gpu: nova-core: run Booter Unloader and FWSEC-SB upon unbinding

When probing the driver, the FWSEC-FRTS firmware creates a WPR2 secure
memory region to store the GSP firmware, and the Booter Loader loads and
starts that firmware into the GSP, making it run in RISC-V mode.

These operations need to be reverted upon unloading, particularly the
WPR2 secure region creation, as its presence prevents the driver from
subsequently probing.

Thus, prepare the Booter Unloader and FWSEC-SB firmware images when
booting the GSP, so they can be executed at unbind time to put the GPU
into a state where it can be probed again.

Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Co-developed-by: Eliot Courtney <ecourtney@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260529-nova-unload-v7-3-678f39209e00@nvidia.com
[acourbot: `Result<()>` -> `Result`]
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

drivers/gpu/nova-core/firmware/booter.rs

@@ -282,7 +282,6 @@ fn new_booter(data: &[u8]) -> Result<Self> {
 #[derive(Copy, Clone, Debug, PartialEq)]
 pub(crate) enum BooterKind {
     Loader,
-    #[expect(unused)]
     Unloader,
 }
 

drivers/gpu/nova-core/firmware/fwsec.rs

@@ -144,7 +144,6 @@ pub(crate) enum FwsecCommand {
     /// image into it.
     Frts { frts_addr: u64, frts_size: u64 },
     /// Asks [`FwsecFirmware`] to load pre-OS apps on the PMU.
-    #[expect(dead_code)]
     Sb,
 }
 

drivers/gpu/nova-core/gpu.rs

@@ -18,7 +18,10 @@
         Falcon, //
     },
     fb::SysmemFlush,
-    gsp::Gsp,
+    gsp::{
+        self,
+        Gsp, //
+    },
     regs,
 };
 
@@ -260,6 +263,8 @@ pub(crate) struct Gpu<'gpu> {
     /// GSP runtime data. Temporarily an empty placeholder.
     #[pin]
     gsp: Gsp,
+    /// GSP unload firmware bundle, if any.
+    unload_bundle: Option<gsp::UnloadBundle>,
 }
 
 impl<'gpu> Gpu<'gpu> {
@@ -293,7 +298,10 @@ pub(crate) fn new(
 
             gsp <- Gsp::new(pdev),
 
-            _: { gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)? },
+            // This member must be initialized last, so the `UnloadBundle` can never be dropped from
+            // outside of the constructed `Gpu`, ensuring that the unload sequence is properly run
+            // in case of failure.
+            unload_bundle: gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)?,
         })
     }
 }
@@ -304,12 +312,13 @@ fn drop(self: Pin<&mut Self>) {
         let this = self.project();
         let device = *this.device;
         let bar = *this.bar;
+        let bundle = this.unload_bundle.take();
 
         let _ = this
             .gsp
             .as_ref()
             .get_ref()
-            .unload(device, bar, &*this.gsp_falcon)
+            .unload(device, bar, &*this.gsp_falcon, &*this.sec2_falcon, bundle)
             .inspect_err(|e| dev_err!(device, "failed to unload GSP: {:?}\n", e));
     }
 }

drivers/gpu/nova-core/gsp.rs

@@ -185,3 +185,6 @@ pub(crate) fn new(pdev: &pci::Device<device::Bound>) -> impl PinInit<Self, Error
         })
     }
 }
+
+/// Opaque bundle required to unload the GSP. Created by [`Gsp::boot`], consumed by [`Gsp::unload`].
+pub(crate) struct UnloadBundle(KBox<dyn hal::UnloadBundle>);

drivers/gpu/nova-core/gsp/boot.rs

@@ -38,7 +38,8 @@ impl super::Gsp {
     /// user-space, patching them with signatures, and building firmware-specific intricate data
     /// structures that the GSP will use at runtime.
     ///
-    /// Upon return, the GSP is up and running, and its runtime object given as return value.
+    /// Upon return, the GSP is up and running, and its unload bundle (to be given as argument to
+    /// [`Self::unload`]) returned.
     pub(crate) fn boot(
         self: Pin<&mut Self>,
         pdev: &pci::Device<device::Bound>,
@@ -46,7 +47,7 @@ pub(crate) fn boot(
         chipset: Chipset,
         gsp_falcon: &Falcon<Gsp>,
         sec2_falcon: &Falcon<Sec2>,
-    ) -> Result {
+    ) -> Result<Option<super::UnloadBundle>> {
         let dev = pdev.as_ref();
         let hal = super::hal::gsp_hal(chipset);
 
