build: make PCI (virtio and vfio) disableable at build time

Although included by default it is now possible to build without PCI
support.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

Cargo.toml

@@ -18,8 +18,9 @@ tempdir= "0.3.7"
 lazy_static= "1.4.0"
 
 [features]
-default = ["acpi"]
+default = ["acpi", "pci"]
 acpi = ["vmm/acpi"]
+pci = ["vmm/pci_support"]
 
 # Integration tests require a special environment to run in
 integration_tests = []

vm-virtio/Cargo.toml

@@ -4,6 +4,10 @@ version = "0.1.0"
 authors = ["Samuel Ortiz <sameo@linux.intel.com>"]
 edition = "2018"
 
+[features]
+default = []
+pci_support = ["pci"]
+
 [dependencies]
 byteorder = "1.3.2"
 devices = { path = "../devices" }
@@ -12,7 +16,7 @@ libc = "0.2.60"
 log = "0.4.8"
 net_gen = { path = "../net_gen" }
 net_util = { path = "../net_util" }
-pci = { path = "../pci" }
+pci = { path = "../pci", optional = true }
 tempfile = "3.1.0"
 virtio-bindings = { path = "../virtio-bindings" }
 vm-allocator = { path = "../vm-allocator" }

vm-virtio/src/lib.rs

@@ -12,6 +12,7 @@
 extern crate epoll;
 #[macro_use]
 extern crate log;
+#[cfg(feature = "pci_support")]
 extern crate pci;
 extern crate vhost_rs;
 extern crate virtio_bindings;

vm-virtio/src/transport/mod.rs

@@ -2,8 +2,11 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
+#[cfg(feature = "pci_support")]
 mod pci_common_config;
+#[cfg(feature = "pci_support")]
 mod pci_device;
-
+#[cfg(feature = "pci_support")]
 pub use pci_common_config::VirtioPciCommonConfig;
+#[cfg(feature = "pci_support")]
 pub use pci_device::VirtioPciDevice;

vm-virtio/src/transport/pci_device.rs

@@ -7,6 +7,7 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 
 extern crate devices;
+#[cfg(feature = "pci_support")]
 extern crate pci;
 extern crate vm_allocator;
 extern crate vm_memory;

vmm/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 [features]
 default = []
 acpi = ["acpi_tables","devices/acpi", "arch/acpi"]
+pci_support = ["pci", "vfio", "vm-virtio/pci_support"]
 
 [dependencies]
 acpi_tables = { path = "../acpi_tables", optional = true }
@@ -18,9 +19,9 @@ kvm-ioctls = { git = "https://github.com/rust-vmm/kvm-ioctls", branch = "master"
 libc = "0.2.62"
 log = "0.4.8"
 net_util = { path = "../net_util" }
-pci = {path = "../pci"}
+pci = {path = "../pci", optional = true}
 qcow = { path = "../qcow" }
-vfio = { path = "../vfio" }
+vfio = { path = "../vfio", optional = true }
 vm-virtio = { path = "../vm-virtio" }
 vm-allocator = { path = "../vm-allocator" }
 vmm-sys-util = { git = "https://github.com/rust-vmm/vmm-sys-util" }

vmm/src/device_manager.rs

@@ -19,6 +19,7 @@ use libc::O_TMPFILE;
 use libc::{EFD_NONBLOCK, TIOCGWINSZ};
 
 use net_util::Tap;
+#[cfg(feature = "pci_support")]
 use pci::{
     InterruptDelivery, InterruptParameters, PciConfigIo, PciDevice, PciInterruptPin, PciRoot,
 };
@@ -32,9 +33,11 @@ use std::os::unix::io::AsRawFd;
 use std::ptr::null_mut;
 use std::result;
 use std::sync::{Arc, Mutex, RwLock};
+#[cfg(feature = "pci_support")]
 use vfio::{VfioDevice, VfioPciDevice, VfioPciError};
 use vm_allocator::SystemAllocator;
 use vm_memory::{Address, GuestMemoryMmap, GuestUsize};
+#[cfg(feature = "pci_support")]
 use vm_virtio::transport::VirtioPciDevice;
 use vm_virtio::{VirtioSharedMemory, VirtioSharedMemoryList};
 use vmm_sys_util::eventfd::EventFd;
@@ -98,6 +101,7 @@ pub enum DeviceManagerError {
     Irq(io::Error),
 
