Feat/vfio user

alioth-cli/src/boot/boot.rs

@@ -31,7 +31,7 @@ use alioth::hv::{CocoSpec, HvSpec, Hypervisor};
 use alioth::loader::{Executable, PayloadSpec};
 use alioth::mem::{MemBackend, MemSpec};
 #[cfg(target_os = "linux")]
-use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec};
+use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec, VfioUserSpec};
 #[cfg(target_os = "linux")]
 use alioth::virtio::DeviceId;
 use alioth::virtio::dev::balloon::BalloonSpec;
@@ -182,6 +182,10 @@ pub struct BootArgs {
     #[arg(long, help(help_text::<VfioContainerSpec>("Add a new VFIO container.")))]
     vfio_container: Vec<String>,
 
+    #[cfg(target_os = "linux")]
+    #[arg(long, help(help_text::<VfioUserSpec>("Assign a vfio-user device to the guest.")))]
+    vfio_user: Vec<String>,
+
     #[arg(long)]
     #[arg(long, help(help_text::<BalloonSpec>("Add a VirtIO balloon device.")))]
     balloon: Option<String>,
@@ -358,6 +362,11 @@ fn parse_args(mut args: BootArgs, objects: HashMap<&str, &str>) -> Result<VmSpec
         let param = serde_aco::from_args(&arg, &objects).context(error::ParseArg { arg })?;
         spec.vfio_group.push(param);
     }
+    #[cfg(target_os = "linux")]
+    for arg in args.vfio_user {
+        let param = serde_aco::from_args(&arg, &objects).context(error::ParseArg { arg })?;
+        spec.vfio_user.push(param);
+    }
 
     Ok(spec)
 }
@@ -460,6 +469,10 @@ fn create<H: Hypervisor>(hypervisor: &H, spec: VmSpec) -> Result<Machine<H>, ali
     for (index, cdev_spec) in spec.vfio_cdev.into_iter().enumerate() {
         vm.add_vfio_cdev(format!("vfio-{index}").into(), cdev_spec)?;
     }
+    #[cfg(target_os = "linux")]
+    for (index, user_spec) in spec.vfio_user.into_iter().enumerate() {
+        vm.add_vfio_user_dev(format!("vfio-user-{index}").into(), user_spec)?;
+    }
 
     #[cfg(target_os = "linux")]
     for container_spec in spec.vfio_container.into_iter() {

alioth-cli/src/boot/boot_test.rs

@@ -22,7 +22,7 @@ use alioth::device::net::MacAddr;
 use alioth::loader::{Executable, PayloadSpec};
 use alioth::mem::{MemBackend, MemSpec};
 #[cfg(target_os = "linux")]
-use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec};
+use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec, VfioUserSpec};
 use alioth::virtio::dev::balloon::BalloonSpec;
 use alioth::virtio::dev::blk::BlkFileSpec;
 use alioth::virtio::dev::entropy::EntropySpec;
@@ -89,6 +89,8 @@ fn test_parse_args() {
         vfio_group: vec!["path=/dev/vfio/26,container=gpu_container,devices=id_gpus".into()],
         #[cfg(target_os = "linux")]
         vfio_container: vec!["name=gpu_container,dev_vfio=/dev/vfio/vfio".into()],
+        #[cfg(target_os = "linux")]
+        vfio_user: vec!["socket=/tmp/nvme.sock".into()],
         ..Default::default()
     };
     let objects = HashMap::from([
@@ -212,6 +214,10 @@ fn test_parse_args() {
             container: Some("gpu_container".into()),
             devices: vec!["0000:06:0d.0".into(), "0000:06:0d.1".into()],
         }],
+        #[cfg(target_os = "linux")]
+        vfio_user: vec![VfioUserSpec {
+            socket: Path::new("/tmp/nvme.sock").into(),
+        }],
     };
     assert_eq!(spec, want);
 }

