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>

src/agent/Cargo.toml

@@ -21,6 +21,7 @@ signal-hook = "0.1.9"
 scan_fmt = "0.2.3"
 scopeguard = "1.0.0"
 regex = "1"
+
 # slog:
 # - Dynamic keys required to allow HashMap keys to be slog::Serialized.
 # - The 'max_*' features allow changing the log level at runtime

src/agent/src/linux_abi.rs

@@ -5,8 +5,10 @@
 
 /// Linux ABI related constants.
 
-pub const SYSFS_DIR: &str = "/sys";
+#[cfg(target_arch = "aarch64")]
+use std::fs;
 
+pub const SYSFS_DIR: &str = "/sys";
 pub const SYSFS_PCI_BUS_PREFIX: &str = "/sys/bus/pci/devices";
 pub const SYSFS_PCI_BUS_RESCAN_FILE: &str = "/sys/bus/pci/rescan";
 #[cfg(any(
@@ -15,9 +17,46 @@ pub const SYSFS_PCI_BUS_RESCAN_FILE: &str = "/sys/bus/pci/rescan";
     target_arch = "x86_64",
     target_arch = "x86"
 ))]
-pub const PCI_ROOT_BUS_PATH: &str = "/devices/pci0000:00";
+pub fn create_pci_root_bus_path() -> String {
+    String::from("/devices/pci0000:00")
+}
+
 #[cfg(target_arch = "aarch64")]
-pub const PCI_ROOT_BUS_PATH: &str = "/devices/platform/4010000000.pcie/pci0000:00";
+pub fn create_pci_root_bus_path() -> String {
+    let ret = String::from("/devices/platform/4010000000.pcie/pci0000:00");
+
+    let mut sysfs_dir = String::from(SYSFS_DIR);
+    let mut start_root_bus_path = String::from("/devices/platform/");
+    let end_root_bus_path = String::from("/pci0000:00");
+
+    sysfs_dir.push_str(&start_root_bus_path);
+    let entries = match fs::read_dir(sysfs_dir) {
+        Ok(e) => e,
+        Err(_) => return ret,
+    };
+    for entry in entries {
+        let pathname = match entry {
+            Ok(p) => p.path(),
+            Err(_) => return ret,
+        };
+        let dir_name = match pathname.file_name() {
+            Some(p) => p.to_str(),
+            None => return ret,
+        };
+        let dir_name = match dir_name {
+            Some(p) => p,
+            None => return ret,
+        };
+        let dir_name = String::from(dir_name);
+        if dir_name.ends_with(".pcie") {
+            start_root_bus_path.push_str(&dir_name);
+            start_root_bus_path.push_str(&end_root_bus_path);
+            return start_root_bus_path;
+        }
+    }
+
+    ret
+}
 
 pub const SYSFS_CPU_ONLINE_PATH: &str = "/sys/devices/system/cpu";
 

src/agent/src/uevent.rs

@@ -48,13 +48,16 @@ impl Uevent {
 
     // Check whether this is a block device hot-add event.
     fn is_block_add_event(&self) -> bool {
+        let pci_root_bus_path = create_pci_root_bus_path();
         self.action == U_EVENT_ACTION_ADD
             && self.subsystem == "block"
-            && self.devpath.starts_with(PCI_ROOT_BUS_PATH)
+            && self.devpath.starts_with(&pci_root_bus_path)
             && self.devname != ""
     }
 
     fn handle_block_add_event(&self, sandbox: &Arc<Mutex<Sandbox>>) {
+        let pci_root_bus_path = create_pci_root_bus_path();
+
         // Keep the same lock order as device::get_device_name(), otherwise it may cause deadlock.
         let mut w = GLOBAL_DEVICE_WATCHER.lock().unwrap();
         let mut sb = sandbox.lock().unwrap();
@@ -69,7 +72,7 @@ impl Uevent {
         let empties: Vec<_> = w
             .iter()
             .filter(|(dev_addr, _)| {
-                let pci_p = format!("{}/{}", PCI_ROOT_BUS_PATH, *dev_addr);
+                let pci_p = format!("{}/{}", pci_root_bus_path, *dev_addr);
 
                 // blk block device
                 devpath.starts_with(pci_p.as_str()) ||