* [PATCH v2 0/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM @ 2022-05-18 21:26 Matthew Rosato 2022-05-18 21:26 ` [PATCH v2 1/1] " Matthew Rosato 0 siblings, 1 reply; 12+ messages in thread From: Matthew Rosato @ 2022-05-18 21:26 UTC (permalink / raw) To: jgg, alex.williamson Cc: cohuck, borntraeger, jjherne, akrowiak, pasic, zhenyuw, zhi.a.wang, hch, intel-gfx, intel-gvt-dev, linux-s390, kvm, linux-kernel As discussed in this thread: https://lore.kernel.org/kvm/20220516172734.GE1343366@nvidia.com/ Let's remove VFIO_GROUP_NOTIFY_SET_KVM and instead assume the association has already been established prior to device_open. For the types today that need a KVM (GVT, vfio-ap) these will fail if a KVM is not found. Looking ahead, vfio-pci-zdev will optionally want the KVM association (enable hardware assists) but it will not be a hard requirement (still want to allow other, non-KVM userspace usage). This is built on top of Jason's group locking series: https://github.com/jgunthorpe/linux/commits/vfio_group_locking And tested with s390x-pci (zdev-kvm series) and vfio-ap (GVT changes are compile-tested only) Changes for v2: - gvt no longer needs release_work, get rid of it (Christoph) - a few compile fixes for gvt - update commit to mention fixes gvt oops (Jason) - s/down_write/down_read/ in a few spots (Jason) - avoid kvm build dependency by holding group read lock over device open/close and put the onus on the driver to obtain a reference if it will actually use the kvm pointer. Document the requirement, use lockdep_assert to ensure lock is held during register_notifer; today all callers are from driver open_device. Matthew Rosato (1): vfio: remove VFIO_GROUP_NOTIFY_SET_KVM drivers/gpu/drm/i915/gvt/gtt.c | 4 +- drivers/gpu/drm/i915/gvt/gvt.h | 3 - drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++--------------------- drivers/s390/crypto/vfio_ap_ops.c | 38 ++++--------- drivers/s390/crypto/vfio_ap_private.h | 3 - drivers/vfio/vfio.c | 75 ++++++++---------------- include/linux/vfio.h | 5 +- 7 files changed, 56 insertions(+), 154 deletions(-) -- 2.27.0 ^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-18 21:26 [PATCH v2 0/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM Matthew Rosato @ 2022-05-18 21:26 ` Matthew Rosato 2022-05-19 6:43 ` [Intel-gfx] " Tian, Kevin ` (2 more replies) 0 siblings, 3 replies; 12+ messages in thread From: Matthew Rosato @ 2022-05-18 21:26 UTC (permalink / raw) To: jgg, alex.williamson Cc: cohuck, borntraeger, jjherne, akrowiak, pasic, zhenyuw, zhi.a.wang, hch, intel-gfx, intel-gvt-dev, linux-s390, kvm, linux-kernel Rather than relying on a notifier for associating the KVM with the group, let's assume that the association has already been made prior to device_open. The first time a device is opened associate the group KVM with the device. This fixes a user-triggerable oops in GVT. Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> --- drivers/gpu/drm/i915/gvt/gtt.c | 4 +- drivers/gpu/drm/i915/gvt/gvt.h | 3 - drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++--------------------- drivers/s390/crypto/vfio_ap_ops.c | 38 ++++--------- drivers/s390/crypto/vfio_ap_private.h | 3 - drivers/vfio/vfio.c | 75 ++++++++---------------- include/linux/vfio.h | 5 +- 7 files changed, 56 insertions(+), 154 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index 9c5cc2800975..b4f69364f9a1 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -51,7 +51,7 @@ static int preallocated_oos_pages = 8192; static bool intel_gvt_is_valid_gfn(struct intel_vgpu *vgpu, unsigned long gfn) { - struct kvm *kvm = vgpu->kvm; + struct kvm *kvm = vgpu->vfio_device.kvm; int idx; bool ret; @@ -1185,7 +1185,7 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu, if (!vgpu->attached) return -EINVAL; - pfn = gfn_to_pfn(vgpu->kvm, ops->get_pfn(entry)); + pfn = gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry)); if (is_error_noslot_pfn(pfn)) return -EINVAL; return PageTransHuge(pfn_to_page(pfn)); diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h index 2af4c83e733c..aee1a45da74b 100644 --- a/drivers/gpu/drm/i915/gvt/gvt.h +++ b/drivers/gpu/drm/i915/gvt/gvt.h @@ -227,9 +227,6 @@ struct intel_vgpu { struct mutex cache_lock; struct notifier_block iommu_notifier; - struct notifier_block group_notifier; - struct kvm *kvm; - struct work_struct release_work; atomic_t released; struct kvm_page_track_notifier_node track_node; diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 7655ffa97d51..e2f6c56ab342 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -228,8 +228,6 @@ static void intel_gvt_cleanup_vgpu_type_groups(struct intel_gvt *gvt) } } -static void intel_vgpu_release_work(struct work_struct *work); - static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, unsigned long size) { @@ -761,23 +759,6 @@ static int intel_vgpu_iommu_notifier(struct notifier_block *nb, return NOTIFY_OK; } -static int intel_vgpu_group_notifier(struct notifier_block *nb, - unsigned long action, void *data) -{ - struct intel_vgpu *vgpu = - container_of(nb, struct intel_vgpu, group_notifier); - - /* the only action we care about */ - if (action == VFIO_GROUP_NOTIFY_SET_KVM) { - vgpu->kvm = data; - - if (!data) - schedule_work(&vgpu->release_work); - } - - return NOTIFY_OK; -} - static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu) { struct intel_vgpu *itr; @@ -789,7 +770,7 @@ static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu) if (!itr->attached) continue; - if (vgpu->kvm == itr->kvm) { + if (vgpu->vfio_device.kvm == itr->vfio_device.kvm) { ret = true; goto out; } @@ -806,7 +787,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) int ret; vgpu->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier; - vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier; events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events, @@ -817,38 +797,32 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) goto out; } - events = VFIO_GROUP_NOTIFY_SET_KVM; - ret = vfio_register_notifier(vfio_dev, VFIO_GROUP_NOTIFY, &events, - &vgpu->group_notifier); - if (ret != 0) { - gvt_vgpu_err("vfio_register_notifier for group failed: %d\n", - ret); - goto undo_iommu; - } - ret = -EEXIST; if (vgpu->attached) - goto undo_register; + goto undo_iommu; ret = -ESRCH; - if (!vgpu->kvm || vgpu->kvm->mm != current->mm) { + if (!vgpu->vfio_device.kvm || + vgpu->vfio_device.kvm->mm != current->mm) { gvt_vgpu_err("KVM is required to use Intel vGPU\n"); - goto undo_register; + goto undo_iommu; } + kvm_get_kvm(vgpu->vfio_device.kvm); + ret = -EEXIST; if (__kvmgt_vgpu_exist(vgpu)) - goto undo_register; + goto undo_iommu; vgpu->attached = true; - kvm_get_kvm(vgpu->kvm); kvmgt_protect_table_init(vgpu); gvt_cache_init(vgpu); vgpu->track_node.track_write = kvmgt_page_track_write; vgpu->track_node.track_flush_slot = kvmgt_page_track_flush_slot; - kvm_page_track_register_notifier(vgpu->kvm, &vgpu->track_node); + kvm_page_track_register_notifier(vgpu->vfio_device.kvm, + &vgpu->track_node); debugfs_create_ulong(KVMGT_DEBUGFS_FILENAME, 0444, vgpu->debugfs, &vgpu->nr_cache_entries); @@ -858,10 +832,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) atomic_set(&vgpu->released, 0); return 0; -undo_register: - vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY, - &vgpu->group_notifier); - undo_iommu: vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &vgpu->iommu_notifier); @@ -880,8 +850,9 @@ static void intel_vgpu_release_msi_eventfd_ctx(struct intel_vgpu *vgpu) } } -static void __intel_vgpu_release(struct intel_vgpu *vgpu) +static void intel_vgpu_close_device(struct vfio_device *vfio_dev) { + struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev); struct drm_i915_private *i915 = vgpu->gvt->gt->i915; int ret; @@ -898,35 +869,19 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu) drm_WARN(&i915->drm, ret, "vfio_unregister_notifier for iommu failed: %d\n", ret); - ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_GROUP_NOTIFY, - &vgpu->group_notifier); - drm_WARN(&i915->drm, ret, - "vfio_unregister_notifier for group failed: %d\n", ret); - debugfs_remove(debugfs_lookup(KVMGT_DEBUGFS_FILENAME, vgpu->debugfs)); - kvm_page_track_unregister_notifier(vgpu->kvm, &vgpu->track_node); - kvm_put_kvm(vgpu->kvm); + kvm_page_track_unregister_notifier(vgpu->vfio_device.kvm, + &vgpu->track_node); kvmgt_protect_table_destroy(vgpu); gvt_cache_destroy(vgpu); intel_vgpu_release_msi_eventfd_ctx(vgpu); - vgpu->kvm = NULL; vgpu->attached = false; -} - -static void intel_vgpu_close_device(struct vfio_device *vfio_dev) -{ - __intel_vgpu_release(vfio_dev_to_vgpu(vfio_dev)); -} - -static void intel_vgpu_release_work(struct work_struct *work) -{ - struct intel_vgpu *vgpu = - container_of(work, struct intel_vgpu, release_work); - __intel_vgpu_release(vgpu); + if (vgpu->vfio_device.kvm) + kvm_put_kvm(vgpu->vfio_device.kvm); } static u64 intel_vgpu_get_bar_addr(struct intel_vgpu *vgpu, int bar) @@ -1675,7 +1630,6 @@ static int intel_vgpu_probe(struct mdev_device *mdev) return PTR_ERR(vgpu); } - INIT_WORK(&vgpu->release_work, intel_vgpu_release_work); vfio_init_group_dev(&vgpu->vfio_device, &mdev->dev, &intel_vgpu_dev_ops); @@ -1713,7 +1667,7 @@ static struct mdev_driver intel_vgpu_mdev_driver = { int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) { - struct kvm *kvm = info->kvm; + struct kvm *kvm = info->vfio_device.kvm; struct kvm_memory_slot *slot; int idx; @@ -1743,7 +1697,7 @@ int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) int intel_gvt_page_track_remove(struct intel_vgpu *info, u64 gfn) { - struct kvm *kvm = info->kvm; + struct kvm *kvm = info->vfio_device.kvm; struct kvm_memory_slot *slot; int idx; diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index e8914024f5b1..17a56bb4cf25 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -1196,6 +1196,8 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev, { struct ap_matrix_mdev *m; + kvm_get_kvm(kvm); + if (kvm->arch.crypto.crycbd) { down_write(&kvm->arch.crypto.pqap_hook_rwsem); kvm->arch.crypto.pqap_hook = &matrix_mdev->pqap_hook; @@ -1282,25 +1284,9 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev) mutex_unlock(&kvm->lock); mutex_unlock(&matrix_dev->lock); } -} -static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, - unsigned long action, void *data) -{ - int notify_rc = NOTIFY_OK; - struct ap_matrix_mdev *matrix_mdev; - - if (action != VFIO_GROUP_NOTIFY_SET_KVM) - return NOTIFY_OK; - - matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier); - - if (!data) - vfio_ap_mdev_unset_kvm(matrix_mdev); - else if (vfio_ap_mdev_set_kvm(matrix_mdev, data)) - notify_rc = NOTIFY_DONE; - - return notify_rc; + if (kvm) + kvm_put_kvm(kvm); } static struct vfio_ap_queue *vfio_ap_find_queue(int apqn) @@ -1402,11 +1388,10 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev) unsigned long events; int ret; - matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier; - events = VFIO_GROUP_NOTIFY_SET_KVM; + if (!vdev->kvm) + return -EPERM; - ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events, - &matrix_mdev->group_notifier); + ret = vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm); if (ret) return ret; @@ -1415,12 +1400,11 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev) ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events, &matrix_mdev->iommu_notifier); if (ret) - goto out_unregister_group; + goto err_kvm; return 0; -out_unregister_group: - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, - &matrix_mdev->group_notifier); +err_kvm: + vfio_ap_mdev_unset_kvm(matrix_mdev); return ret; } @@ -1431,8 +1415,6 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev) vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &matrix_mdev->iommu_notifier); - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, - &matrix_mdev->group_notifier); vfio_ap_mdev_unset_kvm(matrix_mdev); } diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h index 648fcaf8104a..a26efd804d0d 100644 --- a/drivers/s390/crypto/vfio_ap_private.h +++ b/drivers/s390/crypto/vfio_ap_private.h @@ -81,8 +81,6 @@ struct ap_matrix { * @node: allows the ap_matrix_mdev struct to be added to a list * @matrix: the adapters, usage domains and control domains assigned to the * mediated matrix device. - * @group_notifier: notifier block used for specifying callback function for - * handling the VFIO_GROUP_NOTIFY_SET_KVM event * @iommu_notifier: notifier block used for specifying callback function for * handling the VFIO_IOMMU_NOTIFY_DMA_UNMAP even * @kvm: the struct holding guest's state @@ -94,7 +92,6 @@ struct ap_matrix_mdev { struct vfio_device vdev; struct list_head node; struct ap_matrix matrix; - struct notifier_block group_notifier; struct notifier_block iommu_notifier; struct kvm *kvm; crypto_hook pqap_hook; diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index cfcff7764403..272acb62facd 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct vfio_device *device) mutex_lock(&device->dev_set->lock); device->open_count++; + down_read(&device->group->group_rwsem); + if (device->open_count == 1 && device->group->kvm) { + /* + * Here we pass the KVM pointer with the group under the read + * lock. If the device driver will use it, it must obtain a + * reference and release it during close_device. + */ + device->kvm = device->group->kvm; + } + if (device->open_count == 1 && device->ops->open_device) { ret = device->ops->open_device(device); if (ret) goto err_undo_count; } + up_read(&device->group->group_rwsem); mutex_unlock(&device->dev_set->lock); /* @@ -1119,10 +1130,14 @@ static struct file *vfio_device_open(struct vfio_device *device) err_close_device: mutex_lock(&device->dev_set->lock); + down_read(&device->group->group_rwsem); if (device->open_count == 1 && device->ops->close_device) device->ops->close_device(device); err_undo_count: