Kernel: Move all Graphics-related code into Devices/GPU directory

Like the HID, Audio and Storage subsystem, the Graphics subsystem (which
handles GPUs technically) exposes unix device files (typically in /dev).
To ensure consistency across the repository, move all related files to a
new directory under Kernel/Devices called "GPU".

Also remove the redundant "GPU" word from the VirtIO driver directory,
and the word "Graphics" from GraphicsManagement.{h,cpp} filenames.

Kernel/Devices/GPU/VirtIO/GPU3DDevice.h

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2021, Sahan Fernando <sahan.h.fernando@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/DistinctNumeric.h>
+#include <AK/IntrusiveList.h>
+#include <Kernel/Devices/CharacterDevice.h>
+#include <Kernel/Devices/DeviceManagement.h>
+#include <Kernel/Devices/GPU/VirtIO/Protocol.h>
+#include <Kernel/Locking/SpinlockProtected.h>
+
+namespace Kernel::Graphics::VirtIOGPU {
+
+enum class VirGLCommand : u32 {
+    NOP = 0,
+    CREATE_OBJECT = 1,
+    BIND_OBJECT,
+    DESTROY_OBJECT,
+    SET_VIEWPORT_STATE,
+    SET_FRAMEBUFFER_STATE,
+    SET_VERTEX_BUFFERS,
+    CLEAR,
+    DRAW_VBO,
+    RESOURCE_INLINE_WRITE,
+    SET_SAMPLER_VIEWS,
+    SET_INDEX_BUFFER,
+    SET_CONSTANT_BUFFER,
+    SET_STENCIL_REF,
+    SET_BLEND_COLOR,
+    SET_SCISSOR_STATE,
+    BLIT,
+    RESOURCE_COPY_REGION,
+    BIND_SAMPLER_STATES,
+    BEGIN_QUERY,
+    END_QUERY,
+    GET_QUERY_RESULT,
+    SET_POLYGON_STIPPLE,
+    SET_CLIP_STATE,
+    SET_SAMPLE_MASK,
+    SET_STREAMOUT_TARGETS,
+    SET_RENDER_CONDITION,
+    SET_UNIFORM_BUFFER,
+
+    SET_SUB_CTX,
+    CREATE_SUB_CTX,
+    DESTROY_SUB_CTX,
+    BIND_SHADER,
+    SET_TESS_STATE,
+    SET_MIN_SAMPLES,
+    SET_SHADER_BUFFERS,
+    SET_SHADER_IMAGES,
+    MEMORY_BARRIER,
+    LAUNCH_GRID,
+    SET_FRAMEBUFFER_STATE_NO_ATTACH,
+    TEXTURE_BARRIER,
+    SET_ATOMIC_BUFFERS,
+    SET_DBG_FLAGS,
+    GET_QUERY_RESULT_QBO,
+    TRANSFER3D,
+    END_TRANSFERS,
+    COPY_TRANSFER3D,
+    SET_TWEAKS,
+    CLEAR_TEXTURE,
+    PIPE_RESOURCE_CREATE,
+    PIPE_RESOURCE_SET_TYPE,
+    GET_MEMORY_INFO,
+    SEND_STRING_MARKER,
+    MAX_COMMANDS
+};
+
+union ClearType {
+    struct {
+        u32 depth : 1;
+        u32 stencil : 1;
+        u32 color0 : 1;
+        u32 color1 : 1;
+        u32 color2 : 1;
+        u32 color3 : 1;
+        u32 color4 : 1;
+        u32 color5 : 1;
+        u32 color6 : 1;
+        u32 color7 : 1;
+    } flags;
+    u32 value;
+};
+
+}
+
+namespace Kernel {
+
+class VirtIOGraphicsAdapter;
+class VirtIOGPU3DDevice : public CharacterDevice {
+    friend class DeviceManagement;
+
+public:
+    static ErrorOr<NonnullLockRefPtr<VirtIOGPU3DDevice>> try_create(VirtIOGraphicsAdapter&);
+
+private:
+    VirtIOGPU3DDevice(VirtIOGraphicsAdapter const& graphics_adapter, NonnullOwnPtr<Memory::Region> transfer_buffer_region, Graphics::VirtIOGPU::ContextID kernel_context_id);
+
+    class PerContextState final : public AtomicRefCounted<PerContextState> {
+        friend class VirtIOGPU3DDevice;
+
+    public:
+        static ErrorOr<NonnullRefPtr<PerContextState>> try_create(OpenFileDescription& description, Graphics::VirtIOGPU::ContextID context_id)
+        {
+            auto region_result = TRY(MM.allocate_kernel_region(
+                NUM_TRANSFER_REGION_PAGES * PAGE_SIZE,
+                "VIRGL3D userspace upload buffer"sv,
+                Memory::Region::Access::ReadWrite,
+                AllocationStrategy::AllocateNow));
+            return TRY(adopt_nonnull_ref_or_enomem(new (nothrow) PerContextState(description, context_id, move(region_result))));
+        }
+        Graphics::VirtIOGPU::ContextID context_id() { return m_context_id; }
+        Memory::Region& transfer_buffer_region() { return *m_transfer_buffer_region; }
+
+        OpenFileDescription& description() { return m_attached_file_description; }
+
+    private:
+        PerContextState() = delete;
+        PerContextState(OpenFileDescription&, Graphics::VirtIOGPU::ContextID context_id, OwnPtr<Memory::Region> transfer_buffer_region);
+        Graphics::VirtIOGPU::ContextID m_context_id;
+        OwnPtr<Memory::Region> m_transfer_buffer_region;
+
+        // NOTE: We clean this whole object when the file description is closed, therefore we need to hold
+        // a raw reference here instead of a strong reference pointer (e.g. RefPtr, which will make it
+        // possible to leak the attached OpenFileDescription for a context in this device).
+        OpenFileDescription& m_attached_file_description;
+
+        IntrusiveListNode<PerContextState, NonnullRefPtr<PerContextState>> m_list_node;
+    };
+
+    virtual bool can_read(OpenFileDescription const&, u64) const override { return true; }
+    virtual bool can_write(OpenFileDescription const&, u64) const override { return true; }
+    virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override { return ENOTSUP; }
+    virtual ErrorOr<size_t> write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t) override { return ENOTSUP; }
+    virtual StringView class_name() const override { return "virgl3d"sv; }
+
+    virtual ErrorOr<void> ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg) override;
+    virtual void detach(OpenFileDescription&) override;
+
+    using ContextList = IntrusiveListRelaxedConst<&PerContextState::m_list_node>;
+
+private:
+    NonnullLockRefPtr<VirtIOGraphicsAdapter> m_graphics_adapter;
+    // Context used for kernel operations (e.g. flushing resources to scanout)
+    Graphics::VirtIOGPU::ContextID m_kernel_context_id;
+    SpinlockProtected<ContextList, LockRank::None> m_context_state_list;
+    // Memory management for backing buffers
+    NonnullOwnPtr<Memory::Region> m_transfer_buffer_region;
+    constexpr static size_t NUM_TRANSFER_REGION_PAGES = 1024;
+};
+
+}