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, 2 insertions, 0 deletions

diff --git a/src/crosvm.rs b/src/crosvm.rs
index bc39e7f..b7055df 100644
--- a/src/crosvm.rs
+++ b/src/crosvm.rs
@@ -109,6 +109,7 @@ pub struct Config {
     pub virtio_keyboard: Option<PathBuf>,
     pub virtio_input_evdevs: Vec<PathBuf>,
     pub split_irqchip: bool,
+    pub vfio: Option<PathBuf>,
 }
 
 impl Default for Config {
@@ -153,6 +154,7 @@ impl Default for Config {
             virtio_keyboard: None,
             virtio_input_evdevs: Vec::new(),
             split_irqchip: false,
+            vfio: None,
         }
     }
 }