Add a GPUVM abstraction to be used by Rust GPU drivers. GPUVM keeps track of a GPU's virtual address (VA) space and manages the corresponding virtual mappings represented by "GPU VA" objects. It also keeps track of the gem::Object<T> used to back the mappings through GpuVmBo<T>. This abstraction is only usable by drivers that wish to use GPUVM in immediate mode. This allows us to build the locking scheme into the API design. It means that the GEM mutex is used for the GEM gpuva list, and that the resv lock is used for the extobj list. The evicted list is not yet used in this version. This abstraction provides a special handle called the UniqueRefGpuVm, which is a wrapper around ARef<GpuVm> that provides access to the interval tree. Generally, all changes to the address space requires mutable access to this unique handle. Signed-off-by: Asahi Lina <lina+kernel@asahilina.net> Co-developed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260409-gpuvm-rust-v6-1-b16e6ada7261@google.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>