Resguardo inicial

linux-7.2.3/rust/kernel/drm/gpuvm/mod.rs

@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+#![cfg(CONFIG_RUST_DRM_GPUVM)]
+
+//! DRM GPUVM in immediate mode
+//!
+//! Rust abstractions for using GPUVM in immediate mode. This is when the GPUVM state is updated
+//! during `run_job()`, i.e., in the DMA fence signalling critical path, to ensure that the GPUVM
+//! and the GPU's virtual address space has the same state at all times.
+//!
+//! C header: [`include/drm/drm_gpuvm.h`](srctree/include/drm/drm_gpuvm.h)
+
+use kernel::{
+    alloc::{
+        AllocError,
+        Flags as AllocFlags, //
+    },
+    bindings,
+    drm,
+    drm::gem::IntoGEMObject,
+    error::to_result,
+    prelude::*,
+    sync::aref::{
+        ARef,
+        AlwaysRefCounted, //
+    },
+    types::Opaque, //
+};
+
+use core::{
+    cell::UnsafeCell,
+    marker::PhantomData,
+    mem::{
+        ManuallyDrop,
+        MaybeUninit, //
+    },
+    ops::{
+        Deref,
+        DerefMut,
+        Range, //
+    },
+    ptr::{
+        self,
+        NonNull, //
+    }, //
+};
+
+mod sm_ops;
+pub use self::sm_ops::*;
+
+mod vm_bo;
+pub use self::vm_bo::*;
+
+mod va;
+pub use self::va::*;
+
+/// A DRM GPU VA manager.
+///
+/// This object is refcounted, but the locations of mapped ranges may only be accessed or changed
+/// via the special unique handle [`UniqueRefGpuVm`].
+///
+/// # Invariants
+///
+/// * Stored in an allocation managed by the refcount in `self.vm`.
+/// * Access to `data` and the gpuvm interval tree is controlled via the [`UniqueRefGpuVm`] type.
+/// * Does not contain any sparse [`GpuVa<T>`] instances.
+#[pin_data]
+pub struct GpuVm<T: DriverGpuVm> {
+    #[pin]
+    vm: Opaque<bindings::drm_gpuvm>,
+    /// Accessed only through the [`UniqueRefGpuVm`] reference.
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: The GPUVM api does not assume that it is tied to a specific thread. The destructor will
+// drop the `data` field, which is okay because it is guaranteed `Send` by the `DriverGpuVm` trait.
+unsafe impl<T: DriverGpuVm> Send for GpuVm<T> {}
+// SAFETY: The GPUVM api is designed to allow &self methods to be called in parallel.
+unsafe impl<T: DriverGpuVm> Sync for GpuVm<T> {}
+
+// SAFETY: By type invariants, the allocation is managed by the refcount in `self.vm`.
+unsafe impl<T: DriverGpuVm> AlwaysRefCounted for GpuVm<T> {
+    fn inc_ref(&self) {
+        // SAFETY: By type invariants, the allocation is managed by the refcount in `self.vm`.
+        unsafe { bindings::drm_gpuvm_get(self.vm.get()) };
+    }
+
+    unsafe fn dec_ref(obj: NonNull<Self>) {
+        // SAFETY: By type invariants, the allocation is managed by the refcount in `self.vm`.
+        unsafe { bindings::drm_gpuvm_put((*obj.as_ptr()).vm.get()) };
+    }
+}
+
+impl<T: DriverGpuVm> PartialEq for GpuVm<T> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        core::ptr::eq(self.as_raw(), other.as_raw())
+    }
+}
+impl<T: DriverGpuVm> Eq for GpuVm<T> {}
+
+impl<T: DriverGpuVm> GpuVm<T> {
+    const fn vtable() -> &'static bindings::drm_gpuvm_ops {
+        &bindings::drm_gpuvm_ops {
+            vm_free: Some(Self::vm_free),
+            op_alloc: None,
+            op_free: None,
+            vm_bo_alloc: GpuVmBo::<T>::ALLOC_FN,
+            vm_bo_free: GpuVmBo::<T>::FREE_FN,
+            vm_bo_validate: None,
+            sm_step_map: Some(Self::sm_step_map),
+            sm_step_unmap: Some(Self::sm_step_unmap),
+            sm_step_remap: Some(Self::sm_step_remap),
+        }
+    }
+
+    /// Creates a GPUVM instance.
+    #[expect(clippy::new_ret_no_self)]
+    pub fn new<E>(
+        name: &'static CStr,
+        dev: &drm::Device<T::Driver>,
+        r_obj: &T::Object,
+        range: Range<u64>,
+        reserve_range: Range<u64>,
+        data: T,
+    ) -> Result<UniqueRefGpuVm<T>, E>
+    where
+        E: From<AllocError>,
+        E: From<core::convert::Infallible>,
+    {
+        let obj = KBox::try_pin_init::<E>(
+            try_pin_init!(Self {
+                data: UnsafeCell::new(data),
+                vm <- Opaque::ffi_init(|vm| {
+                    // SAFETY: These arguments are valid. `vm` is valid until refcount drops to
+                    // zero. The `vm` is zeroed before calling this method by `__GFP_ZERO` flag
+                    // below.
+                    unsafe {
+                        bindings::drm_gpuvm_init(
+                            vm,
+                            name.as_char_ptr(),
+                            bindings::drm_gpuvm_flags_DRM_GPUVM_IMMEDIATE_MODE
+                                | bindings::drm_gpuvm_flags_DRM_GPUVM_RESV_PROTECTED,
+                            dev.as_raw(),
+                            r_obj.as_raw(),
+                            range.start,
+                            range.end - range.start,
+                            reserve_range.start,
+                            reserve_range.end - reserve_range.start,
+                            const { Self::vtable() },
+                        )
+                    }
+                }),
+            }? E),
+            GFP_KERNEL | __GFP_ZERO,
+        )?;
+        // SAFETY: This transfers the initial refcount to the ARef.
+        let aref = unsafe {
+            ARef::from_raw(NonNull::new_unchecked(KBox::into_raw(
+                Pin::into_inner_unchecked(obj),
+            )))
+        };
+        // INVARIANT: This reference is unique.
