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Kernel/VirtIO: Introduce the concept of transport options

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The VirtIO specification defines many types of devices with different
purposes, and it also defines 3 possible transport mediums where devices
could be connected to the host machine.

We only care about the PCIe transport, but this commit puts the actual
foundations for supporting the lean MMIO transport too in the future.

To ensure things are kept abstracted but still functional, the VirtIO
transport code is responsible for what is deemed as related to an actual
transport type - allocation of interrupt handlers and tinkering with low
level transport-related registers, etc.
This commit is contained in:
Liav A 2023-06-10 14:46:47 +03:00 • committed by Andrew Kaster
parent 68c3f9aa5a
commit d61c23569e
24 changed files with 732 additions and 429 deletions
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340
Kernel/Bus/VirtIO/Device.cpp
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@ -4,274 +4,38 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Boot/CommandLine.h>
#include <Kernel/Bus/PCI/API.h>
#include <Kernel/Bus/PCI/IDs.h>
#include <Kernel/Bus/VirtIO/Console.h>
#include <Kernel/Bus/VirtIO/Device.h>
#include <Kernel/Bus/VirtIO/RNG.h>
#include <Kernel/Sections.h>
namespace Kernel::VirtIO {
UNMAP_AFTER_INIT void detect()
{
if (kernel_command_line().disable_virtio())
return;
MUST(PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
if (device_identifier.hardware_id().is_null())
return;
// TODO: We should also be checking that the device_id is in between 0x1000 - 0x107F inclusive
if (device_identifier.hardware_id().vendor_id != PCI::VendorID::VirtIO)
return;
switch (device_identifier.hardware_id().device_id) {
case PCI::DeviceID::VirtIOConsole: {
auto& console = Console::must_create(device_identifier).leak_ref();
MUST(console.initialize_virtio_resources());
break;
}
case PCI::DeviceID::VirtIOEntropy: {
auto& rng = RNG::must_create(device_identifier).leak_ref();
MUST(rng.initialize_virtio_resources());
break;
}
case PCI::DeviceID::VirtIOGPU: {
// This should have been initialized by the graphics subsystem
break;
}
default:
dbgln_if(VIRTIO_DEBUG, "VirtIO: Unknown VirtIO device with ID: {}", device_identifier.hardware_id().device_id);
break;
}
}));
}
static StringView determine_device_class(PCI::DeviceIdentifier const& device_identifier)
{
if (device_identifier.revision_id().value() == 0) {
// Note: If the device is a legacy (or transitional) device, therefore,
// probe the subsystem ID in the PCI header and figure out the
auto subsystem_device_id = device_identifier.subsystem_id().value();
switch (subsystem_device_id) {
case 1:
return "VirtIONetAdapter"sv;
case 2:
return "VirtIOBlockDevice"sv;
case 3:
return "VirtIOConsole"sv;
case 4:
return "VirtIORNG"sv;
default:
dbgln("VirtIO: Unknown subsystem_device_id {}", subsystem_device_id);
VERIFY_NOT_REACHED();
}
}
auto id = device_identifier.hardware_id();
VERIFY(id.vendor_id == PCI::VendorID::VirtIO);
switch (id.device_id) {
case PCI::DeviceID::VirtIONetAdapter:
return "VirtIONetAdapter"sv;
case PCI::DeviceID::VirtIOBlockDevice:
return "VirtIOBlockDevice"sv;
case PCI::DeviceID::VirtIOConsole:
return "VirtIOConsole"sv;
case PCI::DeviceID::VirtIOEntropy:
return "VirtIORNG"sv;
case PCI::DeviceID::VirtIOGPU:
return "VirtIOGPU"sv;
default:
dbgln("VirtIO: Unknown device_id {}", id.vendor_id);
VERIFY_NOT_REACHED();
}
}
UNMAP_AFTER_INIT ErrorOr<void> Device::initialize_virtio_resources()
{
enable_bus_mastering(device_identifier());
auto capabilities = device_identifier().capabilities();
for (auto& capability : capabilities) {
if (capability.id().value() == PCI::Capabilities::ID::VendorSpecific) {
// We have a virtio_pci_cap
Configuration config {};
auto raw_config_type = capability.read8(0x3);
// NOTE: The VirtIO specification allows iteration of configurations
// through a special PCI capbility structure with the VIRTIO_PCI_CAP_PCI_CFG tag:
//
// "Each structure can be mapped by a Base Address register (BAR) belonging to the function, or accessed via
// the special VIRTIO_PCI_CAP_PCI_CFG field in the PCI configuration space"
//
// "The VIRTIO_PCI_CAP_PCI_CFG capability creates an alternative (and likely suboptimal) access method
// to the common configuration, notification, ISR and device-specific configuration regions."
