diff options
| -rw-r--r-- | drivers/vfio/pci/vfio_pci.c | 112 | ||||
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_private.h | 1 |
2 files changed, 113 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index c9d756b7ee9..1651c0769b7 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -39,6 +39,8 @@ MODULE_PARM_DESC(nointxmask, static DEFINE_MUTEX(driver_lock); +static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev); + static int vfio_pci_enable(struct vfio_pci_device *vdev) { struct pci_dev *pdev = vdev->pdev; @@ -123,6 +125,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) vdev->barmap[bar] = NULL; } + vdev->needs_reset = true; + /* * If we have saved state, restore it. If we can reset the device, * even better. Resetting with current state seems better than @@ -154,11 +158,15 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) if (ret) pr_warn("%s: Failed to reset device %s (%d)\n", __func__, dev_name(&pdev->dev), ret); + else + vdev->needs_reset = false; } pci_restore_state(pdev); out: pci_disable_device(pdev); + + vfio_pci_try_bus_reset(vdev); } static void vfio_pci_release(void *device_data) @@ -923,6 +931,110 @@ static struct pci_driver vfio_pci_driver = { .err_handler = &vfio_err_handlers, }; +/* + * Test whether a reset is necessary and possible. We mark devices as + * needs_reset when they are released, but don't have a function-local reset + * available. If any of these exist in the affected devices, we want to do + * a bus/slot reset. We also need all of the affected devices to be unused, + * so we abort if any device has a non-zero refcnt. driver_lock prevents a + * device from being opened during the scan or unbound from vfio-pci. + */ +static int vfio_pci_test_bus_reset(struct pci_dev *pdev, void *data) +{ + bool *needs_reset = data; + struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver); + int ret = -EBUSY; + + if (pci_drv == &vfio_pci_driver) { + struct vfio_device *device; + struct vfio_pci_device *vdev; + + device = vfio_device_get_from_dev(&pdev->dev); + if (!device) + return ret; + + vdev = vfio_device_data(device); + if (vdev) { + if (vdev->needs_reset) + *needs_reset = true; + + if (!vdev->refcnt) + ret = 0; + } + + vfio_device_put(device); + } + + /* + * TODO: vfio-core considers groups to be viable even if some devices + * are attached to known drivers, like pci-stub or pcieport. We can't + * freeze devices from being unbound to those drivers like we can + * here though, so it would be racy to test for them. We also can't + * use device_lock() to prevent changes as that would interfere with + * PCI-core taking device_lock during bus reset. For now, we require + * devices to be bound to vfio-pci to get a bus/slot reset on release. + */ + + return ret; +} + +/* Clear needs_reset on all affected devices after successful bus/slot reset */ +static int vfio_pci_clear_needs_reset(struct pci_dev *pdev, void *data) +{ + struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver); + + if (pci_drv == &vfio_pci_driver) { + struct vfio_device *device; + struct vfio_pci_device *vdev; + + device = vfio_device_get_from_dev(&pdev->dev); + if (!device) + return 0; + + vdev = vfio_device_data(device); + if (vdev) + vdev->needs_reset = false; + + vfio_device_put(device); + } + + return 0; +} + +/* + * Attempt to do a bus/slot reset if there are devices affected by a reset for + * this device that are needs_reset and all of the affected devices are unused + * (!refcnt). Callers of this function are required to hold driver_lock such + * that devices can not be unbound from vfio-pci or opened by a user while we + * test for and perform a bus/slot reset. + */ +static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev) +{ + bool needs_reset = false, slot = false; + int ret; + + if (!pci_probe_reset_slot(vdev->pdev->slot)) + slot = true; + else if (pci_probe_reset_bus(vdev->pdev->bus)) + return; + + if (vfio_pci_for_each_slot_or_bus(vdev->pdev, + vfio_pci_test_bus_reset, + &needs_reset, slot) || !needs_reset) + return; + + if (slot) + ret = pci_try_reset_slot(vdev->pdev->slot); + else + ret = pci_try_reset_bus(vdev->pdev->bus); + + if (ret) + return; + + vfio_pci_for_each_slot_or_bus(vdev->pdev, + vfio_pci_clear_needs_reset, NULL, slot); +} + static void __exit vfio_pci_cleanup(void) { pci_unregister_driver(&vfio_pci_driver); diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h index 31e7a30196a..671c17a6e6d 100644 --- a/drivers/vfio/pci/vfio_pci_private.h +++ b/drivers/vfio/pci/vfio_pci_private.h @@ -54,6 +54,7 @@ struct vfio_pci_device { bool extended_caps; bool bardirty; bool has_vga; + bool needs_reset; struct pci_saved_state *pci_saved_state; int refcnt; struct eventfd_ctx *err_trigger; |