1 files changed, 32 insertions, 8 deletions
diff --git a/Kernel/Graphics/VirtIOGPU/VirtIOFrameBufferDevice.h b/Kernel/Graphics/VirtIOGPU/VirtIOFrameBufferDevice.h
index 7cfea5dcc8..003ce823fd 100644
--- a/Kernel/Graphics/VirtIOGPU/VirtIOFrameBufferDevice.h
+++ b/Kernel/Graphics/VirtIOGPU/VirtIOFrameBufferDevice.h
@@ -14,6 +14,13 @@
 namespace Kernel::Graphics {
 
 class VirtIOFrameBufferDevice final : public BlockDevice {
+    friend class VirtIOGPUConsole;
+    struct Buffer {
+        size_t framebuffer_offset { 0 };
+        u8* framebuffer_data { nullptr };
+        VirtIOGPUResourceID resource_id { 0 };
+    };
+
 public:
     VirtIOFrameBufferDevice(VirtIOGPU& virtio_gpu, VirtIOGPUScanoutID);
     virtual ~VirtIOFrameBufferDevice() override;
@@ -22,23 +29,23 @@ public:
     virtual void activate_writes();
 
     bool try_to_set_resolution(size_t width, size_t height);
-    void clear_to_black();
+    void clear_to_black(Buffer&);
 
     size_t width() const { return display_info().rect.width; }
     size_t height() const { return display_info().rect.height; }
     size_t pitch() const { return display_info().rect.width * 4; }
 
-    size_t size_in_bytes() const;
     static size_t calculate_framebuffer_size(size_t width, size_t height)
     {
-        return sizeof(u32) * width * height;
+        // VirtIO resources can only map on page boundaries!
+        return page_round_up(sizeof(u32) * width * height);
     }
 
-    void flush_dirty_window(VirtIOGPURect const&);
-    void transfer_framebuffer_data_to_host(VirtIOGPURect const&);
-    void flush_displayed_image(VirtIOGPURect const&);
+    void flush_dirty_window(VirtIOGPURect const&, Buffer&);
+    void transfer_framebuffer_data_to_host(VirtIOGPURect const&, Buffer&);
+    void flush_displayed_image(VirtIOGPURect const&, Buffer&);
 
-    void draw_ntsc_test_pattern();
+    void draw_ntsc_test_pattern(Buffer&);
 
     u8* framebuffer_data();
 
@@ -49,6 +56,8 @@ private:
     VirtIOGPURespDisplayInfo::VirtIOGPUDisplayOne& display_info();
 
     void create_framebuffer();
+    void create_buffer(Buffer&, size_t, size_t);
+    void set_buffer(int);
 
     virtual int ioctl(FileDescription&, unsigned request, FlatPtr arg) override;
     virtual KResultOr<Region*> mmap(Process&, FileDescription&, const Range&, u64 offset, int prot, bool shared) override;
@@ -61,11 +70,26 @@ private:
     virtual mode_t required_mode() const override { return 0666; }
     virtual String device_name() const override { return String::formatted("fb{}", minor()); }
 
+    static bool is_valid_buffer_index(int buffer_index)
+    {
+        return buffer_index == 0 || buffer_index == 1;
+    }
+
+    Buffer& buffer_from_index(int buffer_index)
+    {
+        return buffer_index == 0 ? m_main_buffer : m_back_buffer;
+    }
+    Buffer& current_buffer() const { return *m_current_buffer; }
+
     VirtIOGPU& m_gpu;
     const VirtIOGPUScanoutID m_scanout;
-    VirtIOGPUResourceID m_resource_id { 0 };
+    Buffer* m_current_buffer { nullptr };
+    Atomic<int, AK::memory_order_relaxed> m_last_set_buffer_index { 0 };
+    Buffer m_main_buffer;
+    Buffer m_back_buffer;
     OwnPtr<Region> m_framebuffer;
     RefPtr<VMObject> m_framebuffer_sink_vmobject;
+    size_t m_buffer_size { 0 };
     bool m_are_writes_active { true };
     // FIXME: This needs to be cleaned up if the WindowServer exits while we are in a tty
     WeakPtr<Region> m_userspace_mmap_region;