@@ -57,8 +58,8 @@ pub(crate) fn boot(
 
         let wpr_meta = Coherent::init(dev, GFP_KERNEL, GspFwWprMeta::new(&gsp_fw, &fb_layout))?;
 
-        // Perform the chipset-specific boot sequence.
+        // Perform the chipset-specific boot sequence, and retrieve the unload bundle.
-        hal.boot(
+        let unload_bundle = hal.boot(
             &self,
             dev,
             bar,
@@ -98,7 +99,7 @@ pub(crate) fn boot(
             Err(e) => dev_warn!(pdev, "GPU name unavailable: {:?}\n", e),
         }
 
-        Ok(())
+        Ok(unload_bundle)
     }
 
     /// Shut down the GSP and wait until it is offline.
@@ -130,16 +131,35 @@ pub(crate) fn unload(
         dev: &device::Device<device::Bound>,
         bar: &Bar0,
         gsp_falcon: &Falcon<Gsp>,
+        sec2_falcon: &Falcon<Sec2>,
+        unload_bundle: Option<super::UnloadBundle>,
     ) -> Result {
-        // Shut down the GSP.
+        // Shut down the GSP. Keep going even in case of error.
-        Self::shutdown_gsp(
+        let mut res = Self::shutdown_gsp(
             &self.cmdq,
             bar,
             gsp_falcon,
             commands::PowerStateLevel::Level0,
         )
-        .inspect_err(|e| dev_err!(dev, "Unload guest driver failed: {:?}\n", e))?;
+        .inspect_err(|e| dev_err!(dev, "GSP shutdown failed: {:?}\n", e));
 
-        Ok(())
+        // Run the unload bundle to reset the GSP so it can be booted again.
+        if let Some(unload_bundle) = unload_bundle {
+            res = res.and(
+                unload_bundle
+                    .0
+                    .run(dev, bar, gsp_falcon, sec2_falcon)
+                    .inspect_err(|e| dev_err!(dev, "Unload bundle failed: {:?}\n", e)),
+            );
+        } else {
+            dev_warn!(
+                dev,
+                "Unload bundle is missing, GSP won't be properly reset.\n"
+            );
+
+            res = Err(EAGAIN);
+        }
+
+        res.inspect(|()| dev_info!(dev, "GSP successfully unloaded\n"))
     }
 }

drivers/gpu/nova-core/gsp/hal.rs

@@ -30,9 +30,28 @@
     },
 };
 
+/// Trait for types containing the resources and code required to fully reset the GSP.
+///
+/// The GSP unload code might run in a situation where we cannot load firmware dynamically (e.g.
+/// because we are in shutdown and the file system is not accessible anymore). Thus, the firmware
+/// required for unloading is prepared at load time, and stored here until it needs to be run.
+pub(super) trait UnloadBundle: Send {
+    /// Performs the steps required to properly reset the GSP after it has been stopped.
+    fn run(
+        &self,
+        dev: &device::Device<device::Bound>,
+        bar: &Bar0,
+        gsp_falcon: &Falcon<GspEngine>,
+        sec2_falcon: &Falcon<Sec2>,
+    ) -> Result;
+}
+
 /// Trait implemented by GSP HALs.
 pub(super) trait GspHal: Send {
     /// Performs the GSP boot process, loading and running the required firmwares as needed.
+    ///
+    /// Upon success, returns the [`UnloadBundle`] to be run (if any) in order to properly reset the
+    /// GSP after it has been stopped.
     #[allow(clippy::too_many_arguments)]
     fn boot(
         &self,
@@ -44,7 +63,7 @@ fn boot(
         wpr_meta: &Coherent<GspFwWprMeta>,
         gsp_falcon: &Falcon<GspEngine>,
         sec2_falcon: &Falcon<Sec2>,
-    ) -> Result;
+    ) -> Result<Option<crate::gsp::UnloadBundle>>;
 