+        Ok(UniqueRefGpuVm(aref))
+    }
+
+    /// Access this [`GpuVm`] from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must reference the `struct drm_gpuvm` in a valid [`GpuVm<T>`] that remains
+    /// valid for at least `'a`.
+    #[inline]
+    pub unsafe fn from_raw<'a>(ptr: *mut bindings::drm_gpuvm) -> &'a Self {
+        // SAFETY: Caller passes a pointer to the `drm_gpuvm` in a `GpuVm<T>`. Caller ensures the
+        // pointer is valid for 'a.
+        unsafe { &*kernel::container_of!(Opaque::cast_from(ptr), Self, vm) }
+    }
+
+    /// Returns a raw pointer to the embedded `struct drm_gpuvm`.
+    #[inline]
+    pub fn as_raw(&self) -> *mut bindings::drm_gpuvm {
+        self.vm.get()
+    }
+
+    /// The start of the VA space.
+    #[inline]
+    pub fn va_start(&self) -> u64 {
+        // SAFETY: The `mm_start` field is immutable.
+        unsafe { (*self.as_raw()).mm_start }
+    }
+
+    /// The length of the GPU's virtual address space.
+    #[inline]
+    pub fn va_length(&self) -> u64 {
+        // SAFETY: The `mm_range` field is immutable.
+        unsafe { (*self.as_raw()).mm_range }
+    }
+
+    /// Returns the range of the GPU virtual address space.
+    #[inline]
+    pub fn va_range(&self) -> Range<u64> {
+        let start = self.va_start();
+        // OVERFLOW: This reconstructs the Range<u64> passed to the constructor, so it won't fail.
+        let end = start + self.va_length();
+        Range { start, end }
+    }
+
+    /// Get or create the [`GpuVmBo`] for this gem object.
+    #[inline]
+    pub fn obtain(
+        &self,
+        obj: &T::Object,
+        data: impl PinInit<T::VmBoData>,
+    ) -> Result<ARef<GpuVmBo<T>>, AllocError> {
+        Ok(GpuVmBoAlloc::new(self, obj, data)?.obtain())
+    }
+
+    /// Clean up buffer objects that are no longer used.
+    #[inline]
+    pub fn deferred_cleanup(&self) {
+        // SAFETY: This GPUVM uses immediate mode.
+        unsafe { bindings::drm_gpuvm_bo_deferred_cleanup(self.as_raw()) }
+    }
+
+    /// Check if this GEM object is an external object for this GPUVM.
+    #[inline]
+    pub fn is_extobj(&self, obj: &T::Object) -> bool {
+        // SAFETY: We may call this with any GPUVM and GEM object.
+        unsafe { bindings::drm_gpuvm_is_extobj(self.as_raw(), obj.as_raw()) }
+    }
+
+    /// Free this GPUVM.
+    ///
+    /// # Safety
+    ///
+    /// Called when refcount hits zero.
+    unsafe extern "C" fn vm_free(me: *mut bindings::drm_gpuvm) {
+        // SAFETY: Caller passes a pointer to the `drm_gpuvm` in a `GpuVm<T>`.
+        let me = unsafe { kernel::container_of!(Opaque::cast_from(me), Self, vm).cast_mut() };
+        // SAFETY: By type invariants we can free it when refcount hits zero.
+        drop(unsafe { KBox::from_raw(me) })
+    }
+
+    #[inline]
+    fn raw_resv(&self) -> *mut bindings::dma_resv {
+        // SAFETY: `r_obj` is immutable and valid for duration of GPUVM.
+        unsafe { (*(*self.as_raw()).r_obj).resv }
+    }
+}
+
+/// The manager for a GPUVM.
+pub trait DriverGpuVm: Sized + Send {
+    /// Parent `Driver` for this object.
+    type Driver: drm::Driver<Object = Self::Object>;
+
+    /// The kind of GEM object stored in this GPUVM.
+    type Object: IntoGEMObject;
+
+    /// Data stored with each [`struct drm_gpuva`](struct@GpuVa).
+    type VaData;
+
+    /// Data stored with each [`struct drm_gpuvm_bo`](struct@GpuVmBo).
+    type VmBoData;
+
+    /// The private data passed to callbacks.
+    type SmContext<'ctx>;
+
+    /// Indicates that a new mapping should be created.
+    fn sm_step_map<'op, 'ctx>(
+        &mut self,
+        op: OpMap<'op, Self>,
+        context: &mut Self::SmContext<'ctx>,
+    ) -> Result<OpMapped<'op, Self>, Error>;
+
+    /// Indicates that an existing mapping should be removed.
+    fn sm_step_unmap<'op, 'ctx>(
+        &mut self,
+        op: OpUnmap<'op, Self>,
+        context: &mut Self::SmContext<'ctx>,
+    ) -> Result<OpUnmapped<'op, Self>, Error>;
+
+    /// Indicates that an existing mapping should be split up.
+    fn sm_step_remap<'op, 'ctx>(
+        &mut self,
+        op: OpRemap<'op, Self>,
+        context: &mut Self::SmContext<'ctx>,
+    ) -> Result<OpRemapped<'op, Self>, Error>;
+}
+
+/// The core of the DRM GPU VA manager.
+///
+/// This object is a unique reference to the VM that can access the interval tree and the Rust
+/// `data` field.
+///
+/// # Invariants
+///
+/// Each `GpuVm` instance has at most one `UniqueRefGpuVm` reference.
+pub struct UniqueRefGpuVm<T: DriverGpuVm>(ARef<GpuVm<T>>);
+
+// SAFETY: The GPUVM api is designed to allow &self methods to be called in parallel, and
+// concurrent access to `data` is safe due to the `T: Sync` requirement.
+unsafe impl<T: DriverGpuVm + Sync> Sync for UniqueRefGpuVm<T> {}
+
+impl<T: DriverGpuVm> UniqueRefGpuVm<T> {
+    /// Access the data owned by this `UniqueRefGpuVm` immutably.
+    #[inline]
+    pub fn data_ref(&self) -> &T {
+        // SAFETY: By the type invariants we may access `data`.
+        unsafe { &*self.0.data.get() }
+    }
+
+    /// Access the data owned by this `UniqueRefGpuVm` mutably.
