// Copyright 2018 The Chromium OS Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. use std::convert::TryInto; use base::warn; use vm_memory::GuestAddress; use super::*; /// Contains the data for reading and writing the common configuration structure of a virtio PCI /// device. /// /// * Registers: /// ** About the whole device. /// le32 device_feature_select; // read-write /// le32 device_feature; // read-only for driver /// le32 driver_feature_select; // read-write /// le32 driver_feature; // read-write /// le16 msix_config; // read-write /// le16 num_queues; // read-only for driver /// u8 device_status; // read-write (driver_status) /// u8 config_generation; // read-only for driver /// ** About a specific virtqueue. /// le16 queue_select; // read-write /// le16 queue_size; // read-write, power of 2, or 0. /// le16 queue_msix_vector; // read-write /// le16 queue_enable; // read-write (Ready) /// le16 queue_notify_off; // read-only for driver /// le64 queue_desc; // read-write /// le64 queue_avail; // read-write /// le64 queue_used; // read-write pub struct VirtioPciCommonConfig { pub driver_status: u8, pub config_generation: u8, pub device_feature_select: u32, pub driver_feature_select: u32, pub queue_select: u16, pub msix_config: u16, } impl VirtioPciCommonConfig { pub fn read( &mut self, offset: u64, data: &mut [u8], queues: &mut [Queue], device: &mut dyn VirtioDevice, ) { match data.len() { 1 => { let v = self.read_common_config_byte(offset); data[0] = v; } 2 => { let v = self.read_common_config_word(offset, queues); data.copy_from_slice(&v.to_le_bytes()); } 4 => { let v = self.read_common_config_dword(offset, device); data.copy_from_slice(&v.to_le_bytes()); } 8 => { let v = self.read_common_config_qword(offset); data.copy_from_slice(&v.to_le_bytes()); } _ => (), } } pub fn write( &mut self, offset: u64, data: &[u8], queues: &mut [Queue], device: &mut dyn VirtioDevice, ) { match data.len() { 1 => self.write_common_config_byte(offset, data[0]), 2 => self.write_common_config_word( offset, // This unwrap (and those below) cannot fail since data.len() is checked. u16::from_le_bytes(data.try_into().unwrap()), queues, ), 4 => self.write_common_config_dword( offset, u32::from_le_bytes(data.try_into().unwrap()), queues, device, ), 8 => self.write_common_config_qword( offset, u64::from_le_bytes(data.try_into().unwrap()), queues, ), _ => (), } } fn read_common_config_byte(&self, offset: u64) -> u8 { // The driver is only allowed to do aligned, properly sized access. match offset { 0x14 => self.driver_status, 0x15 => self.config_generation, _ => 0, } } fn write_common_config_byte(&mut self, offset: u64, value: u8) { match offset { 0x14 => self.driver_status = value, _ => { warn!("invalid virtio config byt access: 0x{:x}", offset); } } } fn read_common_config_word(&self, offset: u64, queues: &[Queue]) -> u16 { match offset { 0x10 => self.msix_config, 0x12 => queues.len() as u16, // num_queues 0x16 => self.queue_select, 0x18 => self.with_queue(queues, |q| q.size).unwrap_or(0), 0x1a => self.with_queue(queues, |q| q.vector).unwrap_or(0), 0x1c => { if self.with_queue(queues, |q| q.ready).unwrap_or(false) { 1 } else { 0 } } 0x1e => self.queue_select, // notify_off _ => 0, } } fn write_common_config_word(&mut self, offset: u64, value: u16, queues: &mut [Queue]) { match offset { 0x10 => self.msix_config = value, 0x16 => self.queue_select = value, 0x18 => self.with_queue_mut(queues, |q| q.size = value), 0x1a => self.with_queue_mut(queues, |q| q.vector = value), 0x1c => self.with_queue_mut(queues, |q| q.ready = value == 1), _ => { warn!("invalid virtio register word write: 0x{:x}", offset); } } } fn read_common_config_dword(&self, offset: u64, device: &dyn VirtioDevice) -> u32 { match offset { 0x00 => self.device_feature_select, 0x04 => { // Only 64 bits of features (2 pages) are defined for now, so limit // device_feature_select to avoid shifting by 64 or more bits. if self.device_feature_select < 2 { (device.features() >> (self.device_feature_select * 32)) as u32 } else { 0 } } 0x08 => self.driver_feature_select, _ => 0, } } fn write_common_config_dword( &mut self, offset: u64, value: u32, queues: &mut [Queue], device: &mut dyn VirtioDevice, ) { fn hi(v: &mut GuestAddress, x: u32) { *v = (*v & 0xffffffff) | ((x as u64) << 32) } fn lo(v: &mut GuestAddress, x: u32) { *v = (*v & !0xffffffff) | (x as u64) } match offset { 0x00 => self.device_feature_select = value, 0x08 => self.driver_feature_select = value, 0x0c => { if self.driver_feature_select < 2 { let features: u64 = (value as u64) << (self.driver_feature_select * 32); device.ack_features(features); for queue in queues.iter_mut() { queue.ack_features(features); } } else { warn!