On Tue, Jul 21, 2026 at 8:24 AM Manos Pitsidianakis <[email protected]> wrote: > > Ping. > > I have a different version of the series WIP with a virtio-rng instead > of virtio-rtc, based on > https://lore.kernel.org/lkml/20260529-rust-hw_random-virtio-rng-v1-0-b3153dd90...@pitsidianak.is/ > (which needs a v2 also) > > But since this series hasn't gotten any feedback on the virtio part, I'd > like to ask if there is any before respinning. > > Thanks! >
I also think this will be a great addition, but I have very little knowledge of Rust. Is it easy to implement the simplest virtio-net driver using Rust, without CVQ or extra features, so I can test it and hopefully build features on top? Would it help? Thanks! > On Sun, 10 May 2026 16:38, Manos Pitsidianakis <[email protected]> wrote: > >Hi all, this RFC series adds Rust bindings for Virtio drivers > >(frontends in virtio parlance). > > > >As a PoC, it also adds a sample virtio-rtc driver which performs > >capability discovery through the virtqueue without registering any clock. > > > >Before I send a cleaned-up non-RFC I would like some initial feedback > >(i.e. is it something the upstream wants?) > > > >This was tested with the rust-vmm vhost-device-rtc device backend that I > >wrote[^0]: > > > >[^0]: https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-rtc > > > >Instructions: > > > > Run the daemon in a separate terminal: > > > > $ cargo run --bin vhost-device-rtc -- -s /tmp/rtc.sock > > > > Then run the VM: > > > > $ qemu-system-aarch64 \ > > -machine type=virt,virtualization=off,acpi=on \ > > -cpu host \ > > -smp 8 \ > > -accel kvm \ > > -drive if=virtio,format=qcow2,file=./debian-13-nocloud-arm64-daily.qcow2 > > \ > > -device virtio-net-pci,netdev=unet \ > > -device virtio-scsi-pci \ > > -serial mon:stdio \ > > -m 8192 \ > > -object memory-backend-memfd,id=mem,size=8G,share=on \ > > -numa node,memdev=mem \ > > -display none \ > > -vga none \ > > -kernel /path/to/linux/build/arch/arm64/boot/Image \ > > -device > > vhost-user-test-device,chardev=rtc,id=rtc,virtio-id=17,num_vqs=2,vq_size=1024 > > \ > > -chardev socket,path=/tmp/rtc.sock,id=rtc \ > > ... > > > > Example output: > > [ 1.105238] rust_virtio_rtc: Probe Rust virtio driver sample. > > [ 1.105645] rust_virtio_rtc: Found 1 vqs. > > [ 1.136050] rust_virtio_rtc: process_requestq got buf 16 bytes > > [ 1.136125] rust_virtio_rtc: Got response! Ok(RespCfg { head: ReqHead > > { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, num_clocks: Le16(3), > > reserved: [0, 0, 0, 0, 0, 0] }) > > [ 1.136701] rust_virtio_rtc: Got response! Ok(RespClockCap { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_type: 3, > > leap_second_smearing: 0, flags: 0, reserved: [0, 0, 0, 0, 0] }) > > [ 1.136724] rust_virtio_rtc virtio0: cannot expose clock 0 (type 3, > > variant 0, flags 0) to userspace > > [ 1.137259] rust_virtio_rtc: Got response! Ok(RespRead { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_reading: > > Le64(1777890485031060388) }) > > [ 1.137277] rust_virtio_rtc: #0 clock reading = 1777890485031060388 > > [ 1.137749] rust_virtio_rtc: Got response! Ok(RespClockCap { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_type: 1, > > leap_second_smearing: 0, flags: 0, reserved: [0, 0, 0, 0, 0] }) > > [ 1.137769] rust_virtio_rtc virtio0: cannot expose clock 1 (type 1, > > variant 0, flags 0) to userspace > > [ 1.138247] rust_virtio_rtc: Got response! Ok(RespRead { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_reading: > > Le64(1777890485032086075) }) > > [ 1.138264] rust_virtio_rtc: #1 clock reading = 1777890485032086075 > > [ 1.138730] rust_virtio_rtc: Got response! Ok(RespClockCap { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_type: 2, > > leap_second_smearing: 0, flags: 0, reserved: [0, 0, 0, 0, 0] }) > > [ 1.138751] rust_virtio_rtc virtio0: cannot expose clock 2 (type 2, > > variant 0, flags 0) to userspace > > [ 1.139253] rust_virtio_rtc: Got response! Ok(RespRead { head: > > ReqHead { msg_type: Le16(0), reserved: [0, 0, 0, 0, 