msb_krun_vmm 0.1.27

// Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

//#![deny(warnings)]

#[cfg(feature = "tee")]
use std::fs::File;
#[cfg(feature = "tee")]
use std::io::BufReader;
#[cfg(not(target_os = "windows"))]
use std::os::fd::RawFd;
use std::path::PathBuf;
use std::time::Duration;

#[cfg(feature = "tee")]
use serde::{Deserialize, Serialize};

#[cfg(feature = "blk")]
use crate::vmm_config::block::{BlockBuilder, BlockConfigError, BlockDeviceConfig};
use crate::vmm_config::external_kernel::ExternalKernel;
use crate::vmm_config::firmware::FirmwareConfig;
#[cfg(not(feature = "tee"))]
use crate::vmm_config::fs::*;
use crate::vmm_config::kernel_bundle::InitrdBundle;
use crate::vmm_config::kernel_bundle::{KernelBundle, KernelBundleError};
#[cfg(feature = "tee")]
use crate::vmm_config::kernel_bundle::{QbootBundle, QbootBundleError};
use crate::vmm_config::kernel_cmdline::{KernelCmdlineConfig, KernelCmdlineConfigError};
#[cfg(any(target_os = "linux", target_os = "windows"))]
use crate::vmm_config::machine_config::HostCpuId;
use crate::vmm_config::machine_config::{VmConfig, VmConfigError};
#[cfg(feature = "net")]
use crate::vmm_config::net::{NetBuilder, NetworkInterfaceConfig, NetworkInterfaceError};
use crate::vmm_config::vsock::*;
use crate::vstate::VcpuConfig;
#[cfg(feature = "gpu")]
use devices::virtio::display::DisplayInfo;
#[cfg(feature = "tee")]
use kbs_types::Tee;
#[cfg(feature = "gpu")]
use krun_display::DisplayBackend;
use utils::metrics::MetricsWriter;

type Result<E> = std::result::Result<(), E>;

#[cfg(target_os = "windows")]
pub use crate::vmm_config::vsock::TsiFlags;
#[cfg(not(target_os = "windows"))]
pub use devices::virtio::TsiFlags;

/// Errors encountered when configuring microVM resources.
#[derive(Debug)]
pub enum Error {
    /// JSON is invalid.
    InvalidJson,
    /// Boot source configuration error.
    KernelCmdline(KernelCmdlineConfigError),
    /// Error opening TEE config file.
    #[cfg(feature = "tee")]
    OpenTeeConfig(std::io::Error),
    /// Error parsing TEE config file.
    #[cfg(feature = "tee")]
    ParseTeeConfig(serde_json::Error),
    /// microVM vCpus or memory configuration error.
    VmConfig(VmConfigError),
    /// Vsock device configuration error.
    VsockDevice(VsockConfigError),
}

#[cfg(feature = "tee")]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TeeConfig {
    pub workload_id: String,
    pub cpus: u8,
    pub ram_mib: usize,
    pub tee: Tee,
    pub tee_data: String,
    pub attestation_url: String,
}

#[cfg(feature = "tee")]
impl Default for TeeConfig {
    fn default() -> Self {
        Self {
            workload_id: "".to_string(),
            cpus: 0,
            ram_mib: 0,
            tee: Tee::Sev,
            tee_data: "".to_string(),
            attestation_url: "".to_string(),
        }
    }
}

#[cfg(not(target_os = "windows"))]
pub struct SerialConsoleConfig {
    pub input_fd: RawFd,
    pub output_fd: RawFd,
}

#[cfg(not(target_os = "windows"))]
pub struct DefaultVirtioConsoleConfig {
    pub input_fd: RawFd,
    pub output_fd: RawFd,
    pub err_fd: RawFd,
}

#[cfg(not(target_os = "windows"))]
pub enum VirtioConsoleConfigMode {
    Autoconfigure(DefaultVirtioConsoleConfig),
    Explicit(Vec<PortConfig>),
}

#[cfg(target_os = "windows")]
pub enum VirtioConsoleConfigMode {
    Explicit(Vec<PortConfig>),
}

#[cfg(not(target_os = "windows"))]
pub enum PortConfig {
    Tty {
        name: String,
        tty_fd: RawFd,
    },
    InOut {
        name: String,
        input_fd: RawFd,
        output_fd: RawFd,
    },
    Custom {
        name: String,
        input: Box<dyn devices::virtio::port_io::PortInput + Send>,
        output: Box<dyn devices::virtio::port_io::PortOutput + Send>,
    },
}

