diff --git a/vm/src/config.rs b/vm/src/config.rs
new file mode 100644
index 0000000..a6f48ce
--- /dev/null
+++ b/vm/src/config.rs
@@ -0,0 +1,114 @@
+// 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.
+
+//! Struct for VM configuration.
+
+use android_system_virtmanager::{
+    aidl::android::system::virtmanager::DiskImage::DiskImage as AidlDiskImage,
+    aidl::android::system::virtmanager::VirtualMachineConfig::VirtualMachineConfig,
+    binder::ParcelFileDescriptor,
+};
+use anyhow::{bail, Context, Error};
+use serde::{Deserialize, Serialize};
+use std::fs::{File, OpenOptions};
+use std::io::BufReader;
+use std::path::{Path, PathBuf};
+
+/// 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<PathBuf>,
+    /// The filename of the initial ramdisk for the kernel, if any.
+    pub initrd: Option<PathBuf>,
+    /// 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<PathBuf>,
+    /// 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(())
+    }
+
+    /// Load the configuration for a VM from the given JSON file, and check that it is valid.
+    pub fn load(file: &File) -> Result<VmConfig, Error> {
+        let buffered = BufReader::new(file);
+        let config: VmConfig = serde_json::from_reader(buffered)?;
+        config.validate()?;
+        Ok(config)
+    }
+
+    /// Convert the `VmConfig` to a [`VirtualMachineConfig`] which can be passed to the Virt
+    /// Manager.
+    pub fn to_parcelable(&self) -> Result<VirtualMachineConfig, Error> {
+        Ok(VirtualMachineConfig {
+            kernel: maybe_open_parcel_file(&self.kernel)?,
+            initrd: maybe_open_parcel_file(&self.initrd)?,
+            params: self.params.clone(),
+            bootloader: maybe_open_parcel_file(&self.bootloader)?,
+            disks: self
+                .disks
+                .iter()
+                .map(|disk| {
+                    Ok(AidlDiskImage {
+                        writable: disk.writable,
+                        image: Some(open_parcel_file(&disk.image, disk.writable)?),
+                    })
+                })
+                .collect::<Result<_, Error>>()?,
+        })
+    }
+}
+
+/// 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: PathBuf,
+    /// Whether this disk should be writable by the VM.
+    pub writable: bool,
+}
+
+/// Try to open the given file and wrap it in a [`ParcelFileDescriptor`].
+fn open_parcel_file(filename: &Path, writable: bool) -> Result<ParcelFileDescriptor, Error> {
+    Ok(ParcelFileDescriptor::new(
+        OpenOptions::new()
+            .read(true)
+            .write(writable)
+            .open(filename)
+            .with_context(|| format!("Failed to open {:?}", filename))?,
+    ))
+}
+
+/// If the given filename is `Some`, try to open it and wrap it in a [`ParcelFileDescriptor`].
+fn maybe_open_parcel_file(
+    filename: &Option<PathBuf>,
+) -> Result<Option<ParcelFileDescriptor>, Error> {
+    filename.as_deref().map(|filename| open_parcel_file(filename, false)).transpose()
+}