device->open_count--; + if (device->open_count == 0 && device->kvm) + device->kvm = NULL; + up_read(&device->group->group_rwsem); mutex_unlock(&device->dev_set->lock); module_put(device->dev->driver->owner); err_unassign_container: @@ -1315,9 +1330,13 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) mutex_lock(&device->dev_set->lock); vfio_assert_device_open(device); + down_read(&device->group->group_rwsem); if (device->open_count == 1 && device->ops->close_device) device->ops->close_device(device); device->open_count--; + if (device->open_count == 0 && device->kvm) + device->kvm = NULL; + up_read(&device->group->group_rwsem); mutex_unlock(&device->dev_set->lock); module_put(device->dev->driver->owner); @@ -1726,8 +1745,8 @@ EXPORT_SYMBOL_GPL(vfio_file_enforced_coherent); * @file: VFIO group file * @kvm: KVM to link * - * The kvm pointer will be forwarded to all the vfio_device's attached to the - * VFIO file via the VFIO_GROUP_NOTIFY_SET_KVM notifier. + * When a VFIO device is first opened the KVM will be available in + * device->kvm if one was associated with the group. */ void vfio_file_set_kvm(struct file *file, struct kvm *kvm) { @@ -1738,8 +1757,6 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm) down_write(&group->group_rwsem); group->kvm = kvm; - blocking_notifier_call_chain(&group->notifier, - VFIO_GROUP_NOTIFY_SET_KVM, kvm); up_write(&group->group_rwsem); } EXPORT_SYMBOL_GPL(vfio_file_set_kvm); @@ -2006,7 +2023,8 @@ static int vfio_register_iommu_notifier(struct vfio_group *group, struct vfio_iommu_driver *driver; int ret; - down_read(&group->group_rwsem); + lockdep_assert_held_read(&group->group_rwsem); + container = group->container; driver = container->iommu_driver; if (likely(driver && driver->ops->register_notifier)) @@ -2014,7 +2032,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group, events, nb); else ret = -ENOTTY; - up_read(&group->group_rwsem); return ret; } @@ -2026,7 +2043,8 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group, struct vfio_iommu_driver *driver; int ret; - down_read(&group->group_rwsem); + lockdep_assert_held_read(&group->group_rwsem); + container = group->container; driver = container->iommu_driver; if (likely(driver && driver->ops->unregister_notifier)) @@ -2034,47 +2052,10 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group, nb); else ret = -ENOTTY; - up_read(&group->group_rwsem); return ret; } -static int vfio_register_group_notifier(struct vfio_group *group, - unsigned long *events, - struct notifier_block *nb) -{ - int ret; - bool set_kvm = false; - - if (*events & VFIO_GROUP_NOTIFY_SET_KVM) - set_kvm = true; - - /* clear known events */ - *events &= ~VFIO_GROUP_NOTIFY_SET_KVM; - - /* refuse to continue if still events remaining */ - if (*events) - return -EINVAL; - - ret = blocking_notifier_chain_register(&group->notifier, nb); - if (ret) - return ret; - - /* - * The attaching of kvm and vfio_group might already happen, so - * here we replay once upon registration. - */ - if (set_kvm) { - down_read(&group->group_rwsem); - if (group->kvm) - blocking_notifier_call_chain(&group->notifier, - VFIO_GROUP_NOTIFY_SET_KVM, - group->kvm); - up_read(&group->group_rwsem); - } - return 0; -} - int vfio_register_notifier(struct vfio_device *device, enum vfio_notify_type type, unsigned long *events, struct notifier_block *nb) @@ -2090,9 +2071,6 @@ int vfio_register_notifier(struct vfio_device *device, case VFIO_IOMMU_NOTIFY: ret = vfio_register_iommu_notifier(group, events, nb); break; - case VFIO_GROUP_NOTIFY: - ret = vfio_register_group_notifier(group, events, nb); - break; default: ret = -EINVAL; } @@ -2114,9 +2092,6 @@ int vfio_unregister_notifier(struct vfio_device *device, case VFIO_IOMMU_NOTIFY: ret = vfio_unregister_iommu_notifier(group, nb); break; - case VFIO_GROUP_NOTIFY: - ret = blocking_notifier_chain_unregister(&group->notifier, nb); - break; default: ret = -EINVAL; } diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 45b287826ce6..5f691453e3fb 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -36,6 +36,7 @@ struct vfio_device { struct vfio_device_set *dev_set; struct list_head dev_set_list; unsigned int migration_flags; + struct kvm *kvm; /* Members below here are private, not for driver use */ refcount_t refcount; @@ -155,15 +156,11 @@ extern int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, /* each type has independent events */ enum vfio_notify_type { VFIO_IOMMU_NOTIFY = 0, - VFIO_GROUP_NOTIFY = 1, }; /* events for VFIO_IOMMU_NOTIFY */ #define VFIO_IOMMU_NOTIFY_DMA_UNMAP BIT(0) -/* events for VFIO_GROUP_NOTIFY */ -#define VFIO_GROUP_NOTIFY_SET_KVM BIT(0) - extern int vfio_register_notifier(struct vfio_device *device, enum vfio_notify_type type, unsigned long *required_events, -- 2.27.0 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* RE: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-18 21:26 ` [PATCH v2 1/1] " Matthew Rosato @ 2022-05-19 6:43 ` Tian, Kevin 2022-05-19 12:33 ` [Intel-gfx] " Jason Gunthorpe 2022-05-19 16:23 ` Tony Krowiak 2 siblings, 0 replies; 12+ messages in thread From: Tian, Kevin @ 2022-05-19 6:43 UTC (permalink / raw) To: Matthew Rosato, jgg, alex.williamson Cc: jjherne, akrowiak, kvm, hch, linux-s390, intel-gfx, cohuck, linux-kernel, zhenyuw, pasic, borntraeger, intel-gvt-dev, Wang, Zhi A > From: Matthew Rosato > Sent: Thursday, May 19, 2022 5:26 AM > > Rather than relying on a notifier for associating the KVM with > the group, let's assume that the association has already been > made prior to device_open. The first time a device is opened > associate the group KVM with the device. > > This fixes a user-triggerable oops in GVT. No changelog. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> Not sure whether Christoph wants a s-o-b here when he wrote the snippet to remove the release work of gvt... > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct > vfio_device *device) > > mutex_lock(&device->dev_set->lock); > device->open_count++; > + down_read(&device->group->group_rwsem); > + if (device->open_count == 1 && device->group->kvm) { > + /* > + * Here we pass the KVM pointer with the group under the > read > + * lock. If the device driver will use it, it must obtain a > + * reference and release it during close_device. > + */ > + device->kvm = device->group->kvm; > + } > + > if (device->open_count == 1 && device->ops->open_device) { Merge the two branches so both are under if (device->open_count == 1) {} (and group_rwsem can be also moved inside) > @@ -1315,9 +1330,13 @@ static int vfio_device_fops_release(struct inode > *inode, struct file *filep) > > mutex_lock(&device->dev_set->lock); > vfio_assert_device_open(device); > + down_read(&device->group->group_rwsem); > if (device->open_count == 1 && device->ops->close_device) > device->ops->close_device(device); > device->open_count--; > + if (device->open_count == 0 && device->kvm) > + device->kvm = NULL; This can be moved out of group_rwsem as there is no reference to vfio_group. > + up_read(&device->group->group_rwsem); otherwise, Reviewed-by: Kevin Tian <kevin.tian@intel.com> Thanks Kevin ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Intel-gfx] [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM @ 2022-05-19 6:43 ` Tian, Kevin 0 siblings, 0 replies; 12+ messages in thread From: Tian, Kevin @ 2022-05-19 6:43 UTC (permalink / raw) To: Matthew Rosato, jgg, alex.williamson Cc: jjherne, akrowiak, kvm, linux-s390, intel-gfx, cohuck, linux-kernel, hch, pasic, borntraeger, intel-gvt-dev > From: Matthew Rosato > Sent: Thursday, May 19, 2022 5:26 AM > > Rather than relying on a notifier for associating the KVM with > the group, let's assume that the association has already been > made prior to device_open. The first time a device is opened > associate the group KVM with the device. > > This fixes a user-triggerable oops in GVT. No changelog. