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e4d9fa914e
This is a very basic implementation that only requests 4096 bytes of entropy from the host once, but its still high quality entropy so it should be a good fix for #4490 (boot-time entropy starvation) for virtualized environments. Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
74 lines
2.8 KiB
C++
74 lines
2.8 KiB
C++
/*
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* Copyright (c) 2021, the SerenityOS developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/VirtIO/VirtIORNG.h>
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namespace Kernel {
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VirtIORNG::VirtIORNG(PCI::Address address)
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: CharacterDevice(10, 183)
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, VirtIODevice(address, "VirtIORNG")
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{
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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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success = setup_queues(1);
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}
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if (success) {
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finish_init();
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m_entropy_buffer = MM.allocate_contiguous_kernel_region(PAGE_SIZE, "VirtIORNG", Region::Access::Read | Region::Access::Write);
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if (m_entropy_buffer) {
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memset(m_entropy_buffer->vaddr().as_ptr(), 0, m_entropy_buffer->size());
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supply_buffer_and_notify(REQUESTQ, ScatterGatherList::create_from_physical(m_entropy_buffer->physical_page(0)->paddr(), m_entropy_buffer->size()), BufferType::DeviceWritable, m_entropy_buffer->vaddr().as_ptr());
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}
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}
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}
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VirtIORNG::~VirtIORNG()
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{
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}
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bool VirtIORNG::handle_device_config_change()
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{
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VERIFY_NOT_REACHED(); // Device has no config
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}
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void VirtIORNG::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;
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if (!get_queue(REQUESTQ).get_buffer(&available_entropy))
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return;
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dbgln_if(VIRTIO_DEBUG, "VirtIORNG: 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 ask for more entropy from the host?
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}
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}
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