// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//
// 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.
//
// Copyright © 2019 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause

//! Implements virtio devices, queues, and transport mechanisms.

use std::sync::atomic::{AtomicU8, Ordering};
use std::{fmt, io, result};

use serde::{Deserialize, Serialize};
use thiserror::Error;

#[macro_use]
mod device;
pub mod balloon;
pub mod block;
mod console;
pub mod epoll_helper;
mod iommu;
pub mod mem;
pub mod net;
mod pmem;
mod rng;
mod rtc;
pub mod seccomp_filters;
mod thread_helper;
pub mod transport;
pub mod vdpa;
pub mod vhost_user;
pub mod vsock;
pub mod watchdog;

use vm_memory::bitmap::AtomicBitmap;
use vm_memory::{GuestAddress, GuestMemory};
use vm_virtio::VirtioDeviceType;

pub use self::balloon::Balloon;
pub use self::block::{Block, BlockState};
pub use self::console::{Console, ConsoleResizer, Endpoint};
pub use self::device::{
    ActivationContext, DmaRemapping, VirtioCommon, VirtioDevice, VirtioInterrupt,
    VirtioInterruptType, VirtioSharedMemoryList,
};
pub use self::epoll_helper::{
    EPOLL_HELPER_EVENT_LAST, EpollHelper, EpollHelperError, EpollHelperHandler,
};
pub use self::iommu::{AccessPlatformMapping, Iommu, IommuMapping};
pub use self::mem::{BlocksState, Mem, VIRTIO_MEM_ALIGN_SIZE, VirtioMemMappingSource};
pub use self::net::{Net, NetCtrlEpollHandler};
pub use self::pmem::Pmem;
pub use self::rng::Rng;
pub use self::rtc::Rtc;
pub use self::vdpa::{Vdpa, VdpaDmaMapping};
pub use self::vsock::Vsock;
pub use self::watchdog::Watchdog;

type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>;
type GuestRegionMmap = vm_memory::GuestRegionMmap<AtomicBitmap>;
type MmapRegion = vm_memory::MmapRegion<AtomicBitmap>;

const DEVICE_INIT: u32 = 0x00;
const DEVICE_ACKNOWLEDGE: u32 = 0x01;
const DEVICE_DRIVER: u32 = 0x02;
const DEVICE_DRIVER_OK: u32 = 0x04;
const DEVICE_FEATURES_OK: u32 = 0x08;
const DEVICE_NEEDS_RESET: u32 = 0x40;
const DEVICE_FAILED: u32 = 0x80;

/// Marks a virtio device as `NEEDS_RESET` and notifies the guest via a config
/// change interrupt. Used when a guest induced error (corrupted virtqueue,
/// malformed descriptor chain or similar) is detected and the worker thread
/// has stopped processing the device's queues.
///
/// `context` is included verbatim in the warning log to identify the cause.
pub(crate) fn mark_device_needs_reset(
    device_status: &AtomicU8,
    interrupt_cb: &dyn self::VirtioInterrupt,
    context: fmt::Arguments<'_>,
) {
    log::warn!(
        "Corrupted request detected ({context}). Setting device status to 'NEEDS_RESET' and stopping processing queues until reset."
    );

    device_status.fetch_or(DEVICE_NEEDS_RESET as u8, Ordering::SeqCst);

    if let Err(e) = interrupt_cb.trigger(self::VirtioInterruptType::Config) {
        log::error!("Failed to signal config interrupt: {e:?}");
    }
}

const VIRTIO_F_RING_INDIRECT_DESC: u32 = 28;
const VIRTIO_F_RING_EVENT_IDX: u32 = 29;
const VIRTIO_F_VERSION_1: u32 = 32;
const VIRTIO_F_ACCESS_PLATFORM: u32 = 33;
const VIRTIO_F_IN_ORDER: u32 = 35;
const VIRTIO_F_ORDER_PLATFORM: u32 = 36;
#[expect(dead_code)]
const VIRTIO_F_SR_IOV: u32 = 37;
const VIRTIO_F_NOTIFICATION_DATA: u32 = 38;

#[derive(Error, Debug)]
pub enum ActivateError {
    #[error("Failed to activate virtio device")]
    BadActivate,
    #[error("Failed to clone EventFd")]
    CloneEventFd(#[source] io::Error),
    #[error("Failed to spawn thread")]
    ThreadSpawn(#[source] io::Error),
    #[error("Failed to setup vhost-user-fs daemon")]
    VhostUserFsSetup(#[source] vhost_user::Error),
    #[error("Failed to setup vhost-user daemon")]
    VhostUserSetup(#[source] vhost_user::Error),
    #[error("Failed to create seccomp filter")]
    CreateSeccompFilter(#[source] seccompiler::Error),
    #[error("Failed to create rate limiter")]
    CreateRateLimiter(#[source] io::Error),
    #[error("Failed to activate the vDPA device")]
    ActivateVdpa(#[source] vdpa::Error),
}

pub type ActivateResult = result::Result<(), ActivateError>;

pub type DeviceEventT = u16;

#[derive(Error, Debug)]
pub enum Error {
    #[error("Failed to single used queue")]
    FailedSignalingUsedQueue(#[source] io::Error),
    #[error("I/O Error")]
    IoError(#[source] io::Error),
    #[error("Failed to update memory vhost-user")]
    VhostUserUpdateMemory(#[source] vhost_user::Error),
    #[error("Failed to add memory region vhost-user")]
    VhostUserAddMemoryRegion(#[source] vhost_user::Error),
    #[error("Failed to set shared memory region")]
    SetShmRegionsNotSupported,
    #[error("Failed to process net queue")]
    NetQueuePair(#[source] ::net_util::NetQueuePairError),
}

#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
pub struct TokenBucketConfig {
    pub size: u64,
    pub one_time_burst: Option<u64>,
    pub refill_time: u64,
}

#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
#[serde(deny_unknown_fields)]
pub struct RateLimiterConfig {
    pub bandwidth: Option<TokenBucketConfig>,
    pub ops: Option<TokenBucketConfig>,
}

impl TryInto<rate_limiter::RateLimiter> for RateLimiterConfig {
    type Error = io::Error;

    fn try_into(self) -> result::Result<rate_limiter::RateLimiter, Self::Error> {
        let bw = self.bandwidth.unwrap_or_default();
        let ops = self.ops.unwrap_or_default();
        rate_limiter::RateLimiter::new(
            bw.size,
            bw.one_time_burst.unwrap_or(0),
            bw.refill_time,
            ops.size,
            ops.one_time_burst.unwrap_or(0),
            ops.refill_time,
        )
    }
}

/// Return the host virtual address corresponding to the given guest address range
///
/// Convert an absolute address into an address space (GuestMemory)
/// to a host pointer and verify that the provided size defines a valid
/// range within a single memory region.
/// Return None if it is out of bounds, spans multiple regions, or has
/// zero size at an unmapped GPA.
pub fn get_host_address_range<M: GuestMemory + ?Sized>(
    mem: &M,
    addr: GuestAddress,
    size: usize,
) -> Option<*mut u8> {
    // Reject zero-length, no use of a pointer to an empty range.
    if size == 0 {
        return None;
    }
    let slice = mem.get_slice(addr, size).ok()?;
    Some(slice.ptr_guard_mut().as_ptr())
}
