feat: pci passthrough (#114)

* feat: pci passthrough

* feat: guest device management

* feat: addons mounting and kernel modules support

* feat: more pci work

* fix: kernel build squashfs fixes

* fix: e820entry should be available on all platforms

crates/daemon/src/config.rs

@@ -0,0 +1,55 @@
+use std::{collections::HashMap, path::Path};
+
+use anyhow::Result;
+use serde::{Deserialize, Serialize};
+use tokio::fs;
+
+#[derive(Serialize, Deserialize, Clone, Debug, Default)]
+pub struct DaemonConfig {
+    #[serde(default)]
+    pub pci: DaemonPciConfig,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, Default)]
+pub struct DaemonPciConfig {
+    #[serde(default)]
+    pub devices: HashMap<String, DaemonPciDeviceConfig>,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct DaemonPciDeviceConfig {
+    pub locations: Vec<String>,
+    #[serde(default)]
+    pub permissive: bool,
+    #[serde(default)]
+    #[serde(rename = "msi-translate")]
+    pub msi_translate: bool,
+    #[serde(default)]
+    #[serde(rename = "power-management")]
+    pub power_management: bool,
+    #[serde(default)]
+    #[serde(rename = "rdm-reserve-policy")]
+    pub rdm_reserve_policy: DaemonPciDeviceRdmReservePolicy,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, Default)]
+pub enum DaemonPciDeviceRdmReservePolicy {
+    #[default]
+    #[serde(rename = "strict")]
+    Strict,
+    #[serde(rename = "relaxed")]
+    Relaxed,
+}
+
+impl DaemonConfig {
+    pub async fn load(path: &Path) -> Result<DaemonConfig> {
+        if path.exists() {
+            let content = fs::read_to_string(path).await?;
+            let config: DaemonConfig = toml::from_str(&content)?;
+            Ok(config)
+        } else {
+            fs::write(&path, "").await?;
+            Ok(DaemonConfig::default())
+        }
+    }
+}