devices: Add support for pvpanic device

Introduce emulation of pvpanic device to allow cloud hypervisor to get
the notify from guest's pvpanic driver when guest kernel crash.

Signed-off-by: Yi Wang <foxywang@tencent.com>

devices/src/lib.rs

@@ -19,6 +19,7 @@ pub mod interrupt_controller;
 #[cfg(target_arch = "x86_64")]
 pub mod ioapic;
 pub mod legacy;
+pub mod pvpanic;
 pub mod tpm;
 
 pub use self::acpi::{AcpiGedDevice, AcpiPmTimerDevice, AcpiShutdownDevice};

devices/src/pvpanic.rs

@@ -0,0 +1,24 @@
+// Copyright © 2023 Tencent Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+const PVPANIC_PANICKED: u8 = 1 << 0;
+const PVPANIC_CRASH_LOADED: u8 = 1 << 1;
+
+/// A device for handling guest panic event
+pub struct PvPanicDevice {
+    _id: String,
+    _events: u8,
+}
+
+impl PvPanicDevice {
+    pub fn new() -> PvPanicDevice {
+        let events = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
+
+        PvPanicDevice {
+            _id: String::from("_pvpanic"),
+            _events: events,
+        }
+    }
+}