// Copyright © 2019 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
//

use devices::interrupt_controller::InterruptController;
use hypervisor::IrqRoutingEntry;
use std::collections::HashMap;
use std::io;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, Mutex};
use vm_allocator::SystemAllocator;
use vm_device::interrupt::{
    InterruptIndex, InterruptManager, InterruptSourceConfig, InterruptSourceGroup,
    LegacyIrqGroupConfig, MsiIrqGroupConfig,
};
use vmm_sys_util::eventfd::EventFd;

/// Reuse std::io::Result to simplify interoperability among crates.
pub type Result<T> = std::io::Result<T>;

struct InterruptRoute {
    gsi: u32,
    irq_fd: EventFd,
    registered: AtomicBool,
}

impl InterruptRoute {
    pub fn new(allocator: &mut SystemAllocator) -> Result<Self> {
        let irq_fd = EventFd::new(libc::EFD_NONBLOCK)?;
        let gsi = allocator
            .allocate_gsi()
            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "Failed allocating new GSI"))?;

        Ok(InterruptRoute {
            gsi,
            irq_fd,
            registered: AtomicBool::new(false),
        })
    }

    pub fn enable(&self, vm: &Arc<dyn hypervisor::Vm>) -> Result<()> {
        if !self.registered.load(Ordering::Acquire) {
            vm.register_irqfd(&self.irq_fd, self.gsi).map_err(|e| {
                io::Error::new(
                    io::ErrorKind::Other,
                    format!("Failed registering irq_fd: {}", e),
                )
            })?;

            // Update internals to track the irq_fd as "registered".
            self.registered.store(true, Ordering::Release);
        }

        Ok(())
    }

    pub fn disable(&self, vm: &Arc<dyn hypervisor::Vm>) -> Result<()> {
        if self.registered.load(Ordering::Acquire) {
            vm.unregister_irqfd(&self.irq_fd, self.gsi).map_err(|e| {
                io::Error::new(
                    io::ErrorKind::Other,
                    format!("Failed unregistering irq_fd: {}", e),
                )
            })?;

            // Update internals to track the irq_fd as "unregistered".
            self.registered.store(false, Ordering::Release);
        }

        Ok(())
    }

    pub fn trigger(&self) -> Result<()> {
        self.irq_fd.write(1)
    }

    pub fn notifier(&self) -> Option<EventFd> {
        Some(
            self.irq_fd
                .try_clone()
                .expect("Failed cloning interrupt's EventFd"),
        )
    }
}

pub struct RoutingEntry<IrqRoutingEntry> {
    route: IrqRoutingEntry,
    masked: bool,
}

pub struct MsiInterruptGroup<IrqRoutingEntry> {
    vm: Arc<dyn hypervisor::Vm>,
    gsi_msi_routes: Arc<Mutex<HashMap<u32, RoutingEntry<IrqRoutingEntry>>>>,
    irq_routes: HashMap<InterruptIndex, InterruptRoute>,
}

impl MsiInterruptGroup<IrqRoutingEntry> {
    fn set_gsi_routes(&self, routes: &HashMap<u32, RoutingEntry<IrqRoutingEntry>>) -> Result<()> {
        let mut entry_vec: Vec<IrqRoutingEntry> = Vec::new();
        for (_, entry) in routes.iter() {
            if entry.masked {
                continue;
            }

            entry_vec.push(entry.route);
        }

        self.vm.set_gsi_routing(&entry_vec).map_err(|e| {
            io::Error::new(
                io::ErrorKind::Other,
                format!("Failed setting GSI routing: {}", e),
            )
        })
    }
}

impl MsiInterruptGroup<IrqRoutingEntry> {
    fn new(
        vm: Arc<dyn hypervisor::Vm>,
        gsi_msi_routes: Arc<Mutex<HashMap<u32, RoutingEntry<IrqRoutingEntry>>>>,
        irq_routes: HashMap<InterruptIndex, InterruptRoute>,
    ) -> Self {
        MsiInterruptGroup {
            vm,
            gsi_msi_routes,
            irq_routes,
        }
    }
}

impl InterruptSourceGroup for MsiInterruptGroup<IrqRoutingEntry> {
    fn enable(&self) -> Result<()> {
        for (_, route) in self.irq_routes.iter() {
            route.enable(&self.vm)?;
        }

        Ok(())
    }

    fn disable(&self) -> Result<()> {
        for (_, route) in self.irq_routes.iter() {
            route.disable(&self.vm)?;
        }

