vfio-pci: Re-order device reset

Move the device reset to the end of our disable path, the device
should already be stopped from pci_disable_device().  This also allows
us to manipulate the save/restore to avoid the save/reset/restore +
save/restore that we had before.

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

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index a4dc21b..b179f5a 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -92,9 +92,10 @@ out:
 
 static void vfio_pci_disable(struct vfio_pci_device *vdev)
 {
+       struct pci_dev *pdev = vdev->pdev;
        int bar;
 
-       pci_disable_device(vdev->pdev);
+       pci_disable_device(pdev);
 
        vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
                                VFIO_IRQ_SET_ACTION_TRIGGER,
@@ -104,22 +105,40 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
 
        vfio_config_free(vdev);
 
-       pci_reset_function(vdev->pdev);
-
-       if (pci_load_and_free_saved_state(vdev->pdev,
-                                         &vdev->pci_saved_state) == 0)
-               pci_restore_state(vdev->pdev);
-       else
-               pr_info("%s: Couldn't reload %s saved state\n",
-                       __func__, dev_name(&vdev->pdev->dev));
-
        for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
                if (!vdev->barmap[bar])
                        continue;
-               pci_iounmap(vdev->pdev, vdev->barmap[bar]);
-               pci_release_selected_regions(vdev->pdev, 1 << bar);
+               pci_iounmap(pdev, vdev->barmap[bar]);
+               pci_release_selected_regions(pdev, 1 << bar);
                vdev->barmap[bar] = NULL;
        }
+
+       /*
+        * If we have saved state, restore it.  If we can reset the device,
+        * even better.  Resetting with current state seems better than
+        * nothing, but saving and restoring current state without reset
+        * is just busy work.
+        */
+       if (pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state)) {
+               pr_info("%s: Couldn't reload %s saved state\n",
+                       __func__, dev_name(&pdev->dev));
+
+               if (!vdev->reset_works)
+                       return;
+
+               pci_save_state(pdev);
+       }
+
+       /*
+        * Disable INTx and MSI, presumably to avoid spurious interrupts
+        * during reset.  Stolen from pci_reset_function()
+        */
+       pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+
+       if (vdev->reset_works)
+               __pci_reset_function(pdev);
+
+       pci_restore_state(pdev);
 }
 
 static void vfio_pci_release(void *device_data)