vhost_kern/vdpa: skip tests if device is not found

vDPA simulators are available since Linux 5.7.

The CI may have an older kernel, so to avoid CI failures, for now
we skip the tests if we don't find the device.

Signed-off-by: Stefano Garzarella <[email protected]>

src/vhost_kern/vdpa.rs

@@ -210,12 +210,33 @@ mod tests {
     use super::*;
     use crate::{VhostBackend, VhostUserMemoryRegionInfo, VringConfigData};
     use serial_test::serial;
+    use std::io::ErrorKind;
+
+    /// macro to skip test if vhost-vdpa device path is not found.
+    ///
+    /// vDPA simulators are available since Linux 5.7, but the CI may have
+    /// an older kernel, so for now we skip the test if we don't find
+    /// the device.
+    macro_rules! unwrap_not_found {
+        ( $e:expr ) => {
+            match $e {
+                Ok(v) => v,
+                Err(error) => match error {
+                    Error::VhostOpen(ref e) if e.kind() == ErrorKind::NotFound => {
+                        println!("Err: {:?} SKIPPED", e);
+                        return;
+                    }
+                    e => panic!("Err: {:?}", e),
+                },
+            }
+        };
+    }
 
     #[test]
     #[serial]
     fn test_vdpa_kern_new_device() {
         let m = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
-        let vdpa = VhostKernVdpa::new(VHOST_VDPA_PATH, &m).unwrap();
+        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));
 
         assert!(vdpa.as_raw_fd() >= 0);
         assert!(vdpa.mem().find_region(GuestAddress(0x100)).is_some());
@@ -226,7 +247,7 @@ mod tests {
     #[serial]
     fn test_vdpa_kern_is_valid() {
         let m = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
-        let vdpa = VhostKernVdpa::new(VHOST_VDPA_PATH, &m).unwrap();
+        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));
 
         let mut config = VringConfigData {
             queue_max_size: 32,
@@ -251,7 +272,7 @@ mod tests {
     #[serial]
     fn test_vdpa_kern_ioctls() {
         let m = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
-        let vdpa = VhostKernVdpa::new(VHOST_VDPA_PATH, &m).unwrap();
+        let vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));
 
         let features = vdpa.get_features().unwrap();
         // VIRTIO_F_VERSION_1 (bit 32) should be set
@@ -320,7 +341,7 @@ mod tests {
     #[serial]
     fn test_vdpa_kern_dma() {
         let m = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), 0x10_0000)]).unwrap();
-        let mut vdpa = VhostKernVdpa::new(VHOST_VDPA_PATH, &m).unwrap();
+        let mut vdpa = unwrap_not_found!(VhostKernVdpa::new(VHOST_VDPA_PATH, &m));
 
         let features = vdpa.get_features().unwrap();
         // VIRTIO_F_VERSION_1 (bit 32) should be set