zx/

port.rs

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

//! Type-safe bindings for Zircon port objects.

use crate::{
    GPAddr, MonotonicInstant, NullableHandle, Signals, Status, VcpuContents, guest, ok, sys,
};
use bitflags::bitflags;
use std::mem;

/// An object representing a Zircon
/// [port](https://fuchsia.dev/fuchsia-src/concepts/objects/port.md).
///
/// As essentially a subtype of `NullableHandle`, it can be freely interconverted.
#[derive(Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[repr(transparent)]
pub struct Port(NullableHandle);
impl_handle_based!(Port);

bitflags! {
    /// Options that may be used when creating a `Port`.
    pub struct PortOptions: u32 {
        const BIND_TO_INTERRUPT = sys::ZX_PORT_BIND_TO_INTERRUPT;
    }
}

/// The contents of a `Packet`.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum PacketContents {
    /// A user-generated packet.
    User(UserPacket),
    /// A one-shot signal packet generated via `object_wait_async`.
    SignalOne(SignalPacket),
    /// A guest bell packet
    GuestBell(GuestBellPacket),
    /// A guest mem packet
    GuestMem(GuestMemPacket),
    /// A guest I/O packet
    GuestIo(GuestIoPacket),
    /// A guest VCPU packet
    GuestVcpu(GuestVcpuPacket),
    /// Pager packets
    Pager(PagerPacket),
    /// Interrupt packets
    Interrupt(InterruptPacket),
    /// power transition request packets.
    /// This is gated under syscalls-next.h
    PowerTransition(PowerTransitionPacket),

    #[doc(hidden)]
    __Nonexhaustive,
}

/// Contents of a user packet (one sent by `port_queue`). This is a type-safe wrapper for
/// [zx_packet_user_t](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_wait.md).
#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
pub struct UserPacket(sys::zx_packet_user_t);

/// Contents of a signal packet (one generated by the kernel). This is a type-safe wrapper for
/// [zx_packet_signal_t](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_wait.md).
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct SignalPacket(sys::zx_packet_signal_t);

/// Contents of a guest bell packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_guest_bell_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct GuestBellPacket(sys::zx_packet_guest_bell_t);

/// Contents of a guest memory packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_guest_memory_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct GuestMemPacket(sys::zx_packet_guest_mem_t);

/// Contents of a guest I/O packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_guest_io_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct GuestIoPacket(sys::zx_packet_guest_io_t);

/// Contents of a guest VCPU packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_guest_vcpu_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct GuestVcpuPacket(sys::zx_packet_guest_vcpu_t);

/// Contents of a pager packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_page_request_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct PagerPacket(sys::zx_packet_page_request_t);

/// Contents of an interrupt packet (one received because of an interrupt bound to this port).
/// This is a type-safe wrapper for zx_packet_interrupt_t.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct InterruptPacket(sys::zx_packet_interrupt_t);

/// Contents of a power transition packet generated by the kernel. This is a type-safe wrapper for
/// zx_packet_processor_power_level_transition_request_t
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct PowerTransitionPacket(sys::zx_packet_processor_power_level_transition_request_t);

/// A packet sent through a port. This is a type-safe wrapper for
/// [zx_port_packet_t](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_wait.md).
#[derive(PartialEq, Eq, Debug)]
pub struct Packet(pub(crate) sys::zx_port_packet_t);

impl Packet {
    /// Creates a new packet with `UserPacket` data.
    pub fn from_user_packet(key: u64, status: i32, user: UserPacket) -> Packet {
        Packet(sys::zx_port_packet_t {
            key: key,
            packet_type: sys::zx_packet_type_t::ZX_PKT_TYPE_USER,
            status: status,
            union: user.0,
        })
    }

    /// Creates a new packet with `GuestMemPacket` data.
    pub fn from_guest_mem_packet(key: u64, status: i32, mem: GuestMemPacket) -> Packet {
        let mut raw = sys::zx_port_packet_t {
            key,
            packet_type: sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_MEM,
            status,
            union: Default::default(),
        };
        // transmute_copy doesn't work because the mem packet is too small and
        // transmute_copy requires that Dst is not larger than Src.
        //
        // Note that at the time of writing this only applied to arm64 builds;
        // x64 builds work fine with transmute_copy. This is because the
        // underlying `zx_packet_guest_mem_t` struct has a different size on x64
        // vs arm64.
        let bytes: &[u8; std::mem::size_of::<sys::zx_packet_guest_mem_t>()] =
            unsafe { mem::transmute(&mem.0) };
        raw.union[0..std::mem::size_of::<sys::zx_packet_guest_mem_t>()].copy_from_slice(bytes);
        Packet(raw)
    }

