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Diffstat (limited to 'vhost_rs/src/vhost_kern/mod.rs')
| -rw-r--r-- | vhost_rs/src/vhost_kern/mod.rs | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/vhost_rs/src/vhost_kern/mod.rs b/vhost_rs/src/vhost_kern/mod.rs new file mode 100644 index 0000000..fde50fb --- /dev/null +++ b/vhost_rs/src/vhost_kern/mod.rs @@ -0,0 +1,320 @@ +// 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 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 std::ptr::null; + +use vm_memory::{Address, GuestAddress, 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) + } +} + +fn guest_addr(addr: u64) -> GuestAddress { + GuestAddress::new(addr) +} + +/// Represent an in-kernel vhost device backend. +pub trait VhostKernBackend<'a>: AsRawFd { + /// Associated type to access the guest's memory. + type M: GuestMemory<'a>; + + /// Get the object to access the guest's memory. + fn mem(&self) -> &Self::M; + + /// Check whether the ring configuration is valid. + #[allow(clippy::if_same_then_else)] + #[allow(clippy::needless_bool)] + fn is_valid( + &self, + queue_max_size: u16, + queue_size: u16, + desc_addr: GuestAddress, + avail_addr: GuestAddress, + used_addr: GuestAddress, + ) -> bool { + 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 queue_size > queue_max_size || queue_size == 0 || (queue_size & (queue_size - 1)) != 0 { + false + } else if desc_addr + .checked_add(desc_table_size) + .map_or(true, |v| !self.mem().address_in_range(v)) + { + false + } else if avail_addr + .checked_add(avail_ring_size) + .map_or(true, |v| !self.mem().address_in_range(v)) + { + false + } else if used_addr + .checked_add(used_ring_size) + .map_or(true, |v| !self.mem().address_in_range(v)) + { + false + } else { + true + } + } +} + +impl<'a, T: VhostKernBackend<'a>> VhostBackend for T { + /// Set the current process as the owner of this file descriptor. + /// This must be run before any other vhost ioctls. + fn set_owner(&mut 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(&mut 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, ()) + } + + /// Get a bitmask of supported virtio/vhost features. + fn get_features(&mut 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(&mut 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 guest memory mappings for vhost to use. + fn set_mem_table(&mut 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(&mut 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(&mut 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(&mut 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_max_size` - Maximum queue size supported by the device. + /// * `queue_size` - Actual queue size negotiated by the driver. + /// * `queue_index` - Index of the queue to set addresses for. + /// * `flags` - Bitmask of vring flags. + /// * `desc_table_addr` - Descriptor table address. + /// * `used_ring_addr` - Used ring buffer address. + /// * `avail_ring_addr` - Available ring buffer address. + /// * `log_addr` - Optional address for logging. + fn set_vring_addr(&mut self, queue_index: usize, config_data: &VringConfigData) -> Result<()> { + if !self.is_valid( + config_data.queue_max_size, + config_data.queue_size, + guest_addr(config_data.desc_table_addr), + guest_addr(config_data.used_ring_addr), + guest_addr(config_data.avail_ring_addr), + ) { + return Err(Error::InvalidQueue); + } + + let desc_addr = self + .mem() + .get_host_address(guest_addr(config_data.desc_table_addr)) + .ok_or(Error::DescriptorTableAddress)?; + let used_addr = self + .mem() + .get_host_address(guest_addr(config_data.used_ring_addr)) + .ok_or(Error::UsedAddress)?; + let avail_addr = self + .mem() + .get_host_address(guest_addr(config_data.avail_ring_addr)) + .ok_or(Error::AvailAddress)?; + let log_addr = match config_data.log_addr { + None => null(), + Some(a) => self + .mem() + .get_host_address(guest_addr(a)) + .ok_or(Error::LogAddress)?, + }; + + let vring_addr = vhost_vring_addr { + index: queue_index as u32, + flags: config_data.flags, + desc_user_addr: desc_addr as u64, + used_user_addr: used_addr as u64, + avail_user_addr: avail_addr as u64, + log_guest_addr: log_addr as u64, + }; + + // 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(&mut 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(&mut 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(&mut 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(&mut 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(&mut 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, ()) + } +} |