+    #[inline]
+    pub fn data(&mut self) -> &mut T {
+        // SAFETY: By the type invariants we may access `data`.
+        unsafe { &mut *self.0.data.get() }
+    }
+}
+
+impl<T: DriverGpuVm> Deref for UniqueRefGpuVm<T> {
+    type Target = GpuVm<T>;
+
+    #[inline]
+    fn deref(&self) -> &GpuVm<T> {
+        &self.0
+    }
+}

linux-7.2.3/rust/kernel/drm/gpuvm/sm_ops.rs

@@ -0,0 +1,429 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+use super::*;
+
+/// The actual data that gets threaded through the callbacks.
+struct SmData<'a, 'ctx, T: DriverGpuVm> {
+    gpuvm: &'a mut UniqueRefGpuVm<T>,
+    user_context: &'a mut T::SmContext<'ctx>,
+}
+
+/// Adds an extra field to `SmData` for `sm_map()` callbacks.
+///
+/// # Invariants
+///
+/// `self.vm_bo.gpuvm() == self.sm_data.gpuvm`.
+#[repr(C)]
+struct SmMapData<'a, 'ctx, T: DriverGpuVm> {
+    sm_data: SmData<'a, 'ctx, T>,
+    vm_bo: &'a GpuVmBo<T>,
+}
+
+/// The argument for [`UniqueRefGpuVm::sm_map`].
+pub struct OpMapRequest<'a, 'ctx, T: DriverGpuVm> {
+    /// Address in GPU virtual address space.
+    pub addr: u64,
+    /// Length of mapping to create.
+    pub range: u64,
+    /// Offset in GEM object.
+    pub gem_offset: u64,
+    /// The GEM object to map.
+    pub vm_bo: &'a GpuVmBo<T>,
+    /// The user-provided context type.
+    pub context: &'a mut T::SmContext<'ctx>,
+}
+
+impl<'a, 'ctx, T: DriverGpuVm> OpMapRequest<'a, 'ctx, T> {
+    fn raw_request(&self) -> bindings::drm_gpuvm_map_req {
+        bindings::drm_gpuvm_map_req {
+            map: bindings::drm_gpuva_op_map {
+                va: bindings::drm_gpuva_op_map__bindgen_ty_1 {
+                    addr: self.addr,
+                    range: self.range,
+                },
+                gem: bindings::drm_gpuva_op_map__bindgen_ty_2 {
+                    offset: self.gem_offset,
+                    obj: self.vm_bo.obj().as_raw(),
+                },
+            },
+        }
+    }
+}
+
+/// Represents an `sm_step_map` operation that has not yet been completed.
+pub struct OpMap<'op, T: DriverGpuVm> {
+    op: &'op bindings::drm_gpuva_op_map,
+    // Since these abstractions are designed for immediate mode, the VM BO needs to be
+    // pre-allocated, so we always have it available when we reach this point.
+    vm_bo: &'op GpuVmBo<T>,
+    // This ensures that 'op is invariant, so that `OpMap<'long, T>` does not
+    // coerce to `OpMap<'short, T>`. This ensures that the user can't return
+    // the wrong `OpMapped` value.
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+impl<'op, T: DriverGpuVm> OpMap<'op, T> {
+    /// The base address of the new mapping.
+    pub fn addr(&self) -> u64 {
+        self.op.va.addr
+    }
+
+    /// The length of the new mapping.
+    pub fn length(&self) -> u64 {
+        self.op.va.range
+    }
+
+    /// The offset within the [`drm_gem_object`](DriverGpuVm::Object).
+    pub fn gem_offset(&self) -> u64 {
+        self.op.gem.offset
+    }
+
+    /// The [`drm_gem_object`](DriverGpuVm::Object) to map.
+    pub fn obj(&self) -> &T::Object {
+        // SAFETY: The `obj` pointer is guaranteed to be valid.
+        unsafe { <T::Object as IntoGEMObject>::from_raw(self.op.gem.obj) }
+    }
+
+    /// The [`GpuVmBo`] that the new VA will be associated with.
+    pub fn vm_bo(&self) -> &GpuVmBo<T> {
+        self.vm_bo
+    }
+
+    /// Use the pre-allocated VA to carry out this map operation.
+    pub fn insert(self, va: GpuVaAlloc<T>, va_data: impl PinInit<T::VaData>) -> OpMapped<'op, T> {
+        let va = va.prepare(va_data);
+        // SAFETY: By the type invariants we may access the interval tree.
+        unsafe { bindings::drm_gpuva_map(self.vm_bo.gpuvm().as_raw(), va, self.op) };
+
+        let _gpuva_guard = self.vm_bo().lock_gpuva();
+        // SAFETY: The va is prepared for insertion, and we hold the GEM lock.
+        unsafe { bindings::drm_gpuva_link(va, self.vm_bo.as_raw()) };
+
+        OpMapped {
+            _invariant: self._invariant,
+        }
+    }
+}
+
+/// Represents a completed [`OpMap`] operation.
+pub struct OpMapped<'op, T> {
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+/// Represents an `sm_step_unmap` operation that has not yet been completed.
+pub struct OpUnmap<'op, T: DriverGpuVm> {
+    op: &'op bindings::drm_gpuva_op_unmap,
+    // This ensures that 'op is invariant, so that `OpUnmap<'long, T>` does not
+    // coerce to `OpUnmap<'short, T>`. This ensures that the user can't return the
+    // wrong`OpUnmapped` value.
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+impl<'op, T: DriverGpuVm> OpUnmap<'op, T> {
+    /// Indicates whether this [`GpuVa`] is physically contiguous with the
+    /// original mapping request.
+    ///
+    /// Optionally, if `keep` is set, drivers may keep the actual page table
+    /// mappings for this `drm_gpuva`, adding the missing page table entries
+    /// only and update the `drm_gpuvm` accordingly.
+    pub fn keep(&self) -> bool {
+        self.op.keep
+    }
+
+    /// The range being unmapped.
+    pub fn va(&self) -> &GpuVa<T> {
+        // SAFETY: This is a valid va. It's not the `kernel_alloc_node` because you can't unmap it,
+        // and it's not sparse by the `GpuVm<T>` type invariants.
+        unsafe { GpuVa::<T>::from_raw(self.op.va) }
+    }
+
+    /// Remove the VA.
