| // Copyright (C) 2019 Alibaba Cloud Computing. All rights reserved. |
| // SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause |
| // |
| // Portions Copyright 2017 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-BSD-Google file. |
| |
| //! Traits and structs to control Linux in-kernel vhost drivers. |
| //! |
| //! The initial vhost implementation is a part of the Linux kernel and uses ioctl interface to |
| //! communicate with userspace applications. This sub module provides ioctl based interfaces to |
| //! control the in-kernel net, scsi, vsock vhost drivers. |
| |
| use std::os::unix::io::{AsRawFd, RawFd}; |
| |
| use vm_memory::{Address, GuestAddress, GuestAddressSpace, GuestMemory, GuestUsize}; |
| use vmm_sys_util::eventfd::EventFd; |
| use vmm_sys_util::ioctl::{ioctl, ioctl_with_mut_ref, ioctl_with_ptr, ioctl_with_ref}; |
| |
| use super::{ |
| Error, Result, VhostBackend, VhostUserMemoryRegionInfo, VringConfigData, |
| VHOST_MAX_MEMORY_REGIONS, |
| }; |
| |
| pub mod vhost_binding; |
| use self::vhost_binding::*; |
| |
| #[cfg(feature = "vhost-vsock")] |
| pub mod vsock; |
| |
| #[inline] |
| fn ioctl_result<T>(rc: i32, res: T) -> Result<T> { |
| if rc < 0 { |
| Err(Error::IoctlError(std::io::Error::last_os_error())) |
| } else { |
| Ok(res) |
| } |
| } |
| |
| /// Represent an in-kernel vhost device backend. |
| pub trait VhostKernBackend: AsRawFd { |
| /// Associated type to access guest memory. |
| type AS: GuestAddressSpace; |
| |
| /// Get the object to access the guest's memory. |
| fn mem(&self) -> &Self::AS; |
| |
| /// Check whether the ring configuration is valid. |
| fn is_valid(&self, config_data: &VringConfigData) -> bool { |
| let queue_size = config_data.queue_size; |
| if queue_size > config_data.queue_max_size |
| || queue_size == 0 |
| || (queue_size & (queue_size - 1)) != 0 |
| { |
| return false; |
| } |
| |
| let m = self.mem().memory(); |
| let desc_table_size = 16 * u64::from(queue_size) as GuestUsize; |
| let avail_ring_size = 6 + 2 * u64::from(queue_size) as GuestUsize; |
| let used_ring_size = 6 + 8 * u64::from(queue_size) as GuestUsize; |
| if GuestAddress(config_data.desc_table_addr) |
| .checked_add(desc_table_size) |
| .map_or(true, |v| !m.address_in_range(v)) |
| { |
| return false; |
| } |
| if GuestAddress(config_data.avail_ring_addr) |
| .checked_add(avail_ring_size) |
| .map_or(true, |v| !m.address_in_range(v)) |
| { |
| return false; |
| } |
| if GuestAddress(config_data.used_ring_addr) |
| .checked_add(used_ring_size) |
| .map_or(true, |v| !m.address_in_range(v)) |
| { |
| return false; |
| } |
| |
| config_data.is_log_addr_valid() |
| } |
| } |
| |
| impl<T: VhostKernBackend> VhostBackend for T { |
| /// Get a bitmask of supported virtio/vhost features. |
| fn get_features(&self) -> Result<u64> { |
| let mut avail_features: u64 = 0; |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_mut_ref(self, VHOST_GET_FEATURES(), &mut avail_features) }; |
| ioctl_result(ret, avail_features) |
| } |
| |
| /// Inform the vhost subsystem which features to enable. This should be a subset of |
| /// supported features from VHOST_GET_FEATURES. |
| /// |
| /// # Arguments |
| /// * `features` - Bitmask of features to set. |
| fn set_features(&self, features: u64) -> Result<()> { |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_FEATURES(), &features) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the current process as the owner of this file descriptor. |
| /// This must be run before any other vhost ioctls. |
| fn set_owner(&self) -> Result<()> { |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl(self, VHOST_SET_OWNER()) }; |
| ioctl_result(ret, ()) |
| } |
| |
| fn reset_owner(&self) -> Result<()> { |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl(self, VHOST_RESET_OWNER()) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the guest memory mappings for vhost to use. |
| fn set_mem_table(&self, regions: &[VhostUserMemoryRegionInfo]) -> Result<()> { |
| if regions.is_empty() || regions.len() > VHOST_MAX_MEMORY_REGIONS { |
| return Err(Error::InvalidGuestMemory); |
| } |
| |
| let mut vhost_memory = VhostMemory::new(regions.len() as u16); |
| for (index, region) in regions.iter().enumerate() { |
| vhost_memory.set_region( |
| index as u32, |
| &vhost_memory_region { |
| guest_phys_addr: region.guest_phys_addr, |
| memory_size: region.memory_size, |
| userspace_addr: region.userspace_addr, |
| flags_padding: 0u64, |
| }, |
| )?; |
| } |
| |
| // This ioctl is called with a pointer that is valid for the lifetime |
| // of this function. The kernel will make its own copy of the memory |