//
// Also, it is *very* likely to see this PCI capability as the first vendor-specific capbility of a certain PCI function,
// but this is not guaranteed by the VirtIO specification.
// Therefore, ignore this type of configuration as this is not needed by our implementation currently.
if (raw_config_type == static_cast<u8>(ConfigurationType::PCICapabilitiesAccess))
continue;
if (raw_config_type < static_cast<u8>(ConfigurationType::Common) || raw_config_type > static_cast<u8>(ConfigurationType::PCICapabilitiesAccess)) {
dbgln("{}: Unknown capability configuration type: {}", m_class_name, raw_config_type);
return Error::from_errno(ENXIO);
}
config.cfg_type = static_cast<ConfigurationType>(raw_config_type);
auto cap_length = capability.read8(0x2);
if (cap_length < 0x10) {
dbgln("{}: Unexpected capability size: {}", m_class_name, cap_length);
break;
}
config.bar = capability.read8(0x4);
if (config.bar > 0x5) {
dbgln("{}: Unexpected capability bar value: {}", m_class_name, config.bar);
break;
}
config.offset = capability.read32(0x8);
config.length = capability.read32(0xc);
// NOTE: Configuration length of zero is an invalid configuration, or at the very least a configuration
// type we don't know how to handle correctly...
// The VIRTIO_PCI_CAP_PCI_CFG configuration structure has length of 0
// but because we ignore that type and all other types should have a length
// greater than 0, we should ignore any other configuration in case this condition is not met.
if (config.length == 0) {
dbgln("{}: Found configuration {}, with invalid length of 0", m_class_name, (u32)config.cfg_type);
continue;
}
dbgln_if(VIRTIO_DEBUG, "{}: Found configuration {}, bar: {}, offset: {}, length: {}", m_class_name, (u32)config.cfg_type, config.bar, config.offset, config.length);
if (config.cfg_type == ConfigurationType::Common)
m_use_mmio = true;
else if (config.cfg_type == ConfigurationType::Notify)
m_notify_multiplier = capability.read32(0x10);
m_configs.append(config);
}
}
if (m_use_mmio) {
for (auto& cfg : m_configs) {
auto mapping_io_window = TRY(IOWindow::create_for_pci_device_bar(device_identifier(), static_cast<PCI::HeaderType0BaseRegister>(cfg.bar)));
m_register_bases[cfg.bar] = move(mapping_io_window);
}
m_common_cfg = TRY(get_config(ConfigurationType::Common, 0));
m_notify_cfg = TRY(get_config(ConfigurationType::Notify, 0));
m_isr_cfg = TRY(get_config(ConfigurationType::ISR, 0));
} else {
auto mapping_io_window = TRY(IOWindow::create_for_pci_device_bar(device_identifier(), PCI::HeaderType0BaseRegister::BAR0));
m_register_bases[0] = move(mapping_io_window);
}
// Note: We enable interrupts at least after the m_register_bases[0] ptr is
TRY(m_transport_entity->locate_configurations_and_resources({}, *this));
// NOTE: We enable interrupts at least after the m_register_bases[0] ptr is
// assigned with an IOWindow, to ensure that in case of getting an interrupt
// we can access registers from that IO window range.
PCI::enable_interrupt_line(device_identifier());
enable_irq();
m_transport_entity->enable_interrupts({});
reset_device();
// NOTE: Status bits should be set to 0 to keep them in sync, because
// we reset the device shortly afterwards.
