devices: virtio: add PCI configuration callback function

The idea is that virtio devices can specify additional memory
regions.

BUG=chromium:924405
TEST=run VM

Change-Id: I2a9f233ca8e2bc4fd9b05ee83101b11deb6e7b04
Reviewed-on: https://chromium-review.googlesource.com/1480742
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/devices/src/virtio/virtio_device.rs b/devices/src/virtio/virtio_device.rs
index 82ca012..64018bd 100644
--- a/devices/src/virtio/virtio_device.rs
+++ b/devices/src/virtio/virtio_device.rs
@@ -7,6 +7,7 @@ use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
 
 use super::*;
+use pci::PciBarConfiguration;
 use sys_util::{EventFd, GuestMemory};
 
 /// Trait for virtio devices to be driven by a virtio transport.
@@ -73,4 +74,9 @@ pub trait VirtioDevice: Send {
     fn reset(&mut self) -> Option<(EventFd, Vec<EventFd>)> {
         None
     }
+
+    /// Optionally returns additional BAR configuration needed by device
+    fn get_device_bars(&self) -> Option<Vec<PciBarConfiguration>> {
+        None
+    }
 }