+    pub fn remove(self) -> (OpUnmapped<'op, T>, GpuVaRemoved<T>) {
+        // SAFETY: The op references a valid drm_gpuva in the GPUVM.
+        unsafe { bindings::drm_gpuva_unmap(self.op) };
+        // SAFETY: The va is no longer in the interval tree so we may unlink it.
+        unsafe { bindings::drm_gpuva_unlink_defer(self.op.va) };
+
+        // SAFETY: We just removed this va from the `GpuVm<T>`.
+        let va = unsafe { GpuVaRemoved::from_raw(self.op.va) };
+
+        (
+            OpUnmapped {
+                _invariant: self._invariant,
+            },
+            va,
+        )
+    }
+}
+
+/// Represents a completed [`OpUnmap`] operation.
+pub struct OpUnmapped<'op, T> {
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+/// Represents an `sm_step_remap` operation that has not yet been completed.
+pub struct OpRemap<'op, T: DriverGpuVm> {
+    op: &'op bindings::drm_gpuva_op_remap,
+    // This ensures that 'op is invariant, so that `OpRemap<'long, T>` does not
+    // coerce to `OpRemap<'short, T>`. This ensures that the user can't return the
+    // wrong`OpRemapped` value.
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+impl<'op, T: DriverGpuVm> OpRemap<'op, T> {
+    /// The preceding part of a split mapping.
+    #[inline]
+    pub fn prev(&self) -> Option<&OpRemapMapData> {
+        // SAFETY: We checked for null, so the pointer must be valid.
+        NonNull::new(self.op.prev).map(|ptr| unsafe { OpRemapMapData::from_raw(ptr) })
+    }
+
+    /// The subsequent part of a split mapping.
+    #[inline]
+    pub fn next(&self) -> Option<&OpRemapMapData> {
+        // SAFETY: We checked for null, so the pointer must be valid.
+        NonNull::new(self.op.next).map(|ptr| unsafe { OpRemapMapData::from_raw(ptr) })
+    }
+
+    /// Indicates whether the `drm_gpuva` being removed is physically contiguous with the original
+    /// mapping request.
+    ///
+    /// Optionally, if `keep` is set, drivers may keep the actual page table mappings for this
+    /// `drm_gpuva`, adding the missing page table entries only and update the `drm_gpuvm`
+    /// accordingly.
+    #[inline]
+    pub fn keep(&self) -> bool {
+        // SAFETY: The unmap pointer is always valid.
+        unsafe { (*self.op.unmap).keep }
+    }
+
+    /// The range being unmapped.
+    #[inline]
+    pub fn va_to_unmap(&self) -> &GpuVa<T> {
+        // SAFETY: This is a valid va. It's not the `kernel_alloc_node` because you can't unmap it,
+        // and it's not sparse by the `GpuVm<T>` type invariants.
+        unsafe { GpuVa::<T>::from_raw((*self.op.unmap).va) }
+    }
+
+    /// The [`drm_gem_object`](DriverGpuVm::Object) whose VA is being remapped.
+    #[inline]
+    pub fn obj(&self) -> &T::Object {
+        self.va_to_unmap().obj()
+    }
+
+    /// The [`GpuVmBo`] that is being remapped.
+    #[inline]
+    pub fn vm_bo(&self) -> &GpuVmBo<T> {
+        self.va_to_unmap().vm_bo()
+    }
+
+    /// Update the GPUVM to perform the remapping.
+    pub fn remap(
+        self,
+        va_alloc: [GpuVaAlloc<T>; 2],
+        prev_data: impl PinInit<T::VaData>,
+        next_data: impl PinInit<T::VaData>,
+    ) -> (OpRemapped<'op, T>, OpRemapRet<T>) {
+        let [va1, va2] = va_alloc;
+
+        let mut unused_va = None;
+        let mut prev_ptr = ptr::null_mut();
+        let mut next_ptr = ptr::null_mut();
+        if self.prev().is_some() {
+            prev_ptr = va1.prepare(prev_data);
+        } else {
+            unused_va = Some(va1);
+        }
+        if self.next().is_some() {
+            next_ptr = va2.prepare(next_data);
+        } else {
+            unused_va = Some(va2);
+        }
+
+        // SAFETY: the pointers are non-null when required
+        unsafe { bindings::drm_gpuva_remap(prev_ptr, next_ptr, self.op) };
+
+        let gpuva_guard = self.vm_bo().lock_gpuva();
+        if !prev_ptr.is_null() {
+            // SAFETY: The prev_ptr is a valid drm_gpuva prepared for insertion. The vm_bo is still
+            // valid as the not-yet-unlinked gpuva holds a refcount on the vm_bo.
+            unsafe { bindings::drm_gpuva_link(prev_ptr, self.vm_bo().as_raw()) };
+        }
+        if !next_ptr.is_null() {
+            // SAFETY: The next_ptr is a valid drm_gpuva prepared for insertion. The vm_bo is still
+            // valid as the not-yet-unlinked gpuva holds a refcount on the vm_bo.
+            unsafe { bindings::drm_gpuva_link(next_ptr, self.vm_bo().as_raw()) };
+        }
+        drop(gpuva_guard);
+
+        // SAFETY: The va is no longer in the interval tree so we may unlink it.
+        unsafe { bindings::drm_gpuva_unlink_defer((*self.op.unmap).va) };
+
+        (
+            OpRemapped {
+                _invariant: self._invariant,
+            },
+            OpRemapRet {
+                // SAFETY: We just removed this va from the `GpuVm<T>`.
+                unmapped_va: unsafe { GpuVaRemoved::from_raw((*self.op.unmap).va) },
+                unused_va,
+            },
+        )
+    }
+}
+
+/// Part of an [`OpRemap`] that represents a new mapping.
+#[repr(transparent)]
+pub struct OpRemapMapData(bindings::drm_gpuva_op_map);
+
+impl OpRemapMapData {
+    /// # Safety
+    /// Must reference a valid `drm_gpuva_op_map` for duration of `'a`.
+    unsafe fn from_raw<'a>(ptr: NonNull<bindings::drm_gpuva_op_map>) -> &'a Self {
+        // SAFETY: ok per safety requirements
+        unsafe { ptr.cast().as_ref() }
+    }
+
+    /// The base address of the new mapping.