#[cfg(target_os = "windows")]
pub enum PortConfig {
    ConsoleOutputFile { path: PathBuf },
    NamedPipe { name: String, pipe_name: String },
}

/// Configuration for the vsock device
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum VsockConfig {
    /// Default behavior - vsock created implicitly with heuristics-based TSI
    #[default]
    Implicit,
    /// Explicit configuration with specified TSI features
    Explicit { tsi_flags: TsiFlags },
    /// Vsock device disabled
    Disabled,
}

/// A data structure that encapsulates the device configurations
/// held in the Vmm.
pub struct VmResources {
    /// The vCpu and memory configuration for this microVM.
    vm_config: VmConfig,
    /// Resolved host logical processor for every possible vCPU thread.
    #[cfg(any(target_os = "linux", target_os = "windows"))]
    pub vcpu_affinity: Option<Vec<HostCpuId>>,
    /// The firmware to be loaded into the microVM.
    pub firmware_config: Option<FirmwareConfig>,
    /// The kernel command line for this microVM.
    pub kernel_cmdline: KernelCmdlineConfig,
    /// The parameters for the kernel bundle to be loaded in this microVM.
    pub kernel_bundle: Option<KernelBundle>,
    /// The path to an external kernel, as an alternative to KernelBundle.
    pub external_kernel: Option<ExternalKernel>,
    /// The parameters for the qboot bundle to be loaded in this microVM.
    #[cfg(feature = "tee")]
    pub qboot_bundle: Option<QbootBundle>,
    /// The parameters for the initrd bundle to be loaded in this microVM.
    pub initrd_bundle: Option<InitrdBundle>,
    /// The fs device.
    #[cfg(not(feature = "tee"))]
    pub fs: Vec<FsDeviceConfig>,
    /// Custom filesystem devices.
    #[cfg(not(any(feature = "tee", feature = "aws-nitro")))]
    pub custom_fs: Vec<CustomFsDeviceConfig>,
    /// The vsock device.
    pub vsock: VsockBuilder,
    /// The virtio-blk device.
    #[cfg(feature = "blk")]
    pub block: BlockBuilder,
    /// The network devices builder.
    #[cfg(feature = "net")]
    pub net: NetBuilder,
    /// TEE configuration
    #[cfg(feature = "tee")]
    pub tee_config: TeeConfig,
    /// Flags for the virtio-gpu device.
    pub gpu_virgl_flags: Option<u32>,
    pub gpu_shm_size: Option<usize>,
    #[cfg(feature = "gpu")]
    pub display_backend: Option<DisplayBackend<'static>>,
    #[cfg(feature = "gpu")]
    pub displays: Vec<DisplayInfo>,
    #[cfg(feature = "input")]
    pub input_backends: Vec<(
        krun_input::InputConfigBackend<'static>,
        krun_input::InputEventProviderBackend<'static>,
    )>,
    #[cfg(feature = "snd")]
    /// Enable the virtio-snd device.
    pub snd_device: bool,
    /// File to send console output.
    pub console_output: Option<PathBuf>,
    /// SMBIOS OEM Strings
    pub smbios_oem_strings: Option<Vec<String>>,
    /// Whether to enable nested virtualization.
    pub nested_enabled: bool,
    /// Whether to enable split irqchip
    pub split_irqchip: bool,
    /// Shared metrics state for VMM and device counters.
    pub metrics: MetricsWriter,
    /// Whether to attach the virtio-balloon device.
    pub enable_balloon: bool,
    /// The virtio-mem device backing live memory resize, created by the API
    /// layer when max memory exceeds boot memory. The builder places the
    /// hotplug region and attaches the device; the API layer keeps a clone as
    /// the runtime control handle.
    #[cfg(not(feature = "tee"))]
    pub mem_device: Option<std::sync::Arc<std::sync::Mutex<devices::virtio::Mem>>>,
    /// The CPU capacity device backing live CPU resize, created by the API
    /// layer when max vCPUs exceed the boot count. Also the source of the
    /// enforcement state every vCPU run loop consults.
    #[cfg(not(feature = "tee"))]
    pub cpu_device: Option<std::sync::Arc<std::sync::Mutex<devices::virtio::Cpu>>>,
    /// Guest memory stats polling interval for the virtio-balloon device.
    pub balloon_stats_interval: Option<Duration>,
    /// Whether to attach the virtio-rng device.
    pub enable_rng: bool,
    /// Whether to attach the private microsandbox metrics device.
    pub enable_msb_metrics: bool,
    /// Do not create an implicit console device in the guest
    pub disable_implicit_console: bool,
    /// The console id to use for console= in the kernel cmdline
    pub kernel_console: Option<String>,
    /// Serial consoles to attach to the guest
    #[cfg(not(target_os = "windows"))]
    pub serial_consoles: Vec<SerialConsoleConfig>,
    /// Virtio consoles to attach to the guest
    pub virtio_consoles: Vec<VirtioConsoleConfigMode>,
}