    /// Creates a new packet with `GuestIoPacket` data.
    pub fn from_guest_io_packet(key: u64, status: i32, io: GuestIoPacket) -> Packet {
        let mut raw = sys::zx_port_packet_t {
            key,
            packet_type: sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_IO,
            status,
            union: Default::default(),
        };
        // transmute_copy doesn't work because the io packet is too small and
        // transmute_copy requires that Dst is not larger than Src.
        let bytes: &[u8; std::mem::size_of::<sys::zx_packet_guest_io_t>()] =
            unsafe { mem::transmute(&io.0) };
        raw.union[0..std::mem::size_of::<sys::zx_packet_guest_io_t>()].copy_from_slice(bytes);
        Packet(raw)
    }

    /// Creates a new packet with `GuestVcpuPacket` data.
    pub fn from_guest_vcpu_packet(key: u64, status: i32, vcpu: GuestVcpuPacket) -> Packet {
        Packet(sys::zx_port_packet_t {
            key,
            packet_type: sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_VCPU,
            status,
            union: unsafe { mem::transmute_copy(&vcpu.0) },
        })
    }

    /// Creates a new packet with `PowerTransitionPacket` data.
    pub fn from_power_transition_packet(
        key: u64,
        status: i32,
        power_transition_packet: PowerTransitionPacket,
    ) -> Packet {
        Packet(sys::zx_port_packet_t {
            key: key,
            packet_type:
                sys::zx_packet_type_t::ZX_PKT_TYPE_PROCESSOR_POWER_LEVEL_TRANSITION_REQUEST,
            status: status,
            union: unsafe { mem::transmute_copy(&power_transition_packet.0) },
        })
    }

    /// The packet's key.
    pub fn key(&self) -> u64 {
        self.0.key
    }

    /// The packet's status.
    // TODO: should this type be wrapped?
    pub fn status(&self) -> i32 {
        self.0.status
    }

    /// The contents of the packet.
    pub fn contents(&self) -> PacketContents {
        match self.0.packet_type {
            sys::zx_packet_type_t::ZX_PKT_TYPE_USER => {
                PacketContents::User(UserPacket(self.0.union))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_SIGNAL_ONE => {
                PacketContents::SignalOne(SignalPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_BELL => {
                PacketContents::GuestBell(GuestBellPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_MEM => {
                PacketContents::GuestMem(GuestMemPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_IO => {
                PacketContents::GuestIo(GuestIoPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_GUEST_VCPU => {
                PacketContents::GuestVcpu(GuestVcpuPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_PAGE_REQUEST => {
                PacketContents::Pager(PagerPacket(unsafe { mem::transmute_copy(&self.0.union) }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_INTERRUPT => {
                PacketContents::Interrupt(InterruptPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            sys::zx_packet_type_t::ZX_PKT_TYPE_PROCESSOR_POWER_LEVEL_TRANSITION_REQUEST => {
                PacketContents::PowerTransition(PowerTransitionPacket(unsafe {
                    mem::transmute_copy(&self.0.union)
                }))
            }

            _ => panic!("unexpected packet type"),
        }
    }
}

impl UserPacket {
    pub fn from_u8_array(val: [u8; 32]) -> UserPacket {
        UserPacket(val)
    }

    pub fn as_u8_array(&self) -> &[u8; 32] {
        &self.0
    }

    pub fn as_mut_u8_array(&mut self) -> &mut [u8; 32] {
        &mut self.0
    }
}

impl SignalPacket {
    /// The signals used in the call to `object_wait_async`.
    pub fn trigger(&self) -> Signals {
        Signals::from_bits_truncate(self.0.trigger)
    }

    /// The observed signals.
    pub fn observed(&self) -> Signals {
        Signals::from_bits_truncate(self.0.observed)
    }

    /// A per object count of pending operations.
    pub fn count(&self) -> u64 {
        self.0.count
    }

    // The timestamp at which the packet was enqueued.
    pub fn timestamp(&self) -> sys::zx_time_t {
        self.0.timestamp
    }