     /// Cannot allocate PCI BARs
+    #[cfg(feature = "pci_support")]
     AllocateBars(pci::PciDeviceError),
 
     /// Cannot register ioevent.
@@ -107,6 +111,7 @@ pub enum DeviceManagerError {
     VirtioDevice(vmm_sys_util::errno::Error),
 
     /// Cannot add PCI device
+    #[cfg(feature = "pci_support")]
     AddPciDevice(pci::PciRootError),
 
     /// Cannot open persistent memory file
@@ -128,12 +133,15 @@ pub enum DeviceManagerError {
     ConsoleOutputFileOpen(io::Error),
 
     /// Cannot create a VFIO device
+    #[cfg(feature = "pci_support")]
     VfioCreate(vfio::VfioError),
 
     /// Cannot create a VFIO PCI device
+    #[cfg(feature = "pci_support")]
     VfioPciCreate(vfio::VfioPciError),
 
     /// Failed to map VFIO MMIO region.
+    #[cfg(feature = "pci_support")]
     VfioMapRegion(VfioPciError),
 
     /// Failed to create the KVM device.
@@ -272,9 +280,6 @@ pub struct DeviceManager {
     // IOAPIC
     ioapic: Option<Arc<Mutex<ioapic::Ioapic>>>,
 
-    // PCI root
-    pci: Arc<Mutex<PciConfigIo>>,
-
     // mmap()ed region to unmap on drop
     mmap_regions: Vec<(*mut libc::c_void, usize)>,
 
@@ -395,8 +400,11 @@ impl DeviceManager {
             &mut mmap_regions,
         )?);
 
+        #[allow(unused_mut)]
         let mut cmdline_additions = Vec::new();
 
+        #[cfg(feature = "pci_support")]
+        {
             let pci_root = PciRoot::new(None);
             let mut pci = PciConfigIo::new(pci_root);
 
@@ -413,8 +421,12 @@ impl DeviceManager {
             }
 
             DeviceManager::add_vfio_devices(vm_info, allocator, &mut pci, &mut buses, mem_slots)?;
-
             let pci = Arc::new(Mutex::new(pci));
+            io_bus
+                .insert(pci, 0xcf8, 0x8)
+                .map_err(DeviceManagerError::BusError)?;
+        }
+
 
         let mut dm = DeviceManager {
             io_bus,
@@ -424,7 +436,6 @@ impl DeviceManager {
             #[cfg(feature = "acpi")]
             acpi_device,
             ioapic,
-            pci,
             mmap_regions,
             cmdline_additions,
         };
@@ -767,6 +778,7 @@ impl DeviceManager {
             .map_err(DeviceManagerError::CreateKvmDevice)
     }
 
+    #[cfg(feature = "pci_support")]
     fn add_vfio_devices(
         vm_info: &VmInfo,
         allocator: &mut SystemAllocator,
@@ -808,6 +820,7 @@ impl DeviceManager {
         Ok(())
     }
 
+    #[cfg(feature = "pci_support")]
     fn add_virtio_pci_device(
         virtio_device: Box<dyn vm_virtio::VirtioDevice>,
         memory: &Arc<RwLock<GuestMemoryMmap>>,
@@ -939,11 +952,6 @@ impl DeviceManager {
             .insert(self.acpi_device.clone(), 0x3c0, 0x4)
             .map_err(DeviceManagerError::BusError)?;
 
-        // Insert the PCI root configuration space.
-        self.io_bus
-            .insert(self.pci.clone(), 0xcf8, 0x8)
-            .map_err(DeviceManagerError::BusError)?;
-
         if let Some(ioapic) = &self.ioapic {
             // Insert IOAPIC
             self.mmio_bus

vmm/src/vm.rs

@@ -17,6 +17,7 @@ extern crate libc;
 extern crate linux_loader;
 extern crate net_util;
 extern crate signal_hook;
+#[cfg(feature = "pci_support")]
 extern crate vfio;
 extern crate vm_allocator;
 extern crate vm_memory;