arm: use BootConfigurator to write fdt in memory

src/configurator/aarch64/fdt.rs

@@ -0,0 +1,72 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
+
+//! Traits and structs for loading the device tree.
+
+use vm_memory::{ByteValued, Bytes, GuestAddress, GuestMemory};
+
+use std::error::Error as StdError;
+use std::fmt;
+
+use super::super::{BootConfigurator, Error as BootConfiguratorError, Result};
+
+/// Errors specific to the device tree boot protocol configuration.
+#[derive(Debug, PartialEq)]
+pub enum Error {
+ /// Error writing FDT in memory.
+ WriteFDTToMemory,
+}
+
+impl StdError for Error {
+ fn description(&self) -> &str {
+ use Error::*;
+ match self {
+ WriteFDTToMemory => "Error writing FDT in guest memory.",
+ }
+ }
+}
+
+impl fmt::Display for Error {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(
+ f,
+ "Device Tree Boot Configurator Error: {}",
+ StdError::description(self)
+ )
+ }
+}
+
+impl From<Error> for BootConfiguratorError {
+ fn from(err: Error) -> Self {
+ BootConfiguratorError::Fdt(err)
+ }
+}
+
+/// Boot configurator for device tree.
+pub struct FdtBootConfigurator {}
+
+impl BootConfigurator for FdtBootConfigurator {
+ /// Writes the boot parameters (configured elsewhere) into guest memory.
+ ///
+ /// # Arguments
+ ///
+ /// * `fdt` - flattened device tree.
+ /// * `sections` - unused.
+ /// * `guest_memory` - guest's physical memory.
+ fn write_bootparams<T, S, M>(
+ fdt: (T, GuestAddress),
+ _sections: Option<(Vec<S>, GuestAddress)>,
+ guest_memory: &M,
+ ) -> Result<()>
+ where
+ T: ByteValued,
+ S: ByteValued,
+ M: GuestMemory,
+ {
+ // The VMM has filled an FDT and passed it as a `ByteValued` object.
+ guest_memory
+ .write_obj(fdt.0, fdt.1)
+ .map_err(|_| Error::WriteFDTToMemory.into())
+ }
+}

src/configurator/aarch64/mod.rs

@@ -6,24 +6,4 @@
 
 #![cfg(target_arch = "aarch64")]
 
-use std::error::Error as StdError;
-use std::fmt;
-
-/// Placeholder error type.
-#[derive(Debug, PartialEq)]
-pub enum Error {
- /// Placeholder error value.
- Placeholder,
-}
-
-impl StdError for Error {
- fn description(&self) -> &str {
- unimplemented!()
- }
-}
-
-impl fmt::Display for Error {
- fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
- unimplemented!()
- }
-}
+pub mod fdt;

src/configurator/mod.rs

@@ -29,7 +29,7 @@ pub use x86_64::*;
 #[cfg(target_arch = "aarch64")]
 mod aarch64;
 #[cfg(target_arch = "aarch64")]
-pub use aarch64::Error as ArmError;
+pub use aarch64::*;
 
 /// Errors specific to boot protocol configuration.
 #[derive(Debug, PartialEq)]
@@ -42,7 +42,7 @@ pub enum Error {
  Pvh(pvh::Error),
  /// Errors specific to device tree boot configuration.
  #[cfg(target_arch = "aarch64")]
- Arm(ArmError),
+ Fdt(fdt::Error),
 }
 
 impl StdError for Error {
@@ -54,7 +54,7 @@ impl StdError for Error {
  #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
  Pvh(ref e) => e.description(),
  #[cfg(target_arch = "aarch64")]
- Arm(ref e) => e.description(),
+ Fdt(ref e) => e.description(),
  }
  }
 }