( "invalid ack_features (page {}, value 0x{:x})", self.driver_feature_select, value ); } } 0x20 => self.with_queue_mut(queues, |q| lo(&mut q.desc_table, value)), 0x24 => self.with_queue_mut(queues, |q| hi(&mut q.desc_table, value)), 0x28 => self.with_queue_mut(queues, |q| lo(&mut q.avail_ring, value)), 0x2c => self.with_queue_mut(queues, |q| hi(&mut q.avail_ring, value)), 0x30 => self.with_queue_mut(queues, |q| lo(&mut q.used_ring, value)), 0x34 => self.with_queue_mut(queues, |q| hi(&mut q.used_ring, value)), _ => { warn!("invalid virtio register dword write: 0x{:x}", offset); } } } fn read_common_config_qword(&self, _offset: u64) -> u64 { 0 // Assume the guest has no reason to read write-only registers. } fn write_common_config_qword(&mut self, offset: u64, value: u64, queues: &mut [Queue]) { match offset { 0x20 => self.with_queue_mut(queues, |q| q.desc_table = GuestAddress(value)), 0x28 => self.with_queue_mut(queues, |q| q.avail_ring = GuestAddress(value)), 0x30 => self.with_queue_mut(queues, |q| q.used_ring = GuestAddress(value)), _ => { warn!("invalid virtio register qword write: 0x{:x}", offset); } } } fn with_queue(&self, queues: &[Queue], f: F) -> Option where F: FnOnce(&Queue) -> U, { queues.get(self.queue_select as usize).map(f) } fn with_queue_mut(&self, queues: &mut [Queue], f: F) { if let Some(queue) = queues.get_mut(self.queue_select as usize) { f(queue); } } } #[cfg(test)] mod tests { use super::*; use base::{Event, RawDescriptor}; use vm_memory::GuestMemory; struct DummyDevice(u32); const QUEUE_SIZE: u16 = 256; const QUEUE_SIZES: &'static [u16] = &[QUEUE_SIZE]; const DUMMY_FEATURES: u64 = 0x5555_aaaa; impl VirtioDevice for DummyDevice { fn keep_rds(&self) -> Vec { Vec::new() } fn device_type(&self) -> u32 { return self.0; } fn queue_max_sizes(&self) -> &[u16] { QUEUE_SIZES } fn activate( &mut self, _mem: GuestMemory, _interrupt: Interrupt, _queues: Vec, _queue_evts: Vec, ) { } fn features(&self) -> u64 { DUMMY_FEATURES } } #[test] fn write_base_regs() { let mut regs = VirtioPciCommonConfig { driver_status: 0xaa, config_generation: 0x55, device_feature_select: 0x0, driver_feature_select: 0x0, queue_select: 0xff, msix_config: 0x00, }; let dev = &mut DummyDevice(0) as &mut dyn VirtioDevice; let mut queues = Vec::new(); // Can set all bits of driver_status. regs.write(0x14, &[0x55], &mut queues, dev); let mut read_back = vec![0x00]; regs.read(0x14, &mut read_back, &mut queues, dev); assert_eq!(read_back[0], 0x55); // The config generation register is read only. regs.write(0x15, &[0xaa], &mut queues, dev); let mut read_back = vec![0x00]; regs.read(0x15, &mut read_back, &mut queues, dev); assert_eq!(read_back[0], 0x55); // Device features is read-only and passed through from the device. regs.write(0x04, &[0, 0, 0, 0], &mut queues, dev); let mut read_back = [0u8; 4]; regs.read(0x04, &mut read_back, &mut queues, dev); assert_eq!(u32::from_le_bytes(read_back), DUMMY_FEATURES as u32); // Feature select registers are read/write. regs.write(0x00, &[1, 2, 3, 4], &mut queues, dev); let mut read_back = [0u8; 4]; regs.read(0x00, &mut read_back, &mut queues, dev); assert_eq!(u32::from_le_bytes(read_back), 0x0403_0201); regs.write(0x08, &[1, 2, 3, 4], &mut queues, dev); let mut read_back = [0u8; 4]; regs.read(0x08, &mut read_back, &mut queues, dev); assert_eq!(u32::from_le_bytes(read_back), 0x0403_0201); // 'queue_select' can be read and written. regs.write(0x16, &[0xaa, 0x55], &mut queues, dev); let mut read_back = vec![0x00, 0x00]; regs.read(0x16, &mut read_back, &mut queues, dev); assert_eq!(read_back[0], 0xaa); assert_eq!(read_back[1], 0x55); } }