vfio: Integrate VFIO device into pci device model

Create VFIO device and VFIO PCI device in create_devices() function, and
intergrate it into PciRootBridge, so guest could see this vfio device.

Add a vfio config parameter, this config point to passthrough or mdev
device sysfs path.

For passthrough case, first user unbind host device from its driver,
then bind host device to vfio-pci. Like:
echo 0000:00:02.0 > /sys/bus/pci/devices/0000:00:02.0/driver/unbind
ech0 8086 1912 > /sys/bus/pci/drivers/vfio-pci/new_id
Finally pass the sysfs to crosvm through
--vfio=/sys/bus/pci/devices/0000:00:02.0

For mdev case, user create a mdev device through
echo $UUID > mdev_type/create, then pass this mdev device to crosvm like
--vfio=/sys/bus/pci/devices/0000:00:02.0/$UUID

BUG=chromium:992270
TEST=none

Change-Id: I0f59d6e93f62f9ab0727ad3a867d204f4ff6ad2d
Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1581140
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index 75d08ae..a864833 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -685,6 +685,24 @@ fn set_argument(cfg: &mut Config, name: &str, value: Option<&str>) -> argument::
             }
             cfg.executable_path = Some(Executable::Bios(PathBuf::from(value.unwrap().to_owned())));
         }
+        "vfio" => {
+            let vfio_path = PathBuf::from(value.unwrap());
+            if !vfio_path.exists() {
+                return Err(argument::Error::InvalidValue {
+                    value: value.unwrap().to_owned(),
+                    expected: "the vfio path does not exist",
+                });
+            }
+            if !vfio_path.is_dir() {
+                return Err(argument::Error::InvalidValue {
+                    value: value.unwrap().to_owned(),
+                    expected: "the vfio path should be directory",
+                });
+            }
+
+            cfg.vfio = Some(vfio_path);
+        }
+
         "help" => return Err(argument::Error::PrintHelp),
         _ => unreachable!(),
     }
@@ -774,6 +792,7 @@ fn run_vm(args: std::env::Args) -> std::result::Result<(), ()> {
           #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
           Argument::flag("split-irqchip", "(EXPERIMENTAL) enable split-irqchip support"),
           Argument::value("bios", "PATH", "Path to BIOS/firmware ROM"),
+          Argument::value("vfio", "PATH", "Path to sysfs of pass through or mdev device"),
           Argument::short_flag('h', "help", "Print help message.")];
 
     let mut cfg = Config::default();