m_status = 0;
m_transport_entity->reset_device({});
set_status_bit(DEVICE_STATUS_ACKNOWLEDGE);
set_status_bit(DEVICE_STATUS_DRIVER);
return {};
}
UNMAP_AFTER_INIT VirtIO::Device::Device(PCI::DeviceIdentifier const& device_identifier)
: PCI::Device(const_cast<PCI::DeviceIdentifier&>(device_identifier))
, IRQHandler(device_identifier.interrupt_line().value())
, m_class_name(VirtIO::determine_device_class(device_identifier))
UNMAP_AFTER_INIT VirtIO::Device::Device(NonnullOwnPtr<TransportEntity> transport_entity)
: m_class_name(transport_entity->determine_device_class_name())
, m_transport_entity(move(transport_entity))
{
dbgln("{}: Found @ {}", m_class_name, device_identifier.address());
}
void Device::notify_queue(u16 queue_index)
{
dbgln_if(VIRTIO_DEBUG, "{}: notifying about queue change at idx: {}", m_class_name, queue_index);
if (!m_notify_cfg)
base_io_window().write16(REG_QUEUE_NOTIFY, queue_index);
else
config_write16(*m_notify_cfg, get_queue(queue_index).notify_offset() * m_notify_multiplier, queue_index);
}
auto Device::mapping_for_bar(u8 bar) -> IOWindow&
{
VERIFY(m_use_mmio);
VERIFY(m_register_bases[bar]);
return *m_register_bases[bar];
}
u8 Device::config_read8(Configuration const& config, u32 offset)
{
return mapping_for_bar(config.bar).read8(config.offset + offset);
}
u16 Device::config_read16(Configuration const& config, u32 offset)
{
return mapping_for_bar(config.bar).read16(config.offset + offset);
}
u32 Device::config_read32(Configuration const& config, u32 offset)
{
return mapping_for_bar(config.bar).read32(config.offset + offset);
}
void Device::config_write8(Configuration const& config, u32 offset, u8 value)
{
mapping_for_bar(config.bar).write8(config.offset + offset, value);
}
void Device::config_write16(Configuration const& config, u32 offset, u16 value)
{
mapping_for_bar(config.bar).write16(config.offset + offset, value);
}
void Device::config_write32(Configuration const& config, u32 offset, u32 value)
{
mapping_for_bar(config.bar).write32(config.offset + offset, value);
}
void Device::config_write64(Configuration const& config, u32 offset, u64 value)
{
mapping_for_bar(config.bar).write32(config.offset + offset, (u32)(value & 0xFFFFFFFF));
mapping_for_bar(config.bar).write32(config.offset + offset + 4, (u32)(value >> 32));
}
u8 Device::read_status_bits()
{
if (!m_common_cfg)
return base_io_window().read8(REG_DEVICE_STATUS);
return config_read8(*m_common_cfg, COMMON_CFG_DEVICE_STATUS);
}
void Device::mask_status_bits(u8 status_mask)
{
m_status &= status_mask;
if (!m_common_cfg)
base_io_window().write8(REG_DEVICE_STATUS, m_status);
else
config_write8(*m_common_cfg, COMMON_CFG_DEVICE_STATUS, m_status);
}
void Device::set_status_bit(u8 status_bit)
{
m_status |= status_bit;
if (!m_common_cfg)
base_io_window().write8(REG_DEVICE_STATUS, m_status);
else
config_write8(*m_common_cfg, COMMON_CFG_DEVICE_STATUS, m_status);
}
u64 Device::get_device_features()
{
if (!m_common_cfg)
return base_io_window().read32(REG_DEVICE_FEATURES);
config_write32(*m_common_cfg, COMMON_CFG_DEVICE_FEATURE_SELECT, 0);
auto lower_bits = config_read32(*m_common_cfg, COMMON_CFG_DEVICE_FEATURE);
config_write32(*m_common_cfg, COMMON_CFG_DEVICE_FEATURE_SELECT, 1);
u64 upper_bits = (u64)config_read32(*m_common_cfg, COMMON_CFG_DEVICE_FEATURE) << 32;
return upper_bits | lower_bits;
}
IOWindow& Device::base_io_window()
{
VERIFY(m_register_bases[0]);
return *m_register_bases[0];
m_transport_entity->set_status_bits({}, m_status);
}
bool Device::accept_device_features(u64 device_features, u64 accepted_features)
@ -300,16 +64,9 @@ bool Device::accept_device_features(u64 device_features, u64 accepted_features)
dbgln_if(VIRTIO_DEBUG, "{}: Device features: {}", m_class_name, device_features);
dbgln_if(VIRTIO_DEBUG, "{}: Accepted features: {}", m_class_name, accepted_features);
if (!m_common_cfg) {
base_io_window().write32(REG_GUEST_FEATURES, accepted_features);
} else {
config_write32(*m_common_cfg, COMMON_CFG_DRIVER_FEATURE_SELECT, 0);
config_write32(*m_common_cfg, COMMON_CFG_DRIVER_FEATURE, accepted_features);
config_write32(*m_common_cfg, COMMON_CFG_DRIVER_FEATURE_SELECT, 1);
config_write32(*m_common_cfg, COMMON_CFG_DRIVER_FEATURE, accepted_features >> 32);
}
m_transport_entity->accept_device_features({}, accepted_features);
set_status_bit(DEVICE_STATUS_FEATURES_OK);
m_status = read_status_bits();
m_status = m_transport_entity->read_status_bits();
if (!(m_status & DEVICE_STATUS_FEATURES_OK)) {
set_status_bit(DEVICE_STATUS_FAILED);
dbgln("{}: Features not accepted by host!", m_class_name);
@ -321,70 +78,27 @@ bool Device::accept_device_features(u64 device_features, u64 accepted_features)
return true;
}
void Device::reset_device()
{
dbgln_if(VIRTIO_DEBUG, "{}: Reset device", m_class_name);
if (!m_common_cfg) {
mask_status_bits(0);
while (read_status_bits() != 0) {
// TODO: delay a bit?
