[PATCH v2 2/2] rust: virtio: add virtio support
From: Daniel Almeida
Date: Wed Apr 05 2023 - 16:15:12 EST
This patch adds virtIO support to the rust crate. This includes the
capability to create a virtIO driver (through the module_virtio_driver
macro and the respective Driver trait) as well as initial virtqueue
support.
A sample virtIO module is included for conveninence.
Signed-off-by: Daniel Almeida <daniel.almeida@xxxxxxxxxxxxx>
---
rust/bindings/bindings_helper.h | 3 +
rust/helpers.c | 25 +++
rust/kernel/lib.rs | 2 +
rust/kernel/virtio.rs | 261 ++++++++++++++++++++++++++++++++
rust/kernel/virtio/virtqueue.rs | 126 +++++++++++++++
samples/rust/Kconfig | 10 ++
samples/rust/Makefile | 1 +
samples/rust/rust_virtio.rs | 195 ++++++++++++++++++++++++
8 files changed, 623 insertions(+)
create mode 100644 rust/kernel/virtio.rs
create mode 100644 rust/kernel/virtio/virtqueue.rs
create mode 100644 samples/rust/rust_virtio.rs
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 048bae2197ac..001a492e0554 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -35,6 +35,9 @@
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio.h>
/* `bindgen` gets confused at certain things. */
const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL;
diff --git a/rust/helpers.c b/rust/helpers.c
index bf790f46c763..a80b0ab8ca64 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -39,6 +39,8 @@
#include <linux/skbuff.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
__noreturn void rust_helper_BUG(void)
{
@@ -655,6 +657,29 @@ int rust_helper_fs_parse(struct fs_context *fc,
}
EXPORT_SYMBOL_GPL(rust_helper_fs_parse);
+struct virtqueue *rust_helper_virtio_find_single_vq(struct virtio_device *vdev,
+ vq_callback_t *c,
+ const char *n)
+{
+ return virtio_find_single_vq(vdev, c, n);
+}
+
+EXPORT_SYMBOL_GPL(rust_helper_virtio_find_single_vq);
+
+void rust_helper_virtio_del_vqs(struct virtio_device *vdev)
+{
+ vdev->config->del_vqs(vdev);
+}
+
+EXPORT_SYMBOL_GPL(rust_helper_virtio_del_vqs);
+
+void rust_helper_virtio_device_ready(struct virtio_device *vdev)
+{
+ virtio_device_ready(vdev);
+}
+
+EXPORT_SYMBOL_GPL(rust_helper_virtio_device_ready);
+
/*
* We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
* as the Rust `usize` type, so we can use it in contexts where Rust
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index b23be69919cc..5441b545c5f2 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -74,6 +74,8 @@ pub mod revocable;
pub mod scatterlist;
pub mod security;
pub mod task;
+#[cfg(CONFIG_VIRTIO)]
+pub mod virtio;
pub mod workqueue;
pub mod linked_list;
diff --git a/rust/kernel/virtio.rs b/rust/kernel/virtio.rs
new file mode 100644
index 000000000000..a95a32605728
--- /dev/null
+++ b/rust/kernel/virtio.rs
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Virtio abstractions
+//!
+//! C header: [`include/linux/virtio.h`](../../../../include/media/virtio.h)
+
+use crate::{
+ device, driver,
+ error::{self, from_kernel_result},
+ prelude::*,
+ str::CStr,
+ to_result, ForeignOwnable, ThisModule,
+};
+
+pub mod virtqueue;
+
+/// A VirtIO Device ID entry. Safe wrapper over `struct virtio_device_id`.
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+pub struct DeviceId {
+ /// The device ID in the virtIO protocol.
+ pub device: u32,
+ /// The vendor ID, usually set to VIRTIO_DEV_ANY_ID.
+ pub vendor: u32,
+}
+
+// SAFETY: we ensure that `RawDeviceId::ZERO` is actually a zeroed out version of
+// the raw device id. Offset is not needed, because there is no `data` pointer.
+unsafe impl const crate::driver::RawDeviceId for DeviceId {
+ type RawType = bindings::virtio_device_id;
+
+ const ZERO: Self::RawType = bindings::virtio_device_id {
+ device: 0,
+ vendor: 0,
+ };
+
+ fn to_rawid(&self, _offset: isize) -> Self::RawType {
+ bindings::virtio_device_id {
+ device: self.device,
+ vendor: self.vendor,
+ }
+ }
+}
+
+/// Defines a VirtIO ID table consisting of [`DeviceId`] entries.
