Keep track of all the vfio_devices that have been added to the device set and use this list in vfio_pci_try_bus_reset() instead of trying to work backwards from the pci_device.
The dev_set->lock directly prevents devices from joining/leaving the set, which further implies the pci_device cannot change drivers or that the vfio_device be freed, eliminating the need for get/put's.
Completeness of the device set can be directly measured by checking if every PCI device in the reset group is also in the device set - which proves that VFIO drivers are attached to everything.
This restructuring corrects a call to pci_dev_driver() without holding the device_lock() and removes a hard wiring to &vfio_pci_driver.
Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- drivers/vfio/pci/vfio_pci.c | 110 ++++++++++++++---------------------- drivers/vfio/vfio.c | 10 ++++ include/linux/vfio.h | 2 + 3 files changed, 53 insertions(+), 69 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 22774e447b5f4a..fbc20f6d2dd412 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -404,6 +404,9 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) struct vfio_pci_ioeventfd *ioeventfd, *ioeventfd_tmp; int i, bar;
+ /* For needs_reset */ + lockdep_assert_held(&vdev->vdev.dev_set->lock); + /* Stop the device from further DMA */ pci_clear_master(pdev);
@@ -2139,34 +2142,17 @@ static struct pci_driver vfio_pci_driver = { .err_handler = &vfio_err_handlers, };
-static int vfio_pci_get_unused_devs(struct pci_dev *pdev, void *data) +static int vfio_pci_check_all_devices_bound(struct pci_dev *pdev, void *data) { - struct vfio_devices *devs = data; - struct vfio_device *device; - struct vfio_pci_device *vdev; - - if (devs->cur_index == devs->max_index) - return -ENOSPC; + struct vfio_device_set *dev_set = data; + struct vfio_device *cur;
- device = vfio_device_get_from_dev(&pdev->dev); - if (!device) - return -EINVAL; - - if (pci_dev_driver(pdev) != &vfio_pci_driver) { - vfio_device_put(device); - return -EBUSY; - } - - vdev = container_of(device, struct vfio_pci_device, vdev); - - /* Fault if the device is not unused */ - if (device->open_count) { - vfio_device_put(device); - return -EBUSY; - } + lockdep_assert_held(&dev_set->lock);
- devs->devices[devs->cur_index++] = vdev; - return 0; + list_for_each_entry(cur, &dev_set->device_list, dev_set_list) + if (cur->dev == &pdev->dev) + return 0; + return -EBUSY; }
static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data) @@ -2210,8 +2196,7 @@ static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data) * needs_reset (such as by lack of FLR support) * Then attempt to perform that bus or slot reset. Callers are required * to hold vdev->dev_set->lock, protecting the bus/slot reset group from - * concurrent opens. A vfio_device reference is acquired for each device - * to prevent unbinds during the reset operation. + * concurrent opens. * * NB: vfio-core considers a group to be viable even if some devices are * bound to drivers like pci-stub or pcieport. Here we require all devices @@ -2220,61 +2205,48 @@ static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data) */ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev) { - struct vfio_devices devs = { .cur_index = 0 }; - int i = 0, ret = -EINVAL; - bool slot = false; - struct vfio_pci_device *tmp; - - if (!pci_probe_reset_slot(vdev->pdev->slot)) - slot = true; - else if (pci_probe_reset_bus(vdev->pdev->bus)) - return; + struct vfio_device_set *dev_set = vdev->vdev.dev_set; + struct vfio_pci_device *to_reset = NULL; + struct vfio_pci_device *cur; + int ret;
- if (vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_count_devs, - &i, slot) || !i) + if (pci_probe_reset_slot(vdev->pdev->slot) && + pci_probe_reset_bus(vdev->pdev->bus)) return;
- devs.max_index = i; - devs.devices = kcalloc(i, sizeof(struct vfio_device *), GFP_KERNEL); - if (!devs.devices) - return; + lockdep_assert_held(&vdev->vdev.dev_set->lock);
- if (vfio_pci_for_each_slot_or_bus(vdev->pdev, - vfio_pci_get_unused_devs, - &devs, slot)) - goto put_devs; + /* All VFIO devices have a closed FD */ + list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) + if (cur->vdev.open_count) + return; + + /* All devices in the group to be reset need VFIO devices */ + if (vfio_pci_for_each_slot_or_bus( + vdev->pdev, vfio_pci_check_all_devices_bound, dev_set, + !pci_probe_reset_slot(vdev->pdev->slot))) + return;
/* Does at least one need a reset? */ - for (i = 0; i < devs.cur_index; i++) { - tmp = devs.devices[i]; - if (tmp->needs_reset) { - ret = pci_reset_bus(vdev->pdev); + list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) { + if (cur->needs_reset) { + to_reset = cur; break; } } + if (!to_reset) + return;
-put_devs: - for (i = 0; i < devs.cur_index; i++) { - tmp = devs.devices[i]; - - /* - * If reset was successful, affected devices no longer need - * a reset and we should return all the collateral devices - * to low power. If not successful, we either didn't reset - * the bus or timed out waiting for it, so let's not touch - * the power state. - */ - if (!ret) { - tmp->needs_reset = false; + ret = pci_reset_bus(to_reset->pdev); + if (ret) + return;
- if (tmp != vdev && !disable_idle_d3) - vfio_pci_set_power_state(tmp, PCI_D3hot); - } + list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) { + cur->needs_reset = false;
- vfio_device_put(&tmp->vdev); + if (cur != to_reset && !disable_idle_d3) + vfio_pci_set_power_state(cur, PCI_D3hot); } - - kfree(devs.devices); }
static void __exit vfio_pci_cleanup(void) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 8572d943320214..7e352d68b1b01d 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -129,7 +129,12 @@ int vfio_assign_device_set(struct vfio_device *device, void *set_id) if (dev_set) { dev_set->device_count++; xa_unlock(&vfio_device_set_xa); + + mutex_lock(&dev_set->lock); device->dev_set = dev_set; + list_add_tail(&device->dev_set_list, &dev_set->device_list); + mutex_unlock(&dev_set->lock); + if (dev_set != alloc_dev_set) kfree(alloc_dev_set); return 0; @@ -143,6 +148,7 @@ int vfio_assign_device_set(struct vfio_device *device, void *set_id) if (!alloc_dev_set) return -ENOMEM; mutex_init(&alloc_dev_set->lock); + INIT_LIST_HEAD(&alloc_dev_set->device_list); alloc_dev_set->set_id = set_id; goto again; } @@ -155,6 +161,10 @@ static void vfio_release_device_set(struct vfio_device *device) if (!dev_set) return;
+ mutex_lock(&dev_set->lock); + list_del(&device->dev_set_list); + mutex_unlock(&dev_set->lock); + xa_lock(&vfio_device_set_xa); dev_set->device_count--; if (!dev_set->device_count) { diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 128b4db00adc57..f0e6a72875e471 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -23,6 +23,7 @@ struct vfio_device_set { void *set_id; struct mutex lock; + struct list_head device_list; unsigned int device_count; };
@@ -31,6 +32,7 @@ struct vfio_device { const struct vfio_device_ops *ops; struct vfio_group *group; struct vfio_device_set *dev_set; + struct list_head dev_set_list;
/* Members below here are private, not for driver use */ refcount_t refcount;