// Copyright (C) 2021 Red Hat, Inc. All rights reserved.
// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause

//! Kernel-based vhost-vdpa backend.

use std::fs::{File, OpenOptions};
use std::io::Error as IOError;
use std::os::raw::{c_uchar, c_uint};
use std::os::unix::fs::OpenOptionsExt;
use std::os::unix::io::{AsRawFd, RawFd};

use vm_memory::GuestAddressSpace;
use vmm_sys_util::eventfd::EventFd;
use vmm_sys_util::fam::*;
use vmm_sys_util::ioctl::{ioctl, ioctl_with_mut_ref, ioctl_with_ptr, ioctl_with_ref};

use super::vhost_binding::*;
use super::{ioctl_result, Error, Result, VhostKernBackend, VhostKernFeatures};
use crate::vdpa::*;
use crate::{VhostAccess, VhostIotlbBackend, VhostIotlbMsg, VhostIotlbType, VringConfigData};

// Implement the FamStruct trait for vhost_vdpa_config
generate_fam_struct_impl!(
    vhost_vdpa_config,
    c_uchar,
    buf,
    c_uint,
    len,
    c_uint::MAX as usize
);

type VhostVdpaConfig = FamStructWrapper<vhost_vdpa_config>;

/// Handle for running VHOST_VDPA ioctls.
pub struct VhostKernVdpa<AS: GuestAddressSpace> {
    fd: File,
    mem: AS,
    backend_features_acked: u64,
}

impl<AS: GuestAddressSpace> VhostKernVdpa<AS> {
    /// Open a handle to a new VHOST-VDPA instance.
    pub fn new(path: &str, mem: AS) -> Result<Self> {
        Ok(VhostKernVdpa {
            fd: OpenOptions::new()
                .read(true)
                .write(true)
                .custom_flags(libc::O_CLOEXEC | libc::O_NONBLOCK)
                .open(path)
                .map_err(Error::VhostOpen)?,
            mem,
            backend_features_acked: 0,
        })
    }

    /// Create a `VhostKernVdpa` object with given content.
    pub fn with(fd: File, mem: AS, backend_features_acked: u64) -> Self {
        VhostKernVdpa {
            fd,
            mem,
            backend_features_acked,
        }
    }

    /// Set the addresses for a given vring.
    ///
    /// # Arguments
    /// * `queue_index` - Index of the queue to set addresses for.
    /// * `config_data` - Vring config data, addresses of desc_table, avail_ring
    ///     and used_ring are in the guest address space.
    pub fn set_vring_addr(&self, queue_index: usize, config_data: &VringConfigData) -> Result<()> {
        if !self.is_valid(config_data) {
            return Err(Error::InvalidQueue);
        }

        // vDPA backends expect IOVA (that can be mapped 1:1 with
        // GPA when no IOMMU is involved).
        let vring_addr = vhost_vring_addr {
            index: queue_index as u32,
            flags: config_data.flags,
            desc_user_addr: config_data.desc_table_addr,
            used_user_addr: config_data.used_ring_addr,
            avail_user_addr: config_data.avail_ring_addr,
            log_guest_addr: config_data.get_log_addr(),
        };

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_ref(self, VHOST_SET_VRING_ADDR(), &vring_addr) };
        ioctl_result(ret, ())
    }
}

impl<AS: GuestAddressSpace> VhostVdpa for VhostKernVdpa<AS> {
    fn get_device_id(&self) -> Result<u32> {
        let mut device_id: u32 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_DEVICE_ID(), &mut device_id) };
        ioctl_result(ret, device_id)
    }

    fn get_status(&self) -> Result<u8> {
        let mut status: u8 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_STATUS(), &mut status) };
        ioctl_result(ret, status)
    }

    fn set_status(&self, status: u8) -> Result<()> {
        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_ref(self, VHOST_VDPA_SET_STATUS(), &status) };
        ioctl_result(ret, ())
    }

    fn get_config(&self, offset: u32, buffer: &mut [u8]) -> Result<()> {
        let mut config = VhostVdpaConfig::new(buffer.len())
            .map_err(|_| Error::IoctlError(IOError::from_raw_os_error(libc::ENOMEM)))?;

        config.as_mut_fam_struct().off = offset;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe {
            ioctl_with_ptr(
                self,
                VHOST_VDPA_GET_CONFIG(),
                config.as_mut_fam_struct_ptr(),
            )
        };

        buffer.copy_from_slice(config.as_slice());

