cloud-hypervisor/vm-allocator/src/system.rs

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// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Copyright © 2019 Intel Corporation
//
// 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-3-Clause file.
//
// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
use vm_memory::{GuestAddress, GuestUsize};
use crate::address::AddressAllocator;
use libc::{sysconf, _SC_PAGESIZE};
/// Safe wrapper for `sysconf(_SC_PAGESIZE)`.
#[inline(always)]
fn pagesize() -> usize {
// Trivially safe
unsafe { sysconf(_SC_PAGESIZE) as usize }
}
/// Manages allocating system resources such as address space and interrupt numbers.
///
/// # Example - Use the `SystemAddress` builder.
///
/// ```
/// # use vm_allocator::SystemAllocator;
/// # use vm_memory::{Address, GuestAddress, GuestUsize};
/// let mut allocator = SystemAllocator::new(
/// Some(GuestAddress(0x1000)), Some(0x10000),
/// GuestAddress(0x10000000), 0x10000000,
/// 5).unwrap();
/// assert_eq!(allocator.allocate_irq(), Some(5));
/// assert_eq!(allocator.allocate_irq(), Some(6));
/// assert_eq!(allocator.allocate_mmio_addresses(None, 0x1000), Some(GuestAddress(0x1fffe000)));
///
/// ```
pub struct SystemAllocator {
io_address_space: Option<AddressAllocator>,
mmio_address_space: AddressAllocator,
next_irq: u32,
}
impl SystemAllocator {
/// Creates a new `SystemAllocator` for managing addresses and irq numvers.
/// Can return `None` if `base` + `size` overflows a u64 or if alignment isn't a power
/// of two.
///
/// * `io_base` - The starting address of IO memory.
/// * `io_size` - The size of IO memory.
/// * `mmio_base` - The starting address of MMIO memory.
/// * `mmio_size` - The size of MMIO memory.
/// * `first_irq` - The first irq number to give out.
pub fn new(
io_base: Option<GuestAddress>,
io_size: Option<GuestUsize>,
mmio_base: GuestAddress,
mmio_size: GuestUsize,
first_irq: u32,
) -> Option<Self> {
let page_size = pagesize() as u64;
Some(SystemAllocator {
io_address_space: if let (Some(b), Some(s)) = (io_base, io_size) {
Some(AddressAllocator::new(b, s, Some(0x1))?)
} else {
None
},
mmio_address_space: AddressAllocator::new(mmio_base, mmio_size, Some(page_size))?,
next_irq: first_irq,
})
}
/// Reserves the next available system irq number.
pub fn allocate_irq(&mut self) -> Option<u32> {
if let Some(irq_num) = self.next_irq.checked_add(1) {
self.next_irq = irq_num;
Some(irq_num - 1)
} else {
None
}
}
/// Reserves a section of `size` bytes of IO address space.
pub fn allocate_io_addresses(
&mut self,
address: GuestAddress,
size: GuestUsize,
) -> Option<GuestAddress> {
self.io_address_space
.as_mut()?
.allocate(Some(address), size)
}
/// Reserves a section of `size` bytes of MMIO address space.
pub fn allocate_mmio_addresses(
&mut self,
address: Option<GuestAddress>,
size: GuestUsize,
) -> Option<GuestAddress> {
self.mmio_address_space.allocate(address, size)
}
/// Free an IO address range.
/// We can only free a range if it matches exactly an already allocated range.
pub fn free_io_addresses(&mut self, address: GuestAddress, size: GuestUsize) {
if let Some(io_address) = self.io_address_space.as_mut() {
io_address.free(address, size)
}
}
/// Free an MMIO address range.
/// We can only free a range if it matches exactly an already allocated range.
pub fn free_mmio_addresses(&mut self, address: GuestAddress, size: GuestUsize) {
self.mmio_address_space.free(address, size)
}
}