     /// Performs HAL-specific post-GSP boot tasks.
     ///

drivers/gpu/nova-core/gsp/hal/gh100.rs

@@ -41,7 +41,7 @@ fn boot(
         _wpr_meta: &Coherent<GspFwWprMeta>,
         _gsp_falcon: &Falcon<GspEngine>,
         _sec2_falcon: &Falcon<Sec2>,
-    ) -> Result {
+    ) -> Result<Option<crate::gsp::UnloadBundle>> {
         Err(ENOTSUPP)
     }
 }

drivers/gpu/nova-core/gsp/hal/tu102.rs

@@ -32,7 +32,10 @@
     },
     gpu::Chipset,
     gsp::{
-        hal::GspHal,
+        hal::{
+            GspHal,
+            UnloadBundle, //
+        },
         sequencer::{
             GspSequencer,
             GspSequencerParams, //
@@ -44,6 +47,124 @@
     vbios::Vbios, //
 };
 
+// A ready-to-run FWSEC unload firmware.
+//
+// Since there are two variants of the prepared firmware (with and without a bootloader), this type
+// abstracts the difference.
+enum FwsecUnloadFirmware {
+    WithoutBl(FwsecFirmware),
+    WithBl(FwsecFirmwareWithBl),
+}
+
+impl FwsecUnloadFirmware {
+    /// Loads the FWSEC SB firmware, as well as its bootloader if `chipset` requires it.
+    fn new(
+        dev: &device::Device<device::Bound>,
+        bar: &Bar0,
+        chipset: Chipset,
+        bios: &Vbios,
+        gsp_falcon: &Falcon<GspEngine>,
+    ) -> Result<Self> {
+        let fwsec_sb = FwsecFirmware::new(dev, gsp_falcon, bar, bios, FwsecCommand::Sb)?;
+
+        Ok(if chipset.needs_fwsec_bootloader() {
+            Self::WithBl(FwsecFirmwareWithBl::new(fwsec_sb, dev, chipset)?)
+        } else {
+            Self::WithoutBl(fwsec_sb)
+        })
+    }
+
+    /// Runs the FWSEC SB firmware.
+    fn run(
+        &self,
+        dev: &device::Device<device::Bound>,
+        bar: &Bar0,
+        gsp_falcon: &Falcon<GspEngine>,
+    ) -> Result {
+        match self {
+            Self::WithoutBl(fw) => fw.run(dev, gsp_falcon, bar),
+            Self::WithBl(fw) => fw.run(dev, gsp_falcon, bar),
+        }
+    }
+}
+
+// Contains the firmware required to fully reset GSP on chipsets where the GSP is started using
+// FWSEC/Booter.
+struct Sec2UnloadBundle {
+    fwsec_sb: FwsecUnloadFirmware,
+    booter_unloader: BooterFirmware,
+}
+
+impl Sec2UnloadBundle {
+    /// Load and prepare the resources required to properly reset the GSP after it has been stopped.
+    fn build(
+        dev: &device::Device<device::Bound>,
+        bar: &Bar0,
+        chipset: Chipset,
+        bios: &Vbios,
+        gsp_falcon: &Falcon<GspEngine>,
+        sec2_falcon: &Falcon<Sec2>,
+    ) -> Result<KBox<dyn UnloadBundle>> {
+        KBox::new(
+            Self {
+                fwsec_sb: FwsecUnloadFirmware::new(dev, bar, chipset, bios, gsp_falcon)?,
+                booter_unloader: BooterFirmware::new(
+                    dev,
+                    BooterKind::Unloader,
+                    chipset,
+                    FIRMWARE_VERSION,
+                    sec2_falcon,
+                    bar,
+                )?,
+            },
+            GFP_KERNEL,
+        )
+        .map(|b| b as KBox<dyn UnloadBundle>)
+        .map_err(Into::into)
+    }
+}
+
+impl UnloadBundle for Sec2UnloadBundle {
+    fn run(
+        &self,
+        dev: &device::Device<device::Bound>,
+        bar: &Bar0,
+        gsp_falcon: &Falcon<GspEngine>,
+        sec2_falcon: &Falcon<Sec2>,
+    ) -> Result {
+        // Run FWSEC-SB to reset the GSP falcon to its pre-libos state.
+        self.fwsec_sb.run(dev, bar, gsp_falcon)?;
+
+        // Remove WPR2 region if set.
+        let wpr2_hi = bar.read(regs::NV_PFB_PRI_MMU_WPR2_ADDR_HI);
+        if wpr2_hi.is_wpr2_set() {
+            sec2_falcon.reset(bar)?;
+            sec2_falcon.load(dev, bar, &self.booter_unloader)?;
+
+            // Sentinel value to confirm that Booter Unloader has run.
+            const MAILBOX_SENTINEL: u32 = 0xff;
+            let (mbox0, _) =
+                sec2_falcon.boot(bar, Some(MAILBOX_SENTINEL), Some(MAILBOX_SENTINEL))?;
+            if mbox0 != 0 {
+                dev_err!(dev, "Booter Unloader returned error 0x{:x}\n", mbox0);
+                return Err(EINVAL);
+            }
+
+            // Confirm that the WPR2 region has been removed.
+            let wpr2_hi = bar.read(regs::NV_PFB_PRI_MMU_WPR2_ADDR_HI);
+            if wpr2_hi.is_wpr2_set() {
+                dev_err!(
+                    dev,
+                    "WPR2 region still set after Booter Unloader returned\n"
+                );
+                return Err(EBUSY);
+            }
+        }
+
+        Ok(())
+    }
+}
+
 /// Helper function to load and run the FWSEC-FRTS firmware and confirm that it has properly
 /// created the WPR2 region.
 fn run_fwsec_frts(
@@ -143,9 +264,24 @@ fn boot(
         wpr_meta: &Coherent<GspFwWprMeta>,
         gsp_falcon: &Falcon<GspEngine>,
         sec2_falcon: &Falcon<Sec2>,
-    ) -> Result {
+    ) -> Result<Option<crate::gsp::UnloadBundle>> {
         let bios = Vbios::new(dev, bar)?;
 
