mirror of
https://github.com/RGBCube/serenity
synced 2025-05-19 02:35:06 +00:00
87a32ab869
Rename the initialize method to initialize_virtio_resources so it's clear what this method is intended for. To ensure healthier device initialization, we could also return the type of ErrorOr<void> from this method, so in all overriden instances and in the original method code, we could leverage TRY() pattern which also does simplify the code a bit.
77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
/*
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* Copyright (c) 2021, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Bus/VirtIO/RNG.h>
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#include <Kernel/Sections.h>
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namespace Kernel::VirtIO {
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UNMAP_AFTER_INIT NonnullLockRefPtr<RNG> RNG::must_create(PCI::DeviceIdentifier const& device_identifier)
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{
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return adopt_lock_ref_if_nonnull(new RNG(device_identifier)).release_nonnull();
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}
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UNMAP_AFTER_INIT ErrorOr<void> RNG::initialize_virtio_resources()
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{
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TRY(Device::initialize_virtio_resources());
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bool success = negotiate_features([&](auto) {
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return 0;
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});
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if (!success)
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return Error::from_errno(EIO);
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success = setup_queues(1);
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if (!success)
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return Error::from_errno(EIO);
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finish_init();
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m_entropy_buffer = TRY(MM.allocate_contiguous_kernel_region(PAGE_SIZE, "VirtIO::RNG"sv, Memory::Region::Access::ReadWrite));
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memset(m_entropy_buffer->vaddr().as_ptr(), 0, m_entropy_buffer->size());
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request_entropy_from_host();
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return {};
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}
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UNMAP_AFTER_INIT RNG::RNG(PCI::DeviceIdentifier const& device_identifier)
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: VirtIO::Device(device_identifier)
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{
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}
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bool RNG::handle_device_config_change()
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{
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return false; // Device has no config
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}
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void RNG::handle_queue_update(u16 queue_index)
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{
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VERIFY(queue_index == REQUESTQ);
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size_t available_entropy = 0, used;
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auto& queue = get_queue(REQUESTQ);
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{
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SpinlockLocker lock(queue.lock());
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auto chain = queue.pop_used_buffer_chain(used);
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if (chain.is_empty())
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return;
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VERIFY(chain.length() == 1);
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chain.for_each([&available_entropy](PhysicalAddress, size_t length) {
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available_entropy = length;
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});
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chain.release_buffer_slots_to_queue();
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}
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dbgln_if(VIRTIO_DEBUG, "VirtIO::RNG: received {} bytes of entropy!", available_entropy);
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for (auto i = 0u; i < available_entropy; i++) {
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m_entropy_source.add_random_event(m_entropy_buffer->vaddr().as_ptr()[i]);
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}
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// TODO: When should we get some more entropy?
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}
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void RNG::request_entropy_from_host()
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{
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auto& queue = get_queue(REQUESTQ);
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SpinlockLocker lock(queue.lock());
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QueueChain chain(queue);
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chain.add_buffer_to_chain(m_entropy_buffer->physical_page(0)->paddr(), PAGE_SIZE, BufferType::DeviceWritable);
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supply_chain_and_notify(REQUESTQ, chain);
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}
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}
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