        ioctl_result(ret, ())
    }

    fn set_config(&self, offset: u32, buffer: &[u8]) -> Result<()> {
        let mut config = VhostVdpaConfig::new(buffer.len())
            .map_err(|_| Error::IoctlError(IOError::from_raw_os_error(libc::ENOMEM)))?;

        config.as_mut_fam_struct().off = offset;
        config.as_mut_slice().copy_from_slice(buffer);

        let ret =
            // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
            // return value checked.
            unsafe { ioctl_with_ptr(self, VHOST_VDPA_SET_CONFIG(), config.as_fam_struct_ptr()) };
        ioctl_result(ret, ())
    }

    fn set_vring_enable(&self, queue_index: usize, enabled: bool) -> Result<()> {
        let vring_state = vhost_vring_state {
            index: queue_index as u32,
            num: enabled as u32,
        };

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_ref(self, VHOST_VDPA_SET_VRING_ENABLE(), &vring_state) };
        ioctl_result(ret, ())
    }

    fn get_vring_num(&self) -> Result<u16> {
        let mut vring_num: u16 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_VRING_NUM(), &mut vring_num) };
        ioctl_result(ret, vring_num)
    }

    fn set_config_call(&self, fd: &EventFd) -> Result<()> {
        let event_fd: ::std::os::raw::c_int = fd.as_raw_fd();

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_ref(self, VHOST_VDPA_SET_CONFIG_CALL(), &event_fd) };
        ioctl_result(ret, ())
    }

    fn get_iova_range(&self) -> Result<VhostVdpaIovaRange> {
        let mut low_iova_range = vhost_vdpa_iova_range { first: 0, last: 0 };

        let ret =
            // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
            // return value checked.
            unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_IOVA_RANGE(), &mut low_iova_range) };

        let iova_range = VhostVdpaIovaRange {
            first: low_iova_range.first,
            last: low_iova_range.last,
        };

        ioctl_result(ret, iova_range)
    }

    fn get_config_size(&self) -> Result<u32> {
        let mut config_size: u32 = 0;

        let ret =
            // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
            // return value checked.
            unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_CONFIG_SIZE(), &mut config_size) };
        ioctl_result(ret, config_size)
    }

    fn get_vqs_count(&self) -> Result<u32> {
        let mut vqs_count: u32 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_VQS_COUNT(), &mut vqs_count) };
        ioctl_result(ret, vqs_count)
    }

    fn get_group_num(&self) -> Result<u32> {
        let mut group_num: u32 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_GROUP_NUM(), &mut group_num) };
        ioctl_result(ret, group_num)
    }

    fn get_as_num(&self) -> Result<u32> {
        let mut as_num: u32 = 0;

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_AS_NUM(), &mut as_num) };
        ioctl_result(ret, as_num)
    }

    fn get_vring_group(&self, queue_index: u32) -> Result<u32> {
        let mut vring_state = vhost_vring_state {
            index: queue_index,
            ..Default::default()
        };

        let ret =
            // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
            // return value checked.
            unsafe { ioctl_with_mut_ref(self, VHOST_VDPA_GET_VRING_GROUP(), &mut vring_state) };
        ioctl_result(ret, vring_state.num)
    }

    fn set_group_asid(&self, group_index: u32, asid: u32) -> Result<()> {
        let vring_state = vhost_vring_state {
            index: group_index,
            num: asid,
        };

        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl_with_ref(self, VHOST_VDPA_GET_VRING_GROUP(), &vring_state) };
        ioctl_result(ret, ())
    }

    fn suspend(&self) -> Result<()> {
        // SAFETY: This ioctl is called on a valid vhost-vdpa fd and has its
        // return value checked.
        let ret = unsafe { ioctl(self, VHOST_VDPA_SUSPEND()) };
        ioctl_result(ret, ())
    }

    fn dma_map(&self, iova: u64, size: u64, vaddr: *const u8, readonly: bool) -> Result<()> {
        let iotlb = VhostIotlbMsg {
            iova,
            size,
            userspace_addr: vaddr as u64,
            perm: match readonly {
                true => VhostAccess::ReadOnly,
                false => VhostAccess::ReadWrite,
            },
            msg_type: VhostIotlbType::Update,
        };

        self.send_iotlb_msg(&iotlb)
    }

    fn dma_unmap(&self, iova: u64, size: u64) -> Result<()> {
        let iotlb = VhostIotlbMsg {
            iova,
            size,
            msg_type: VhostIotlbType::Invalidate,
            ..Default::default()
        };

        self.send_iotlb_msg(&iotlb)
    }
}

impl<AS: GuestAddressSpace> VhostKernBackend for VhostKernVdpa<AS> {
    type AS = AS;

    fn mem(&self) -> &Self::AS {
        &self.mem
    }

    /// Check whether the ring configuration is valid.
    fn is_valid(&self, config_data: &VringConfigData) -> bool {
        let queue_size = config_data.queue_size;
        if queue_size > config_data.queue_max_size
            || queue_size == 0
            || (queue_size & (queue_size - 1)) != 0
        {
            return false;
        }