0, 0] }, clock_reading: > > Le64(338567896865557) }) > > [ 1.139270] rust_virtio_rtc: #2 clock reading = 338567896865557 > > > >Concerns - Notes - TODOs > >======================== > > > >- Virtqueue lifetimes don't neatly apply to Rust as expected, so a lot > > of times we have to go through unsafe pointer dereferences (though > > which are guaranteed by Virtio subsystem to be valid, for example when > > a callback is called with the vq argument). There's a potential for > > misuse and definitely could use better thinking. > >- `struct virtio_device` is not reference-counted like other implemented > > device types in rust/kernel. Maybe we need to change C API first to > > make them reference counted, assuming this doesn't break anything? > >- The sample driver obviously conflicts with the C implementation, so > > this would either need to move out of samples/ or figure out some way > > to handle this in kbuild. > >- kernel::virtio module and its types need a few rustdoc examples that I > > will add in followup series > >- Note that the registration of RTC clocks etc in the sample driver is > > not done, I'm putting it off until I receive some feedback first. The > > sample driver otherwise does send and receive data from the virtqueue > > as a PoC. > > > >PS: No LLMs used so any mistakes and goofs are solely written by me. > > > >Signed-off-by: Manos Pitsidianakis <[email protected]> > >--- > >Changes in v3: > >- Removed unused methods from virtio API > >- Clean up how scattergather lists are added to virtqueues by using > > owned SGTables only, and make the API safe(r) > >- Add RAII cleanup for find_vqs return value that calls del_vqs > >- Reset device after remove callback > >- Significantly clean up sample driver as a result of the other cleanups > >- Link to v2: > >https://lore.kernel.org/r/[email protected] > > > >Changes in v2: > >- Move helper ifdefs to helper file (thanks Alice) > >- Changed CONFIG checks to IS_ENABLED to allow for CONFIG_VIRTIO=m > >- Split all use imports to one item per line according to style guide > >- Fixed wait_for_completion_interruptible*() rustdocs > >- Use Jiffy type alias in wait_for_completion_interruptible_timeout() > >- Pepper and salt #[inline]s wherever appropriate as per style guide > >- Split probe() into probe() and init() to allow cleaning up if init > > fails > >- Remove unnecessary Send and Sync unsafe impls for > > kernel::virtio::Device > >- Remove unnecessary LeSize and BeSize > >- Accept Option<_> for virtqueue callback when creating a VirtqueueInfo > >- Made all vq buffer adding operations unsafe > >- Use AtomicU16 instead of Cell<u16> for sample virtio driver > >- Fix RespHead field types in sample virtio driver > >- Fix response error checking in sample virtio driver > >- Change some device contexts in method signatures > >- Link to v1: > >https://lore.kernel.org/r/[email protected] > > > >--- > >Manos Pitsidianakis (6): > > rust/bindings: generate virtio bindings > > rust/helpers: add virtio.c > > rust/kernel/device: return parent at same context > > rust: add virtio module > > rust: impl interruptible waits for Completion > > samples/rust: Add sample virtio-rtc driver [WIP] > > > > MAINTAINERS | 9 + > > rust/bindings/bindings_helper.h | 5 + > > rust/helpers/helpers.c | 1 + > > rust/helpers/virtio.c | 37 ++++ > > rust/kernel/device.rs | 2 +- > > rust/kernel/lib.rs | 2 + > > rust/kernel/sync/completion.rs | 42 +++- > > rust/kernel/virtio.rs | 423 > > ++++++++++++++++++++++++++++++++++++++++ > > rust/kernel/virtio/utils.rs | 57 ++++++ > > rust/kernel/virtio/virtqueue.rs | 314 +++++++++++++++++++++++++++++ > > samples/rust/Kconfig | 15 ++ > > samples/rust/Makefile | 1 + > > samples/rust/rust_virtio_rtc.rs | 403 ++++++++++++++++++++++++++++++++++++++ > > 13 files changed, 1309 insertions(+), 2 deletions(-) > >--- > >base-commit: 028ef9c96e96197026887c0f092424679298aae8 > >change-id: 20260504-rust-virtio-8523b01dfdc2 > > > >Best regards, > >-- > >Manos Pitsidianakis <[email protected]> > > > > > -- > > foo >