+    pub fn addr(&self) -> u64 {
+        self.0.va.addr
+    }
+
+    /// The length of the new mapping.
+    pub fn length(&self) -> u64 {
+        self.0.va.range
+    }
+
+    /// The offset within the [`drm_gem_object`](DriverGpuVm::Object).
+    pub fn gem_offset(&self) -> u64 {
+        self.0.gem.offset
+    }
+}
+
+/// Struct containing objects removed or not used by [`OpRemap::remap`].
+pub struct OpRemapRet<T: DriverGpuVm> {
+    /// The `drm_gpuva` that was removed.
+    pub unmapped_va: GpuVaRemoved<T>,
+    /// If the remap did not split the region into two pieces, then the unused `drm_gpuva` is
+    /// returned here.
+    pub unused_va: Option<GpuVaAlloc<T>>,
+}
+
+/// Represents a completed [`OpRemap`] operation.
+pub struct OpRemapped<'op, T> {
+    _invariant: PhantomData<*mut &'op mut T>,
+}
+
+impl<T: DriverGpuVm> UniqueRefGpuVm<T> {
+    /// Create a mapping, removing or remapping anything that overlaps.
+    ///
+    /// Internally calls the [`DriverGpuVm`] callbacks similar to [`Self::sm_unmap`], except that
+    /// the [`DriverGpuVm::sm_step_map`] is called once to create the requested mapping.
+    #[inline]
+    pub fn sm_map(&mut self, req: OpMapRequest<'_, '_, T>) -> Result {
+        if req.vm_bo.gpuvm() != &**self {
+            return Err(EINVAL);
+        }
+
+        let gpuvm = self.as_raw();
+        let raw_req = req.raw_request();
+        // INVARIANT: Checked above that `vm_bo.gpuvm() == self`.
+        let mut p = SmMapData {
+            sm_data: SmData {
+                gpuvm: self,
+                user_context: req.context,
+            },
+            vm_bo: req.vm_bo,
+        };
+        // SAFETY:
+        // * raw_request() creates a valid request.
+        // * The private data is valid to be interpreted as both SmData and SmMapData since the
+        //   first field of SmMapData is SmData.
+        to_result(unsafe {
+            bindings::drm_gpuvm_sm_map(gpuvm, (&raw mut p).cast(), &raw const raw_req)
+        })
+    }
+
+    /// Remove any mappings in the given region.
+    ///
+    /// Internally calls [`DriverGpuVm::sm_step_unmap`] for ranges entirely contained within the
+    /// given range, and [`DriverGpuVm::sm_step_remap`] for ranges that overlap with the range.
+    #[inline]
+    pub fn sm_unmap(&mut self, addr: u64, length: u64, context: &mut T::SmContext<'_>) -> Result {
+        let gpuvm = self.as_raw();
+        let mut p = SmData {
+            gpuvm: self,
+            user_context: context,
+        };
+        // SAFETY:
+        // * raw_request() creates a valid request.
+        // * The private data is a valid SmData.
+        to_result(unsafe { bindings::drm_gpuvm_sm_unmap(gpuvm, (&raw mut p).cast(), addr, length) })
+    }
+}
+
+impl<T: DriverGpuVm> GpuVm<T> {
+    /// # Safety
+    /// Must be called from `sm_map` with a pointer to `SmMapData`.
+    pub(super) unsafe extern "C" fn sm_step_map(
+        op: *mut bindings::drm_gpuva_op,
+        p: *mut c_void,
+    ) -> c_int {
+        // SAFETY: If we reach `sm_step_map` then we were called from `sm_map` which always passes
+        // an `SmMapData` as private data.
+        let p = unsafe { &mut *p.cast::<SmMapData<'_, '_, T>>() };
+        let op = OpMap {
+            // SAFETY: sm_step_map is called with a map operation.
+            op: unsafe { &(*op).__bindgen_anon_1.map },
+            vm_bo: p.vm_bo,
+            _invariant: PhantomData,
+        };
+        match p
+            .sm_data
+            .gpuvm
+            .data()
+            .sm_step_map(op, p.sm_data.user_context)
+        {
+            Ok(OpMapped { .. }) => 0,
+            Err(err) => err.to_errno(),
+        }
+    }
+
+    /// # Safety
+    /// Must be called from `sm_map` or `sm_unmap` with a pointer to `SmMapData` or `SmData`.
+    pub(super) unsafe extern "C" fn sm_step_unmap(
+        op: *mut bindings::drm_gpuva_op,
+        p: *mut c_void,
+    ) -> c_int {
+        // SAFETY: The caller provides a pointer that can be treated as `SmData`.
+        let p = unsafe { &mut *p.cast::<SmData<'_, '_, T>>() };
+        let op = OpUnmap {
+            // SAFETY: sm_step_unmap is called with an unmap operation.
+            op: unsafe { &(*op).__bindgen_anon_1.unmap },
+            _invariant: PhantomData,
+        };
+        match p.gpuvm.data().sm_step_unmap(op, p.user_context) {
+            Ok(OpUnmapped { .. }) => 0,
+            Err(err) => err.to_errno(),
+        }
+    }
+
+    /// # Safety
+    /// Must be called from `sm_map` or `sm_unmap` with a pointer to `SmMapData` or `SmData`.
+    pub(super) unsafe extern "C" fn sm_step_remap(
+        op: *mut bindings::drm_gpuva_op,
+        p: *mut c_void,
+    ) -> c_int {
+        // SAFETY: The caller provides a pointer that can be treated as `SmData`.
+        let p = unsafe { &mut *p.cast::<SmData<'_, '_, T>>() };
+        let op = OpRemap {
+            // SAFETY: sm_step_remap is called with a remap operation.
+            op: unsafe { &(*op).__bindgen_anon_1.remap },
+            _invariant: PhantomData,
+        };
+        match p.gpuvm.data().sm_step_remap(op, p.user_context) {
+            Ok(OpRemapped { .. }) => 0,
+            Err(err) => err.to_errno(),
+        }
+    }
+}

linux-7.2.3/rust/kernel/drm/gpuvm/va.rs

@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+use super::*;
+
+/// Represents that a range of a GEM object is mapped in this [`GpuVm`] instance.