        // Since vDPA could be dealing with IOVAs corresponding to GVAs, it
        // wouldn't make sense to go through the validation of the descriptor
        // table address, available ring address and used ring address against
        // the guest memory representation we have access to.

        config_data.is_log_addr_valid()
    }
}

impl<AS: GuestAddressSpace> AsRawFd for VhostKernVdpa<AS> {
    fn as_raw_fd(&self) -> RawFd {
        self.fd.as_raw_fd()
    }
}

impl<AS: GuestAddressSpace> VhostKernFeatures for VhostKernVdpa<AS> {
    fn get_backend_features_acked(&self) -> u64 {
        self.backend_features_acked
    }

    fn set_backend_features_acked(&mut self, features: u64) {
        self.backend_features_acked = features;
    }
}

#[cfg(test)]
mod tests {
    const VHOST_VDPA_PATH: &str = "/dev/vhost-vdpa-0";

    use std::alloc::{alloc, dealloc, Layout};
    use vm_memory::{GuestAddress, GuestMemory, GuestMemoryMmap};
    use vmm_sys_util::eventfd::EventFd;

    use super::*;
    use crate::{
        VhostBackend, VhostUserDirtyLogRegion, VhostUserMemoryRegionInfo, VringConfigData,
    };
    use serial_test::serial;
    use std::io::ErrorKind;

    /// macro to skip test if vhost-vdpa device path is not found.
    ///
    /// vDPA simulators are available since Linux 5.7, but the CI may have
    /// an older kernel, so for now we skip the test if we don't find
    /// the device.
    macro_rules! unwrap_not_found {
        ( $e:expr ) => {
            match $e {
                Ok(v) => v,
                Err(error) => match error {
                    Error::VhostOpen(ref e) if e.kind() == ErrorKind::NotFound => {
                        println!("Err: {:?} SKIPPED", e);
                        return;
                    }
                    e => panic!("Err: {:?}", e),
                },
            }
        };
    }

    macro_rules! validate_ioctl {
        ( $e:expr, $ref_value:expr ) => {
            match $e {
                Ok(v) => assert_eq!(v, $ref_value),
                Err(error) => match error {
                    Error::IoctlError(e) if e.raw_os_error().unwrap() == libc::ENOTTY => {
                        println!("Err: {:?} SKIPPED", e);
                    }
                    e => panic!("Err: {:?}", e),
                },
            }
        };
    }

    #[test]
    #[serial]
    fn test_vdpa_kern_new_device() {
        let m = GuestMemoryMmap::<()>::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));

        assert!(vdpa.as_raw_fd() >= 0);
        assert!(vdpa.mem().find_region(GuestAddress(0x100)).is_some());
        assert!(vdpa.mem().find_region(GuestAddress(0x10_0000)).is_none());
    }

    #[test]
    #[serial]
    fn test_vdpa_kern_is_valid() {
        let m = GuestMemoryMmap::<()>::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));

        let mut config = VringConfigData {
            queue_max_size: 32,
            queue_size: 32,
            flags: 0,
            desc_table_addr: 0x1000,
            used_ring_addr: 0x2000,
            avail_ring_addr: 0x3000,
            log_addr: None,
        };
        assert!(vdpa.is_valid(&config));

        config.queue_size = 0;
        assert!(!vdpa.is_valid(&config));
        config.queue_size = 31;
        assert!(!vdpa.is_valid(&config));
        config.queue_size = 33;
        assert!(!vdpa.is_valid(&config));
    }

    #[test]
    #[serial]
    fn test_vdpa_kern_ioctls() {
        let m = GuestMemoryMmap::<()>::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));

        let features = vdpa.get_features().unwrap();
        // VIRTIO_F_VERSION_1 (bit 32) should be set
        assert_ne!(features & (1 << 32), 0);
        vdpa.set_features(features).unwrap();

        vdpa.set_owner().unwrap();

        vdpa.set_mem_table(&[]).unwrap_err();

        let region = VhostUserMemoryRegionInfo::new(
            0x0,
            0x10_0000,
            m.get_host_address(GuestAddress(0x0)).unwrap() as u64,
            0,
            -1,
        );
        vdpa.set_mem_table(&[region]).unwrap();

        let device_id = vdpa.get_device_id().unwrap();
        assert!(device_id > 0);

        assert_eq!(vdpa.get_status().unwrap(), 0x0);
        vdpa.set_status(0x1).unwrap();
        assert_eq!(vdpa.get_status().unwrap(), 0x1);

        let mut vec = vec![0u8; 8];
        vdpa.get_config(0, &mut vec).unwrap();
        vdpa.set_config(0, &vec).unwrap();

        let eventfd = EventFd::new(0).unwrap();

