nub_host_common/
outb.rs

1/*
2Copyright 2025 The Hyperlight Authors.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8    http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17use core::convert::TryFrom;
18
19use anyhow::{Error, anyhow};
20
21/// Exception codes for the x86 architecture.
22/// These are helpful to identify the type of exception that occurred
23/// together with OutBAction::Abort.
24#[repr(u8)]
25#[derive(Debug, Clone, Copy)]
26pub enum Exception {
27    DivideByZero = 0,
28    Debug = 1,
29    NonMaskableInterrupt = 2,
30    Breakpoint = 3,
31    Overflow = 4,
32    BoundRangeExceeded = 5,
33    InvalidOpcode = 6,
34    DeviceNotAvailable = 7,
35    DoubleFault = 8,
36    CoprocessorSegmentOverrun = 9,
37    InvalidTSS = 10,
38    SegmentNotPresent = 11,
39    StackSegmentFault = 12,
40    GeneralProtectionFault = 13,
41    PageFault = 14,
42    Reserved = 15,
43    X87FloatingPointException = 16,
44    AlignmentCheck = 17,
45    MachineCheck = 18,
46    SIMDFloatingPointException = 19,
47    VirtualizationException = 20,
48    SecurityException = 30,
49    NoException = 0xFF,
50}
51
52impl TryFrom<u8> for Exception {
53    type Error = Error;
54
55    fn try_from(value: u8) -> Result<Self, Self::Error> {
56        use Exception::*;
57        let exception = match value {
58            0 => DivideByZero,
59            1 => Debug,
60            2 => NonMaskableInterrupt,
61            3 => Breakpoint,
62            4 => Overflow,
63            5 => BoundRangeExceeded,
64            6 => InvalidOpcode,
65            7 => DeviceNotAvailable,
66            8 => DoubleFault,
67            9 => CoprocessorSegmentOverrun,
68            10 => InvalidTSS,
69            11 => SegmentNotPresent,
70            12 => StackSegmentFault,
71            13 => GeneralProtectionFault,
72            14 => PageFault,
73            15 => Reserved,
74            16 => X87FloatingPointException,
75            17 => AlignmentCheck,
76            18 => MachineCheck,
77            19 => SIMDFloatingPointException,
78            20 => VirtualizationException,
79            30 => SecurityException,
80            0xFF => NoException,
81            _ => return Err(anyhow!("Unknown exception code: {:#x}", value)),
82        };
83
84        Ok(exception)
85    }
86}
87
88/// Supported actions when issuing an OUTB actions by Hyperlight.
89/// These are handled by the sandbox-level outb dispatcher.
90/// - Log: for logging,
91/// - CallFunction: makes a call to a host function,
92/// - Abort: aborts the execution of the guest,
93/// - DebugPrint: prints a message to the host
94pub enum OutBAction {
95    Log = 99,
96    CallFunction = 101,
97    Abort = 102,
98    DebugPrint = 103,
99}
100
101/// IO-port actions intercepted at the hypervisor level (in `run_vcpu`)
102/// before they ever reach the sandbox outb handler.  These are split
103/// from [`OutBAction`] so the outb handler does not need unreachable
104/// match arms for ports it can never see.
105pub enum VmAction {
106    /// IO port for PV timer configuration. The guest writes a 32-bit
107    /// LE value representing the desired timer period in microseconds.
108    /// A value of 0 disables the timer.
109    PvTimerConfig = 107,
110    /// IO port the guest writes to signal "I'm done" to the host.
111    /// This replaces the `hlt` instruction for halt signaling so that
112    /// KVM's in-kernel LAPIC (which absorbs HLT exits) does not interfere
113    /// with hyperlight's halt-based guest-host protocol.
114    Halt = 108,
115}
116
117impl TryFrom<u16> for OutBAction {
118    type Error = anyhow::Error;
119    fn try_from(val: u16) -> anyhow::Result<Self> {
120        match val {
121            99 => Ok(OutBAction::Log),
122            101 => Ok(OutBAction::CallFunction),
123            102 => Ok(OutBAction::Abort),
124            103 => Ok(OutBAction::DebugPrint),
125            _ => Err(anyhow::anyhow!("Invalid OutBAction value: {}", val)),
126        }
127    }
128}
129
130impl TryFrom<u16> for VmAction {
131    type Error = anyhow::Error;
132    fn try_from(val: u16) -> anyhow::Result<Self> {
133        match val {
134            107 => Ok(VmAction::PvTimerConfig),
135            108 => Ok(VmAction::Halt),
136            _ => Err(anyhow::anyhow!("Invalid VmAction value: {}", val)),
137        }
138    }
139}
nub_host_common/outb.rs

nub_host_common/
outb.rs