+///
+/// Does not assume that GEM lock is held.
+///
+/// # Invariants
+///
+/// * This is a valid `drm_gpuva` object that is resident in a [`GpuVm<T>`] instance.
+/// * It is associated with a [`GpuVmBo<T>`]. Or in other words, it's not an
+///   `gpuvm->kernel_alloc_node` and `DRM_GPUVA_SPARSE` is not set.
+/// * The associated [`GpuVmBo<T>`] is part of the GEM list.
+#[repr(C)]
+#[pin_data]
+pub struct GpuVa<T: DriverGpuVm> {
+    #[pin]
+    inner: Opaque<bindings::drm_gpuva>,
+    #[pin]
+    data: T::VaData,
+}
+
+impl<T: DriverGpuVm> PartialEq for GpuVa<T> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        core::ptr::eq(self.as_raw(), other.as_raw())
+    }
+}
+impl<T: DriverGpuVm> Eq for GpuVa<T> {}
+
+impl<T: DriverGpuVm> GpuVa<T> {
+    /// Access this [`GpuVa`] from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// * For the duration of `'a`, the pointer must reference a valid `drm_gpuva` associated with
+    ///   a [`GpuVm<T>`].
+    /// * It must be associated with a [`GpuVmBo<T>`].
+    /// * The associated [`GpuVmBo<T>`] is part of the GEM list.
+    #[inline]
+    pub unsafe fn from_raw<'a>(ptr: *mut bindings::drm_gpuva) -> &'a Self {
+        // CAST: `drm_gpuva` is first field and `repr(C)`.
+        // SAFETY: The safety requirements match the invariants of `GpuVa`.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Returns a raw pointer to underlying C value.
+    #[inline]
+    pub fn as_raw(&self) -> *mut bindings::drm_gpuva {
+        self.inner.get()
+    }
+
+    /// Returns the address of this mapping in the GPU virtual address space.
+    #[inline]
+    pub fn addr(&self) -> u64 {
+        // SAFETY: The `va.addr` field of `drm_gpuva` is immutable.
+        unsafe { (*self.as_raw()).va.addr }
+    }
+
+    /// Returns the length of this mapping.
+    #[inline]
+    pub fn length(&self) -> u64 {
+        // SAFETY: The `va.range` field of `drm_gpuva` is immutable.
+        unsafe { (*self.as_raw()).va.range }
+    }
+
+    /// Returns `addr..addr+length`.
+    #[inline]
+    pub fn range(&self) -> Range<u64> {
+        let addr = self.addr();
+        addr..addr + self.length()
+    }
+
+    /// Returns the offset within the GEM object.
+    #[inline]
+    pub fn gem_offset(&self) -> u64 {
+        // SAFETY: The `gem.offset` field of `drm_gpuva` is immutable.
+        unsafe { (*self.as_raw()).gem.offset }
+    }
+
+    /// Returns the GEM object.
+    #[inline]
+    pub fn obj(&self) -> &T::Object {
+        // SAFETY: The `gem.obj` field of `drm_gpuva` is immutable. We know that it's not null
+        // because this VA is associated with a `GpuVmBo<T>`.
+        unsafe { <T::Object as IntoGEMObject>::from_raw((*self.as_raw()).gem.obj) }
+    }
+
+    /// Returns the underlying [`GpuVmBo`] object that backs this [`GpuVa`].
+    #[inline]
+    pub fn vm_bo(&self) -> &GpuVmBo<T> {
+        // SAFETY: The `vm_bo` field of `drm_gpuva` is immutable. We know that it's not null
+        // because this VA is associated with a `GpuVmBo<T>`. The BO is in the GEM list by the type
+        // invariants.
+        unsafe { GpuVmBo::from_raw((*self.as_raw()).vm_bo) }
+    }
+}
+
+/// A pre-allocated [`GpuVa`] object.
+///
+/// # Invariants
+///
+/// The memory is zeroed.
+pub struct GpuVaAlloc<T: DriverGpuVm>(KBox<MaybeUninit<GpuVa<T>>>);
+
+impl<T: DriverGpuVm> GpuVaAlloc<T> {
+    /// Pre-allocate a [`GpuVa`] object.
+    pub fn new(flags: AllocFlags) -> Result<GpuVaAlloc<T>, AllocError> {
+        // INVARIANTS: Memory allocated with __GFP_ZERO.
+        Ok(GpuVaAlloc(KBox::new_uninit(flags | __GFP_ZERO)?))
+    }
+
+    /// Prepare this `drm_gpuva` for insertion into the GPUVM.
+    #[must_use]
+    pub(super) fn prepare(mut self, va_data: impl PinInit<T::VaData>) -> *mut bindings::drm_gpuva {
+        let va_ptr = MaybeUninit::as_mut_ptr(&mut self.0);
+        // SAFETY: The `data` field is pinned.
+        let Ok(()) = unsafe { va_data.__pinned_init(&raw mut (*va_ptr).data) };
+        KBox::into_raw(self.0).cast()
+    }
+}
+
+/// A [`GpuVa`] object that has been removed.
+///
+/// # Invariants
+///
+/// The `drm_gpuva` is not resident in the [`GpuVm`].
+pub struct GpuVaRemoved<T: DriverGpuVm>(KBox<GpuVa<T>>);
+
+impl<T: DriverGpuVm> GpuVaRemoved<T> {
+    /// Convert a raw pointer into a [`GpuVaRemoved`].
+    ///
+    /// # Safety
+    ///
+    /// * Must have been removed from a [`GpuVm<T>`].
+    /// * It must not be a `gpuvm->kernel_alloc_node` va.
+    pub(super) unsafe fn from_raw(ptr: *mut bindings::drm_gpuva) -> Self {
+        // SAFETY: Since it used to be a VA in a `GpuVm<T>` and it's not a kernel_alloc_node, this
+        // pointer references a `GpuVa<T>` with a valid `T::VaData`. Since it has been removed, we
+        // can take ownership of the allocation.
+        GpuVaRemoved(unsafe { KBox::from_raw(ptr.cast()) })
+    }
+
+    /// Take ownership of the VA data.