+#[macro_export]
+macro_rules! define_virtio_id_table {
+ ($data_type:ty, $($t:tt)*) => {
+ $crate::define_id_table!(ID_TABLE, $crate::virtio::DeviceId, $data_type, $($t)*);
+ };
+}
+
+/// A registration of a virtio driver.
+pub type Registration<T> = driver::Registration<Adapter<T>>;
+
+/// An adapter for the registration of virtio drivers.
+pub struct Adapter<T: Driver>(T);
+
+impl<T: Driver> driver::DriverOps for Adapter<T> {
+ type RegType = bindings::virtio_driver;
+
+ unsafe fn register(
+ reg: *mut bindings::virtio_driver,
+ name: &'static CStr,
+ _module: &'static ThisModule,
+ ) -> Result {
+ // SAFETY: By the safety requirements of this function `reg` is non-null
+ // and valid.
+ let virtio_driver = unsafe { &mut *reg };
+
+ virtio_driver.driver.name = name.as_char_ptr();
+ virtio_driver.probe = Some(Self::probe_callback);
+ virtio_driver.remove = Some(Self::remove_callback);
+ if let Some(t) = T::ID_TABLE {
+ virtio_driver.id_table = t.as_ref();
+ }
+
+ to_result(unsafe { bindings::register_virtio_driver(reg) })
+ }
+
+ unsafe fn unregister(reg: *mut bindings::virtio_driver) {
+ // SAFETY: By the safety requirements of this function `reg` was passed
+ // (and updated) by a previous successful call to
+ // `register_virtio_driver`.
+ unsafe { bindings::unregister_virtio_driver(reg) };
+ }
+}
+
+impl<T: Driver> Adapter<T> {
+ extern "C" fn probe_callback(virtio_device: *mut bindings::virtio_device) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `virtio_device` is valid by the contract with the C code.
+ // `dev` is alive only for the duration of this call, so it is
+ // guaranteed to remain alive for the lifetime of `virtio_device`.
+ let mut dev = unsafe { Device::from_ptr(virtio_device) };
+ if let Some(data) = T::probe(&mut dev)? {
+ // SAFETY: `virtio_device` is passed in by the kernel and
+ // assumed to be valid.
+ unsafe { (*virtio_device).priv_ = data.into_foreign() as _ }
+ }
+
+ // Either `probe()` or `device_ready()` must pass Self::Data, as we
+ // assume `virtio_device.priv_` is set to a valid object throughout
+ // the code.
+ // SAFETY: `virtio_device` is passed in by the kernel and
+ // assumed to be valid.
+ if !(unsafe { *virtio_device }).priv_.is_null() {
+ Ok(0)
+ } else {
+ Err(EINVAL)
+ }
+ }
+ }
+
+ // Note, this type is a wrapper over a kernel pointer, meaning that we
+ // cannot be sure that the pointee is actually going away when the wrapper
+ // is dropped. Thus, release resources here instead, since the kernel will
+ // call this when the actual pointee is to be removed.
+ extern "C" fn remove_callback(virtio_device: *mut bindings::virtio_device) {
+ // SAFETY: `virtio_device` is guaranteed to be a valid, non-null
+ // pointer. `priv_` was set on `probe()`.
+ let ptr = unsafe { (*virtio_device).priv_ };
+ // SAFETY:
+ // - We allocated this pointer using `T::Data::into_foreign`, so it is
+ // safe to turn back into a `T::Data`.
+ // - The allocation happened in probe()`, no-one freed the memory and
+ // `remove` is the canonical kernel location to free driver data. So,
+ // it is OK to convert the pointer back to a Rust structure here.
+ let data = unsafe { T::Data::from_foreign(ptr) };
+ T::remove(&data);
+
+ // SAFETY: just a couple of FFI call with a valid pointer.
+ unsafe {
+ bindings::virtio_del_vqs(virtio_device);
+ bindings::virtio_reset_device(virtio_device);
+ }
+ <T::Data as driver::DeviceRemoval>::device_remove(&data);
+ }
+}
+
+/// A virtio driver.
