1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308
use crate::PAGE_SIZE;
use bitflags::*;
use volatile::{ReadOnly, Volatile, WriteOnly};
/// MMIO Device Legacy Register Interface.
///
/// Ref: 4.2.4 Legacy interface
#[repr(C)]
pub struct VirtIOHeader {
/// Magic value
magic: ReadOnly<u32>,
/// Device version number
///
/// Legacy device returns value 0x1.
version: ReadOnly<u32>,
/// Virtio Subsystem Device ID
device_id: ReadOnly<u32>,
/// Virtio Subsystem Vendor ID
vendor_id: ReadOnly<u32>,
/// Flags representing features the device supports
device_features: ReadOnly<u32>,
/// Device (host) features word selection
device_features_sel: WriteOnly<u32>,
/// Reserved
__r1: [ReadOnly<u32>; 2],
/// Flags representing device features understood and activated by the driver
driver_features: WriteOnly<u32>,
/// Activated (guest) features word selection
driver_features_sel: WriteOnly<u32>,
/// Guest page size
///
/// The driver writes the guest page size in bytes to the register during
/// initialization, before any queues are used. This value should be a
/// power of 2 and is used by the device to calculate the Guest address
/// of the first queue page (see QueuePFN).
guest_page_size: WriteOnly<u32>,
/// Reserved
__r2: ReadOnly<u32>,
/// Virtual queue index
///
/// Writing to this register selects the virtual queue that the following
/// operations on the QueueNumMax, QueueNum, QueueAlign and QueuePFN
/// registers apply to. The index number of the first queue is zero (0x0).
queue_sel: WriteOnly<u32>,
/// Maximum virtual queue size
///
/// Reading from the register returns the maximum size of the queue the
/// device is ready to process or zero (0x0) if the queue is not available.
/// This applies to the queue selected by writing to QueueSel and is
/// allowed only when QueuePFN is set to zero (0x0), so when the queue is
/// not actively used.
queue_num_max: ReadOnly<u32>,
/// Virtual queue size
///
/// Queue size is the number of elements in the queue. Writing to this
/// register notifies the device what size of the queue the driver will use.
/// This applies to the queue selected by writing to QueueSel.
queue_num: WriteOnly<u32>,
/// Used Ring alignment in the virtual queue
///
/// Writing to this register notifies the device about alignment boundary
/// of the Used Ring in bytes. This value should be a power of 2 and
/// applies to the queue selected by writing to QueueSel.
queue_align: WriteOnly<u32>,
/// Guest physical page number of the virtual queue
///
/// Writing to this register notifies the device about location of the
/// virtual queue in the Guest’s physical address space. This value is
/// the index number of a page starting with the queue Descriptor Table.
/// Value zero (0x0) means physical address zero (0x00000000) and is illegal.
/// When the driver stops using the queue it writes zero (0x0) to this
/// register. Reading from this register returns the currently used page
/// number of the queue, therefore a value other than zero (0x0) means that
/// the queue is in use. Both read and write accesses apply to the queue
/// selected by writing to QueueSel.
queue_pfn: Volatile<u32>,
/// new interface only
queue_ready: Volatile<u32>,
/// Reserved
__r3: [ReadOnly<u32>; 2],
/// Queue notifier
queue_notify: WriteOnly<u32>,
/// Reserved
__r4: [ReadOnly<u32>; 3],
/// Interrupt status
interrupt_status: ReadOnly<u32>,
/// Interrupt acknowledge
interrupt_ack: WriteOnly<u32>,
/// Reserved
__r5: [ReadOnly<u32>; 2],
/// Device status
///
/// Reading from this register returns the current device status flags.
/// Writing non-zero values to this register sets the status flags,
/// indicating the OS/driver progress. Writing zero (0x0) to this register
/// triggers a device reset. The device sets QueuePFN to zero (0x0) for
/// all queues in the device. Also see 3.1 Device Initialization.
status: Volatile<DeviceStatus>,
/// Reserved
__r6: [ReadOnly<u32>; 3],
// new interface only since here
queue_desc_low: WriteOnly<u32>,
queue_desc_high: WriteOnly<u32>,
/// Reserved
__r7: [ReadOnly<u32>; 2],
queue_avail_low: WriteOnly<u32>,
queue_avail_high: WriteOnly<u32>,
/// Reserved
__r8: [ReadOnly<u32>; 2],
queue_used_low: WriteOnly<u32>,
queue_used_high: WriteOnly<u32>,
/// Reserved
__r9: [ReadOnly<u32>; 21],
config_generation: ReadOnly<u32>,
}
impl VirtIOHeader {
/// Verify a valid header.
pub fn verify(&self) -> bool {
self.magic.read() == 0x7472_6976 && self.version.read() == 1 && self.device_id.read() != 0
}
/// Get the device type.
pub fn device_type(&self) -> DeviceType {
match self.device_id.read() {
x @ 1..=13 | x @ 16..=24 => unsafe { core::mem::transmute(x as u8) },
_ => DeviceType::Invalid,
}
}
/// Get the vendor ID.
pub fn vendor_id(&self) -> u32 {
self.vendor_id.read()
}
/// Begin initializing the device.