+    pub fn into_inner(self) -> T::VaData
+    where
+        T::VaData: Unpin,
+    {
+        KBox::into_inner(self.0).data
+    }
+}
+
+impl<T: DriverGpuVm> Deref for GpuVaRemoved<T> {
+    type Target = T::VaData;
+    fn deref(&self) -> &T::VaData {
+        &self.0.data
+    }
+}
+
+impl<T: DriverGpuVm> DerefMut for GpuVaRemoved<T>
+where
+    T::VaData: Unpin,
+{
+    fn deref_mut(&mut self) -> &mut T::VaData {
+        &mut self.0.data
+    }
+}

linux-7.2.3/rust/kernel/drm/gpuvm/vm_bo.rs

@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+use super::*;
+
+/// Represents that a given GEM object has at least one mapping on this [`GpuVm`] instance.
+///
+/// Does not assume that GEM lock is held.
+///
+/// # Invariants
+///
+/// * Allocated with `kmalloc` and refcounted via `inner`.
+/// * Is present in the gem list.
+#[repr(C)]
+#[pin_data]
+pub struct GpuVmBo<T: DriverGpuVm> {
+    #[pin]
+    inner: Opaque<bindings::drm_gpuvm_bo>,
+    #[pin]
+    data: T::VmBoData,
+}
+
+// SAFETY: By type invariants, the allocation is managed by the refcount in `self.inner`.
+unsafe impl<T: DriverGpuVm> AlwaysRefCounted for GpuVmBo<T> {
+    fn inc_ref(&self) {
+        // SAFETY: By type invariants, the allocation is managed by the refcount in `self.inner`.
+        unsafe { bindings::drm_gpuvm_bo_get(self.inner.get()) };
+    }
+
+    unsafe fn dec_ref(obj: NonNull<Self>) {
+        // CAST: `drm_gpuvm_bo` is first field of repr(C) struct.
+        // SAFETY: By type invariants, the allocation is managed by the refcount in `self.inner`.
+        // This GPUVM instance uses immediate mode, so we may put the refcount using the deferred
+        // mechanism.
+        unsafe { bindings::drm_gpuvm_bo_put_deferred(obj.as_ptr().cast()) };
+    }
+}
+
+impl<T: DriverGpuVm> PartialEq for GpuVmBo<T> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        core::ptr::eq(self.as_raw(), other.as_raw())
+    }
+}
+impl<T: DriverGpuVm> Eq for GpuVmBo<T> {}
+
+impl<T: DriverGpuVm> GpuVmBo<T> {
+    /// The function pointer for allocating a GpuVmBo stored in the gpuvm vtable.
+    ///
+    /// Allocation is always implemented according to [`Self::vm_bo_alloc`], but it is set to
+    /// `None` if the default gpuvm behavior is the same as `vm_bo_alloc`.
+    ///
+    /// This may be `Some` even if `FREE_FN` is `None`, or vice-versa.
+    pub(super) const ALLOC_FN: Option<unsafe extern "C" fn() -> *mut bindings::drm_gpuvm_bo> = {
+        use core::alloc::Layout;
+        let base = Layout::new::<bindings::drm_gpuvm_bo>();
+        let rust = Layout::new::<Self>();
+        assert!(base.size() <= rust.size());
+        if base.size() != rust.size() || base.align() != rust.align() {
+            Some(Self::vm_bo_alloc)
+        } else {
+            // This causes GPUVM to allocate a `GpuVmBo<T>` with `kzalloc(sizeof(drm_gpuvm_bo))`.
+            None
+        }
+    };
+
+    /// The function pointer for freeing a GpuVmBo stored in the gpuvm vtable.
+    ///
+    /// Freeing is always implemented according to [`Self::vm_bo_free`], but it is set to `None` if
+    /// the default gpuvm behavior is the same as `vm_bo_free`.
+    ///
+    /// This may be `Some` even if `ALLOC_FN` is `None`, or vice-versa.
+    pub(super) const FREE_FN: Option<unsafe extern "C" fn(*mut bindings::drm_gpuvm_bo)> = {
+        if core::mem::needs_drop::<Self>() {
+            Some(Self::vm_bo_free)
+        } else {
+            // This causes GPUVM to free a `GpuVmBo<T>` with `kfree`.
+            None
+        }
+    };
+
+    /// Custom function for allocating a `drm_gpuvm_bo`.
+    ///
+    /// # Safety
+    ///
+    /// Always safe to call.
+    unsafe extern "C" fn vm_bo_alloc() -> *mut bindings::drm_gpuvm_bo {
+        let raw_ptr = KBox::<Self>::new_uninit(GFP_KERNEL | __GFP_ZERO)
+            .map(KBox::into_raw)
+            .unwrap_or(ptr::null_mut());
+
+        // CAST: `drm_gpuvm_bo` is first field of `Self`.
+        raw_ptr.cast()
+    }
+
+    /// Custom function for freeing a `drm_gpuvm_bo`.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must have been allocated with [`GpuVmBo::ALLOC_FN`], and must not be used after
+    /// this call.
+    unsafe extern "C" fn vm_bo_free(ptr: *mut bindings::drm_gpuvm_bo) {
+        // CAST: `drm_gpuvm_bo` is first field of `Self`.
+        // SAFETY:
+        // * The ptr was allocated from kmalloc with the layout of `GpuVmBo<T>`.
+        // * `ptr->inner` has no destructor.
+        // * `ptr->data` contains a valid `T::VmBoData` that we can drop.
+        drop(unsafe { KBox::<Self>::from_raw(ptr.cast()) });
+    }
+
+    /// Access this [`GpuVmBo`] from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// For the duration of `'a`, the pointer must reference a valid `drm_gpuvm_bo` associated with
+    /// a [`GpuVm<T>`]. The BO must also be present in the GEM list.
+    #[inline]
+    pub(crate) unsafe fn from_raw<'a>(ptr: *mut bindings::drm_gpuvm_bo) -> &'a Self {
+        // SAFETY: `drm_gpuvm_bo` is first field and `repr(C)`.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Returns a raw pointer to underlying C value.
+    #[inline]
+    pub fn as_raw(&self) -> *mut bindings::drm_gpuvm_bo {
+        self.inner.get()
+    }
+
+    /// The [`GpuVm`] that this GEM object is mapped in.