+pub trait Driver {
+ /// Data stored on device by driver in `virtio_device.priv`
+ type Data: ForeignOwnable + Send + Sync + driver::DeviceRemoval = ();
+
+ /// The table of [`DeviceId`]s supported by the driver.
+ const ID_TABLE: Option<driver::IdTable<'static, DeviceId, ()>> = None;
+ /// The virtio features offered. This depends on the specifics of the given
+ /// VirtIO protocol for the device and can be empty.
+ const FEATURES: &'static [i32] = &[];
+
+ /// VirtIO driver probe.
+ ///
+ /// Called when a new virtio device is added or discovered.
+ /// Implementers should attempt to initialize the device here.
+ fn probe(dev: &mut Device) -> Result<Option<Self::Data>>;
+
+ /// VirtIO driver remove.
+ ///
+ /// Called when a virtio device is removed.
+ /// Implementers should prepare the device for complete removal here.
+ ///
+ /// In particular, implementers must ensure no buffers are left over in the
+ /// virtqueues in use by calling [`virtqueue::get_buf()`] until `None` is
+ /// returned.
+ fn remove(_data: &Self::Data) {}
+}
+
+/// A VirtIO device.
+///
+/// # Invariants
+///
+/// The field `ptr` is non-null and valid for the lifetime of the object.
+pub struct Device {
+ ptr: *mut bindings::virtio_device,
+}
+
+impl Device {
+ /// Creates a new device from the given pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be non-null and valid. It must remain valid for the lifetime of the returned
+ /// instance.
+ pub unsafe fn from_ptr(ptr: *mut bindings::virtio_device) -> Self {
+ // INVARIANT: The safety requirements of the function ensure the lifetime invariant.
+ Self { ptr }
+ }
+
+ /// Returns id of the VirtIO device.
+ pub fn id(&self) -> i32 {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ unsafe { (*self.ptr).id.device as _ }
+ }
+
+ /// Returns the `Virtqueue` associated with `name`, if any.
+ pub fn find_virtqueue<T: virtqueue::Operations>(
+ &self,
+ name: &CStr,
+ ) -> Result<virtqueue::Virtqueue<T>> {
+ let callback = if T::HAS_CALLBACK {
+ Some(virtqueue::Virtqueue::<T>::vq_callback as _)
+ } else {
+ None
+ };
+
+ // SAFETY: ptr is valid due to the type invariant, callback points to a
+ // valid address and the pointer passed in is passed in by the kernel,
+ // so it is assumed to be valid.
+ let vq = unsafe { bindings::virtio_find_single_vq(self.ptr, callback, name.as_char_ptr()) };
+ let vq = error::from_kernel_err_ptr(vq)?;
+
+ // SAFETY: vq is checked with `from_kernel_err_ptr`
+ Ok(unsafe { virtqueue::Virtqueue::from_ptr(vq) })
+ }
+
+ /// Returns the Virtio Device's private data.
+ pub fn data<T: Driver>(&self) -> <T::Data as ForeignOwnable>::Borrowed<'_> {
+ unsafe { <T::Data as ForeignOwnable>::borrow((*self.ptr).priv_) }
+ }
+
+ /// Returns a pointer to the [`bindings::virtio_device`] associated with
+ /// this [`Device`].
+ pub fn raw_device(&self) -> *mut bindings::virtio_device {
+ self.ptr
+ }
+
+ /// Wrapper over the C-side `virtio_device_ready`. Enable virtqueue use in
+ /// the probe function. Drivers must call this to use virtqueues in the
+ /// probe function.
+ ///
+ /// `data` can be optionally be set through `device_ready()` instead of
+ /// `probe()`.
+ pub fn device_ready<T: Driver>(&self, data: Option<T::Data>) {
+ if let Some(data) = data {
+ // SAFETY: `virtio_device` is passed in by the kernel and
+ // assumed to be valid.
+ unsafe { (*self.ptr).priv_ = data.into_foreign() as _ }
+ }
+
+ // SAFETY: just a FFI call on a valid pointer.
+ unsafe {
+ bindings::virtio_device_ready(self.ptr);
+ }
+ }
+}
+
+// SAFETY: The device returned by `raw_device` is the raw virtio device.