        Ok(())
    }

    fn trigger(&self, index: InterruptIndex) -> Result<()> {
        if let Some(route) = self.irq_routes.get(&index) {
            return route.trigger();
        }

        Err(io::Error::new(
            io::ErrorKind::Other,
            format!("trigger: Invalid interrupt index {}", index),
        ))
    }

    fn notifier(&self, index: InterruptIndex) -> Option<EventFd> {
        if let Some(route) = self.irq_routes.get(&index) {
            return route.notifier();
        }

        None
    }

    fn update(&self, index: InterruptIndex, config: InterruptSourceConfig) -> Result<()> {
        if let Some(route) = self.irq_routes.get(&index) {
            let entry = RoutingEntry::<_>::make_entry(&self.vm, route.gsi, &config)?;
            let mut routes = self.gsi_msi_routes.lock().unwrap();
            routes.insert(route.gsi, *entry);
            return self.set_gsi_routes(&routes);
        }

        Err(io::Error::new(
            io::ErrorKind::Other,
            format!("update: Invalid interrupt index {}", index),
        ))
    }

    fn mask(&self, index: InterruptIndex) -> Result<()> {
        if let Some(route) = self.irq_routes.get(&index) {
            let mut routes = self.gsi_msi_routes.lock().unwrap();
            if let Some(entry) = routes.get_mut(&route.gsi) {
                entry.masked = true;
            } else {
                return Err(io::Error::new(
                    io::ErrorKind::Other,
                    format!("mask: No existing route for interrupt index {}", index),
                ));
            }
            self.set_gsi_routes(&routes)?;
            return route.disable(&self.vm);
        }

        Err(io::Error::new(
            io::ErrorKind::Other,
            format!("mask: Invalid interrupt index {}", index),
        ))
    }

    fn unmask(&self, index: InterruptIndex) -> Result<()> {
        if let Some(route) = self.irq_routes.get(&index) {
            let mut routes = self.gsi_msi_routes.lock().unwrap();
            if let Some(entry) = routes.get_mut(&route.gsi) {
                entry.masked = false;
            } else {
                return Err(io::Error::new(
                    io::ErrorKind::Other,
                    format!("mask: No existing route for interrupt index {}", index),
                ));
            }
            self.set_gsi_routes(&routes)?;
            return route.enable(&self.vm);
        }

        Err(io::Error::new(
            io::ErrorKind::Other,
            format!("unmask: Invalid interrupt index {}", index),
        ))
    }
}

pub struct LegacyUserspaceInterruptGroup {
    ioapic: Arc<Mutex<dyn InterruptController>>,
    irq: u32,
}

impl LegacyUserspaceInterruptGroup {
    fn new(ioapic: Arc<Mutex<dyn InterruptController>>, irq: u32) -> Self {
        LegacyUserspaceInterruptGroup { ioapic, irq }
    }
}

impl InterruptSourceGroup for LegacyUserspaceInterruptGroup {
    fn trigger(&self, _index: InterruptIndex) -> Result<()> {
        self.ioapic
            .lock()
            .unwrap()
            .service_irq(self.irq as usize)
            .map_err(|e| {
                io::Error::new(
                    io::ErrorKind::Other,
                    format!("failed to inject IRQ #{}: {:?}", self.irq, e),
                )
            })
    }

    fn update(&self, _index: InterruptIndex, _config: InterruptSourceConfig) -> Result<()> {
        Ok(())
    }

    fn notifier(&self, _index: InterruptIndex) -> Option<EventFd> {
        self.ioapic.lock().unwrap().notifier(self.irq as usize)
    }
}

pub struct LegacyUserspaceInterruptManager {
    ioapic: Arc<Mutex<dyn InterruptController>>,
}

pub struct MsiInterruptManager<IrqRoutingEntry> {
    allocator: Arc<Mutex<SystemAllocator>>,
    vm: Arc<dyn hypervisor::Vm>,
    gsi_msi_routes: Arc<Mutex<HashMap<u32, RoutingEntry<IrqRoutingEntry>>>>,
}

impl LegacyUserspaceInterruptManager {
    pub fn new(ioapic: Arc<Mutex<dyn InterruptController>>) -> Self {
        LegacyUserspaceInterruptManager { ioapic }
    }
}

impl MsiInterruptManager<IrqRoutingEntry> {
    pub fn new(allocator: Arc<Mutex<SystemAllocator>>, vm: Arc<dyn hypervisor::Vm>) -> Self {
        // Create a shared list of GSI that can be shared through all PCI
        // devices. This way, we can maintain the full list of used GSI,
        // preventing one device from overriding interrupts setting from
        // another one.
        let gsi_msi_routes = Arc::new(Mutex::new(HashMap::new()));