    /// Get a reference to the raw underlying packet.
    pub fn raw_packet(&self) -> &sys::zx_packet_signal_t {
        &self.0
    }
}

impl GuestBellPacket {
    /// The guest physical address that was accessed that triggered the bell.
    pub fn addr(&self) -> GPAddr {
        GPAddr(self.0.addr)
    }
}

impl GuestMemPacket {
    pub fn from_raw(mem: sys::zx_packet_guest_mem_t) -> GuestMemPacket {
        GuestMemPacket(mem)
    }

    /// The guest physical address that was accessed that triggered this signal.
    pub fn addr(&self) -> GPAddr {
        GPAddr(self.0.addr)
    }
}

#[cfg(target_arch = "aarch64")]
impl GuestMemPacket {
    /// Size of the access.
    ///
    /// Returns `None` should it find and invalid size in the packet.
    pub fn access_size(&self) -> Option<guest::MemAccessSize> {
        match self.0.access_size {
            1 => Some(guest::MemAccessSize::Bits8),
            2 => Some(guest::MemAccessSize::Bits16),
            4 => Some(guest::MemAccessSize::Bits32),
            8 => Some(guest::MemAccessSize::Bits64),
            _ => None,
        }
    }

    /// Whether or not data should be sign extended.
    pub fn sign_extend(&self) -> bool {
        self.0.sign_extend
    }

    /// Register number of the Rt operand of the faulting instruction.
    pub fn reg(&self) -> u8 {
        self.0.xt
    }

    /// For `AccessType::Write` this is the data that was being written.
    pub fn data(&self) -> Option<guest::MemData> {
        if let guest::AccessType::Write = self.access_type() {
            self.access_size().map(|size| match size {
                guest::MemAccessSize::Bits8 => guest::MemData::Data8(self.0.data as u8),
                guest::MemAccessSize::Bits16 => guest::MemData::Data16(self.0.data as u16),
                guest::MemAccessSize::Bits32 => guest::MemData::Data32(self.0.data as u32),
                guest::MemAccessSize::Bits64 => guest::MemData::Data64(self.0.data),
            })
        } else {
            None
        }
    }

    /// Type of access (read or write).
    pub fn access_type(&self) -> guest::AccessType {
        match self.0.read {
            true => guest::AccessType::Read,
            false => guest::AccessType::Write,
        }
    }
}

#[cfg(target_arch = "x86_64")]
impl GuestMemPacket {
    /// Specifies the default operand size encoded by the CS descriptor.
    ///
    /// Returns a `None` should it find an invalid size in the packet.
    pub fn default_operand_size(&self) -> Option<guest::CSDefaultOperandSize> {
        // TODO: use try_from when it is stable.
        match self.0.default_operand_size {
            2 => Some(guest::CSDefaultOperandSize::Bits16),
            4 => Some(guest::CSDefaultOperandSize::Bits32),
            _ => None,
        }
    }
}

impl GuestIoPacket {
    pub fn from_raw(io: sys::zx_packet_guest_io_t) -> GuestIoPacket {
        GuestIoPacket(io)
    }

    /// First port number of the attempted access
    pub fn port(&self) -> u16 {
        self.0.port
    }

    /// Size of the access.
    ///
    /// Returns `None` should it find an invalid size in the packet.
    pub fn access_size(&self) -> Option<guest::PortAccessSize> {
        match self.0.access_size {
            1 => Some(guest::PortAccessSize::Bits8),
            2 => Some(guest::PortAccessSize::Bits16),
            4 => Some(guest::PortAccessSize::Bits32),
            _ => None,
        }
    }

    /// Type of access (read or write).
    pub fn access_type(&self) -> guest::AccessType {
        match self.0.input {
            true => guest::AccessType::Read,
            false => guest::AccessType::Write,
        }
    }

    /// For `PortAccessType::Write` this is the data that was being written.
    pub fn data(&self) -> Option<guest::PortData> {
        if let guest::AccessType::Write = self.access_type() {
            self.access_size().map(|size| match size {
                guest::PortAccessSize::Bits8 => guest::PortData::Data8(self.0.data[0]),
                guest::PortAccessSize::Bits16 => {
                    guest::PortData::Data16(u16::from_ne_bytes([self.0.data[0], self.0.data[1]]))
                }
                guest::PortAccessSize::Bits32 => {
                    guest::PortData::Data32(u32::from_ne_bytes(self.0.data))
                }
            })
        } else {
            None
        }
    }
}

impl GuestVcpuPacket {
    pub fn from_raw(vcpu: sys::zx_packet_guest_vcpu_t) -> GuestVcpuPacket {
        GuestVcpuPacket(vcpu)
    }