+        // Try and prepare the unload bundle. If this fails, the GPU will need to be reset
+        // before the driver can be probed again.
+        let unload_bundle =
+            Sec2UnloadBundle::build(dev, bar, chipset, &bios, gsp_falcon, sec2_falcon)
+                .inspect_err(|e| {
+                    dev_warn!(dev, "Failed to prepare unload firmware: {:?}\n", e);
+                    dev_warn!(dev, "The GSP won't be able to unload properly on unbind.\n");
+                    dev_warn!(
+                        dev,
+                        "The GPU will need to be reset before the driver can bind again.\n"
+                    );
+                })
+                .map(crate::gsp::UnloadBundle)
+                .ok();
+
         // FWSEC-FRTS is not executed on chips where the FRTS region size is 0 (e.g. GA100).
         if !fb_layout.frts.is_empty() {
             run_fwsec_frts(dev, chipset, gsp_falcon, bar, &bios, fb_layout)?;
@@ -175,7 +311,7 @@ fn boot(
         )?
         .run(dev, bar, sec2_falcon, wpr_meta)?;
 
-        Ok(())
+        Ok(unload_bundle)
     }
 
     fn post_boot(

drivers/gpu/nova-core/regs.rs

@@ -175,6 +175,11 @@ impl NV_PFB_PRI_MMU_WPR2_ADDR_HI {
     pub(crate) fn higher_bound(self) -> u64 {
         u64::from(self.hi_val()) << 12
     }
+
+    /// Returns whether the WPR2 region is currently set.
+    pub(crate) fn is_wpr2_set(self) -> bool {
+        self.hi_val() != 0
+    }
 }
 
 // PGSP