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> Not sure whether Christoph wants a s-o-b here when he wrote the snippet to remove the release work of gvt... > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct > vfio_device *device) > > mutex_lock(&device->dev_set->lock); > device->open_count++; > + down_read(&device->group->group_rwsem); > + if (device->open_count == 1 && device->group->kvm) { > + /* > + * Here we pass the KVM pointer with the group under the > read > + * lock. If the device driver will use it, it must obtain a > + * reference and release it during close_device. > + */ > + device->kvm = device->group->kvm; > + } > + > if (device->open_count == 1 && device->ops->open_device) { Merge the two branches so both are under if (device->open_count == 1) {} (and group_rwsem can be also moved inside) > @@ -1315,9 +1330,13 @@ static int vfio_device_fops_release(struct inode > *inode, struct file *filep) > > mutex_lock(&device->dev_set->lock); > vfio_assert_device_open(device); > + down_read(&device->group->group_rwsem); > if (device->open_count == 1 && device->ops->close_device) > device->ops->close_device(device); > device->open_count--; > + if (device->open_count == 0 && device->kvm) > + device->kvm = NULL; This can be moved out of group_rwsem as there is no reference to vfio_group. > + up_read(&device->group->group_rwsem); otherwise, Reviewed-by: Kevin Tian <kevin.tian@intel.com> Thanks Kevin ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-19 6:43 ` [Intel-gfx] " Tian, Kevin @ 2022-05-19 6:48 ` hch -1 siblings, 0 replies; 12+ messages in thread From: hch @ 2022-05-19 6:48 UTC (permalink / raw) To: Tian, Kevin Cc: Matthew Rosato, jgg, alex.williamson, jjherne, akrowiak, kvm, hch, linux-s390, intel-gfx, cohuck, linux-kernel, zhenyuw, pasic, borntraeger, intel-gvt-dev, Wang, Zhi A On Thu, May 19, 2022 at 06:43:06AM +0000, Tian, Kevin wrote: > > This fixes a user-triggerable oops in GVT. > > No changelog. ?? the cover latter clearly states what has changed since v1, and this patch has a good commit log. This is exactly how it is supposed to be done. > > > > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > > Not sure whether Christoph wants a s-o-b here when he wrote > the snippet to remove the release work of gvt... That's just tivial code removal, so no. > > > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct > > vfio_device *device) > > > > mutex_lock(&device->dev_set->lock); > > device->open_count++; > > + down_read(&device->group->group_rwsem); > > + if (device->open_count == 1 && device->group->kvm) { > > + /* > > + * Here we pass the KVM pointer with the group under the > > read > > + * lock. If the device driver will use it, it must obtain a > > + * reference and release it during close_device. > > + */ > > + device->kvm = device->group->kvm; > > + } > > + > > if (device->open_count == 1 && device->ops->open_device) { > > Merge the two branches so both are under if (device->open_count == 1) {} > (and group_rwsem can be also moved inside) Yeah. And we don't really need the device->group->kvm check, as it would otherwise assign NULL which is perfectly fine. But otherwise this also looks good to me: Reviewed-by: Christoph Hellwig <hch@lst.de> ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Intel-gfx] [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM @ 2022-05-19 6:48 ` hch 0 siblings, 0 replies; 12+ messages in thread From: hch @ 2022-05-19 6:48 UTC (permalink / raw) To: Tian, Kevin Cc: jjherne, akrowiak, kvm, Matthew Rosato, linux-s390, intel-gfx, cohuck, linux-kernel, hch, jgg, pasic, borntraeger, intel-gvt-dev On Thu, May 19, 2022 at 06:43:06AM +0000, Tian, Kevin wrote: > > This fixes a user-triggerable oops in GVT. > > No changelog. ?? the cover latter clearly states what has changed since v1, and this patch has a good commit log. This is exactly how it is supposed to be done. > > > > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > > Not sure whether Christoph wants a s-o-b here when he wrote > the snippet to remove the release work of gvt... That's just tivial code removal, so no. > > > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct > > vfio_device *device) > > > > mutex_lock(&device->dev_set->lock); > > device->open_count++; > > + down_read(&device->group->group_rwsem); > > + if (device->open_count == 1 && device->group->kvm) { > > + /* > > + * Here we pass the KVM pointer with the group under the > > read > > + * lock. If the device driver will use it, it must obtain a > > + * reference and release it during close_device. > > + */ > > + device->kvm = device->group->kvm; > > + } > > + > > if (device->open_count == 1 && device->ops->open_device) { > > Merge the two branches so both are under if (device->open_count == 1) {} > (and group_rwsem can be also moved inside) Yeah. And we don't really need the device->group->kvm check, as it would otherwise assign NULL which is perfectly fine. But otherwise this also looks good to me: Reviewed-by: Christoph Hellwig <hch@lst.de> ^ permalink raw reply [flat|nested] 12+ messages in thread