+    #[inline]
+    pub fn gpuvm(&self) -> &GpuVm<T> {
+        // SAFETY: The `obj` pointer is guaranteed to be valid.
+        unsafe { GpuVm::<T>::from_raw((*self.inner.get()).vm) }
+    }
+
+    /// The [`drm_gem_object`](DriverGpuVm::Object) for these mappings.
+    #[inline]
+    pub fn obj(&self) -> &T::Object {
+        // SAFETY: The `obj` pointer is guaranteed to be valid.
+        unsafe { <T::Object as IntoGEMObject>::from_raw((*self.inner.get()).obj) }
+    }
+
+    /// The driver data with this buffer object.
+    #[inline]
+    pub fn data(&self) -> &T::VmBoData {
+        &self.data
+    }
+
+    pub(super) fn lock_gpuva(&self) -> crate::sync::MutexGuard<'_, ()> {
+        // SAFETY: The GEM object is valid.
+        let ptr = unsafe { &raw mut (*self.obj().as_raw()).gpuva.lock };
+        // SAFETY: The GEM object is valid, so the mutex is properly initialized.
+        let mutex = unsafe { crate::sync::Mutex::from_raw(ptr) };
+        mutex.lock()
+    }
+}
+
+/// A pre-allocated [`GpuVmBo`] object.
+///
+/// # Invariants
+///
+/// Points at a `drm_gpuvm_bo` that contains a valid `T::VmBoData`, has a refcount of one, and is
+/// absent from any gem, extobj, or evict lists.
+pub(super) struct GpuVmBoAlloc<T: DriverGpuVm>(NonNull<GpuVmBo<T>>);
+
+impl<T: DriverGpuVm> GpuVmBoAlloc<T> {
+    /// Create a new pre-allocated [`GpuVmBo`].
+    ///
+    /// It's intentional that the initializer is infallible because `drm_gpuvm_bo_put` will call
+    /// drop on the data, so we don't have a way to free it when the data is missing.
+    #[inline]
+    pub(super) fn new(
+        gpuvm: &GpuVm<T>,
+        gem: &T::Object,
+        value: impl PinInit<T::VmBoData>,
+    ) -> Result<GpuVmBoAlloc<T>, AllocError> {
+        // CAST: `GpuVmBoAlloc::vm_bo_alloc` ensures that this memory was allocated with the layout
+        // of `GpuVmBo<T>`. The type is repr(C), so `container_of` is not required.
+        // SAFETY: The provided gpuvm and gem ptrs are valid for the duration of this call.
+        let raw_ptr = unsafe {
+            bindings::drm_gpuvm_bo_create(gpuvm.as_raw(), gem.as_raw()).cast::<GpuVmBo<T>>()
+        };
+        let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+        // SAFETY: `ptr->data` is a valid pinned location.
+        let Ok(()) = unsafe { value.__pinned_init(&raw mut (*raw_ptr).data) };
+        // INVARIANTS: We just created the vm_bo so it's absent from lists, and the data is valid
+        // as we just initialized it.
+        Ok(GpuVmBoAlloc(ptr))
+    }
+
+    /// Returns a raw pointer to underlying C value.
+    #[inline]
+    pub(super) fn as_raw(&self) -> *mut bindings::drm_gpuvm_bo {
+        // SAFETY: The pointer references a valid `drm_gpuvm_bo`.
+        unsafe { (*self.0.as_ptr()).inner.get() }
+    }
+
+    /// Look up whether there is an existing [`GpuVmBo`] for this gem object.
+    ///
+    /// The caller should not hold the GEM mutex or DMA resv lock.
+    #[inline]
+    pub(super) fn obtain(self) -> ARef<GpuVmBo<T>> {
+        let me = ManuallyDrop::new(self);
+        // SAFETY: Valid `drm_gpuvm_bo` not already in the lists. We do not access `me` after this
+        // call.
+        let ptr = unsafe { bindings::drm_gpuvm_bo_obtain_prealloc(me.as_raw()) };
+
+        // SAFETY: `drm_gpuvm_bo_obtain_prealloc` always returns a non-null ptr
+        let nonnull = unsafe { NonNull::new_unchecked(ptr.cast()) };
+
+        // INVARIANTS: `drm_gpuvm_bo_obtain_prealloc` ensures that the bo is in the GEM list.
+        // SAFETY: We received one refcount from `drm_gpuvm_bo_obtain_prealloc`.
+        let ret = unsafe { ARef::<GpuVmBo<T>>::from_raw(nonnull) };
+
+        // Ensure that external objects are in the extobj list.
+        //
+        // Note that we must call `extobj_add` even if `ptr != me` to avoid a race condition where
+        // we could end up using the extobj before the thread with `ptr == me` calls extobj_add.
+        if ret.gpuvm().is_extobj(ret.obj()) {
+            let resv_lock = ret.gpuvm().raw_resv();
+            // TODO: Use a proper lock guard here once a dma_resv lock abstraction exists.
+            // SAFETY: The GPUVM is still alive, so its resv lock is too.
+            unsafe { bindings::dma_resv_lock(resv_lock, ptr::null_mut()) };
+            // SAFETY: We hold the GPUVMs resv lock.
+            unsafe { bindings::drm_gpuvm_bo_extobj_add(ptr) };
+            // SAFETY: We took the lock, so we can unlock it.
+            unsafe { bindings::dma_resv_unlock(resv_lock) };
+        }
+
+        ret
+    }
+}
+
+impl<T: DriverGpuVm> Deref for GpuVmBoAlloc<T> {
+    type Target = GpuVmBo<T>;
+    #[inline]
+    fn deref(&self) -> &GpuVmBo<T> {
+        // SAFETY: By the type invariants we may deref while `Self` exists.
+        unsafe { self.0.as_ref() }
+    }
+}
+
+impl<T: DriverGpuVm> Drop for GpuVmBoAlloc<T> {
+    #[inline]
+    fn drop(&mut self) {
+        // TODO: Call drm_gpuvm_bo_destroy_not_in_lists() directly.
+        // SAFETY: It's safe to perform a deferred put in any context.
+        unsafe { bindings::drm_gpuvm_bo_put_deferred(self.as_raw()) };
+    }
+}