    pub fn contents(&self) -> VcpuContents {
        match self.0.r#type {
            sys::zx_packet_guest_vcpu_type_t::ZX_PKT_GUEST_VCPU_INTERRUPT => unsafe {
                VcpuContents::Interrupt {
                    mask: self.0.union.interrupt.mask,
                    vector: self.0.union.interrupt.vector,
                }
            },
            sys::zx_packet_guest_vcpu_type_t::ZX_PKT_GUEST_VCPU_STARTUP => unsafe {
                VcpuContents::Startup {
                    id: self.0.union.startup.id,
                    entry: self.0.union.startup.entry,
                }
            },
            _ => panic!("unexpected VCPU packet type"),
        }
    }
}

impl PagerPacket {
    /// Returns the page request command.
    pub fn command(&self) -> sys::zx_page_request_command_t {
        self.0.command
    }

    /// Returns the range for the page request.
    pub fn range(&self) -> std::ops::Range<u64> {
        self.0.offset..self.0.offset + self.0.length
    }
}

impl InterruptPacket {
    pub fn timestamp(&self) -> sys::zx_time_t {
        self.0.timestamp
    }
}

impl PowerTransitionPacket {
    pub fn from_raw(
        packet: sys::zx_packet_processor_power_level_transition_request_t,
    ) -> PowerTransitionPacket {
        PowerTransitionPacket(packet)
    }

    pub fn domain_id(&self) -> u32 {
        self.0.domain_id
    }

    pub fn options(&self) -> u32 {
        self.0.options
    }

    pub fn control_interface(&self) -> u64 {
        self.0.control_interface
    }

    pub fn control_argument(&self) -> u64 {
        self.0.control_argument
    }
}

impl Port {
    /// Create an IO port, allowing IO packets to be read and enqueued.
    ///
    /// Wraps the
    /// [zx_port_create](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_create.md)
    /// syscall.
    ///
    /// # Panics
    ///
    /// If the kernel reports no memory available to create a port or the process' job policy
    /// denies port creation.
    pub fn create() -> Self {
        Self::create_with_opts(PortOptions::from_bits_truncate(0))
    }

    pub fn create_with_opts(opts: PortOptions) -> Self {
        unsafe {
            let mut handle = 0;
            let status = sys::zx_port_create(opts.bits(), &mut handle);
            ok(status).expect(
                "port creation always succeeds except with OOM or when job policy denies it",
            );
            NullableHandle::from_raw(handle).into()
        }
    }

    /// Attempt to queue a user packet to the IO port.
    ///
    /// Wraps the
    /// [zx_port_queue](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_queue.md)
    /// syscall.
    pub fn queue(&self, packet: &Packet) -> Result<(), Status> {
        let status =
            unsafe { sys::zx_port_queue(self.raw_handle(), std::ptr::from_ref(&packet.0)) };
        ok(status)
    }

    /// Wait for a packet to arrive on a (V2) port.
    ///
    /// Wraps the
    /// [zx_port_wait](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_wait.md)
    /// syscall.
    pub fn wait(&self, deadline: MonotonicInstant) -> Result<Packet, Status> {
        let mut packet = Default::default();
        ok(unsafe { sys::zx_port_wait(self.raw_handle(), deadline.into_nanos(), &mut packet) })?;
        Ok(Packet(packet))
    }

    /// Cancel pending wait_async calls for a given key.
    ///
    /// Wraps the
    /// [zx_port_cancel_key](https://fuchsia.dev/fuchsia-src/reference/syscalls/port_cancel_key.md)
    /// syscall.
    pub fn cancel(&self, key: u64) -> Result<(), Status> {
        let options = 0;
        let status = unsafe { sys::zx_port_cancel_key(self.raw_handle(), options, key) };
        ok(status)
    }
}

bitflags! {
    /// Options for wait_async
    #[repr(transparent)]
    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
    pub struct WaitAsyncOpts: u32 {
        /// When set, causes the system to capture a timestamp when the wait triggered.
        const TIMESTAMP = sys::ZX_WAIT_ASYNC_TIMESTAMP;

        /// When set, causes the system to capture a boot timestamp when the wait triggered.
        const BOOT_TIMESTAMP = sys::ZX_WAIT_ASYNC_BOOT_TIMESTAMP;

        /// When set, causes the port to not enqueue a packet for signals active at
        /// the time of the zx_object_wait_async() call.
        const EDGE_TRIGGERED = sys::ZX_WAIT_ASYNC_EDGE;
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{Duration, Event};
    use assert_matches::assert_matches;

