The last user of this function is in PCI callbacks that want to convert their struct pci_dev to a vfio_device. Instead of searching use the vfio_device available trivially through the drvdata. When a callback in the device_driver is called, the caller must hold the device_lock() on dev. The purpose of the device_lock is to prevent remove() from being called (see __device_release_driver), and allow the driver to safely interact with its drvdata without races. The PCI core correctly follows this and holds the device_lock() when calling error_detected (see report_error_detected) and sriov_configure (see sriov_numvfs_store). Further, since the drvdata holds a positive refcount on the vfio_device any access of the drvdata, under the driver_lock, from a driver callback needs no further protection or refcounting. Thus the remark in the vfio_device_get_from_dev() comment does not apply here, VFIO PCI drivers all call vfio_unregister_group_dev() from their remove callbacks under the driver lock and cannot race with the remaining callers. Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> --- .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 12 +++++- drivers/vfio/pci/mlx5/main.c | 10 ++++- drivers/vfio/pci/vfio_pci.c | 18 +++++++- drivers/vfio/pci/vfio_pci_core.c | 42 ++++--------------- drivers/vfio/vfio.c | 41 +----------------- include/linux/vfio.h | 2 - include/linux/vfio_pci_core.h | 9 ++-- 7 files changed, 50 insertions(+), 84 deletions(-) v2: - Rebase on the vfio_mdev_no_group branch, which is on top of gvt & iommu - Delete vfio_group_get_from_dev() as well due to the rebase v1: https://lore.kernel.org/r/0-v1-7f2292e6b2ba+44839-vfio_get_from_dev_jgg@xxxxxxxxxx diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index 767b5d47631a49..14bf85ff6cbe96 100644 --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -1305,9 +1305,19 @@ static const struct pci_device_id hisi_acc_vfio_pci_table[] = { MODULE_DEVICE_TABLE(pci, hisi_acc_vfio_pci_table); +static pci_ers_result_t hisi_acc_aer_err_detected(struct pci_dev *pdev, + pci_channel_state_t state) +{ + struct hisi_acc_vf_core_device *hisi_acc_vdev = + dev_get_drvdata(&pdev->dev); + + return vfio_pci_core_aer_err_detected(&hisi_acc_vdev->core_device, + state); +} + static const struct pci_error_handlers hisi_acc_vf_err_handlers = { .reset_done = hisi_acc_vf_pci_aer_reset_done, - .error_detected = vfio_pci_core_aer_err_detected, + .error_detected = hisi_acc_aer_err_detected, }; static struct pci_driver hisi_acc_vfio_pci_driver = { diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c index bbec5d288fee97..fbba1d52a4cf64 100644 --- a/drivers/vfio/pci/mlx5/main.c +++ b/drivers/vfio/pci/mlx5/main.c @@ -643,9 +643,17 @@ static const struct pci_device_id mlx5vf_pci_table[] = { MODULE_DEVICE_TABLE(pci, mlx5vf_pci_table); +static pci_ers_result_t mlx5vf_pci_aer_err_detected(struct pci_dev *pdev, + pci_channel_state_t state) +{ + struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev); + + return vfio_pci_core_aer_err_detected(&mvdev->core_device, state); +} + static const struct pci_error_handlers mlx5vf_err_handlers = { .reset_done = mlx5vf_pci_aer_reset_done, - .error_detected = vfio_pci_core_aer_err_detected, + .error_detected = mlx5vf_pci_aer_err_detected, }; static struct pci_driver mlx5vf_pci_driver = { diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 58839206d1ca7f..fbd413a4c54360 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -174,10 +174,12 @@ static void vfio_pci_remove(struct pci_dev *pdev) static int vfio_pci_sriov_configure(struct pci_dev *pdev, int nr_virtfn) { + struct vfio_pci_core_device *vdev = dev_get_drvdata(&pdev->dev); + if (!enable_sriov) return -ENOENT; - return vfio_pci_core_sriov_configure(pdev, nr_virtfn); + return vfio_pci_core_sriov_configure(vdev, nr_virtfn); } static const struct pci_device_id vfio_pci_table[] = { @@ -187,13 +189,25 @@ static const struct pci_device_id vfio_pci_table[] = { MODULE_DEVICE_TABLE(pci, vfio_pci_table); +static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev, + pci_channel_state_t state) +{ + struct vfio_pci_core_device *vdev = dev_get_drvdata(&pdev->dev); + + return vfio_pci_core_aer_err_detected(vdev, state); +} + +static const struct pci_error_handlers vfio_pci_err_handlers = { + .error_detected = vfio_pci_aer_err_detected, +}; + static struct pci_driver vfio_pci_driver = { .name = "vfio-pci", .id_table = vfio_pci_table, .probe = vfio_pci_probe, .remove = vfio_pci_remove, .sriov_configure = vfio_pci_sriov_configure, - .err_handler = &vfio_pci_core_err_handlers, + .err_handler = &vfio_pci_err_handlers, .driver_managed_dma = true, }; diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 06b6f3594a1316..9778d713f546d2 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1890,9 +1890,7 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_register_device); void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev) { - struct pci_dev *pdev = vdev->pdev; - - vfio_pci_core_sriov_configure(pdev, 0); + vfio_pci_core_sriov_configure(vdev, 0); vfio_unregister_group_dev(&vdev->vdev); @@ -1904,18 +1902,10 @@ void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev) } EXPORT_SYMBOL_GPL(vfio_pci_core_unregister_device); -pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev, - pci_channel_state_t state) +pci_ers_result_t +vfio_pci_core_aer_err_detected(struct vfio_pci_core_device *vdev, + pci_channel_state_t state) { - struct vfio_pci_core_device *vdev; - struct vfio_device *device; - - device = vfio_device_get_from_dev(&pdev->dev); - if (device == NULL) - return PCI_ERS_RESULT_DISCONNECT; - - vdev = container_of(device, struct vfio_pci_core_device, vdev); - mutex_lock(&vdev->igate); if (vdev->err_trigger) @@ -1923,26 +1913,18 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev, mutex_unlock(&vdev->igate); - vfio_device_put(device); - return PCI_ERS_RESULT_CAN_RECOVER; } EXPORT_SYMBOL_GPL(vfio_pci_core_aer_err_detected); -int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn) +int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev, + int nr_virtfn) { - struct vfio_pci_core_device *vdev; - struct vfio_device *device; + struct pci_dev *pdev = vdev->pdev; int ret = 0; device_lock_assert(&pdev->dev); - device = vfio_device_get_from_dev(&pdev->dev); - if (!device) - return -ENODEV; - - vdev = container_of(device, struct vfio_pci_core_device, vdev); - if (nr_virtfn) { mutex_lock(&vfio_pci_sriov_pfs_mutex); /* @@ -1960,8 +1942,7 @@ int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn) ret = pci_enable_sriov(pdev, nr_virtfn); if (ret) goto out_del; - ret = nr_virtfn; - goto out_put; + return ret; } pci_disable_sriov(pdev); @@ -1971,17 +1952,10 @@ int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn) list_del_init(&vdev->sriov_pfs_item); out_unlock: mutex_unlock(&vfio_pci_sriov_pfs_mutex); -out_put: - vfio_device_put(device); return ret; } EXPORT_SYMBOL_GPL(vfio_pci_core_sriov_configure); -const struct pci_error_handlers vfio_pci_core_err_handlers = { - .error_detected = vfio_pci_core_aer_err_detected, -}; -EXPORT_SYMBOL_GPL(vfio_pci_core_err_handlers); - static bool vfio_dev_in_groups(struct vfio_pci_core_device *vdev, struct vfio_pci_group_info *groups) { diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index f7d1898129ad1c..fcff23fd256a67 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -444,31 +444,15 @@ static void vfio_group_get(struct vfio_group *group) refcount_inc(&group->users); } -static struct vfio_group *vfio_group_get_from_dev(struct device *dev) -{ - struct iommu_group *iommu_group; - struct vfio_group *group; - - iommu_group = iommu_group_get(dev); - if (!iommu_group) - return NULL; - - group = vfio_group_get_from_iommu(iommu_group); - iommu_group_put(iommu_group); - - return group; -} - /* * Device objects - create, release, get, put, search */ /* Device reference always implies a group reference */ -void vfio_device_put(struct vfio_device *device) +static void vfio_device_put(struct vfio_device *device) { if (refcount_dec_and_test(&device->refcount)) complete(&device->comp); } -EXPORT_SYMBOL_GPL(vfio_device_put); static bool vfio_device_try_get(struct vfio_device *device) { @@ -633,29 +617,6 @@ int vfio_register_emulated_iommu_dev(struct vfio_device *device) } EXPORT_SYMBOL_GPL(vfio_register_emulated_iommu_dev); -/* - * Get a reference to the vfio_device for a device. Even if the - * caller thinks they own the device, they could be racing with a - * release call path, so we can't trust drvdata for the shortcut. - * Go the long way around, from the iommu_group to the vfio_group - * to the vfio_device. - */ -struct vfio_device *vfio_device_get_from_dev(struct device *dev) -{ - struct vfio_group *group; - struct vfio_device *device; - - group = vfio_group_get_from_dev(dev); - if (!group) - return NULL; - - device = vfio_group_get_device(group, dev); - vfio_group_put(group); - - return device; -} -EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); - static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, char *buf) { diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 9a9981c2622896..de8dd31b0639b0 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -125,8 +125,6 @@ void vfio_uninit_group_dev(struct vfio_device *device); int vfio_register_group_dev(struct vfio_device *device); int vfio_register_emulated_iommu_dev(struct vfio_device *device); void vfio_unregister_group_dev(struct vfio_device *device); -extern struct vfio_device *vfio_device_get_from_dev(struct device *dev); -extern void vfio_device_put(struct vfio_device *device); int vfio_assign_device_set(struct vfio_device *device, void *set_id); diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 48f2dd3c568c83..a0978ce126395c 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -227,8 +227,8 @@ void vfio_pci_core_init_device(struct vfio_pci_core_device *vdev, int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev); void vfio_pci_core_uninit_device(struct vfio_pci_core_device *vdev); void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev); -int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn); -extern const struct pci_error_handlers vfio_pci_core_err_handlers; +int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev, + int nr_virtfn); long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd, unsigned long arg); int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, @@ -243,8 +243,9 @@ int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf); int vfio_pci_core_enable(struct vfio_pci_core_device *vdev); void vfio_pci_core_disable(struct vfio_pci_core_device *vdev); void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev); -pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev, - pci_channel_state_t state); +pci_ers_result_t +vfio_pci_core_aer_err_detected(struct vfio_pci_core_device *vdev, + pci_channel_state_t state); static inline bool vfio_pci_is_vga(struct pci_dev *pdev) { base-commit: 21ce7c292b5684f930cc63f3841ec692bbd6c10a -- 2.36.0
