vfio-pci: Enable device before attempting reset

Devices making use of PM reset are getting incorrectly identified as
not supporting reset because pci_pm_reset() fails unless the device is
in D0 power state.  When first attached to vfio_pci devices are
typically in an unknown power state.  We can fix this by explicitly
setting the power state or simply calling pci_enable_device() before
attempting a pci_reset_function().  We need to enable the device
anyway, so move this up in our vfio_pci_enable() function, which also
simplifies the error path a bit.

Note that pci_disable_device() does not explicitly set the power
state, so there's no need to re-order vfio_pci_disable().

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 10 insertions, 13 deletions

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 306b90cf051f..b28e66c4376a 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -43,6 +43,10 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
         u16 cmd;
         u8 msix_pos;
 
+        ret = pci_enable_device(pdev);
+        if (ret)
+                return ret;
+
         vdev->reset_works = (pci_reset_function(pdev) == 0);
         pci_save_state(pdev);
         vdev->pci_saved_state = pci_store_saved_state(pdev);
@@ -51,8 +55,11 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
                          __func__, dev_name(&pdev->dev));
 
         ret = vfio_config_init(vdev);
-        if (ret)
-                goto out;
+        if (ret) {
+                pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state);
+                pci_disable_device(pdev);
+                return ret;
+        }
 
         if (likely(!nointxmask))
                 vdev->pci_2_3 = pci_intx_mask_supported(pdev);
@@ -77,17 +84,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
         } else
                 vdev->msix_bar = 0xFF;
 
-        ret = pci_enable_device(pdev);
-        if (ret)
-                goto out;
-
-        return ret;
-
-out:
-        kfree(vdev->pci_saved_state);
-        vdev->pci_saved_state = NULL;
-        vfio_config_free(vdev);
-        return ret;
+        return 0;
 }
 
 static void vfio_pci_disable(struct vfio_pci_device *vdev)