+unsafe impl device::RawDevice for Device {
+ fn raw_device(&self) -> *mut bindings::device {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ unsafe { &mut (*self.ptr).dev }
+ }
+}
+
+/// Declares a kernel module that exposes a single virtio driver.
+#[macro_export]
+macro_rules! module_virtio_driver {
+ ($($f:tt)*) => {
+ $crate::module_driver!(<T>, $crate::virtio::Adapter<T>, { $($f)* });
+ };
+}
diff --git a/rust/kernel/virtio/virtqueue.rs b/rust/kernel/virtio/virtqueue.rs
new file mode 100644
index 000000000000..a735f3d997a9
--- /dev/null
+++ b/rust/kernel/virtio/virtqueue.rs
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Virtqueue abstractions.
+//!
+//! C header: [`include/linux/virtio.h`](../../../../include/linux/virtio.h)
+
+use core::marker::PhantomData;
+
+use crate::error;
+use crate::prelude::*;
+use crate::scatterlist::Scatterlist;
+use crate::virtio;
+use crate::ForeignOwnable;
+
+/// The Virtqueue's operations.
+#[vtable]
+pub trait Operations: Sized {
+ /// Data passed into the callback.
+ type PrivateData: ForeignOwnable;
+
+ /// The virtqueue callback.
+ fn callback(virtqueue: Virtqueue<Self>);
+}
+
+/// A Virtqueue abstraction.
+pub struct Virtqueue<T: Operations> {
+ /// The underlying pointer.
+ ptr: *mut bindings::virtqueue,
+ /// A Phantom so T gets used.
+ phantom: PhantomData<T>,
+}
+
+impl<T: Operations> Virtqueue<T> {
+ /// # Safety
+ /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+ /// returned [`Virtqueue`] instance.
+ ///
+ /// Caller must ensure that get_buf() returns None before the Virtqueue is
+ /// dropped, so that ownership of the passed in T::PrivateData can be
+ /// retrieved.
+ pub unsafe fn from_ptr(ptr: *mut bindings::virtqueue) -> Self {
+ Self {
+ ptr,
+ phantom: PhantomData,
+ }
+ }
+
+ /// A wrapper over the C side `virtqueue_add_sgs()`. Adds scatterlists to
+ /// the [`Virtqueue`] for processing.
+ pub fn add_sgs(
+ &mut self,
+ out_sgs: &mut [Scatterlist],
+ in_sgs: &mut [Scatterlist],
+ data: T::PrivateData,
+ gfp: u32,
+ ) -> Result {
+ let mut sgs = Vec::new();
+
+ let num_out = out_sgs.len();
+ let num_in = in_sgs.len();
+
+ for s in out_sgs {
+ sgs.try_push(s.inner().get())?;
+ }
+ for s in in_sgs {
+ sgs.try_push(s.inner().get())?;
+ }
+
+ // SAFETY: `self.ptr` is valid as per the type invariant.
+ let res = unsafe {
+ bindings::virtqueue_add_sgs(
+ self.ptr,
+ sgs.as_mut_ptr(),
+ num_out as u32,
+ num_in as u32,
+ data.into_foreign() as _,
+ gfp,
+ )
+ };
+
+ error::to_result(res)
+ }
+
+ /// A wrapper over the C side `virtqueue_kick()`. Notifies the VirtIO device
+ /// of activity in this [`Virtqueue`].
+ pub fn kick(&mut self) -> Result {
+ let res = unsafe { bindings::virtqueue_kick(self.ptr) };
+ error::to_result(res as i32)
+ }
+
+ /// Returns the underlying [`virtio::Device`].
+ pub fn virtio_device(&self) -> virtio::Device {
+ // SAFETY: The virtio framework places a pointer to the VirtIO device
+ // when creating the virtqueue
+ unsafe { virtio::Device::from_ptr((*self.ptr).vdev) }
+ }
+
+ /// A wrapper over the C side `virtqueue_get_buf()`. Returns the next used
+ /// buffer, if any, alongside with the amount of data written.
+ pub fn get_buf(&mut self) -> Option<(T::PrivateData, u32)> {
+ let mut len = 0;
+
+ let data = unsafe {
+ let buf = bindings::virtqueue_get_buf(self.ptr, &mut len as _);
+
+ if buf.is_null() {
+ return None;
+ }
+
+ // SAFETY: if there is a buffer token, it came from
+ // `into_foreign()` as called in `add_sgs()`.
