1 // Copyright 2024, Linaro Limited 2 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> 3 // SPDX-License-Identifier: GPL-2.0-or-later 4 5 #![cfg_attr(not(MESON), doc = include_str!("../README.md"))] 6 7 #[allow( 8 dead_code, 9 improper_ctypes_definitions, 10 improper_ctypes, 11 non_camel_case_types, 12 non_snake_case, 13 non_upper_case_globals, 14 unsafe_op_in_unsafe_fn, 15 clippy::missing_const_for_fn, 16 clippy::too_many_arguments, 17 clippy::approx_constant, 18 clippy::use_self, 19 clippy::useless_transmute, 20 clippy::missing_safety_doc, 21 )] 22 #[rustfmt::skip] 23 pub mod bindings; 24 25 unsafe impl Send for bindings::Property {} 26 unsafe impl Sync for bindings::Property {} 27 unsafe impl Sync for bindings::TypeInfo {} 28 unsafe impl Sync for bindings::VMStateDescription {} 29 30 pub mod definitions; 31 pub mod device_class; 32 33 #[cfg(test)] 34 mod tests; 35 36 use std::alloc::{GlobalAlloc, Layout}; 37 38 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 39 extern "C" { 40 fn g_aligned_alloc0( 41 n_blocks: bindings::gsize, 42 n_block_bytes: bindings::gsize, 43 alignment: bindings::gsize, 44 ) -> bindings::gpointer; 45 fn g_aligned_free(mem: bindings::gpointer); 46 } 47 48 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 49 extern "C" { 50 fn qemu_memalign(alignment: usize, size: usize) -> *mut ::core::ffi::c_void; 51 fn qemu_vfree(ptr: *mut ::core::ffi::c_void); 52 } 53 54 extern "C" { 55 fn g_malloc0(n_bytes: bindings::gsize) -> bindings::gpointer; 56 fn g_free(mem: bindings::gpointer); 57 } 58 59 /// An allocator that uses the same allocator as QEMU in C. 60 /// 61 /// It is enabled by default with the `allocator` feature. 62 /// 63 /// To set it up manually as a global allocator in your crate: 64 /// 65 /// ```ignore 66 /// use qemu_api::QemuAllocator; 67 /// 68 /// #[global_allocator] 69 /// static GLOBAL: QemuAllocator = QemuAllocator::new(); 70 /// ``` 71 #[derive(Clone, Copy, Debug)] 72 #[repr(C)] 73 pub struct QemuAllocator { 74 _unused: [u8; 0], 75 } 76 77 #[cfg_attr(all(feature = "allocator", not(test)), global_allocator)] 78 pub static GLOBAL: QemuAllocator = QemuAllocator::new(); 79 80 impl QemuAllocator { 81 // From the glibc documentation, on GNU systems, malloc guarantees 16-byte 82 // alignment on 64-bit systems and 8-byte alignment on 32-bit systems. See 83 // https://www.gnu.org/software/libc/manual/html_node/Malloc-Examples.html. 84 // This alignment guarantee also applies to Windows and Android. On Darwin 85 // and OpenBSD, the alignment is 16 bytes on both 64-bit and 32-bit systems. 86 #[cfg(all( 87 target_pointer_width = "32", 88 not(any(target_os = "macos", target_os = "openbsd")) 89 ))] 90 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(8); 91 #[cfg(all( 92 target_pointer_width = "64", 93 not(any(target_os = "macos", target_os = "openbsd")) 94 ))] 95 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16); 96 #[cfg(all( 97 any(target_pointer_width = "32", target_pointer_width = "64"), 98 any(target_os = "macos", target_os = "openbsd") 99 ))] 100 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16); 101 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))] 102 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = None; 103 104 pub const fn new() -> Self { 105 Self { _unused: [] } 106 } 107 } 108 109 impl Default for QemuAllocator { 110 fn default() -> Self { 111 Self::new() 112 } 113 } 114 115 // Sanity check. 116 const _: [(); 8] = [(); ::core::mem::size_of::<*mut ::core::ffi::c_void>()]; 117 118 unsafe impl GlobalAlloc for QemuAllocator { 119 unsafe fn alloc(&self, layout: Layout) -> *mut u8 { 120 if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0)) 121 { 122 // SAFETY: g_malloc0() is safe to call. 123 unsafe { g_malloc0(layout.size().try_into().unwrap()).cast::<u8>() } 124 } else { 125 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 126 { 127 // SAFETY: g_aligned_alloc0() is safe to call. 128 unsafe { 129 g_aligned_alloc0( 130 layout.size().try_into().unwrap(), 131 1, 132 layout.align().try_into().unwrap(), 133 ) 134 .cast::<u8>() 135 } 136 } 137 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 138 { 139 // SAFETY: qemu_memalign() is safe to call. 140 unsafe { qemu_memalign(layout.align(), layout.size()).cast::<u8>() } 141 } 142 } 143 } 144 145 unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) { 146 if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0)) 147 { 148 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid 149 // glib-allocated pointer, so `g_free`ing is safe. 150 unsafe { g_free(ptr.cast::<_>()) } 151 } else { 152 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 153 { 154 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned 155 // glib-allocated pointer, so `g_aligned_free`ing is safe. 156 unsafe { g_aligned_free(ptr.cast::<_>()) } 157 } 158 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 159 { 160 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned 161 // glib-allocated pointer, so `qemu_vfree`ing is safe. 162 unsafe { qemu_vfree(ptr.cast::<_>()) } 163 } 164 } 165 } 166 } 167