impl Default for VmResources {
    fn default() -> Self {
        Self {
            vm_config: VmConfig::default(),
            #[cfg(any(target_os = "linux", target_os = "windows"))]
            vcpu_affinity: None,
            firmware_config: None,
            kernel_cmdline: KernelCmdlineConfig::default(),
            kernel_bundle: None,
            external_kernel: None,
            #[cfg(feature = "tee")]
            qboot_bundle: None,
            initrd_bundle: None,
            #[cfg(not(feature = "tee"))]
            fs: Vec::new(),
            #[cfg(not(any(feature = "tee", feature = "aws-nitro")))]
            custom_fs: Vec::new(),
            vsock: VsockBuilder::default(),
            #[cfg(feature = "blk")]
            block: BlockBuilder::default(),
            #[cfg(feature = "net")]
            net: NetBuilder::default(),
            #[cfg(feature = "tee")]
            tee_config: TeeConfig::default(),
            gpu_virgl_flags: None,
            gpu_shm_size: None,
            #[cfg(feature = "gpu")]
            display_backend: None,
            #[cfg(feature = "gpu")]
            displays: Vec::new(),
            #[cfg(feature = "input")]
            input_backends: Vec::new(),
            #[cfg(feature = "snd")]
            snd_device: false,
            console_output: None,
            smbios_oem_strings: None,
            nested_enabled: false,
            split_irqchip: false,
            metrics: MetricsWriter::default(),
            enable_balloon: true,
            #[cfg(not(feature = "tee"))]
            mem_device: None,
            #[cfg(not(feature = "tee"))]
            cpu_device: None,
            balloon_stats_interval: Some(Duration::from_secs(1)),
            enable_rng: true,
            enable_msb_metrics: true,
            disable_implicit_console: false,
            kernel_console: None,
            #[cfg(not(target_os = "windows"))]
            serial_consoles: Vec::new(),
            virtio_consoles: Vec::new(),
        }
    }
}

impl VmResources {
    /// Returns a VcpuConfig based on the vm config.
    pub fn vcpu_config(&self) -> VcpuConfig {
        // The unwraps are ok to use because the values are initialized using defaults if not
        // supplied by the user.
        let vcpu_count = self.vm_config().vcpu_count.unwrap();
        VcpuConfig {
            vcpu_count,
            max_vcpu_count: self.vm_config().max_vcpu_count.unwrap_or(vcpu_count),
            ht_enabled: self.vm_config().ht_enabled.unwrap(),
            cpu_template: self.vm_config().cpu_template,
        }
    }

    /// Returns the VmConfig.
    pub fn vm_config(&self) -> &VmConfig {
        &self.vm_config
    }

    /// Set the machine configuration of the microVM.
    pub fn set_vm_config(&mut self, machine_config: &VmConfig) -> Result<VmConfigError> {
        if machine_config.vcpu_count == Some(0) {
            return Err(VmConfigError::InvalidVcpuCount);
        }

        if machine_config.mem_size_mib == Some(0) {
            return Err(VmConfigError::InvalidMemorySize);
        }

        let ht_enabled = machine_config
            .ht_enabled
            .unwrap_or_else(|| self.vm_config.ht_enabled.unwrap());

        let vcpu_count_value = machine_config
            .vcpu_count
            .unwrap_or_else(|| self.vm_config.vcpu_count.unwrap());

