1 files changed, 94 insertions, 0 deletions
diff --git a/Kernel/Memory/SharedFramebufferVMObject.h b/Kernel/Memory/SharedFramebufferVMObject.h
new file mode 100644
index 0000000000..90e195aa34
--- /dev/null
+++ b/Kernel/Memory/SharedFramebufferVMObject.h
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/Forward.h>
+#include <Kernel/Memory/AllocationStrategy.h>
+#include <Kernel/Memory/AnonymousVMObject.h>
+#include <Kernel/Memory/MemoryManager.h>
+#include <Kernel/Memory/PageFaultResponse.h>
+#include <Kernel/PhysicalAddress.h>
+
+namespace Kernel::Memory {
+
+class SharedFramebufferVMObject final : public VMObject {
+public:
+    class FakeWritesFramebufferVMObject final : public VMObject {
+    public:
+        static ErrorOr<NonnullRefPtr<FakeWritesFramebufferVMObject>> try_create(Badge<SharedFramebufferVMObject>, SharedFramebufferVMObject const& parent_object);
+
+    private:
+        FakeWritesFramebufferVMObject(SharedFramebufferVMObject const& parent_object, FixedArray<RefPtr<PhysicalPage>>&& new_physical_pages)
+            : VMObject(move(new_physical_pages))
+            , m_parent_object(parent_object)
+        {
+        }
+        virtual StringView class_name() const override { return "FakeWritesFramebufferVMObject"sv; }
+        virtual ErrorOr<NonnullRefPtr<VMObject>> try_clone() override { return Error::from_errno(ENOTIMPL); }
+        virtual Span<RefPtr<PhysicalPage> const> physical_pages() const override { return m_parent_object->fake_sink_framebuffer_physical_pages(); }
+        virtual Span<RefPtr<PhysicalPage>> physical_pages() override { return m_parent_object->fake_sink_framebuffer_physical_pages(); }
+        NonnullRefPtr<SharedFramebufferVMObject> m_parent_object;
+    };
+
+    class RealWritesFramebufferVMObject final : public VMObject {
+    public:
+        static ErrorOr<NonnullRefPtr<RealWritesFramebufferVMObject>> try_create(Badge<SharedFramebufferVMObject>, SharedFramebufferVMObject const& parent_object);
+
+    private:
+        RealWritesFramebufferVMObject(SharedFramebufferVMObject const& parent_object, FixedArray<RefPtr<PhysicalPage>>&& new_physical_pages)
+            : VMObject(move(new_physical_pages))
+            , m_parent_object(parent_object)
+        {
+        }
+        virtual StringView class_name() const override { return "RealWritesFramebufferVMObject"sv; }
+        virtual ErrorOr<NonnullRefPtr<VMObject>> try_clone() override { return Error::from_errno(ENOTIMPL); }
+        virtual Span<RefPtr<PhysicalPage> const> physical_pages() const override { return m_parent_object->real_framebuffer_physical_pages(); }
+        virtual Span<RefPtr<PhysicalPage>> physical_pages() override { return m_parent_object->real_framebuffer_physical_pages(); }
+        NonnullRefPtr<SharedFramebufferVMObject> m_parent_object;
+    };
+
+    virtual ~SharedFramebufferVMObject() override = default;
+
+    static ErrorOr<NonnullRefPtr<SharedFramebufferVMObject>> try_create_for_physical_range(PhysicalAddress paddr, size_t size);
+    static ErrorOr<NonnullRefPtr<SharedFramebufferVMObject>> try_create_at_arbitrary_physical_range(size_t size);
+    virtual ErrorOr<NonnullRefPtr<VMObject>> try_clone() override { return Error::from_errno(ENOTIMPL); }
+
+    void switch_to_fake_sink_framebuffer_writes(Badge<Kernel::DisplayConnector>);
+    void switch_to_real_framebuffer_writes(Badge<Kernel::DisplayConnector>);
+
+    virtual Span<RefPtr<PhysicalPage> const> physical_pages() const override;
+    virtual Span<RefPtr<PhysicalPage>> physical_pages() override;
+
+    Span<RefPtr<PhysicalPage>> fake_sink_framebuffer_physical_pages();
+    Span<RefPtr<PhysicalPage> const> fake_sink_framebuffer_physical_pages() const;
+
+    Span<RefPtr<PhysicalPage>> real_framebuffer_physical_pages();
+    Span<RefPtr<PhysicalPage> const> real_framebuffer_physical_pages() const;
+
+    FakeWritesFramebufferVMObject const& fake_writes_framebuffer_vmobject() const { return *m_fake_writes_framebuffer_vmobject; }
+    FakeWritesFramebufferVMObject& fake_writes_framebuffer_vmobject() { return *m_fake_writes_framebuffer_vmobject; }
+
+    RealWritesFramebufferVMObject const& real_writes_framebuffer_vmobject() const { return *m_real_writes_framebuffer_vmobject; }
+    RealWritesFramebufferVMObject& real_writes_framebuffer_vmobject() { return *m_real_writes_framebuffer_vmobject; }
+
+private:
+    SharedFramebufferVMObject(FixedArray<RefPtr<PhysicalPage>>&& new_physical_pages, CommittedPhysicalPageSet, AnonymousVMObject& real_framebuffer_vmobject);
+
+    virtual StringView class_name() const override { return "SharedFramebufferVMObject"sv; }
+
+    ErrorOr<void> create_fake_writes_framebuffer_vm_object();
+    ErrorOr<void> create_real_writes_framebuffer_vm_object();
+
+    NonnullRefPtr<AnonymousVMObject> m_real_framebuffer_vmobject;
+    RefPtr<FakeWritesFramebufferVMObject> m_fake_writes_framebuffer_vmobject;
+    RefPtr<RealWritesFramebufferVMObject> m_real_writes_framebuffer_vmobject;
+    bool m_writes_are_faked { false };
+    mutable RecursiveSpinlock m_writes_state_lock;
+    CommittedPhysicalPageSet m_committed_pages;
+};
+
+}