Kernel: Add base support for VirtIO devices

Based on pull #3236 by tomuta, this adds helper methods for generic device initialization, and partily-broken virtqueue helper methods Co-authored-by: Tom <tomut@yahoo.com> Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
2025-07-27 01:07:36 +00:00 · 2021-01-02 19:53:05 +02:00 · 2021-01-02 19:53:05 +02:00 · 62303d46d1
commit 62303d46d1
parent 40a1f89d67
9 changed files with 832 additions and 2 deletions
--- a/Kernel/VirtIO/VirtIOQueue.h
+++ b/Kernel/VirtIO/VirtIOQueue.h
@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <Kernel/SpinLock.h>
+#include <Kernel/VM/MemoryManager.h>
+
+namespace Kernel {
+
+enum class BufferType {
+    DeviceReadable = 0,
+    DeviceWritable = 1
+};
+
+class VirtIOQueue {
+public:
+    VirtIOQueue(u16 queue_size, u16 notify_offset);
+    ~VirtIOQueue();
+
+    bool is_null() const { return !m_region; }
+    u16 notify_offset() const { return m_notify_offset; }
+
+    void enable_interrupts();
+    void disable_interrupts();
+
+    PhysicalAddress descriptor_area() const { return to_physical(m_descriptors); }
+    PhysicalAddress driver_area() const { return to_physical(m_driver); }
+    PhysicalAddress device_area() const { return to_physical(m_device); }
+
+    bool supply_buffer(const u8* buffer, u32 len, BufferType);
+    bool new_data_available() const;
+
+    bool handle_interrupt();
+    Function<void()> on_data_available;
+
+private:
+    PhysicalAddress to_physical(void* ptr) const
+    {
+        auto offset = FlatPtr(ptr) - m_region->vaddr().get();
+        return m_region->physical_page(0)->paddr().offset(offset);
+    }
+    struct VirtIOQueueDescriptor {
+        u64 address;
+        u32 length;
+        u16 flags;
+        u16 next;
+    };
+
+    struct VirtIOQueueDriver {
+        u16 flags;
+        u16 index;
+        u16 rings[];
+    };
+
+    struct VirtIOQueueDeviceItem {
+        u32 index;
+        u32 length;
+    };
+
+    struct VirtIOQueueDevice {
+        u16 flags;
+        u16 index;
+        VirtIOQueueDeviceItem rings[];
+    };
+
+    const u16 m_queue_size;
+    const u16 m_notify_offset;
+    u16 m_free_buffers;
+    u16 m_free_head { 0 };
+    u16 m_used_tail { 0 };
+
+    VirtIOQueueDescriptor* m_descriptors { nullptr };
+    VirtIOQueueDriver* m_driver { nullptr };
+    VirtIOQueueDevice* m_device { nullptr };
+    OwnPtr<Region> m_region;
+    SpinLock<u8> m_lock;
+};
+
+}