From 8209652159f2e3cc7cdb5de9e475001058282274 Mon Sep 17 00:00:00 2001
From: Christopher Desiniotis <cdesiniotis@nvidia.com>
Date: Fri, 8 Jul 2022 13:11:01 -0700
Subject: [PATCH] Detect driver bound to mdev devices

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>
---
 pkg/nvmdev/mock.go        |  9 +++++++++
 pkg/nvmdev/nvmdev.go      | 15 +++++++++++++++
 pkg/nvmdev/nvmdev_test.go |  1 +
 3 files changed, 25 insertions(+)

diff --git a/pkg/nvmdev/mock.go b/pkg/nvmdev/mock.go
index ed7a055..626e3e9 100644
--- a/pkg/nvmdev/mock.go
+++ b/pkg/nvmdev/mock.go
@@ -196,6 +196,15 @@ func (m *MockNvmdev) AddMockA100Mdev(uuid string, mdevType string, mdevTypeDir s
 		return err
 	}
 
+	_, err = os.Create(filepath.Join(mdevDeviceDir, "vfio_mdev"))
+	if err != nil {
+		return err
+	}
+	err = os.Symlink(filepath.Join(mdevDeviceDir, "vfio_mdev"), filepath.Join(mdevDeviceDir, "driver"))
+	if err != nil {
+		return err
+	}
+
 	err = os.Symlink(mdevDeviceDir, filepath.Join(m.mdevDevicesRoot, uuid))
 	if err != nil {
 		return err
diff --git a/pkg/nvmdev/nvmdev.go b/pkg/nvmdev/nvmdev.go
index 3e4befe..dfcfef7 100644
--- a/pkg/nvmdev/nvmdev.go
+++ b/pkg/nvmdev/nvmdev.go
@@ -56,6 +56,7 @@ type Device struct {
 	Path     string
 	UUID     string
 	MDEVType string
+	Driver   string
 	Parent   *ParentDevice
 }
 
@@ -143,10 +144,16 @@ func NewDevice(root string, uuid string) (*Device, error) {
 		return nil, fmt.Errorf("error getting mdev type: %v", err)
 	}
 
+	driver, err := m.driver()
+	if err != nil {
+		return nil, fmt.Errorf("error detecting driver: %v", err)
+	}
+
 	device := Device{
 		Path:     path,
 		UUID:     uuid,
 		MDEVType: mdevType,
+		Driver:   driver,
 		Parent:   parent,
 	}
 
@@ -193,6 +200,14 @@ func (m mdev) Type() (string, error) {
 	return mdevTypeSplit[1], nil
 }
 
+func (m mdev) driver() (string, error) {
+	driver, err := filepath.EvalSymlinks(path.Join(string(m), "driver"))
+	if err != nil {
+		return "", err
+	}
+	return filepath.Base(driver), nil
+}
+
 // NewParentDevice constructs a ParentDevice
 func NewParentDevice(devicePath string) (*ParentDevice, error) {
 	nvdevice, err := nvpci.NewDevice(devicePath)
diff --git a/pkg/nvmdev/nvmdev_test.go b/pkg/nvmdev/nvmdev_test.go
index d044a9c..78d1058 100644
--- a/pkg/nvmdev/nvmdev_test.go
+++ b/pkg/nvmdev/nvmdev_test.go
@@ -46,4 +46,5 @@ func TestNvmdev(t *testing.T) {
 	mdevs, err := nvmdev.GetAllDevices()
 	require.Nil(t, err, "Error getting NVIDIA MDEV (vGPU) devices")
 	require.Equal(t, 1, len(mdevs), "Wrong number of NVIDIA MDEV (vGPU) devices")
+	require.Equal(t, "vfio_mdev", mdevs[0].Driver, "Wrong driver detected for mdev device")
 }