    #[test]
    fn port_basic() {
        let ten_ms = Duration::from_millis(10);

        let port = Port::create();

        // Waiting now should time out.
        assert_eq!(port.wait(MonotonicInstant::after(ten_ms)), Err(Status::TIMED_OUT));

        // Send a valid packet.
        let packet = Packet::from_user_packet(42, 123, UserPacket::from_u8_array([13; 32]));
        assert!(port.queue(&packet).is_ok());

        // Waiting should succeed this time. We should get back the packet we sent.
        let read_packet = port.wait(MonotonicInstant::after(ten_ms)).unwrap();
        assert_eq!(read_packet, packet);
    }

    #[test]
    fn create_with_opts() {
        let _port = Port::create_with_opts(PortOptions::BIND_TO_INTERRUPT);
    }

    #[test]
    fn wait_async_once() {
        let ten_ms = Duration::from_millis(10);
        let key = 42;

        let port = Port::create();
        let event = Event::create();
        let no_opts = WaitAsyncOpts::empty();

        assert!(event.wait_async(&port, key, Signals::USER_0 | Signals::USER_1, no_opts).is_ok());

        // Waiting without setting any signal should time out.
        assert_eq!(port.wait(MonotonicInstant::after(ten_ms)), Err(Status::TIMED_OUT));

        // If we set a signal, we should be able to wait for it.
        assert!(event.signal(Signals::NONE, Signals::USER_0).is_ok());
        let read_packet = port.wait(MonotonicInstant::after(ten_ms)).unwrap();
        assert_eq!(read_packet.key(), key);
        assert_eq!(read_packet.status(), 0);
        match read_packet.contents() {
            PacketContents::SignalOne(sig) => {
                assert_eq!(sig.trigger(), Signals::USER_0 | Signals::USER_1);
                assert_eq!(sig.observed(), Signals::USER_0);
                assert_eq!(sig.count(), 1);
            }
            _ => panic!("wrong packet type"),
        }

        // Shouldn't get any more packets.
        assert_eq!(port.wait(MonotonicInstant::after(ten_ms)), Err(Status::TIMED_OUT));

        // Calling wait_async again should result in another packet.
        assert!(event.wait_async(&port, key, Signals::USER_0, no_opts).is_ok());
        let read_packet = port.wait(MonotonicInstant::after(ten_ms)).unwrap();
        assert_eq!(read_packet.key(), key);
        assert_eq!(read_packet.status(), 0);
        match read_packet.contents() {
            PacketContents::SignalOne(sig) => {
                assert_eq!(sig.trigger(), Signals::USER_0);
                assert_eq!(sig.observed(), Signals::USER_0);
                assert_eq!(sig.count(), 1);
            }
            _ => panic!("wrong packet type"),
        }

        // Calling wait_async_handle then cancel, we should not get a packet as cancel will
        // remove it from  the queue.
        assert!(event.wait_async(&port, key, Signals::USER_0, no_opts).is_ok());
        assert!(port.cancel(key).is_ok());
        assert_eq!(port.wait(MonotonicInstant::after(ten_ms)), Err(Status::TIMED_OUT));

        // If the event is signalled after the cancel, we also shouldn't get a packet.
        assert!(event.signal(Signals::USER_0, Signals::NONE).is_ok()); // clear signal
        assert!(event.wait_async(&port, key, Signals::USER_0, no_opts).is_ok());
        assert!(port.cancel(key).is_ok());
        assert!(event.signal(Signals::NONE, Signals::USER_0).is_ok());
        assert_eq!(port.wait(MonotonicInstant::after(ten_ms)), Err(Status::TIMED_OUT));
    }

    #[test]
    fn guest_mem_packet() {
        #[cfg(target_arch = "x86_64")]
        let guest_mem_packet = sys::zx_packet_guest_mem_t {
            addr: 0xaaaabbbbccccdddd,
            cr3: 0x0123456789abcdef,
            rip: 0xffffffff00000000,
            instruction_size: 8,
            default_operand_size: 2,
        };
        #[cfg(target_arch = "aarch64")]
        let guest_mem_packet = sys::zx_packet_guest_mem_t {
            addr: 0x8877665544332211,
            access_size: 8,
            sign_extend: true,
            xt: 0xf3,
            read: false,
            data: 0x1122334455667788,
        };
        #[cfg(target_arch = "riscv64")]
        let guest_mem_packet = {
            let mut ret = sys::zx_packet_guest_mem_t::default();
            ret.addr = 0x8877665544332211;
            ret
        };
        const KEY: u64 = 0x5555555555555555;
        const STATUS: i32 = sys::ZX_ERR_INTERNAL;

        let packet =
            Packet::from_guest_mem_packet(KEY, STATUS, GuestMemPacket::from_raw(guest_mem_packet));

        assert_matches!(packet.contents(), PacketContents::GuestMem(GuestMemPacket(packet)) if packet == guest_mem_packet);
        assert_eq!(packet.key(), KEY);
        assert_eq!(packet.status(), STATUS);
    }