///
/// Ref: virtio 3.1.1 Device Initialization
pub fn begin_init(&mut self, negotiate_features: impl FnOnce(u64) -> u64) {
self.status.write(DeviceStatus::ACKNOWLEDGE);
self.status.write(DeviceStatus::DRIVER);
let features = self.read_device_features();
self.write_driver_features(negotiate_features(features));
self.status.write(DeviceStatus::FEATURES_OK);
self.guest_page_size.write(PAGE_SIZE as u32);
}
/// Finish initializing the device.
pub fn finish_init(&mut self) {
self.status.write(DeviceStatus::DRIVER_OK);
}
/// Read device features.
fn read_device_features(&mut self) -> u64 {
self.device_features_sel.write(0); // device features [0, 32)
let mut device_features_bits = self.device_features.read().into();
self.device_features_sel.write(1); // device features [32, 64)
device_features_bits += (self.device_features.read() as u64) << 32;
device_features_bits
}
/// Write device features.
fn write_driver_features(&mut self, driver_features: u64) {
self.driver_features_sel.write(0); // driver features [0, 32)
self.driver_features.write(driver_features as u32);
self.driver_features_sel.write(1); // driver features [32, 64)
self.driver_features.write((driver_features >> 32) as u32);
}
/// Set queue.
pub fn queue_set(&mut self, queue: u32, size: u32, align: u32, pfn: u32) {
self.queue_sel.write(queue);
self.queue_num.write(size);
self.queue_align.write(align);
self.queue_pfn.write(pfn);
}
/// Get guest physical page number of the virtual queue.
pub fn queue_physical_page_number(&mut self, queue: u32) -> u32 {
self.queue_sel.write(queue);
self.queue_pfn.read()
}
/// Whether the queue is in used.
pub fn queue_used(&mut self, queue: u32) -> bool {
self.queue_physical_page_number(queue) != 0
}
/// Get the max size of queue.
pub fn max_queue_size(&self) -> u32 {
self.queue_num_max.read()
}
/// Notify device.
pub fn notify(&mut self, queue: u32) {
self.queue_notify.write(queue);
}
/// Acknowledge interrupt and return true if success.
pub fn ack_interrupt(&mut self) -> bool {
let interrupt = self.interrupt_status.read();
if interrupt != 0 {
self.interrupt_ack.write(interrupt);
true
} else {
false
}
}
/// Get the pointer to config space (at offset 0x100)
pub fn config_space(&self) -> *mut u64 {
(self as *const _ as usize + CONFIG_SPACE_OFFSET) as _
}
}
bitflags! {
/// The device status field.
struct DeviceStatus: u32 {
/// Indicates that the guest OS has found the device and recognized it
/// as a valid virtio device.
const ACKNOWLEDGE = 1;
/// Indicates that the guest OS knows how to drive the device.
const DRIVER = 2;
/// Indicates that something went wrong in the guest, and it has given
/// up on the device. This could be an internal error, or the driver
/// didn’t like the device for some reason, or even a fatal error
/// during device operation.
const FAILED = 128;
/// Indicates that the driver has acknowledged all the features it
/// understands, and feature negotiation is complete.
const FEATURES_OK = 8;
/// Indicates that the driver is set up and ready to drive the device.
const DRIVER_OK = 4;
/// Indicates that the device has experienced an error from which it
/// can’t recover.
const DEVICE_NEEDS_RESET = 64;
}
}
const CONFIG_SPACE_OFFSET: usize = 0x100;
/// Types of virtio devices.
#[repr(u8)]
#[derive(Debug, Eq, PartialEq)]
#[allow(missing_docs)]
pub enum DeviceType {
Invalid = 0,
Network = 1,
Block = 2,
Console = 3,
EntropySource = 4,
MemoryBallooning = 5,
IoMemory = 6,
Rpmsg = 7,
ScsiHost = 8,
_9P = 9,
Mac80211 = 10,
RprocSerial = 11,
VirtioCAIF = 12,
MemoryBalloon = 13,
GPU = 16,
Timer = 17,
Input = 18,
Socket = 19,
Crypto = 20,
SignalDistributionModule = 21,
Pstore = 22,
IOMMU = 23,
Memory = 24,
}