        // If hyperthreading is enabled or is to be enabled in this call
        // only allow vcpu count to be 1 or even.
        if ht_enabled && vcpu_count_value > 1 && vcpu_count_value % 2 == 1 {
            return Err(VmConfigError::InvalidVcpuCount);
        }

        if let Some(max_vcpu_count) = machine_config.max_vcpu_count {
            if max_vcpu_count < vcpu_count_value
                || max_vcpu_count > crate::vmm_config::machine_config::MAX_SUPPORTED_VCPUS
            {
                return Err(VmConfigError::InvalidMaxVcpuCount);
            }
            if ht_enabled && max_vcpu_count > 1 && max_vcpu_count % 2 == 1 {
                return Err(VmConfigError::InvalidMaxVcpuCount);
            }
            // Booting a wider possible topology than the online count relies on parked
            // vCPUs waiting for wake-ups (INIT/SIPI on x86, PSCI on aarch64) and on
            // non-TEE boot topology tables. On x86 Windows the AP startup router
            // provides exactly that and on aarch64 Windows WHP's in-hypervisor PSCI
            // does, so only the still-unwired platforms reject.
            #[cfg(any(target_arch = "riscv64", feature = "tee"))]
            if max_vcpu_count > vcpu_count_value {
                return Err(VmConfigError::MaxCapacityUnsupported);
            }
        }

        if let Some(max_mem_size_mib) = machine_config.max_mem_size_mib {
            let mem_size_mib = machine_config
                .mem_size_mib
                .unwrap_or_else(|| self.vm_config.mem_size_mib.unwrap());
            if max_mem_size_mib < mem_size_mib {
                return Err(VmConfigError::InvalidMaxMemorySize);
            }
        }

        // Update all the fields that have a new value.
        self.vm_config.vcpu_count = Some(vcpu_count_value);
        self.vm_config.ht_enabled = Some(ht_enabled);
        self.vm_config.max_vcpu_count = machine_config.max_vcpu_count;
        self.vm_config.max_mem_size_mib = machine_config.max_mem_size_mib;

        if machine_config.mem_size_mib.is_some() {
            self.vm_config.mem_size_mib = machine_config.mem_size_mib;
        }
        let memory_total_bytes = self
            .vm_config
            .mem_size_mib
            .unwrap_or(128)
            .saturating_mul(1024)
            .saturating_mul(1024) as u64;
        self.metrics.set_memory_total_bytes(memory_total_bytes);

        if machine_config.cpu_template.is_some() {
            self.vm_config.cpu_template = machine_config.cpu_template;
        }

        Ok(())
    }

    /// Set the guest kernel cmdline configuration.
    pub fn set_kernel_cmdline(
        &mut self,
        kernel_cmdline_cfg: KernelCmdlineConfig,
    ) -> Result<KernelCmdlineConfigError> {
        self.kernel_cmdline = kernel_cmdline_cfg;
        Ok(())
    }

    pub fn kernel_bundle(&self) -> Option<&KernelBundle> {
        self.kernel_bundle.as_ref()
    }

    pub fn set_kernel_bundle(&mut self, kernel_bundle: KernelBundle) -> Result<KernelBundleError> {
        // Safe because this call just returns the page size and doesn't have any side effects.
        let page_size = utils::page_size();

        if kernel_bundle.host_addr == 0 || (kernel_bundle.host_addr as usize) & (page_size - 1) != 0
        {
            return Err(KernelBundleError::InvalidHostAddress);
        }

        if (kernel_bundle.guest_addr as usize) & (page_size - 1) != 0 {
            return Err(KernelBundleError::InvalidGuestAddress);
        }

        self.kernel_bundle = Some(kernel_bundle);
        Ok(())
    }

    pub fn external_kernel(&self) -> Option<&ExternalKernel> {
        self.external_kernel.as_ref()
    }

    pub fn set_external_kernel(&mut self, external_kernel: ExternalKernel) {
        self.external_kernel = Some(external_kernel);
    }

    pub fn set_firmware_config(&mut self, firmware_config: FirmwareConfig) {
        self.firmware_config = Some(firmware_config);
    }

    #[cfg(feature = "tee")]
    pub fn qboot_bundle(&self) -> Option<&QbootBundle> {
        self.qboot_bundle.as_ref()
    }

