diff options
| -rw-r--r-- | drivers/vfio/pci/vfio_pci.c | 160 | ||||
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_private.h | 6 |
2 files changed, 142 insertions, 24 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 50cdedfca9fe..ea0670c60c80 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -56,8 +56,6 @@ module_param(disable_idle_d3, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(disable_idle_d3, "Disable using the PCI D3 low power state for idle, unused devices"); -static DEFINE_MUTEX(driver_lock); - static inline bool vfio_vga_disabled(void) { #ifdef CONFIG_VFIO_PCI_VGA @@ -393,14 +391,14 @@ static void vfio_pci_release(void *device_data) { struct vfio_pci_device *vdev = device_data; - mutex_lock(&driver_lock); + mutex_lock(&vdev->reflck->lock); if (!(--vdev->refcnt)) { vfio_spapr_pci_eeh_release(vdev->pdev); vfio_pci_disable(vdev); } - mutex_unlock(&driver_lock); + mutex_unlock(&vdev->reflck->lock); module_put(THIS_MODULE); } @@ -413,7 +411,7 @@ static int vfio_pci_open(void *device_data) if (!try_module_get(THIS_MODULE)) return -ENODEV; - mutex_lock(&driver_lock); + mutex_lock(&vdev->reflck->lock); if (!vdev->refcnt) { ret = vfio_pci_enable(vdev); @@ -424,7 +422,7 @@ static int vfio_pci_open(void *device_data) } vdev->refcnt++; error: - mutex_unlock(&driver_lock); + mutex_unlock(&vdev->reflck->lock); if (ret) module_put(THIS_MODULE); return ret; @@ -1187,6 +1185,9 @@ static const struct vfio_device_ops vfio_pci_ops = { .request = vfio_pci_request, }; +static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev); +static void vfio_pci_reflck_put(struct vfio_pci_reflck *reflck); + static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct vfio_pci_device *vdev; @@ -1233,6 +1234,14 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) return ret; } + ret = vfio_pci_reflck_attach(vdev); + if (ret) { + vfio_del_group_dev(&pdev->dev); + vfio_iommu_group_put(group, &pdev->dev); + kfree(vdev); + return ret; + } + if (vfio_pci_is_vga(pdev)) { vga_client_register(pdev, vdev, NULL, vfio_pci_set_vga_decode); vga_set_legacy_decoding(pdev, @@ -1264,6 +1273,8 @@ static void vfio_pci_remove(struct pci_dev *pdev) if (!vdev) return; + vfio_pci_reflck_put(vdev->reflck); + vfio_iommu_group_put(pdev->dev.iommu_group, &pdev->dev); kfree(vdev->region); mutex_destroy(&vdev->ioeventfds_lock); @@ -1320,16 +1331,97 @@ static struct pci_driver vfio_pci_driver = { .err_handler = &vfio_err_handlers, }; +static DEFINE_MUTEX(reflck_lock); + +static struct vfio_pci_reflck *vfio_pci_reflck_alloc(void) +{ + struct vfio_pci_reflck *reflck; + + reflck = kzalloc(sizeof(*reflck), GFP_KERNEL); + if (!reflck) + return ERR_PTR(-ENOMEM); + + kref_init(&reflck->kref); + mutex_init(&reflck->lock); + + return reflck; +} + +static void vfio_pci_reflck_get(struct vfio_pci_reflck *reflck) +{ + kref_get(&reflck->kref); +} + +static int vfio_pci_reflck_find(struct pci_dev *pdev, void *data) +{ + struct vfio_pci_reflck **preflck = data; + struct vfio_device *device; + struct vfio_pci_device *vdev; + + device = vfio_device_get_from_dev(&pdev->dev); + if (!device) + return 0; + + if (pci_dev_driver(pdev) != &vfio_pci_driver) { + vfio_device_put(device); + return 0; + } + + vdev = vfio_device_data(device); + + if (vdev->reflck) { + vfio_pci_reflck_get(vdev->reflck); + *preflck = vdev->reflck; + vfio_device_put(device); + return 1; + } + + vfio_device_put(device); + return 0; +} + +static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev) +{ + bool slot = !pci_probe_reset_slot(vdev->pdev->slot); + + mutex_lock(&reflck_lock); + + if (pci_is_root_bus(vdev->pdev->bus) || + vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_reflck_find, + &vdev->reflck, slot) <= 0) + vdev->reflck = vfio_pci_reflck_alloc(); + + mutex_unlock(&reflck_lock); + + return PTR_ERR_OR_ZERO(vdev->reflck); +} + +static void vfio_pci_reflck_release(struct kref *kref) +{ + struct vfio_pci_reflck *reflck = container_of(kref, + struct vfio_pci_reflck, + kref); + + kfree(reflck); + mutex_unlock(&reflck_lock); +} + +static void vfio_pci_reflck_put(struct vfio_pci_reflck *reflck) +{ + kref_put_mutex(&reflck->kref, vfio_pci_reflck_release, &reflck_lock); +} + struct vfio_devices { struct vfio_device **devices; int cur_index; int max_index; }; -static int vfio_pci_get_devs(struct pci_dev *pdev, void *data) +static int vfio_pci_get_unused_devs(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; @@ -1343,16 +1435,28 @@ static int vfio_pci_get_devs(struct pci_dev *pdev, void *data) return -EBUSY; } + vdev = vfio_device_data(device); + + /* Fault if the device is not unused */ + if (vdev->refcnt) { + vfio_device_put(device); + return -EBUSY; + } + devs->devices[devs->cur_index++] = 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 are required to hold driver_lock when calling this to - * prevent device opens and concurrent bus reset attempts. We prevent device - * unbinds by acquiring and holding a reference to the vfio_device. + * If a bus or slot reset is available for the provided device and: + * - All of the devices affected by that bus or slot reset are unused + * (!refcnt) + * - At least one of the affected devices is marked dirty via + * needs_reset (such as by lack of FLR support) + * Then attempt to perform that bus or slot reset. Callers are required + * to hold vdev->reflck->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. * * 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 @@ -1363,7 +1467,7 @@ 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 needs_reset = false, slot = false; + bool slot = false; struct vfio_pci_device *tmp; if (!pci_probe_reset_slot(vdev->pdev->slot)) @@ -1381,28 +1485,36 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev) return; if (vfio_pci_for_each_slot_or_bus(vdev->pdev, - vfio_pci_get_devs, &devs, slot)) + vfio_pci_get_unused_devs, + &devs, slot)) goto put_devs; + /* Does at least one need a reset? */ for (i = 0; i < devs.cur_index; i++) { tmp = vfio_device_data(devs.devices[i]); - if (tmp->needs_reset) - needs_reset = true; - if (tmp->refcnt) - goto put_devs; + if (tmp->needs_reset) { + ret = pci_reset_bus(vdev->pdev); + break; + } } - if (needs_reset) - ret = pci_reset_bus(vdev->pdev); - put_devs: for (i = 0; i < devs.cur_index; i++) { tmp = vfio_device_data(devs.devices[i]); - if (!ret) + + /* + * 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; - if (!tmp->refcnt && !disable_idle_d3) - pci_set_power_state(tmp->pdev, PCI_D3hot); + if (tmp != vdev && !disable_idle_d3) + pci_set_power_state(tmp->pdev, PCI_D3hot); + } vfio_device_put(devs.devices[i]); } diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h index cde3b5d3441a..aa2355e67340 100644 --- a/drivers/vfio/pci/vfio_pci_private.h +++ b/drivers/vfio/pci/vfio_pci_private.h @@ -76,6 +76,11 @@ struct vfio_pci_dummy_resource { struct list_head res_next; }; +struct vfio_pci_reflck { + struct kref kref; + struct mutex lock; +}; + struct vfio_pci_device { struct pci_dev *pdev; void __iomem *barmap[PCI_STD_RESOURCE_END + 1]; @@ -104,6 +109,7 @@ struct vfio_pci_device { bool needs_reset; bool nointx; struct pci_saved_state *pci_saved_state; + struct vfio_pci_reflck *reflck; int refcnt; int ioeventfds_nr; struct eventfd_ctx *err_trigger; |