ladybird/Kernel/VirtIO/VirtIOConsole.h
Idan Horowitz d1f7a2f9a5 Kernel: Finish base implementation of VirtQueues
This commit includes a lot of small changes and additions needed to
finalize the base implementation of VirtIOQueues and VirtDevices:
* The device specific driver implementation now has to handle setting
up the queues it needs before letting the base device class know it
finised initialization
* Supplying buffers to VirtQueues is now done via ScatterGatherLists
instead of arbitary buffer pointers - this ensures the pointers are
physical and allows us to follow the specification in regards to the
requirement that individual descriptors must point to physically
contiguous buffers. This can be further improved in the future by
implementating support for the Indirect-Descriptors feature (as
defined by the specification) to reduce descriptor usage for very
fragmented buffers.
* When supplying buffers to a VirtQueue the driver must supply a
(temporarily-)unique token (usually the supplied buffer's virtual
address) to ensure the driver can discern which buffer has finished
processing by the device in the case in which the device does not
offer the F_IN_ORDER feature.
* Device drivers now handle queue updates (supplied buffers being
returned from the device) by implementing a single pure virtual
method instead of setting a seperate callback for each queue
* Two new VirtQueue methods were added to allow the device driver
to either discard or get used/returned buffers from the device by
cleanly removing them off the descriptor chain (This also allows
the VirtQueue implementation to reuse those freed descriptors)

This also includes the necessary changes to the VirtIOConsole
implementation to match these interface changes.

Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
2021-04-17 10:21:23 +02:00

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2.7 KiB
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/*
* Copyright (c) 2021, 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/Devices/CharacterDevice.h>
#include <Kernel/VirtIO/VirtIO.h>
namespace Kernel {
#define VIRTIO_CONSOLE_PCI_DEVICE_ID 0x1003
#define VIRTIO_CONSOLE_F_SIZE (1 << 0)
#define VIRTIO_CONSOLE_F_MULTIPORT (1 << 1)
#define VIRTIO_CONSOLE_F_EMERG_WRITE (1 << 2)
#define RECEIVEQ 0
#define TRANSMITQ 1
class VirtIOConsole final : public CharacterDevice
, public VirtIODevice {
public:
VirtIOConsole(PCI::Address);
virtual ~VirtIOConsole() override;
private:
virtual const char* class_name() const override { return m_class_name.characters(); }
virtual bool can_read(const FileDescription&, size_t) const override;
virtual KResultOr<size_t> read(FileDescription&, u64, UserOrKernelBuffer&, size_t) override;
virtual bool can_write(const FileDescription&, size_t) const override;
virtual KResultOr<size_t> write(FileDescription&, u64, const UserOrKernelBuffer&, size_t) override;
virtual mode_t required_mode() const override { return 0666; }
virtual bool handle_device_config_change() override;
virtual String device_name() const override { return String::formatted("hvc{}", minor()); }
virtual void handle_queue_update(u16 queue_index) override;
OwnPtr<Region> m_receive_region;
OwnPtr<Region> m_transmit_region;
static unsigned next_device_id;
};
}