| // tables. As always, check the return value. |
| let ret = unsafe { ioctl_with_ptr(self, VHOST_SET_MEM_TABLE(), vhost_memory.as_ptr()) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set base address for page modification logging. |
| /// |
| /// # Arguments |
| /// * `base` - Base address for page modification logging. |
| fn set_log_base(&self, base: u64, fd: Option<RawFd>) -> Result<()> { |
| if fd.is_some() { |
| return Err(Error::LogAddress); |
| } |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_LOG_BASE(), &base) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Specify an eventfd file descriptor to signal on log write. |
| fn set_log_fd(&self, fd: RawFd) -> Result<()> { |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let val: i32 = fd; |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_LOG_FD(), &val) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the number of descriptors in the vring. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to set descriptor count for. |
| /// * `num` - Number of descriptors in the queue. |
| fn set_vring_num(&self, queue_index: usize, num: u16) -> Result<()> { |
| let vring_state = vhost_vring_state { |
| index: queue_index as u32, |
| num: u32::from(num), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_NUM(), &vring_state) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the addresses for a given vring. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to set addresses for. |
| /// * `config_data` - Vring config data. |
| fn set_vring_addr(&self, queue_index: usize, config_data: &VringConfigData) -> Result<()> { |
| if !self.is_valid(config_data) { |
| return Err(Error::InvalidQueue); |
| } |
| |
| let vring_addr = vhost_vring_addr { |
| index: queue_index as u32, |
| flags: config_data.flags, |
| desc_user_addr: config_data.desc_table_addr, |
| used_user_addr: config_data.used_ring_addr, |
| avail_user_addr: config_data.avail_ring_addr, |
| log_guest_addr: config_data.get_log_addr(), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its |
| // return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_ADDR(), &vring_addr) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the first index to look for available descriptors. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to modify. |
| /// * `num` - Index where available descriptors start. |
| fn set_vring_base(&self, queue_index: usize, base: u16) -> Result<()> { |
| let vring_state = vhost_vring_state { |
| index: queue_index as u32, |
| num: u32::from(base), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_BASE(), &vring_state) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Get a bitmask of supported virtio/vhost features. |
| fn get_vring_base(&self, queue_index: usize) -> Result<u32> { |
| let vring_state = vhost_vring_state { |
| index: queue_index as u32, |
| num: 0, |
| }; |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_GET_VRING_BASE(), &vring_state) }; |
| ioctl_result(ret, vring_state.num) |
| } |
| |
| /// Set the eventfd to trigger when buffers have been used by the host. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to modify. |
| /// * `fd` - EventFd to trigger. |
| fn set_vring_call(&self, queue_index: usize, fd: &EventFd) -> Result<()> { |
| let vring_file = vhost_vring_file { |
| index: queue_index as u32, |
| fd: fd.as_raw_fd(), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_CALL(), &vring_file) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the eventfd that will be signaled by the guest when buffers are |
| /// available for the host to process. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to modify. |
| /// * `fd` - EventFd that will be signaled from guest. |
| fn set_vring_kick(&self, queue_index: usize, fd: &EventFd) -> Result<()> { |
| let vring_file = vhost_vring_file { |
| index: queue_index as u32, |
| fd: fd.as_raw_fd(), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_KICK(), &vring_file) }; |
| ioctl_result(ret, ()) |
| } |
| |
| /// Set the eventfd to signal an error from the vhost backend. |
| /// |
| /// # Arguments |
| /// * `queue_index` - Index of the queue to modify. |
| /// * `fd` - EventFd that will be signaled from the backend. |
| fn set_vring_err(&self, queue_index: usize, fd: &EventFd) -> Result<()> { |
| let vring_file = vhost_vring_file { |
| index: queue_index as u32, |
| fd: fd.as_raw_fd(), |
| }; |
| |
| // This ioctl is called on a valid vhost fd and has its return value checked. |
| let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_ERR(), &vring_file) }; |
| ioctl_result(ret, ()) |
| } |
| } |