        MsiInterruptManager {
            allocator,
            vm,
            gsi_msi_routes,
        }
    }
}

impl InterruptManager for LegacyUserspaceInterruptManager {
    type GroupConfig = LegacyIrqGroupConfig;

    fn create_group(&self, config: Self::GroupConfig) -> Result<Arc<dyn InterruptSourceGroup>> {
        Ok(Arc::new(LegacyUserspaceInterruptGroup::new(
            self.ioapic.clone(),
            config.irq as u32,
        )))
    }

    fn destroy_group(&self, _group: Arc<dyn InterruptSourceGroup>) -> Result<()> {
        Ok(())
    }
}

impl InterruptManager for MsiInterruptManager<IrqRoutingEntry> {
    type GroupConfig = MsiIrqGroupConfig;

    fn create_group(&self, config: Self::GroupConfig) -> Result<Arc<dyn InterruptSourceGroup>> {
        let mut allocator = self.allocator.lock().unwrap();
        let mut irq_routes: HashMap<InterruptIndex, InterruptRoute> =
            HashMap::with_capacity(config.count as usize);
        for i in config.base..config.base + config.count {
            irq_routes.insert(i, InterruptRoute::new(&mut allocator)?);
        }

        Ok(Arc::new(MsiInterruptGroup::new(
            self.vm.clone(),
            self.gsi_msi_routes.clone(),
            irq_routes,
        )))
    }

    fn destroy_group(&self, _group: Arc<dyn InterruptSourceGroup>) -> Result<()> {
        Ok(())
    }
}

#[cfg(feature = "kvm")]
pub mod kvm {
    use super::*;
    use hypervisor::kvm::KVM_MSI_VALID_DEVID;
    use hypervisor::kvm::{kvm_irq_routing_entry, KVM_IRQ_ROUTING_IRQCHIP, KVM_IRQ_ROUTING_MSI};
    use pci::PciBdf;

    type KvmRoutingEntry = RoutingEntry<kvm_irq_routing_entry>;
    pub type KvmMsiInterruptManager = MsiInterruptManager<kvm_irq_routing_entry>;

    impl KvmRoutingEntry {
        pub fn make_entry(
            vm: &Arc<dyn hypervisor::Vm>,
            gsi: u32,
            config: &InterruptSourceConfig,
        ) -> Result<Box<Self>> {
            if let InterruptSourceConfig::MsiIrq(cfg) = &config {
                let mut kvm_route = kvm_irq_routing_entry {
                    gsi,
                    type_: KVM_IRQ_ROUTING_MSI,
                    ..Default::default()
                };

                kvm_route.u.msi.address_lo = cfg.low_addr;
                kvm_route.u.msi.address_hi = cfg.high_addr;
                kvm_route.u.msi.data = cfg.data;

                if vm.check_extension(hypervisor::Cap::MsiDevid) {
                    // On AArch64, there is limitation on the range of the 'devid',
                    // it can not be greater than 65536 (the max of u16).
                    //
                    // BDF can not be used directly, because 'segment' is in high
                    // 16 bits. The layout of the u32 BDF is:
                    // |---- 16 bits ----|-- 8 bits --|-- 5 bits --|-- 3 bits --|
                    // |      segment    |     bus    |   device   |  function  |
                    //
                    // Now that we support 1 bus only in a segment, we can build a
                    // 'devid' by replacing the 'bus' bits with the low 8 bits of
                    // 'segment' data.
                    // This way we can resolve the range checking problem and give
                    // different `devid` to all the devices. Limitation is that at
                    // most 256 segments can be supported.
                    //
                    let bdf: PciBdf = PciBdf::from(cfg.devid);
                    let modified_bdf: PciBdf =
                        PciBdf::new(0, bdf.segment() as u8, bdf.device(), bdf.function());
                    kvm_route.flags = KVM_MSI_VALID_DEVID;
                    kvm_route.u.msi.__bindgen_anon_1.devid = modified_bdf.into();
                }

                let kvm_entry = KvmRoutingEntry {
                    route: kvm_route,
                    masked: false,
                };

