diff --git a/virtmanager/src/config.rs b/virtmanager/src/config.rs
new file mode 100644
index 0000000..c0d23f0
--- /dev/null
+++ b/virtmanager/src/config.rs
@@ -0,0 +1,68 @@
+// Copyright 2021, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Function and types for VM configuration.
+
+use anyhow::{bail, Context, Error};
+use serde::{Deserialize, Serialize};
+use std::fs::File;
+use std::io::BufReader;
+
+/// Configuration for a particular VM to be started.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct VmConfig {
+    /// The filename of the kernel image, if any.
+    pub kernel: Option<String>,
+    /// The filename of the initial ramdisk for the kernel, if any.
+    pub initrd: Option<String>,
+    /// Parameters to pass to the kernel. As far as the VMM and boot protocol are concerned this is
+    /// just a string, but typically it will contain multiple parameters separated by spaces.
+    pub params: Option<String>,
+    /// The bootloader to use. If this is supplied then the kernel and initrd must not be supplied;
+    /// the bootloader is instead responsibly for loading the kernel from one of the disks.
+    pub bootloader: Option<String>,
+    /// Disk images to be made available to the VM.
+    #[serde(default)]
+    pub disks: Vec<DiskImage>,
+}
+
+impl VmConfig {
+    /// Ensure that the configuration has a valid combination of fields set, or return an error if
+    /// not.
+    pub fn validate(&self) -> Result<(), Error> {
+        if self.bootloader.is_none() && self.kernel.is_none() {
+            bail!("VM must have either a bootloader or a kernel image.");
+        }
+        if self.bootloader.is_some() && (self.kernel.is_some() || self.initrd.is_some()) {
+            bail!("Can't have both bootloader and kernel/initrd image.");
+        }
+        Ok(())
+    }
+}
+
+/// A disk image to be made available to the VM.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct DiskImage {
+    /// The filename of the disk image.
+    pub image: String,
+    /// Whether this disk should be writable by the VM.
+    pub writable: bool,
+}
+
+/// Load the configuration for the VM with the given ID from a JSON file.
+pub fn load_vm_config(path: &str) -> Result<VmConfig, Error> {
+    let file = File::open(path).with_context(|| format!("Failed to open {}", path))?;
+    let buffered = BufReader::new(file);
+    Ok(serde_json::from_reader(buffered)?)
+}