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/*
* Copyright (c) 2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <Kernel/Locking/Spinlock.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Memory/ScatterGatherList.h>
namespace Kernel::VirtIO {
class Device;
class QueueChain;
#define VIRTQ_DESC_F_NEXT 1
#define VIRTQ_DESC_F_INDIRECT 4
#define VIRTQ_AVAIL_F_NO_INTERRUPT 1
#define VIRTQ_USED_F_NO_NOTIFY 1
enum class BufferType {
DeviceReadable = 0,
DeviceWritable = 2
};
class Queue {
public:
static ErrorOr<NonnullOwnPtr<Queue>> try_create(u16 queue_size, u16 notify_offset);
~Queue();
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 new_data_available() const;
bool has_free_slots() const;
Optional<u16> take_free_slot();
QueueChain pop_used_buffer_chain(size_t& used);
void discard_used_buffers();
Spinlock& lock() { return m_lock; }
bool should_notify() const;
private:
Queue(NonnullOwnPtr<Memory::Region> queue_region, u16 queue_size, u16 notify_offset);
void reclaim_buffer_chain(u16 chain_start_index, u16 chain_end_index, size_t length_of_chain);
PhysicalAddress to_physical(const void* ptr) const
{
auto offset = FlatPtr(ptr) - m_queue_region->vaddr().get();
return m_queue_region->physical_page(0)->paddr().offset(offset);
}
struct [[gnu::packed]] QueueDescriptor {
u64 address;
u32 length;
u16 flags;
u16 next;
};
struct [[gnu::packed]] QueueDriver {
u16 flags;
u16 index;
u16 rings[];
};
struct [[gnu::packed]] QueueDeviceItem {
u32 index;
u32 length;
};
struct [[gnu::packed]] QueueDevice {
u16 flags;
u16 index;
QueueDeviceItem 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 };
u16 m_driver_index_shadow { 0 };
QueueDescriptor* m_descriptors { nullptr };
QueueDriver* m_driver { nullptr };
QueueDevice* m_device { nullptr };
NonnullOwnPtr<Memory::Region> m_queue_region;
Spinlock m_lock;
friend class QueueChain;
};
class QueueChain {
public:
QueueChain(Queue& queue)
: m_queue(queue)
{
}
QueueChain(Queue& queue, u16 start_index, u16 end_index, size_t chain_length)
: m_queue(queue)
, m_start_of_chain_index(start_index)
, m_end_of_chain_index(end_index)
, m_chain_length(chain_length)
{
}
QueueChain(QueueChain&& other)
: m_queue(other.m_queue)
, m_start_of_chain_index(move(other.m_start_of_chain_index))
, m_end_of_chain_index(move(other.m_end_of_chain_index))
, m_chain_length(other.m_chain_length)
, m_chain_has_writable_pages(other.m_chain_has_writable_pages)
{
other.m_start_of_chain_index = {};
other.m_end_of_chain_index = {};
other.m_chain_length = 0;
other.m_chain_has_writable_pages = false;
}
QueueChain& operator=(QueueChain&& other)
{
VERIFY(&m_queue == &other.m_queue);
ensure_chain_is_empty();
m_start_of_chain_index = other.m_start_of_chain_index;
m_end_of_chain_index = other.m_end_of_chain_index;
m_chain_length = other.m_chain_length;
m_chain_has_writable_pages = other.m_chain_has_writable_pages;
other.m_start_of_chain_index = {};
other.m_end_of_chain_index = {};
other.m_chain_length = 0;
other.m_chain_has_writable_pages = false;
return *this;
}
~QueueChain()
{
ensure_chain_is_empty();
}
[[nodiscard]] Queue& queue() const { return m_queue; }
[[nodiscard]] bool is_empty() const { return m_chain_length == 0; }
[[nodiscard]] size_t length() const { return m_chain_length; }
bool add_buffer_to_chain(PhysicalAddress buffer_start, size_t buffer_length, BufferType buffer_type);
void submit_to_queue();
void release_buffer_slots_to_queue();
void for_each(Function<void(PhysicalAddress, size_t)> callback)
{
VERIFY(m_queue.lock().is_locked());
if (!m_start_of_chain_index.has_value())
return;
auto index = m_start_of_chain_index.value();
for (size_t i = 0; i < m_chain_length; ++i) {
auto addr = m_queue.m_descriptors[index].address;
auto length = m_queue.m_descriptors[index].length;
callback(PhysicalAddress(addr), length);
index = m_queue.m_descriptors[index].next;
}
}
private:
void ensure_chain_is_empty() const
{
VERIFY(!m_start_of_chain_index.has_value());
VERIFY(!m_end_of_chain_index.has_value());
VERIFY(m_chain_length == 0);
}
Queue& m_queue;
Optional<u16> m_start_of_chain_index {};
Optional<u16> m_end_of_chain_index {};
size_t m_chain_length {};
bool m_chain_has_writable_pages { false };
};
}
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