Add an optional bus callback sriov_configure() to pci::Driver trait, using the vtable attribute to query if the driver implements the callback. The callback is invoked when a user-space application writes the number of VFs to the sysfs file `sriov_numvfs` to enable SR-IOV, or zero to disable SR-IOV for a PCI device.
Suggested-by: Danilo Krummrich <[email protected]> Signed-off-by: Peter Colberg <[email protected]> --- rust/kernel/pci.rs | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index a4c27c674bd8bdf5e3316789d38d566e90b93fe2..88bd114970431bf8c3edef94c1d48567d895eaf6 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -83,6 +83,10 @@ unsafe fn register( (*pdrv.get()).remove = Some(Self::remove_callback); (*pdrv.get()).id_table = T::ID_TABLE.as_ptr(); (*pdrv.get()).managed_sriov = true; + #[cfg(CONFIG_PCI_IOV)] + if T::HAS_SRIOV_CONFIGURE { + (*pdrv.get()).sriov_configure = Some(Self::sriov_configure_callback); + } } // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`. @@ -135,6 +139,20 @@ extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) { T::unbind(pdev, data); } + + #[cfg(CONFIG_PCI_IOV)] + extern "C" fn sriov_configure_callback( + pdev: *mut bindings::pci_dev, + nr_virtfn: c_int, + ) -> c_int { + // SAFETY: The PCI bus only ever calls the sriov_configure callback with a valid pointer to + // a `struct pci_dev`. + // + // INVARIANT: `pdev` is valid for the duration of `sriov_configure_callback()`. + let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal>>() }; + + from_result(|| T::sriov_configure(pdev, nr_virtfn)) + } } /// Declares a kernel module that exposes a single PCI driver. @@ -325,6 +343,44 @@ pub trait Driver: Send { fn unbind(dev: &Device<device::Core>, this: Pin<&Self>) { let _ = (dev, this); } + + /// Single Root I/O Virtualization (SR-IOV) configure. + /// + /// Called when a user-space application enables or disables the SR-IOV capability for a + /// [`Device`] by writing the number of Virtual Functions (VF), `nr_virtfn` or zero to the + /// sysfs file `sriov_numvfs` for this device. Implementing this callback is optional. + /// + /// Further, and unlike for a PCI driver written in C, when a PF device with enabled VFs is + /// unbound from its bound [`Driver`], the `sriov_configure()` callback is invoked to disable + /// SR-IOV before the `unbind()` callback. This guarantees that when a VF device is bound to a + /// driver, the underlying PF device is bound to a driver, too. + /// + /// Upon success, this callback must return the number of VFs that were enabled, or zero if + /// SR-IOV was disabled. + /// + /// See [PCI Express I/O Virtualization]. + /// + /// [PCI Express I/O Virtualization]: https://docs.kernel.org/PCI/pci-iov-howto.html + /// + /// # Examples + /// + /// ``` + /// # use kernel::{device::Core, pci, prelude::*}; + /// #[cfg(CONFIG_PCI_IOV)] + /// fn sriov_configure(dev: &pci::Device<Core>, nr_virtfn: i32) -> Result<i32> { + /// if nr_virtfn == 0 { + /// dev.disable_sriov(); + /// } else { + /// dev.enable_sriov(nr_virtfn)?; + /// } + /// Ok(nr_virtfn) + /// } + /// ``` + #[cfg(CONFIG_PCI_IOV)] + fn sriov_configure(dev: &Device<device::Core>, nr_virtfn: i32) -> Result<i32> { + let _ = (dev, nr_virtfn); + build_error!(crate::error::VTABLE_DEFAULT_ERROR) + } } /// The PCI device representation. -- 2.52.0
