Add tests exercising the PCI configuration space helpers.

Suggested-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
 samples/rust/rust_driver_pci.rs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs
index bfb053059667..26f0887a74e8 100644
--- a/samples/rust/rust_driver_pci.rs
+++ b/samples/rust/rust_driver_pci.rs
@@ -5,6 +5,7 @@
 //! To make this driver probe, QEMU must be run with `-device pci-testdev`.
 
 use kernel::{
+    device::Bound,
     device::Core,
     devres::Devres,
     io::{
@@ -68,6 +69,32 @@ fn testdev(index: &TestIndex, bar: &Bar0) -> Result<u32> {
 
         Ok(bar.read32(Regs::COUNT))
     }
+
+    fn config_space(pdev: &pci::Device<Bound>) -> Result {
+        let config = pdev.config_space()?;
+
+        // TODO: use the register!() macro for defining PCI configuration space registers once it
+        // has been move out of nova-core.
+        dev_info!(
+            pdev.as_ref(),
+            "pci-testdev config space read8 rev ID: {:x}\n",
+            config.read8(0x8)
+        );
+
+        dev_info!(
+            pdev.as_ref(),
+            "pci-testdev config space read16 vendor ID: {:x}\n",
+            config.read16(0)
+        );
+
+        dev_info!(
+            pdev.as_ref(),
+            "pci-testdev config space read32 BAR 0: {:x}\n",
+            config.read32(0x10)
+        );
+
+        Ok(())
+    }
 }
 
 impl pci::Driver for SampleDriver {
@@ -99,6 +126,7 @@ fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> impl PinInit<Self, Er
                         "pci-testdev data-match count: {}\n",
                         Self::testdev(info, bar)?
                     );
+                    Self::config_space(pdev)?;
                 },
                 pdev: pdev.into(),
             }))
-- 
2.51.0