    #[test]
    fn guest_io_packet() {
        const GUEST_IO_PACKET: sys::zx_packet_guest_io_t = sys::zx_packet_guest_io_t {
            port: 0xabcd,
            access_size: 4,
            input: true,
            data: [0xaa, 0xbb, 0xcc, 0xdd],
        };
        const KEY: u64 = 0x0123456789abcdef;
        const STATUS: i32 = sys::ZX_ERR_NO_RESOURCES;

        let packet =
            Packet::from_guest_io_packet(KEY, STATUS, GuestIoPacket::from_raw(GUEST_IO_PACKET));

        assert_matches!(packet.contents(), PacketContents::GuestIo(GuestIoPacket(packet)) if packet == GUEST_IO_PACKET);
        assert_eq!(packet.key(), KEY);
        assert_eq!(packet.status(), STATUS);
    }

    #[test]
    fn guest_vcpu_interrupt_packet() {
        // Unable to use 'const' here because we need Default::default to initialize the PadBytes.
        let mut guest_vcpu_packet = sys::zx_packet_guest_vcpu_t::default();
        guest_vcpu_packet.r#type = sys::zx_packet_guest_vcpu_type_t::ZX_PKT_GUEST_VCPU_INTERRUPT;
        guest_vcpu_packet.union = sys::zx_packet_guest_vcpu_union_t {
            interrupt: {
                let mut interrupt = sys::zx_packet_guest_vcpu_interrupt_t::default();
                interrupt.mask = 0xaaaaaaaaaaaaaaaa;
                interrupt.vector = 0x12;
                interrupt
            },
        };
        const KEY: u64 = 0x0123456789abcdef;
        const STATUS: i32 = sys::ZX_ERR_NO_RESOURCES;

        let packet = Packet::from_guest_vcpu_packet(
            KEY,
            STATUS,
            GuestVcpuPacket::from_raw(guest_vcpu_packet),
        );

        assert_matches!(packet.contents(), PacketContents::GuestVcpu(GuestVcpuPacket(packet)) if packet == guest_vcpu_packet);
        assert_eq!(packet.key(), KEY);
        assert_eq!(packet.status(), STATUS);
    }

    #[test]
    fn guest_vcpu_startup_packet() {
        let mut guest_vcpu_packet = sys::zx_packet_guest_vcpu_t::default();
        guest_vcpu_packet.r#type = sys::zx_packet_guest_vcpu_type_t::ZX_PKT_GUEST_VCPU_STARTUP;
        guest_vcpu_packet.union = sys::zx_packet_guest_vcpu_union_t {
            startup: sys::zx_packet_guest_vcpu_startup_t { id: 16, entry: 0xffffffff11111111 },
        };
        const KEY: u64 = 0x0123456789abcdef;
        const STATUS: i32 = sys::ZX_ERR_NO_RESOURCES;

        let packet = Packet::from_guest_vcpu_packet(
            KEY,
            STATUS,
            GuestVcpuPacket::from_raw(guest_vcpu_packet),
        );

        assert_matches!(packet.contents(), PacketContents::GuestVcpu(GuestVcpuPacket(packet)) if packet == guest_vcpu_packet);
        assert_eq!(packet.key(), KEY);
        assert_eq!(packet.status(), STATUS);
    }

    #[test]
    fn power_transition_packet() {
        let power_transition_packet =
            sys::zx_packet_processor_power_level_transition_request_t::default();
        const KEY: u64 = 0x0123456789abcdef;
        const STATUS: i32 = sys::ZX_ERR_NO_RESOURCES;

        let packet = Packet::from_power_transition_packet(
            KEY,
            STATUS,
            PowerTransitionPacket::from_raw(power_transition_packet),
        );

        assert_matches!(
            packet.contents(),
            PacketContents::PowerTransition(PowerTransitionPacket(packet)) if packet == power_transition_packet
        );
        assert_eq!(packet.key(), KEY);
        assert_eq!(packet.status(), STATUS);
    }
}