* RE: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-19 6:48 ` [Intel-gfx] " hch @ 2022-05-19 6:52 ` Tian, Kevin -1 siblings, 0 replies; 12+ messages in thread From: Tian, Kevin @ 2022-05-19 6:52 UTC (permalink / raw) To: hch Cc: Matthew Rosato, jgg, alex.williamson, jjherne, akrowiak, kvm, linux-s390, intel-gfx, cohuck, linux-kernel, zhenyuw, pasic, borntraeger, intel-gvt-dev, Wang, Zhi A > From: hch@infradead.org <hch@infradead.org> > Sent: Thursday, May 19, 2022 2:48 PM > > On Thu, May 19, 2022 at 06:43:06AM +0000, Tian, Kevin wrote: > > > This fixes a user-triggerable oops in GVT. > > > > No changelog. > > ?? > > the cover latter clearly states what has changed since v1, and this > patch has a good commit log. This is exactly how it is supposed to > be done. sigh... don't know why I missed the coverletter. ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Intel-gfx] [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM @ 2022-05-19 6:52 ` Tian, Kevin 0 siblings, 0 replies; 12+ messages in thread From: Tian, Kevin @ 2022-05-19 6:52 UTC (permalink / raw) To: hch Cc: jjherne, akrowiak, kvm, Matthew Rosato, linux-s390, intel-gfx, cohuck, linux-kernel, pasic, jgg, borntraeger, intel-gvt-dev > From: hch@infradead.org <hch@infradead.org> > Sent: Thursday, May 19, 2022 2:48 PM > > On Thu, May 19, 2022 at 06:43:06AM +0000, Tian, Kevin wrote: > > > This fixes a user-triggerable oops in GVT. > > > > No changelog. > > ?? > > the cover latter clearly states what has changed since v1, and this > patch has a good commit log. This is exactly how it is supposed to > be done. sigh... don't know why I missed the coverletter. ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-18 21:26 ` [PATCH v2 1/1] " Matthew Rosato @ 2022-05-19 12:33 ` Jason Gunthorpe 2022-05-19 12:33 ` [Intel-gfx] " Jason Gunthorpe 2022-05-19 16:23 ` Tony Krowiak 2 siblings, 0 replies; 12+ messages in thread From: Jason Gunthorpe @ 2022-05-19 12:33 UTC (permalink / raw) To: Matthew Rosato Cc: alex.williamson, cohuck, borntraeger, jjherne, akrowiak, pasic, zhenyuw, zhi.a.wang, hch, intel-gfx, intel-gvt-dev, linux-s390, kvm, linux-kernel On Wed, May 18, 2022 at 05:26:07PM -0400, Matthew Rosato wrote: > Rather than relying on a notifier for associating the KVM with > the group, let's assume that the association has already been > made prior to device_open. The first time a device is opened > associate the group KVM with the device. > > This fixes a user-triggerable oops in GVT. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > drivers/gpu/drm/i915/gvt/gtt.c | 4 +- > drivers/gpu/drm/i915/gvt/gvt.h | 3 - > drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++--------------------- > drivers/s390/crypto/vfio_ap_ops.c | 38 ++++--------- > drivers/s390/crypto/vfio_ap_private.h | 3 - > drivers/vfio/vfio.c | 75 ++++++++---------------- > include/linux/vfio.h | 5 +- > 7 files changed, 56 insertions(+), 154 deletions(-) I'm fine with this, thanks for finishing it > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index e8914024f5b1..17a56bb4cf25 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -1196,6 +1196,8 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev, > { > struct ap_matrix_mdev *m; > > + kvm_get_kvm(kvm); > + [..] > + if (kvm) > + kvm_put_kvm(kvm); > } This extra ref traffic is not necessary, the kvm will have a valid ref because we are under the group_rwsem here and then the function will obtain a ref when it stores it in matrix_mdev->kvm. > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index cfcff7764403..272acb62facd 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct vfio_device *device) > > mutex_lock(&device->dev_set->lock); > device->open_count++; > + down_read(&device->group->group_rwsem); > + if (device->open_count == 1 && device->group->kvm) { > + /* > + * Here we pass the KVM pointer with the group under the read > + * lock. If the device driver will use it, it must obtain a > + * reference and release it during close_device. > + */ > + device->kvm = device->group->kvm; > + } But it is a bit ugly to keep the device->kvm in the struct device without holding a reference count. It is probably worth adding a comment to the definition in the struct as well that the device driver must reference it or never touch it. Jason ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Intel-gfx] [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM @ 2022-05-19 12:33 ` Jason Gunthorpe 0 siblings, 0 replies; 12+ messages in thread From: Jason Gunthorpe @ 2022-05-19 12:33 UTC (permalink / raw) To: Matthew Rosato Cc: jjherne, akrowiak, kvm, hch, linux-s390, intel-gfx, cohuck, linux-kernel, pasic, borntraeger, intel-gvt-dev On Wed, May 18, 2022 at 05:26:07PM -0400, Matthew Rosato wrote: > Rather than relying on a notifier for associating the KVM with > the group, let's assume that the association has already been > made prior to device_open. The first time a device is opened > associate the group KVM with the device. > > This fixes a user-triggerable oops in GVT. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > drivers/gpu/drm/i915/gvt/gtt.c | 4 +- > drivers/gpu/drm/i915/gvt/gvt.h | 3 - > drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++--------------------- > drivers/s390/crypto/vfio_ap_ops.c | 38 ++++--------- > drivers/s390/crypto/vfio_ap_private.h | 3 - > drivers/vfio/vfio.c | 75 ++++++++---------------- > include/linux/vfio.h | 5 +- > 7 files changed, 56 insertions(+), 154 deletions(-) I'm fine with this, thanks for finishing it > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index e8914024f5b1..17a56bb4cf25 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -1196,6 +1196,8 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev, > { > struct ap_matrix_mdev *m; > > + kvm_get_kvm(kvm); > + [..] > + if (kvm) > + kvm_put_kvm(kvm); > } This extra ref traffic is not necessary, the kvm will have a valid ref because we are under the group_rwsem here and then the function will obtain a ref when it stores it in matrix_mdev->kvm. > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index cfcff7764403..272acb62facd 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct vfio_device *device) > > mutex_lock(&device->dev_set->lock); > device->open_count++; > + down_read(&device->group->group_rwsem); > + if (device->open_count == 1 && device->group->kvm) { > + /* > + * Here we pass the KVM pointer with the group under the read > + * lock. If the device driver will use it, it must obtain a > + * reference and release it during close_device. > + */ > + device->kvm = device->group->kvm; > + } But it is a bit ugly to keep the device->kvm in the struct device without holding a reference count. It is probably worth adding a comment to the definition in the struct as well that the device driver must reference it or never touch it. Jason ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-18 21:26 ` [PATCH v2 1/1] " Matthew Rosato 2022-05-19 6:43 ` [Intel-gfx] " Tian, Kevin 2022-05-19 12:33 ` [Intel-gfx] " Jason Gunthorpe @ 2022-05-19 16:23 ` Tony Krowiak 2022-05-19 16:35 ` Matthew Rosato 2 siblings, 1 reply; 12+ messages in thread From: Tony Krowiak @ 2022-05-19 16:23 UTC (permalink / raw) To: Matthew Rosato, jgg, alex.williamson Cc: cohuck, borntraeger, jjherne, pasic, zhenyuw, zhi.a.wang, hch, intel-gfx, intel-gvt-dev, linux-s390, kvm, linux-kernel I made a few comments, but other than that this looks good to me: Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com> On 5/18/22 5:26 PM, Matthew Rosato wrote: > Rather than relying on a notifier for associating the KVM with > the group, let's assume that the association has already been > made prior to device_open. The first time a device is opened > associate the group KVM with the device. > > This fixes a user-triggerable oops in GVT. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > drivers/gpu/drm/i915/gvt/gtt.c | 4 +- > drivers/gpu/drm/i915/gvt/gvt.h | 3 - > drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++--------------------- > drivers/s390/crypto/vfio_ap_ops.c | 38 ++++--------- > drivers/s390/crypto/vfio_ap_private.h | 3 - > drivers/vfio/vfio.c | 75 ++++++++---------------- > include/linux/vfio.h | 5 +- > 7 files changed, 56 insertions(+), 154 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c > index 9c5cc2800975..b4f69364f9a1 100644 > --- a/drivers/gpu/drm/i915/gvt/gtt.c > +++ b/drivers/gpu/drm/i915/gvt/gtt.c > @@ -51,7 +51,7 @@ static int preallocated_oos_pages = 8192; > > static bool intel_gvt_is_valid_gfn(struct intel_vgpu *vgpu, unsigned long gfn) > { > - struct kvm *kvm = vgpu->kvm; > + struct kvm *kvm = vgpu->vfio_device.kvm; > int idx; > bool ret; > > @@ -1185,7 +1185,7 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu, > > if (!vgpu->attached) > return -EINVAL; > - pfn = gfn_to_pfn(vgpu->kvm, ops->get_pfn(entry)); > + pfn = gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry)); > if (is_error_noslot_pfn(pfn)) > return -EINVAL; > return PageTransHuge(pfn_to_page(pfn)); > diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h > index 2af4c83e733c..aee1a45da74b 100644 > --- a/drivers/gpu/drm/i915/gvt/gvt.h > +++ b/drivers/gpu/drm/i915/gvt/gvt.h > @@ -227,9 +227,6 @@ struct intel_vgpu { > struct mutex cache_lock; > > struct notifier_block iommu_notifier; > - struct notifier_block group_notifier; > - struct kvm *kvm; > - struct work_struct release_work; > atomic_t released; > > struct kvm_page_track_notifier_node track_node; > diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c > index 7655ffa97d51..e2f6c56ab342 100644 > --- a/drivers/gpu/drm/i915/gvt/kvmgt.c > +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c > @@ -228,8 +228,6 @@ static void intel_gvt_cleanup_vgpu_type_groups(struct intel_gvt *gvt) > } > } > > -static void intel_vgpu_release_work(struct work_struct *work); > - > static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, > unsigned long size) > { > @@ -761,23 +759,6 @@ static int intel_vgpu_iommu_notifier(struct notifier_block *nb, > return NOTIFY_OK; > } > > -static int intel_vgpu_group_notifier(struct notifier_block *nb, > - unsigned long action, void *data) > -{ > - struct intel_vgpu *vgpu = > - container_of(nb, struct intel_vgpu, group_notifier); > - > - /* the only action we care about */ > - if (action == VFIO_GROUP_NOTIFY_SET_KVM) { > - vgpu->kvm = data; > - > - if (!data) > - schedule_work(&vgpu->release_work); > - } > - > - return NOTIFY_OK; > -} > - > static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu) > { > struct intel_vgpu *itr; > @@ -789,7 +770,7 @@ static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu) > if (!itr->attached) > continue; > > - if (vgpu->kvm == itr->kvm) { > + if (vgpu->vfio_device.kvm == itr->vfio_device.kvm) { > ret = true; > goto out; > } > @@ -806,7 +787,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) > int ret; > > vgpu->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier; > - vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier; > > events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; > ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events, > @@ -817,38 +797,32 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) > goto out; > } > > - events = VFIO_GROUP_NOTIFY_SET_KVM; > - ret = vfio_register_notifier(vfio_dev, VFIO_GROUP_NOTIFY, &events, > - &vgpu->group_notifier); > - if (ret != 0) { > - gvt_vgpu_err("vfio_register_notifier for group failed: %d\n", > - ret); > - goto undo_iommu; > - } > - > ret = -EEXIST; > if (vgpu->attached) > - goto undo_register; > + goto undo_iommu; > > ret = -ESRCH; > - if (!vgpu->kvm || vgpu->kvm->mm != current->mm) { > + if (!vgpu->vfio_device.kvm || > + vgpu->vfio_device.kvm->mm != current->mm) { > gvt_vgpu_err("KVM is required to use Intel vGPU\n"); > - goto undo_register; > + goto undo_iommu; > } > > + kvm_get_kvm(vgpu->vfio_device.kvm); > + > ret = -EEXIST; > if (__kvmgt_vgpu_exist(vgpu)) > - goto undo_register; > + goto undo_iommu; > > vgpu->attached = true; > - kvm_get_kvm(vgpu->kvm); > > kvmgt_protect_table_init(vgpu); > gvt_cache_init(vgpu); > > vgpu->track_node.track_write = kvmgt_page_track_write; > vgpu->track_node.track_flush_slot = kvmgt_page_track_flush_slot; > - kvm_page_track_register_notifier(vgpu->kvm, &vgpu->track_node); > + kvm_page_track_register_notifier(vgpu->vfio_device.kvm, > + &vgpu->track_node); > > debugfs_create_ulong(KVMGT_DEBUGFS_FILENAME, 0444, vgpu->debugfs, > &vgpu->nr_cache_entries); > @@ -858,10 +832,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev) > atomic_set(&vgpu->released, 0); > return 0; > > -undo_register: > - vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY, > - &vgpu->group_notifier); > - > undo_iommu: > vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, > &vgpu->iommu_notifier); > @@ -880,8 +850,9 @@ static void intel_vgpu_release_msi_eventfd_ctx(struct intel_vgpu *vgpu) > } > } > > -static void __intel_vgpu_release(struct intel_vgpu *vgpu) > +static void intel_vgpu_close_device(struct vfio_device *vfio_dev) > { > + struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev); > struct drm_i915_private *i915 = vgpu->gvt->gt->i915; > int ret; > > @@ -898,35 +869,19 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu) > drm_WARN(&i915->drm, ret, > "vfio_unregister_notifier for iommu failed: %d\n", ret); > > - ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_GROUP_NOTIFY, > - &vgpu->group_notifier); > - drm_WARN(&i915->drm, ret, > - "vfio_unregister_notifier for group failed: %d\n", ret); > - > debugfs_remove(debugfs_lookup(KVMGT_DEBUGFS_FILENAME, vgpu->debugfs)); > > - kvm_page_track_unregister_notifier(vgpu->kvm, &vgpu->track_node); > - kvm_put_kvm(vgpu->kvm); > + kvm_page_track_unregister_notifier(vgpu->vfio_device.kvm, > + &vgpu->track_node); > kvmgt_protect_table_destroy(vgpu); > gvt_cache_destroy(vgpu); > > intel_vgpu_release_msi_eventfd_ctx(vgpu); > > - vgpu->kvm = NULL; > vgpu->attached = false; > -} > - > -static void intel_vgpu_close_device(struct vfio_device *vfio_dev) > -{ > - __intel_vgpu_release(vfio_dev_to_vgpu(vfio_dev)); > -} > - > -static void intel_vgpu_release_work(struct work_struct *work) > -{ > - struct intel_vgpu *vgpu = > - container_of(work, struct intel_vgpu, release_work); > > - __intel_vgpu_release(vgpu); > + if (vgpu->vfio_device.kvm) > + kvm_put_kvm(vgpu->vfio_device.kvm); > } > > static u64 intel_vgpu_get_bar_addr(struct intel_vgpu *vgpu, int bar) > @@ -1675,7 +1630,6 @@ static int intel_vgpu_probe(struct mdev_device *mdev) > return PTR_ERR(vgpu); > } > > - INIT_WORK(&vgpu->release_work, intel_vgpu_release_work); > vfio_init_group_dev(&vgpu->vfio_device, &mdev->dev, > &intel_vgpu_dev_ops); > > @@ -1713,7 +1667,7 @@ static struct mdev_driver intel_vgpu_mdev_driver = { > > int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) > { > - struct kvm *kvm = info->kvm; > + struct kvm *kvm = info->vfio_device.kvm; > struct kvm_memory_slot *slot; > int idx; > > @@ -1743,7 +1697,7 @@ int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) > > int intel_gvt_page_track_remove(struct intel_vgpu *info, u64 gfn) > { > - struct kvm *kvm = info->kvm; > + struct kvm *kvm = info->vfio_device.kvm; > struct kvm_memory_slot *slot; > int idx; > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index e8914024f5b1..17a56bb4cf25 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -1196,6 +1196,8 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev, > { > struct ap_matrix_mdev *m; > > + kvm_get_kvm(kvm); > + I'm not sure what version of the code on which the patch was rebased, but in the latest master branch from our repository the kvm_get_kvm(kvm) function is called inside of the if block below. I'm fine with moving outside of the block, but I don't see a corresponding removal of it from inside the block. > if (kvm->arch.crypto.crycbd) { > down_write(&kvm->arch.crypto.pqap_hook_rwsem); > kvm->arch.crypto.pqap_hook = &matrix_mdev->pqap_hook; > @@ -1282,25 +1284,9 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev) > mutex_unlock(&kvm->lock); > mutex_unlock(&matrix_dev->lock); > } > -} > > -static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, > - unsigned long action, void *data) > -{ > - int notify_rc = NOTIFY_OK; > - struct ap_matrix_mdev *matrix_mdev; > - > - if (action != VFIO_GROUP_NOTIFY_SET_KVM) > - return NOTIFY_OK; > - > - matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier); > - > - if (!data) > - vfio_ap_mdev_unset_kvm(matrix_mdev); > - else if (vfio_ap_mdev_set_kvm(matrix_mdev, data)) > - notify_rc = NOTIFY_DONE; > - > - return notify_rc; Similarly, there is a call to kvm_put_kvm(kvm) inside the if block. Again, I'm okay with moving this outside of the if block, but I would think the call inside the if block ought to be removed. > + if (kvm) > + kvm_put_kvm(kvm); > } > > static struct vfio_ap_queue *vfio_ap_find_queue(int apqn) > @@ -1402,11 +1388,10 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev) > unsigned long events; > int ret; > > - matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier; > - events = VFIO_GROUP_NOTIFY_SET_KVM; > + if (!vdev->kvm) > + return -EPERM; Perhaps -EINVAL or -EFAULT? > > - ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events, > - &matrix_mdev->group_notifier); > + ret = vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm); > if (ret) > return ret; > > @@ -1415,12 +1400,11 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev) > ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events, > &matrix_mdev->iommu_notifier); > if (ret) > - goto out_unregister_group; > + goto err_kvm; > return 0; > > -out_unregister_group: > - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, > - &matrix_mdev->group_notifier); > +err_kvm: > + vfio_ap_mdev_unset_kvm(matrix_mdev); > return ret; > } > > @@ -1431,8 +1415,6 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev) > > vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, > &matrix_mdev->iommu_notifier); > - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, > - &matrix_mdev->group_notifier); > vfio_ap_mdev_unset_kvm(matrix_mdev); I'm not sure if this matters, but the vfio_ap_mdev_unset_kvm(matrix_mdev) function uses the KVM pointer stored in matrix_mdev->kvm. I can't imagine the KVM pointer stored in vdev->kvm being different than matrix_mdev->kvm, but thought I should point it out. Previously, this function was called by the notifier handler which did not have access to the KVM pointer which is why it was retrieved from matrix_mdev->kvm. Even if the vdev->kvm and matrix_mdev->kvm did not match, we should probably go ahead and call the unset function anyway to remove access to AP resources for the guest and reset the queues. > } > > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h > index 648fcaf8104a..a26efd804d0d 100644 > --- a/drivers/s390/crypto/vfio_ap_private.h > +++ b/drivers/s390/crypto/vfio_ap_private.h > @@ -81,8 +81,6 @@ struct ap_matrix { > * @node: allows the ap_matrix_mdev struct to be added to a list > * @matrix: the adapters, usage domains and control domains assigned to the > * mediated matrix device. > - * @group_notifier: notifier block used for specifying callback function for > - * handling the VFIO_GROUP_NOTIFY_SET_KVM event > * @iommu_notifier: notifier block used for specifying callback function for > * handling the VFIO_IOMMU_NOTIFY_DMA_UNMAP even > * @kvm: the struct holding guest's state > @@ -94,7 +92,6 @@ struct ap_matrix_mdev { > struct vfio_device vdev; > struct list_head node; > struct ap_matrix matrix; > - struct notifier_block group_notifier; > struct notifier_block iommu_notifier; > struct kvm *kvm; > crypto_hook pqap_hook; > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index cfcff7764403..272acb62facd 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -1083,11 +1083,22 @@ static struct file *vfio_device_open(struct vfio_device *device) > > mutex_lock(&device->dev_set->lock); > device->open_count++; > + down_read(&device->group->group_rwsem); > + if (device->open_count == 1 && device->group->kvm) { > + /* > + * Here we pass the KVM pointer with the group under the read > + * lock. If the device driver will use it, it must obtain a > + * reference and release it during close_device. > + */ > + device->kvm = device->group->kvm; > + } > + > if (device->open_count == 1 && device->ops->open_device) { > ret = device->ops->open_device(device); > if (ret) > goto err_undo_count; > } > + up_read(&device->group->group_rwsem); > mutex_unlock(&device->dev_set->lock); > > /* > @@ -1119,10 +1130,14 @@ static struct file *vfio_device_open(struct vfio_device *device) > > err_close_device: > mutex_lock(&device->dev_set->lock); > + down_read(&device->group->group_rwsem); > if (device->open_count == 1 && device->ops->close_device) > device->ops->close_device(device); > err_undo_count: > device->open_count--; > + if (device->open_count == 0 && device->kvm) > + device->kvm = NULL; > + up_read(&device->group->group_rwsem); > mutex_unlock(&device->dev_set->lock); > module_put(device->dev->driver->owner); > err_unassign_container: > @@ -1315,9 +1330,13 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) > > mutex_lock(&device->dev_set->lock); > vfio_assert_device_open(device); > + down_read(&device->group->group_rwsem); > if (device->open_count == 1 && device->ops->close_device) > device->ops->close_device(device); > device->open_count--; > + if (device->open_count == 0 && device->kvm) > + device->kvm = NULL; > + up_read(&device->group->group_rwsem); > mutex_unlock(&device->dev_set->lock); > > module_put(device->dev->driver->owner); > @@ -1726,8 +1745,8 @@ EXPORT_SYMBOL_GPL(vfio_file_enforced_coherent); > * @file: