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/xen/xenclient/src/error.rs

@@ -1,5 +1,7 @@
 use std::io;
 
+use crate::pci::PciBdf;
+
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
     #[error("io issue encountered: {0}")]
@@ -34,6 +36,16 @@ pub enum Error {
     ElfInvalidImage,
     #[error("provided elf image does not contain xen support")]
     ElfXenSupportMissing,
+    #[error("regex error: {0}")]
+    RegexError(#[from] regex::Error),
+    #[error("error: {0}")]
+    GenericError(String),
+    #[error("failed to parse int: {0}")]
+    ParseIntError(#[from] std::num::ParseIntError),
+    #[error("invalid pci bdf string")]
+    InvalidPciBdfString,
+    #[error("pci device {0} is not assignable")]
+    PciDeviceNotAssignable(PciBdf),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;