acpi_spec/
mcfg.rs

1// Copyright (c) Microsoft Corporation.
2// Licensed under the MIT License.
3
4#[cfg(feature = "alloc")]
5pub use self::alloc_parse::*;
6
7use super::Table;
8use crate::packed_nums::*;
9use core::mem::size_of;
10use static_assertions::const_assert_eq;
11use thiserror::Error;
12use zerocopy::FromBytes;
13use zerocopy::Immutable;
14use zerocopy::IntoBytes;
15use zerocopy::KnownLayout;
16use zerocopy::Ref;
17use zerocopy::Unaligned;
18
19#[repr(C)]
20#[derive(Copy, Clone, Debug, IntoBytes, Immutable, KnownLayout, FromBytes, Unaligned)]
21pub struct McfgHeader {
22    pub rsvd: u64_ne,
23}
24
25impl McfgHeader {
26    pub fn new() -> Self {
27        McfgHeader { rsvd: 0.into() }
28    }
29}
30
31impl Table for McfgHeader {
32    const SIGNATURE: [u8; 4] = *b"MCFG";
33}
34
35pub const MCFG_REVISION: u8 = 1;
36
37#[repr(C)]
38#[derive(Copy, Clone, Debug, IntoBytes, Immutable, KnownLayout, FromBytes, Unaligned)]
39pub struct McfgSegmentBusRange {
40    pub ecam_base: u64_ne,
41    pub segment: u16_ne,
42    pub start_bus: u8,
43    pub end_bus: u8,
44    pub rsvd: u32_ne,
45}
46
47const_assert_eq!(size_of::<McfgSegmentBusRange>(), 16);
48
49impl McfgSegmentBusRange {
50    pub fn new(ecam_base: u64, segment: u16, start_bus: u8, end_bus: u8) -> Self {
51        Self {
52            ecam_base: ecam_base.into(),
53            segment: segment.into(),
54            start_bus,
55            end_bus,
56            rsvd: 0.into(),
57        }
58    }
59}
60
61#[derive(Debug, Error)]
62pub enum ParseMcfgError {
63    #[error("could not read standard ACPI header")]
64    MissingAcpiHeader,
65    #[error("invalid signature. expected b\"MCFG\", found {0:?}")]
66    InvalidSignature([u8; 4]),
67    #[error("mismatched lengh, header: {0}, actual: {1}")]
68    MismatchedLength(usize, usize),
69    #[error("could not read fixed MCFG header")]
70    MissingFixedHeader,
71    #[error("could not read segment bus range structure")]
72    BadSegmentBusRange,
73}
74
75pub fn parse_mcfg<'a>(
76    raw_mcfg: &'a [u8],
77    mut on_segment_bus_range: impl FnMut(&'a McfgSegmentBusRange),
78) -> Result<(&'a crate::Header, &'a McfgHeader), ParseMcfgError> {
79    let raw_mcfg_len = raw_mcfg.len();
80    let (acpi_header, buf) = Ref::<_, crate::Header>::from_prefix(raw_mcfg)
81        .map_err(|_| ParseMcfgError::MissingAcpiHeader)?;
82
83    if acpi_header.signature != *b"MCFG" {
84        return Err(ParseMcfgError::InvalidSignature(acpi_header.signature));
85    }
86
87    if acpi_header.length.get() as usize != raw_mcfg_len {
88        return Err(ParseMcfgError::MismatchedLength(
89            acpi_header.length.get() as usize,
90            raw_mcfg_len,
91        ));
92    }
93
94    let (mcfg_header, mut buf) =
95        Ref::<_, McfgHeader>::from_prefix(buf).map_err(|_| ParseMcfgError::MissingFixedHeader)?;
96
97    while !buf.is_empty() {
98        let (sbr, rest) = Ref::<_, McfgSegmentBusRange>::from_prefix(buf)
99            .map_err(|_| ParseMcfgError::BadSegmentBusRange)?;
100        on_segment_bus_range(Ref::into_ref(sbr));
101        buf = rest
102    }
103
104    Ok((Ref::into_ref(acpi_header), Ref::into_ref(mcfg_header)))
105}
106
107#[cfg(feature = "alloc")]
108pub mod alloc_parse {
109    use super::*;
110    use alloc::vec::Vec;
111
112    #[derive(Debug)]
113    pub struct BorrowedMcfg<'a> {
114        pub acpi_header: &'a crate::Header,
115        pub mcfg_header: &'a McfgHeader,
116        pub segment_bus_ranges: Vec<&'a McfgSegmentBusRange>,
117    }
118
119    #[derive(Debug)]
120    pub struct OwnedMcfg {
121        pub acpi_header: crate::Header,
122        pub mcfg_header: McfgHeader,
123        pub segment_bus_ranges: Vec<McfgSegmentBusRange>,
124    }
125
126    impl From<BorrowedMcfg<'_>> for OwnedMcfg {
127        fn from(b: BorrowedMcfg<'_>) -> Self {
128            OwnedMcfg {
129                acpi_header: *b.acpi_header,
130                mcfg_header: *b.mcfg_header,
131                segment_bus_ranges: b.segment_bus_ranges.into_iter().copied().collect(),
132            }
133        }
134    }
135
136    impl BorrowedMcfg<'_> {
137        pub fn new(raw_mcfg: &[u8]) -> Result<BorrowedMcfg<'_>, ParseMcfgError> {
138            let mut segment_bus_ranges = Vec::new();
139            let (acpi_header, mcfg_header) = parse_mcfg(raw_mcfg, |x| segment_bus_ranges.push(x))?;
140
141            Ok(BorrowedMcfg {
142                acpi_header,
143                mcfg_header,
144                segment_bus_ranges,
145            })
146        }
147    }
148
149    impl OwnedMcfg {
150        pub fn new(raw_mcfg: &[u8]) -> Result<OwnedMcfg, ParseMcfgError> {
151            Ok(BorrowedMcfg::new(raw_mcfg)?.into())
152        }
153    }
154}
acpi_spec/mcfg.rs

acpi_spec/
mcfg.rs