        // set_log_base() and set_log_fd() are not supported by vhost-vdpa
        vdpa.set_log_base(
            0x4000,
            Some(VhostUserDirtyLogRegion {
                mmap_size: 0x1000,
                mmap_offset: 0x10,
                mmap_handle: 1,
            }),
        )
        .unwrap_err();
        vdpa.set_log_base(0x4000, None).unwrap_err();
        vdpa.set_log_fd(eventfd.as_raw_fd()).unwrap_err();

        let max_queues = vdpa.get_vring_num().unwrap();
        vdpa.set_vring_num(0, max_queues + 1).unwrap_err();

        vdpa.set_vring_num(0, 32).unwrap();

        let config = VringConfigData {
            queue_max_size: 32,
            queue_size: 32,
            flags: 0,
            desc_table_addr: 0x1000,
            used_ring_addr: 0x2000,
            avail_ring_addr: 0x3000,
            log_addr: None,
        };
        vdpa.set_vring_addr(0, &config).unwrap();
        vdpa.set_vring_base(0, 1).unwrap();
        vdpa.set_vring_call(0, &eventfd).unwrap();
        vdpa.set_vring_kick(0, &eventfd).unwrap();
        vdpa.set_vring_err(0, &eventfd).unwrap();

        vdpa.set_config_call(&eventfd).unwrap();

        let iova_range = vdpa.get_iova_range().unwrap();
        // vDPA-block simulator returns [0, u64::MAX] range
        assert_eq!(iova_range.first, 0);
        assert_eq!(iova_range.last, u64::MAX);

        let (config_size, vqs_count, group_num, as_num, vring_group) = if device_id == 1 {
            (24, 3, 2, 2, 0)
        } else if device_id == 2 {
            (60, 1, 1, 1, 0)
        } else {
            panic!("Unexpected device id {}", device_id)
        };

        validate_ioctl!(vdpa.get_config_size(), config_size);
        validate_ioctl!(vdpa.get_vqs_count(), vqs_count);
        validate_ioctl!(vdpa.get_group_num(), group_num);
        validate_ioctl!(vdpa.get_as_num(), as_num);
        validate_ioctl!(vdpa.get_vring_group(0), vring_group);
        validate_ioctl!(vdpa.set_group_asid(0, 12345), ());

        if vdpa.get_backend_features().unwrap() & (1 << VHOST_BACKEND_F_SUSPEND)
            == (1 << VHOST_BACKEND_F_SUSPEND)
        {
            validate_ioctl!(vdpa.suspend(), ());
        }

        assert_eq!(vdpa.get_vring_base(0).unwrap(), 1);

        vdpa.set_vring_enable(0, true).unwrap();
        vdpa.set_vring_enable(0, false).unwrap();
    }

    #[test]
    #[serial]
    fn test_vdpa_kern_dma() {
        let m = GuestMemoryMmap::<()>::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
        let mut vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));

        let features = vdpa.get_features().unwrap();
        // VIRTIO_F_VERSION_1 (bit 32) should be set
        assert_ne!(features & (1 << 32), 0);
        vdpa.set_features(features).unwrap();

        let backend_features = vdpa.get_backend_features().unwrap();
        assert_ne!(backend_features & (1 << VHOST_BACKEND_F_IOTLB_MSG_V2), 0);
        vdpa.set_backend_features(backend_features).unwrap();

        vdpa.set_owner().unwrap();

        vdpa.dma_map(0xFFFF_0000, 0xFFFF, std::ptr::null::<u8>(), false)
            .unwrap_err();

        let layout = Layout::from_size_align(0xFFFF, 1).unwrap();

        // SAFETY: Safe because layout has non-zero size.
        let ptr = unsafe { alloc(layout) };

        vdpa.dma_map(0xFFFF_0000, 0xFFFF, ptr, false).unwrap();
        vdpa.dma_unmap(0xFFFF_0000, 0xFFFF).unwrap();

        // SAFETY: Safe because `ptr` is allocated with the same allocator
        // using the same `layout`.
        unsafe { dealloc(ptr, layout) };
    }
}