                return Ok(Box::new(kvm_entry));
            } else if let InterruptSourceConfig::LegacyIrq(cfg) = &config {
                let mut kvm_route = kvm_irq_routing_entry {
                    gsi,
                    type_: KVM_IRQ_ROUTING_IRQCHIP,
                    ..Default::default()
                };
                kvm_route.u.irqchip.irqchip = cfg.irqchip;
                kvm_route.u.irqchip.pin = cfg.pin;
                let kvm_entry = KvmRoutingEntry {
                    route: kvm_route,
                    masked: false,
                };

                return Ok(Box::new(kvm_entry));
            }

            Err(io::Error::new(
                io::ErrorKind::Other,
                "Interrupt config type not supported",
            ))
        }
    }
}

#[cfg(feature = "mshv")]
pub mod mshv {
    use super::*;
    use hypervisor::mshv::*;

    type MshvRoutingEntry = RoutingEntry<mshv_msi_routing_entry>;
    pub type MshvMsiInterruptManager = MsiInterruptManager<mshv_msi_routing_entry>;

    impl MshvRoutingEntry {
        pub fn make_entry(
            _vm: &Arc<dyn hypervisor::Vm>,
            gsi: u32,
            config: &InterruptSourceConfig,
        ) -> Result<Box<Self>> {
            if let InterruptSourceConfig::MsiIrq(cfg) = &config {
                let route = mshv_msi_routing_entry {
                    gsi,
                    address_lo: cfg.low_addr,
                    address_hi: cfg.high_addr,
                    data: cfg.data,
                };
                let entry = MshvRoutingEntry {
                    route,
                    masked: false,
                };

                return Ok(Box::new(entry));
            }

            Err(io::Error::new(
                io::ErrorKind::Other,
                "Interrupt config type not supported",
            ))
        }
    }
}

#[cfg(target_arch = "aarch64")]
#[cfg(test)]
mod tests {
    use arch::aarch64::gic::kvm::{create_gic, save_pending_tables};
    use arch::aarch64::gic::{
        get_dist_regs, get_icc_regs, get_redist_regs, set_dist_regs, set_icc_regs, set_redist_regs,
    };

    #[test]
    fn test_create_gic() {
        let hv = hypervisor::new().unwrap();
        let vm = hv.create_vm().unwrap();

        assert!(create_gic(&vm, 1).is_ok());
    }

    #[test]
    fn test_get_set_dist_regs() {
        let hv = hypervisor::new().unwrap();
        let vm = hv.create_vm().unwrap();
        let _ = vm.create_vcpu(0, None).unwrap();
        let gic = create_gic(&vm, 1).expect("Cannot create gic");

        let res = get_dist_regs(gic.device());
        assert!(res.is_ok());
        let state = res.unwrap();
        assert_eq!(state.len(), 568);

        let res = set_dist_regs(gic.device(), &state);
        assert!(res.is_ok());
    }

    #[test]
    fn test_get_set_redist_regs() {
        let hv = hypervisor::new().unwrap();
        let vm = hv.create_vm().unwrap();
        let _ = vm.create_vcpu(0, None).unwrap();
        let gic = create_gic(&vm, 1).expect("Cannot create gic");

        let gicr_typer = vec![123];
        let res = get_redist_regs(gic.device(), &gicr_typer);
        assert!(res.is_ok());
        let state = res.unwrap();
        println!("{}", state.len());
        assert!(state.len() == 24);

        assert!(set_redist_regs(gic.device(), &gicr_typer, &state).is_ok());
    }

    #[test]
    fn test_get_set_icc_regs() {
        let hv = hypervisor::new().unwrap();
        let vm = hv.create_vm().unwrap();
        let _ = vm.create_vcpu(0, None).unwrap();
        let gic = create_gic(&vm, 1).expect("Cannot create gic");

        let gicr_typer = vec![123];
        let res = get_icc_regs(gic.device(), &gicr_typer);
        assert!(res.is_ok());
        let state = res.unwrap();
        println!("{}", state.len());
        assert!(state.len() == 9);

        assert!(set_icc_regs(gic.device(), &gicr_typer, &state).is_ok());
    }

    #[test]
    fn test_save_pending_tables() {
        let hv = hypervisor::new().unwrap();
        let vm = hv.create_vm().unwrap();
        let _ = vm.create_vcpu(0, None).unwrap();
        let gic = create_gic(&vm, 1).expect("Cannot create gic");

        assert!(save_pending_tables(gic.device()).is_ok());
    }
}