}
return;
}
config_write8(*m_common_cfg, COMMON_CFG_DEVICE_STATUS, 0);
while (config_read8(*m_common_cfg, COMMON_CFG_DEVICE_STATUS) != 0) {
// TODO: delay a bit?
}
}
bool Device::setup_queue(u16 queue_index)
{
if (!m_common_cfg)
return false;
config_write16(*m_common_cfg, COMMON_CFG_QUEUE_SELECT, queue_index);
u16 queue_size = config_read16(*m_common_cfg, COMMON_CFG_QUEUE_SIZE);
if (queue_size == 0) {
dbgln_if(VIRTIO_DEBUG, "{}: Queue[{}] is unavailable!", m_class_name, queue_index);
return true;
}
u16 queue_notify_offset = config_read16(*m_common_cfg, COMMON_CFG_QUEUE_NOTIFY_OFF);
auto queue_or_error = Queue::try_create(queue_size, queue_notify_offset);
auto queue_or_error = m_transport_entity->setup_queue({}, queue_index);
if (queue_or_error.is_error())
return false;
auto queue = queue_or_error.release_value();
config_write64(*m_common_cfg, COMMON_CFG_QUEUE_DESC, queue->descriptor_area().get());
config_write64(*m_common_cfg, COMMON_CFG_QUEUE_DRIVER, queue->driver_area().get());
config_write64(*m_common_cfg, COMMON_CFG_QUEUE_DEVICE, queue->device_area().get());
dbgln_if(VIRTIO_DEBUG, "{}: Queue[{}] configured with size: {}", m_class_name, queue_index, queue_size);
dbgln_if(VIRTIO_DEBUG, "{}: Queue[{}] configured with size: {}", m_class_name, queue_index, queue->size());
m_queues.append(move(queue));
return true;
}
bool Device::activate_queue(u16 queue_index)
{
if (!m_common_cfg)
return false;
config_write16(*m_common_cfg, COMMON_CFG_QUEUE_SELECT, queue_index);
config_write16(*m_common_cfg, COMMON_CFG_QUEUE_ENABLE, true);
dbgln_if(VIRTIO_DEBUG, "{}: Queue[{}] activated", m_class_name, queue_index);
return true;
}
bool Device::setup_queues(u16 requested_queue_count)
{
VERIFY(!m_did_setup_queues);
m_did_setup_queues = true;
if (m_common_cfg) {
auto maximum_queue_count = config_read16(*m_common_cfg, COMMON_CFG_NUM_QUEUES);
auto* common_cfg = m_transport_entity->get_config(ConfigurationType::Common).release_value_but_fixme_should_propagate_errors();
if (common_cfg) {
auto maximum_queue_count = m_transport_entity->config_read16(*common_cfg, COMMON_CFG_NUM_QUEUES);
if (requested_queue_count == 0) {
m_queue_count = maximum_queue_count;
} else if (requested_queue_count > maximum_queue_count) {
@ -404,7 +118,7 @@ bool Device::setup_queues(u16 requested_queue_count)
return false;
}
for (u16 i = 0; i < m_queue_count; i++) { // Queues can only be activated *after* all others queues were also configured
if (!activate_queue(i))
if (!m_transport_entity->activate_queue({}, i))
return false;
}
return true;
@ -420,16 +134,9 @@ void Device::finish_init()
dbgln_if(VIRTIO_DEBUG, "{}: Finished initialization", m_class_name);
}
u8 Device::isr_status()
bool Device::handle_irq(Badge<TransportInterruptHandler>)
{
if (!m_isr_cfg)
return base_io_window().read8(REG_ISR_STATUS);
return config_read8(*m_isr_cfg, 0);
}
bool Device::handle_irq(RegisterState const&)
{
u8 isr_type = isr_status();
u8 isr_type = m_transport_entity->isr_status();
if ((isr_type & (QUEUE_INTERRUPT | DEVICE_CONFIG_INTERRUPT)) == 0) {
dbgln_if(VIRTIO_DEBUG, "{}: Handling interrupt with unknown type: {}", class_name(), isr_type);
return false;
@ -460,8 +167,9 @@ void Device::supply_chain_and_notify(u16 queue_index, QueueChain& chain)
VERIFY(&chain.queue() == &queue);
VERIFY(queue.lock().is_locked());
chain.submit_to_queue();
auto descriptor = TransportEntity::NotifyQueueDescriptor { queue_index, get_queue(queue_index).notify_offset() };
if (queue.should_notify())
notify_queue(queue_index);
m_transport_entity->notify_queue({}, descriptor);
}
}