alioth-cli/src/boot/config.rs

@@ -21,7 +21,7 @@ use alioth::device::console::ConsoleSpec;
 use alioth::device::fw_cfg::FwCfgItemSpec;
 use alioth::loader::PayloadSpec;
 #[cfg(target_os = "linux")]
-use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec};
+use alioth::vfio::{VfioCdevSpec, VfioContainerSpec, VfioGroupSpec, VfioIoasSpec, VfioUserSpec};
 use alioth::virtio::dev::balloon::BalloonSpec;
 use alioth::virtio::dev::blk::BlkFileSpec;
 use alioth::virtio::dev::entropy::EntropySpec;
@@ -119,4 +119,6 @@ pub struct VmSpec {
     pub vfio_group: Vec<VfioGroupSpec>,
     #[cfg(target_os = "linux")]
     pub vfio_container: Vec<VfioContainerSpec>,
+    #[cfg(target_os = "linux")]
+    pub vfio_user: Vec<VfioUserSpec>,
 }

alioth/src/sys/linux/vfio.rs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use bitfield::bitfield;
+use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};
 
 use crate::sys::ioctl::ioctl_io;
 use crate::{
@@ -80,7 +81,7 @@ consts! {
 }
 
 #[repr(C)]
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
 pub struct VfioRegionInfo {
     pub argsz: u32,
     pub flags: VfioRegionInfoFlag,
@@ -116,7 +117,7 @@ consts! {
 }
 
 #[repr(C)]
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
 pub struct VfioIrqInfo {
     pub argsz: u32,
     pub flags: VfioIrqInfoFlag,

alioth/src/vfio/user/bindings.rs

@@ -0,0 +1,130 @@
+// Copyright 2026 Google LLC
+//
+// 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
+//
+//     https://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.
+
+use bitfield::bitfield;
+use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};
+
+use crate::sys::vfio::{VfioDeviceInfoFlag, VfioIrqSetFlag};
+use crate::{bitflags, consts};
+
+consts! {
+    pub struct VfioUserCmd(u16) {
+        VERSION = 1;
+        DMA_MAP = 2;
+        DMA_UNMAP = 3;
+        DEVICE_GET_INFO = 4;
+        DEVICE_GET_REGION_INFO = 5;
+        DEVICE_GET_REGION_IO_FDS = 6;
+        DEVICE_GET_IRQ_INFO = 7;
+        DEVICE_SET_IRQS = 8;
+        REGION_READ = 9;
+        REGION_WRITE = 10;
+        DMA_READ = 11;
+        DMA_WRITE = 12;
+        DEVICE_RESET = 13;
+        REGION_WRITE_MULTI = 15;
+        DEVICE_FEATURE = 16;
+        MIG_DATA_READ = 17;
+        MIG_DATA_WRITE = 18;
+    }
+}
+
+consts! {
+    pub struct VfioUserMessageType(u8) {
+        COMMAND = 0;
+        REPLY = 1;
+    }
+}
+
+bitfield! {
+    #[derive(Copy, Clone, Default, IntoBytes, FromBytes, Immutable, KnownLayout)]
+    pub struct VfioUserHeaderFlag(u32);
+    impl Debug;
+    impl new;
+    pub u8, from into VfioUserMessageType, ty, set_ty: 3, 0;
+    pub no_reply, set_no_reply: 4;
+    pub error, set_error: 5;
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserHeader {
+    pub msg_id: u16,
+    pub cmd: VfioUserCmd,
+    pub msg_size: u32,
+    pub flags: VfioUserHeaderFlag,
+    pub error_no: u32,
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserVersion {
+    pub major: u16,
+    pub minor: u16,
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserDeviceInfo {
+    pub argsz: u32,
+    pub flags: VfioDeviceInfoFlag,
+    pub num_regions: u32,
+    pub num_irqs: u32,
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserIrqSet {
+    pub argsz: u32,
+    pub flags: VfioIrqSetFlag,
+    pub index: u32,
+    pub start: u32,
+    pub count: u32,
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserRegionAccess {
+    pub offset: u64,
+    pub region: u32,
+    pub count: u32,
+}
+
+bitflags! {
+    pub struct VfioUserDmaMapFlag(u32) {
+        READ = 1 << 0;
+        WRITE = 1 << 1;
+        MMAP = 1 << 2;
+        FILE_IO = 1 << 3;
+    }
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserDmaMap {
+    pub argsz: u32,
+    pub flags: VfioUserDmaMapFlag,
+    pub offset: u64,
+    pub addr: u64,
+    pub size: u64,
+}
+
+#[derive(Debug, Copy, Clone, FromBytes, IntoBytes, Immutable, Default)]
+#[repr(C)]
+pub struct VfioUserDmaUnmap {
+    pub argsz: u32,
+    pub flags: u32,
+    pub addr: u64,
+    pub size: u64,
+}