    #[cfg(feature = "tee")]
    pub fn set_qboot_bundle(&mut self, qboot_bundle: QbootBundle) -> Result<QbootBundleError> {
        if qboot_bundle.size != 0x10000 {
            return Err(QbootBundleError::InvalidSize);
        }

        self.qboot_bundle = Some(qboot_bundle);
        Ok(())
    }

    pub fn initrd_bundle(&self) -> Option<&InitrdBundle> {
        self.initrd_bundle.as_ref()
    }

    pub fn set_initrd_bundle(&mut self, initrd_bundle: InitrdBundle) -> Result<KernelBundleError> {
        self.initrd_bundle = Some(initrd_bundle);
        Ok(())
    }

    #[cfg(not(feature = "tee"))]
    pub fn add_fs_device(&mut self, config: FsDeviceConfig) {
        self.fs.push(config)
    }

    #[cfg(feature = "blk")]
    pub fn add_block_device(&mut self, config: BlockDeviceConfig) -> Result<BlockConfigError> {
        self.block.insert(config, self.metrics.clone())
    }

    /// Adds a block device with an optional per-device hard dirty-data budget.
    #[cfg(feature = "blk")]
    pub fn add_block_device_with_writeback_limit(
        &mut self,
        config: BlockDeviceConfig,
        writeback_limit_bytes: Option<u64>,
    ) -> Result<BlockConfigError> {
        self.block
            .insert_with_writeback_limit(config, writeback_limit_bytes, self.metrics.clone())
    }

    /// Sets a vsock device to be attached when the VM starts.
    pub fn set_vsock_device(&mut self, config: VsockDeviceConfig) -> Result<VsockConfigError> {
        self.vsock.insert(config)
    }

    pub fn set_gpu_virgl_flags(&mut self, virgl_flags: u32) {
        self.gpu_virgl_flags = Some(virgl_flags);
    }

    pub fn set_gpu_shm_size(&mut self, shm_size: usize) {
        self.gpu_shm_size = Some(shm_size);
    }

    #[cfg(feature = "snd")]
    pub fn set_snd_device(&mut self, enabled: bool) {
        self.snd_device = enabled;
    }

    pub fn set_console_output(&mut self, console_output: PathBuf) {
        self.console_output = Some(console_output);
    }

    /// Sets a network device to be attached when the VM starts.
    #[cfg(feature = "net")]
    pub fn add_network_interface(
        &mut self,
        config: NetworkInterfaceConfig,
    ) -> Result<NetworkInterfaceError> {
        self.net.insert(config)
    }

    #[cfg(feature = "tee")]
    pub fn tee_config(&self) -> &TeeConfig {
        &self.tee_config
    }

    #[cfg(feature = "tee")]
    pub fn set_tee_config(&mut self, filepath: PathBuf) -> Result<Error> {
        let file = File::open(filepath.as_path()).map_err(Error::OpenTeeConfig)?;
        let reader = BufReader::new(file);
        let tee_config: TeeConfig =
            serde_json::from_reader(reader).map_err(Error::ParseTeeConfig)?;

        // Override VmConfig with TeeConfig values
        self.set_vm_config(&VmConfig {
            vcpu_count: Some(tee_config.cpus),
            mem_size_mib: Some(tee_config.ram_mib),
            max_vcpu_count: None,
            max_mem_size_mib: None,
            ht_enabled: Some(false),
            cpu_template: None,
        })
        .map_err(Error::VmConfig)?;

        self.tee_config = tee_config;

        Ok(())
    }
}

#[cfg(all(test, not(target_os = "windows")))]
mod tests {
    #[cfg(feature = "gpu")]
    use crate::resources::DisplayBackendConfig;
    use crate::resources::VmResources;
    use crate::vmm_config::machine_config::{CpuFeaturesTemplate, VmConfig, VmConfigError};
    use crate::vmm_config::vsock::tests::{default_config, TempSockFile};
    use crate::vstate::VcpuConfig;
    use utils::tempfile::TempFile;

    fn default_vm_resources() -> VmResources {
        VmResources::default()
    }

    #[test]
    fn test_vcpu_config() {
        let vm_resources = default_vm_resources();
        let expected_vcpu_config = VcpuConfig {
            vcpu_count: vm_resources.vm_config().vcpu_count.unwrap(),
            max_vcpu_count: vm_resources.vm_config().vcpu_count.unwrap(),
            ht_enabled: vm_resources.vm_config().ht_enabled.unwrap(),
            cpu_template: vm_resources.vm_config().cpu_template,
        };

        let vcpu_config = vm_resources.vcpu_config();
        assert_eq!(vcpu_config, expected_vcpu_config);
    }