+ <T::PrivateData as ForeignOwnable>::from_foreign(buf)
+ };
+
+ Some((data, len))
+ }
+
+ pub(crate) unsafe extern "C" fn vq_callback(vq: *mut bindings::virtqueue) {
+ // SAFETY: the caller should guarantee that `vq` is valid for the lifetime
+ // of `Self`.
+ let virtqueue = unsafe { Self::from_ptr(vq) };
+ T::callback(virtqueue);
+ }
+}
+
+unsafe impl<T: Operations> Send for Virtqueue<T> {}
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index 189c10ced6d4..0507c57170ec 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -163,4 +163,14 @@ config SAMPLE_RUST_SELFTESTS
If unsure, say N.
+config SAMPLE_RUST_VIRTIO
+ tristate "Virtio"
+ help
+ This option builds the Rust virtio module sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_minimal.
+
+ If unsure, say N.
+
endif # SAMPLES_RUST
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 420bcefeb082..24059795480f 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -15,5 +15,6 @@ obj-$(CONFIG_SAMPLE_RUST_NETFILTER) += rust_netfilter.o
obj-$(CONFIG_SAMPLE_RUST_ECHO_SERVER) += rust_echo_server.o
obj-$(CONFIG_SAMPLE_RUST_FS) += rust_fs.o
obj-$(CONFIG_SAMPLE_RUST_SELFTESTS) += rust_selftests.o
+obj-$(CONFIG_SAMPLE_RUST_VIRTIO) += rust_virtio.o
subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs
diff --git a/samples/rust/rust_virtio.rs b/samples/rust/rust_virtio.rs
new file mode 100644
index 000000000000..fddab8674909
--- /dev/null
+++ b/samples/rust/rust_virtio.rs
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust virtio device driver sample. Retrieves a random number from the guest
+//! using VirtIO Entropy.
+
+// impl_self_work_adapter!() does not compile otherwise.
+#![allow(unreachable_code)]
+
+use kernel::bindings;
+use kernel::module_virtio_driver;
+use kernel::prelude::*;
+use kernel::scatterlist;
+use kernel::sync::smutex::Mutex;
+use kernel::sync::Arc;
+use kernel::sync::UniqueArc;
+use kernel::virtio::virtqueue;
+use kernel::virtio::virtqueue::Virtqueue;
+use kernel::workqueue;
+use kernel::Opaque;
+
+module_virtio_driver! {
+ type: Driver,
+ name: "rust_virtio",
+ license: "GPL",
+}
+
+struct AckWork {
+ work: workqueue::Work,
+ raw_dev: *mut kernel::bindings::virtio_device,
+}
+
+impl AckWork {
+ pub(crate) fn new(raw_dev: *mut kernel::bindings::virtio_device) -> Result<Arc<Self>> {
+ let work = UniqueArc::try_new(Self {
+ // SAFETY: init_work_item!() is called below
+ work: unsafe { workqueue::Work::new() },
+ raw_dev,
+ })?;
+
+ kernel::init_work_item!(&work);
+
+ Ok(work.into())
+ }
+}
+
+kernel::impl_self_work_adapter!(AckWork, work, |w| {
+ // SAFETY:
+ //
+ // If the work still exists, the driver data still exists (as it is its
+ // sole owner).
+ //
+ // If the driver data still exisits, then the underlying kernel::Device
+ // is alive (as it holds a reference obtained from get_device())
+ //
+ // If the contained struct device* is alive, the outermost struct
+ // virtio_device* is presumed alive and valid.
+ //
+ // Other virtio drivers (in C) just use container_of here as they embed
+ // the work struct in their driver struct itself.
+ let virtio_dev = unsafe { kernel::virtio::Device::from_ptr(w.raw_dev) };
+ let virtio_device_data = virtio_dev.data::<Driver>();
+
+ let mut vq = virtio_device_data.vq.lock();
+
+ if let Some(resp) = vq.get_buf() {
+ pr_crit!("Retrieving response, host wrote {} bytes", resp.1);
+ // SAFETY: Just a FFI call on a completion that was previously
+ // initialized with `init_completion`.
+ unsafe { bindings::complete(resp.0.completion.get()) }
+ }
+});
+
+// SAFETY: the fields are not exposed. Nothing can be done.
