vmm_vhost/
backend.rs

1// Copyright (C) 2019-2021 Alibaba Cloud. All rights reserved.
2// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
3//
4// Portions Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
5//
6// Portions Copyright 2017 The Chromium OS Authors. All rights reserved.
7// Use of this source code is governed by a BSD-style license that can be
8// found in the LICENSE-BSD-Google file.
9
10//! Common traits and structs for vhost-user backend drivers.
11
12use base::RawDescriptor;
13
14/// Maximum number of memory regions supported.
15pub const VHOST_MAX_MEMORY_REGIONS: usize = 255;
16
17/// Vring configuration data.
18pub struct VringConfigData {
19    /// Actual queue size negotiated by the driver.
20    pub queue_size: u16,
21    /// Bitmask of vring flags.
22    pub flags: u32,
23    /// Descriptor table address.
24    pub desc_table_addr: u64,
25    /// Used ring buffer address.
26    pub used_ring_addr: u64,
27    /// Available ring buffer address.
28    pub avail_ring_addr: u64,
29    /// Optional address for logging.
30    pub log_addr: Option<u64>,
31}
32
33impl VringConfigData {
34    /// Check whether the log (flag, address) pair is valid.
35    pub fn is_log_addr_valid(&self) -> bool {
36        if self.flags & 0x1 != 0 && self.log_addr.is_none() {
37            return false;
38        }
39
40        true
41    }
42
43    /// Get the log address, default to zero if not available.
44    pub fn get_log_addr(&self) -> u64 {
45        if self.flags & 0x1 != 0 && self.log_addr.is_some() {
46            self.log_addr.unwrap()
47        } else {
48            0
49        }
50    }
51}
52
53/// Memory region configuration data.
54pub struct VhostUserMemoryRegionInfo {
55    /// Guest physical address of the memory region.
56    pub guest_phys_addr: u64,
57    /// Size of the memory region.
58    pub memory_size: u64,
59    /// Virtual address in the current process.
60    pub userspace_addr: u64,
61    /// Offset where region starts in the mapped memory.
62    pub mmap_offset: u64,
63    /// File descriptor for mmap.
64    pub mmap_handle: RawDescriptor,
65}
66
67#[cfg(test)]
68mod tests {
69    use super::*;
70
71    #[test]
72    fn test_vring_config_data() {
73        let mut config = VringConfigData {
74            queue_size: 0x2000,
75            flags: 0x0,
76            desc_table_addr: 0x4000,
77            used_ring_addr: 0x5000,
78            avail_ring_addr: 0x6000,
79            log_addr: None,
80        };
81
82        assert!(config.is_log_addr_valid());
83        assert_eq!(config.get_log_addr(), 0);
84
85        config.flags = 0x1;
86        assert!(!config.is_log_addr_valid());
87        assert_eq!(config.get_log_addr(), 0);
88
89        config.log_addr = Some(0x7000);
90        assert!(config.is_log_addr_valid());
91        assert_eq!(config.get_log_addr(), 0x7000);
92
93        config.flags = 0x0;
94        assert!(config.is_log_addr_valid());
95        assert_eq!(config.get_log_addr(), 0);
96    }
97}
vmm_vhost/backend.rs

vmm_vhost/
backend.rs
