[PATCH v3 10/10] samples: rust: add SR-IOV driver sample

[Peter Colberg <pcolberg@redhat.com>]

Add a new SR-IOV driver sample that demonstrates how to enable and
disable the Single Root I/O Virtualization capability for a PCI device.

The sample may be exercised using QEMU's 82576 (igb) emulation.

Link: https://www.qemu.org/docs/master/system/devices/igb.html
Signed-off-by: Peter Colberg <pcolberg@redhat.com>
---
Changes in v3:
- Drop redundant `.as_ref()` for `dev_*` prints.

Changes in v2:
- Use "kernel vertical" style on imports.
- Demonstrate how to reach driver data of PF device from VF device.
---
 MAINTAINERS                       |   1 +
 samples/rust/Kconfig              |  11 ++++
 samples/rust/Makefile             |   1 +
 samples/rust/rust_driver_sriov.rs | 127 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 140 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 61bf550fd37c274843e516e00068bb2ab1e152ac..8551a9474fc26309d0714aafa104a5e1ed29156b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20454,6 +20454,7 @@ F:	rust/helpers/pci.c
 F:	rust/kernel/pci.rs
 F:	rust/kernel/pci/
 F:	samples/rust/rust_driver_pci.rs
+F:	samples/rust/rust_driver_sriov.rs
 
 PCIE BANDWIDTH CONTROLLER
 M:	Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index c49ab910634596aea4a1a73dac87585e084f420a..f244df89c4fc9d741915f581de76107e8eb0121b 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -128,6 +128,17 @@ config SAMPLE_RUST_DRIVER_PLATFORM
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_DRIVER_SRIOV
+	tristate "SR-IOV Driver"
+	depends on PCI_IOV
+	help
+	  This option builds the Rust SR-IOV driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_driver_sriov.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_DRIVER_USB
 	tristate "USB Driver"
 	depends on USB = y
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 6c0aaa58ccccfd12ef019f68ca784f6d977bc668..19d700f8210151e298cc049dacc249a121d0f2c4 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_I2C)		+= rust_driver_i2c.o
 obj-$(CONFIG_SAMPLE_RUST_I2C_CLIENT)		+= rust_i2c_client.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI)		+= rust_driver_pci.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM)	+= rust_driver_platform.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_SRIOV)		+= rust_driver_sriov.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB)		+= rust_driver_usb.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX)		+= rust_driver_faux.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY)	+= rust_driver_auxiliary.o
diff --git a/samples/rust/rust_driver_sriov.rs b/samples/rust/rust_driver_sriov.rs
new file mode 100644
index 0000000000000000000000000000000000000000..a4f7b99d9490f8fed2ab1fedb238c53304af89ee
--- /dev/null
+++ b/samples/rust/rust_driver_sriov.rs
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust SR-IOV driver sample based on QEMU's 82576 ([igb]) emulation.
+//!
+//! To make this driver probe, QEMU must be run with `-device igb`.
+//!
+//! Further, enable [vIOMMU] with interrupt remapping using, e.g.,
+//!
+//! `-M q35,accel=kvm,kernel-irqchip=split -device intel-iommu,intremap=on,caching-mode=on`
+//!
+//! and append `intel_iommu=on` to the guest kernel arguments.
+//!
+//! [igb]: https://www.qemu.org/docs/master/system/devices/igb.html
+//! [vIOMMU]: https://wiki.qemu.org/Features/VT-d
+
+use kernel::{
+    device::Core,
+    pci,
+    prelude::*,
+    sync::aref::ARef, //
+};
+
+use core::any::TypeId;
+
+#[pin_data(PinnedDrop)]
+struct SampleDriver {
+    pdev: ARef<pci::Device>,
+    private: TypeId,
+}
+
+kernel::pci_device_table!(
+    PCI_TABLE,
+    MODULE_PCI_TABLE,
+    <SampleDriver as pci::Driver>::IdInfo,
+    [
+        // E1000_DEV_ID_82576
+        (pci::DeviceId::from_id(pci::Vendor::INTEL, 0x10c9), ()),
+        // E1000_DEV_ID_82576_VF
+        (pci::DeviceId::from_id(pci::Vendor::INTEL, 0x10ca), ())
+    ]
+);
+
+#[vtable]
+impl pci::Driver for SampleDriver {
+    type IdInfo = ();
+
+    const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
+
+    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
+        pin_init::pin_init_scope(move || {
+            dev_info!(
+                pdev,
+                "Probe Rust SR-IOV driver sample (PCI ID: {}, 0x{:x}).\n",
+                pdev.vendor_id(),
+                pdev.device_id()
+            );
+
+            if pdev.is_virtfn() {
+                let physfn = pdev.physfn()?;
+                let drvdata = physfn.as_ref().drvdata::<Self>()?;
+
+                assert!(physfn.is_physfn());
+
+                dev_info!(
+                    pdev,
+                    "Parent device is PF (PCI ID: {}, 0x{:x}).\n",
+                    physfn.vendor_id(),
+                    physfn.device_id()
+                );
+
+                dev_info!(
+                    pdev,
+                    "We have access to the private data of {:?}.\n",
+                    drvdata.private
+                );
+            }
+
+            pdev.enable_device_mem()?;
+            pdev.set_master();
+
+            Ok(try_pin_init!(Self {
+                pdev: pdev.into(),
+                private: TypeId::of::<Self>()
+            }))
+        })
+    }
+
+    fn sriov_configure(pdev: &pci::Device<Core>, nr_virtfn: i32) -> Result<i32> {
+        assert!(pdev.is_physfn());
+
+        if nr_virtfn == 0 {
+            dev_info!(
+                pdev,
+                "Disable SR-IOV (PCI ID: {}, 0x{:x}).\n",
+                pdev.vendor_id(),
+                pdev.device_id()
+            );
+            pdev.disable_sriov();
+        } else {
+            dev_info!(
+                pdev,
+                "Enable SR-IOV (PCI ID: {}, 0x{:x}).\n",
+                pdev.vendor_id(),
+                pdev.device_id()
+            );
+            pdev.enable_sriov(nr_virtfn)?;
+        }
+
+        assert_eq!(pdev.num_vf(), nr_virtfn);
+        Ok(nr_virtfn)
+    }
+}
+
+#[pinned_drop]
+impl PinnedDrop for SampleDriver {
+    fn drop(self: Pin<&mut Self>) {
+        dev_info!(self.pdev, "Remove Rust SR-IOV driver sample.\n");
+    }
+}
+
+kernel::module_pci_driver! {
+    type: SampleDriver,
+    name: "rust_driver_sriov",
+    authors: ["Peter Colberg"],
+    description: "Rust SR-IOV driver",
+    license: "GPL v2",
+}

-- 
2.53.0