+unsafe impl Send for AckWork {}
+unsafe impl Sync for AckWork {}
+
+struct Request {
+ inner: Mutex<RequestInner>,
+ completion: Opaque<bindings::completion>,
+}
+
+struct RequestInner {
+ data: [u8; 64],
+}
+
+fn send_request(
+ vq: &Mutex<Virtqueue<VirtqueueCallback>>,
+ request: <VirtqueueCallback as virtqueue::Operations>::PrivateData,
+) -> Result {
+ let mut inner_guard = request.inner.lock();
+ // SAFETY: inner_guard.data points to an owned array, buflen is the size of
+ // the array.
+ let mut in_sgs = unsafe {
+ [scatterlist::Scatterlist::init_one(
+ inner_guard.data.as_mut_ptr() as *mut core::ffi::c_void,
+ core::mem::size_of_val(&inner_guard.data) as u32,
+ )]
+ };
+
+ // SAFETY: Just a FFI call on a valid bindgen type.
+ unsafe { bindings::init_completion(request.completion.get()) }
+
+ {
+ let mut vq = vq.lock();
+ let mut out_sgs = [];
+ vq.add_sgs(
+ &mut out_sgs[..],
+ &mut in_sgs[..],
+ Arc::clone(&request),
+ bindings::GFP_KERNEL,
+ )?;
+
+ vq.kick()?;
+ }
+
+ pr_crit!("Request sent, waiting");
+
+ // SAFETY: Just a FFI call on a valid bindgen type that was previously
+ // passed to `init_completion`.
+ unsafe { bindings::wait_for_completion(request.completion.get()) }
+
+ pr_crit!("Request completed, response was {:?}", inner_guard.data);
+ Ok(())
+}
+
+struct Driver {
+ /// The virtqueue.
+ vq: Mutex<Virtqueue<VirtqueueCallback>>,
+ /// The ack work that is awaken by the ack callback.
+ work: Arc<AckWork>,
+}
+
+impl kernel::driver::DeviceRemoval for Driver {
+ fn device_remove(&self) {
+ let mut vq = self.vq.lock();
+ while let Some(_buf) = vq.get_buf() {
+ // Actual drivers should take care to retrieve any left over buffers
+ // so `T::PrivateData` can drop.
+ }
+ }
+}
+
+impl kernel::virtio::Driver for Driver {
+ type Data = Arc<Self>;
+
+ kernel::define_virtio_id_table! {(), [
+ (kernel::virtio::DeviceId {
+ device: bindings::VIRTIO_ID_RNG,
+ vendor: bindings::VIRTIO_DEV_ANY_ID,
+ }, None),
+ ]}
+
+ fn probe(virtio_dev: &mut kernel::virtio::Device) -> Result<Option<Self::Data>> {
+ pr_info!("rust_virtio: probing");
+
+ let vq = virtio_dev.find_virtqueue::<VirtqueueCallback>(kernel::c_str!("input"))?;
+ let vq = Mutex::new(vq);
+
+ let work = AckWork::new(virtio_dev.raw_device())?;
+ let data = Arc::try_new(Self { vq, work })?;
+
+ // We want to use the virtqueues here in this example.
+ virtio_dev.device_ready::<Self>(Some(Arc::clone(&data)));
+
+ let request = Arc::try_new(Request {
+ inner: Mutex::new(RequestInner { data: [0; 64] }),
+ completion: Opaque::new(Default::default()),
+ })?;
+
+ send_request(&data.vq, Arc::clone(&request))?;
+
+ pr_info!("rust_virtio probed succesfully!");
+
+ Ok(None)
+ }
+}
+
+pub(crate) struct VirtqueueCallback;
+
+#[vtable]
+impl virtqueue::Operations for VirtqueueCallback {
+ type PrivateData = Arc<Request>;
+
+ fn callback(vq: Virtqueue<Self>) {
+ let vdev = vq.virtio_device();
+ let data = vdev.data::<Driver>();
+ let data = &*data;
+
+ pr_info!("virtqueue callback called successfully!");
+
+ // Enqueue work in order to retrieve the data and complete the
+ // completion.
+ kernel::workqueue::system().enqueue(Arc::clone(&data.work));
+ }
+}
--
2.40.0