    #[test]
    fn test_vm_config() {
        let vm_resources = default_vm_resources();
        let expected_vm_cfg = VmConfig::default();

        assert_eq!(vm_resources.vm_config(), &expected_vm_cfg);
    }

    #[test]
    fn test_set_vm_config() {
        let mut vm_resources = default_vm_resources();
        let mut aux_vm_config = VmConfig {
            vcpu_count: Some(32),
            mem_size_mib: Some(512),
            max_vcpu_count: None,
            max_mem_size_mib: None,
            ht_enabled: Some(true),
            cpu_template: Some(CpuFeaturesTemplate::T2),
        };

        assert_ne!(vm_resources.vm_config, aux_vm_config);
        vm_resources.set_vm_config(&aux_vm_config).unwrap();
        assert_eq!(vm_resources.vm_config, aux_vm_config);

        // Invalid vcpu count.
        aux_vm_config.vcpu_count = Some(0);
        assert_eq!(
            vm_resources.set_vm_config(&aux_vm_config),
            Err(VmConfigError::InvalidVcpuCount)
        );
        aux_vm_config.vcpu_count = Some(33);
        assert_eq!(
            vm_resources.set_vm_config(&aux_vm_config),
            Err(VmConfigError::InvalidVcpuCount)
        );
        aux_vm_config.vcpu_count = Some(32);

        // Invalid mem_size_mib.
        aux_vm_config.mem_size_mib = Some(0);
        assert_eq!(
            vm_resources.set_vm_config(&aux_vm_config),
            Err(VmConfigError::InvalidMemorySize)
        );
    }

    #[test]
    fn test_set_vm_config_max_capacity() {
        let mut vm_resources = default_vm_resources();
        let mut vm_config = VmConfig {
            vcpu_count: Some(2),
            mem_size_mib: Some(1024),
            max_vcpu_count: Some(8),
            max_mem_size_mib: Some(8192),
            ht_enabled: Some(false),
            cpu_template: None,
        };

        vm_resources.set_vm_config(&vm_config).unwrap();
        let vcpu_config = vm_resources.vcpu_config();
        assert_eq!(vcpu_config.vcpu_count, 2);
        assert_eq!(vcpu_config.max_vcpu_count, 8);

        // Without explicit capacity, max tracks the effective count.
        vm_config.max_vcpu_count = None;
        vm_config.max_mem_size_mib = None;
        vm_resources.set_vm_config(&vm_config).unwrap();
        assert_eq!(vm_resources.vcpu_config().max_vcpu_count, 2);

        // Max vcpus below the effective count.
        vm_config.max_vcpu_count = Some(1);
        assert_eq!(
            vm_resources.set_vm_config(&vm_config),
            Err(VmConfigError::InvalidMaxVcpuCount)
        );

        // Max vcpus above the supported limit.
        vm_config.max_vcpu_count = Some(65);
        assert_eq!(
            vm_resources.set_vm_config(&vm_config),
            Err(VmConfigError::InvalidMaxVcpuCount)
        );

        // Odd max vcpus with hyperthreading enabled.
        vm_config.max_vcpu_count = Some(3);
        vm_config.ht_enabled = Some(true);
        assert_eq!(
            vm_resources.set_vm_config(&vm_config),
            Err(VmConfigError::InvalidMaxVcpuCount)
        );
        vm_config.ht_enabled = Some(false);

        // Max memory below the boot memory size.
        vm_config.max_vcpu_count = Some(8);
        vm_config.max_mem_size_mib = Some(512);
        assert_eq!(
            vm_resources.set_vm_config(&vm_config),
            Err(VmConfigError::InvalidMaxMemorySize)
        );
    }

    #[test]
    fn test_set_vsock_device() {
        let mut vm_resources = default_vm_resources();
        let tmp_sock_file = TempSockFile::new(TempFile::new().unwrap());
        let new_vsock_cfg = default_config(&tmp_sock_file);
        assert!(vm_resources.vsock.get().is_none());
        vm_resources
            .set_vsock_device(new_vsock_cfg.clone())
            .unwrap();
        let actual_vsock_cfg = vm_resources.vsock.get().unwrap();
        assert_eq!(
            actual_vsock_cfg.lock().unwrap().id(),
            &new_vsock_cfg.vsock_id
        );
    }
}