Re: [PATCH v2 07/12] rust: pci: add an error_detected callback

["Danilo Krummrich" <dakr@kernel.org>]

On Fri Oct 23, 2026 at 5:40 PM CEST, Simon Song wrote:
> VFIO PCI variant drivers will use error_detected() to notify userspace
> of PCI errors through vfio-pci-core.
>
> Adding error_detected() to pci::Driver lets VFIO variants reuse the PCI
> adapter's error callback dispatch. A following patch removes the
> duplicate vfio::pci::Adapter.
>
> Suggested-by: Zhi Wang <zhiw@nvidia.com>
> Signed-off-by: Simon Song <xinmengs@nvidia.com>
> ---
>  rust/kernel/pci.rs      | 33 +++++++++++++++++++++++++++++++--
>  rust/kernel/vfio/pci.rs |  6 ++++++
>  2 files changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index 1951b3c8a5c..ddc28099087 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -109,7 +109,7 @@ unsafe fn register(
>              (*pdrv.get()).remove = Some(Self::remove_callback);
>              (*pdrv.get()).id_table = T::ID_TABLE.as_ptr();
>              (*pdrv.get()).driver_managed_dma = T::DRIVER_MANAGED_DMA;
> -            if T::HAS_RESET_PREPARE || T::HAS_RESET_DONE {
> +            if T::HAS_ERROR_DETECTED || T::HAS_RESET_PREPARE || T::HAS_RESET_DONE {
>                  (*pdrv.get()).err_handler = &Self::ERROR_HANDLERS;
>              }
>              #[cfg(CONFIG_PCI_IOV)]
> @@ -223,8 +223,27 @@ extern "C" fn reset_done_callback(pdev: *mut bindings::pci_dev) {
>          };
>      }
>  
> +    extern "C" fn error_detected_callback(
> +        pdev: *mut bindings::pci_dev,
> +        state: bindings::pci_channel_state_t,
> +    ) -> bindings::pci_ers_result_t {
> +        // SAFETY: PCI error recovery holds the device lock.
> +        let dev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() };
> +        // SAFETY: The device lock prevents removal of installed driver data.
> +        unsafe {
> +            Self::callback_data_with(&raw mut (*pdev).dev, |data| {

Please use Device::drvdata_borrow().

> +                T::error_detected(dev, data, state)
> +            })
> +        }
> +        .unwrap_or(bindings::pci_ers_result_PCI_ERS_RESULT_CAN_RECOVER)
> +    }
> +
>      const ERROR_HANDLERS: bindings::pci_error_handlers = bindings::pci_error_handlers {
> -        error_detected: None,
> +        error_detected: if T::HAS_ERROR_DETECTED {
> +            Some(Self::error_detected_callback)
> +        } else {
> +            None
> +        },
>          mmio_enabled: None,
>          slot_reset: None,
>          reset_prepare: if T::HAS_RESET_PREPARE {
> @@ -461,6 +480,16 @@ fn reset_done<'bound>(dev: &Device<device::Core<'_>>, this: Pin<&Self::Data<'bou
>          build_error!(crate::error::VTABLE_DEFAULT_ERROR)
>      }
>  
> +    /// Handle a PCI error and return the PCI recovery result, with the device lock held.
> +    fn error_detected<'bound>(

This can use #[optional].

> +        dev: &Device<device::Core<'_>>,
> +        this: Pin<&Self::Data<'bound>>,
> +        state: bindings::pci_channel_state_t,

This should be represented as a Rust type, maybe something like:

	#[derive(Clone, Copy, Debug, PartialEq, Eq)]
	pub enum ChannelState {
	    /// The I/O channel remains operational.
	    Normal,
	    /// I/O to the device is blocked.
	    Frozen,
	    /// The device has permanently failed.
	    PermanentFailure,
	}

> +    ) -> bindings::pci_ers_result_t {
> +        let _ = (dev, this, state);
> +        build_error!(crate::error::VTABLE_DEFAULT_ERROR)
> +    }
> +
>      /// Enables Single Root I/O Virtualization (SR-IOV) for a PF.
>      ///
>      /// Called when userspace writes a nonzero VF count to `sriov_numvfs`. The token carries the
> diff --git a/rust/kernel/vfio/pci.rs b/rust/kernel/vfio/pci.rs
> index db30dbce6a8..0fbc6a920dc 100644
> --- a/rust/kernel/vfio/pci.rs
> +++ b/rust/kernel/vfio/pci.rs
> @@ -1096,6 +1096,12 @@ pub fn reset_done(&self) -> Result {
>          // SAFETY: This owner keeps the pinned registration data alive.
>          unsafe { self.dev.registration_data_with(T::reset_done) }
>      }
> +
> +    /// Signal the VFIO error interrupt and return the PCI recovery result.
> +    pub fn error_detected(&self) -> bindings::pci_ers_result_t {

Same for bindings::pci_ers_result_t.

> +        // SAFETY: This owner keeps the initialized VFIO core device alive.
> +        unsafe { bindings::vfio_pci_core_aer_err_detected(self.dev.core_device()) }
> +    }
>  }
>  
>  impl<T: Operations> Drop for Registration<'_, T> {
> -- 
> 2.43.7