VFIO group file > * @kvm: KVM to link > * > - * The kvm pointer will be forwarded to all the vfio_device's attached to the > - * VFIO file via the VFIO_GROUP_NOTIFY_SET_KVM notifier. > + * When a VFIO device is first opened the KVM will be available in > + * device->kvm if one was associated with the group. > */ > void vfio_file_set_kvm(struct file *file, struct kvm *kvm) > { > @@ -1738,8 +1757,6 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm) > > down_write(&group->group_rwsem); > group->kvm = kvm; > - blocking_notifier_call_chain(&group->notifier, > - VFIO_GROUP_NOTIFY_SET_KVM, kvm); > up_write(&group->group_rwsem); > } > EXPORT_SYMBOL_GPL(vfio_file_set_kvm); > @@ -2006,7 +2023,8 @@ static int vfio_register_iommu_notifier(struct vfio_group *group, > struct vfio_iommu_driver *driver; > int ret; > > - down_read(&group->group_rwsem); > + lockdep_assert_held_read(&group->group_rwsem); > + > container = group->container; > driver = container->iommu_driver; > if (likely(driver && driver->ops->register_notifier)) > @@ -2014,7 +2032,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group, > events, nb); > else > ret = -ENOTTY; > - up_read(&group->group_rwsem); > > return ret; > } > @@ -2026,7 +2043,8 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group, > struct vfio_iommu_driver *driver; > int ret; > > - down_read(&group->group_rwsem); > + lockdep_assert_held_read(&group->group_rwsem); > + > container = group->container; > driver = container->iommu_driver; > if (likely(driver && driver->ops->unregister_notifier)) > @@ -2034,47 +2052,10 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group, > nb); > else > ret = -ENOTTY; > - up_read(&group->group_rwsem); > > return ret; > } > > -static int vfio_register_group_notifier(struct vfio_group *group, > - unsigned long *events, > - struct notifier_block *nb) > -{ > - int ret; > - bool set_kvm = false; > - > - if (*events & VFIO_GROUP_NOTIFY_SET_KVM) > - set_kvm = true; > - > - /* clear known events */ > - *events &= ~VFIO_GROUP_NOTIFY_SET_KVM; > - > - /* refuse to continue if still events remaining */ > - if (*events) > - return -EINVAL; > - > - ret = blocking_notifier_chain_register(&group->notifier, nb); > - if (ret) > - return ret; > - > - /* > - * The attaching of kvm and vfio_group might already happen, so > - * here we replay once upon registration. > - */ > - if (set_kvm) { > - down_read(&group->group_rwsem); > - if (group->kvm) > - blocking_notifier_call_chain(&group->notifier, > - VFIO_GROUP_NOTIFY_SET_KVM, > - group->kvm); > - up_read(&group->group_rwsem); > - } > - return 0; > -} > - > int vfio_register_notifier(struct vfio_device *device, > enum vfio_notify_type type, unsigned long *events, > struct notifier_block *nb) > @@ -2090,9 +2071,6 @@ int vfio_register_notifier(struct vfio_device *device, > case VFIO_IOMMU_NOTIFY: > ret = vfio_register_iommu_notifier(group, events, nb); > break; > - case VFIO_GROUP_NOTIFY: > - ret = vfio_register_group_notifier(group, events, nb); > - break; > default: > ret = -EINVAL; > } > @@ -2114,9 +2092,6 @@ int vfio_unregister_notifier(struct vfio_device *device, > case VFIO_IOMMU_NOTIFY: > ret = vfio_unregister_iommu_notifier(group, nb); > break; > - case VFIO_GROUP_NOTIFY: > - ret = blocking_notifier_chain_unregister(&group->notifier, nb); > - break; > default: > ret = -EINVAL; > } > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 45b287826ce6..5f691453e3fb 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -36,6 +36,7 @@ struct vfio_device { > struct vfio_device_set *dev_set; > struct list_head dev_set_list; > unsigned int migration_flags; > + struct kvm *kvm; > > /* Members below here are private, not for driver use */ > refcount_t refcount; > @@ -155,15 +156,11 @@ extern int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, > /* each type has independent events */ > enum vfio_notify_type { > VFIO_IOMMU_NOTIFY = 0, > - VFIO_GROUP_NOTIFY = 1, > }; > > /* events for VFIO_IOMMU_NOTIFY */ > #define VFIO_IOMMU_NOTIFY_DMA_UNMAP BIT(0) > > -/* events for VFIO_GROUP_NOTIFY */ > -#define VFIO_GROUP_NOTIFY_SET_KVM BIT(0) > - > extern int vfio_register_notifier(struct vfio_device *device, > enum vfio_notify_type type, > unsigned long *required_events, ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM 2022-05-19 16:23 ` Tony Krowiak @ 2022-05-19 16:35 ` Matthew Rosato 0 siblings, 0 replies; 12+ messages in thread From: Matthew Rosato @ 2022-05-19 16:35 UTC (permalink / raw) To: Tony Krowiak, jgg, alex.williamson Cc: cohuck, borntraeger, jjherne, pasic, zhenyuw, zhi.a.wang, hch, intel-gfx, intel-gvt-dev, linux-s390, kvm, linux-kernel On 5/19/22 12:23 PM, Tony Krowiak wrote: > I made a few comments, but other than that this looks good to > me: > > Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com> > ... > I'm not sure what version of the code on which the patch was rebased, Was on top of Jason's vfio_group_locking series, but now would apply on vfio-next since Alex pulled that series in to vfio-next. > but in the > latest master branch from our repository the kvm_get_kvm(kvm) function is > called inside of the if block below. I'm fine with moving outside of the > block, but > I don't see a corresponding removal of it from inside the block. Yeah, I didn't notice those there. v3 will simply remove my get/put additions and leave yours as-is. ... >> vfio_ap_mdev_group_notifier; >> - events = VFIO_GROUP_NOTIFY_SET_KVM; >> + if (!vdev->kvm) >> + return -EPERM; > > Perhaps -EINVAL or -EFAULT? > Whichever you'd prefer? If I don't hear back I'll just use -EINVAL in v3. >> - ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events, >> - &matrix_mdev->group_notifier); >> + ret = vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm); >> if (ret) >> return ret; >> @@ -1415,12 +1400,11 @@ static int vfio_ap_mdev_open_device(struct >> vfio_device *vdev) >> ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events, >> &matrix_mdev->iommu_notifier); >> if (ret) >> - goto out_unregister_group; >> + goto err_kvm; >> return 0; >> -out_unregister_group: >> - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, >> - &matrix_mdev->group_notifier); >> +err_kvm: >> + vfio_ap_mdev_unset_kvm(matrix_mdev); >> return ret; >> } >> @@ -1431,8 +1415,6 @@ static void vfio_ap_mdev_close_device(struct >> vfio_device *vdev) >> vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, >> &matrix_mdev->iommu_notifier); >> - vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY, >> - &matrix_mdev->group_notifier); >> vfio_ap_mdev_unset_kvm(matrix_mdev); > > I'm not sure if this matters, but the vfio_ap_mdev_unset_kvm(matrix_mdev) > function uses the KVM pointer stored in matrix_mdev->kvm. I can't imagine > the KVM pointer stored in vdev->kvm being different than matrix_mdev->kvm, With this patch matrix_mdev->kvm is set from the value in vdev->kvm during vfio_ap_mdev_set_kvm (basically, doing the work that the notifier was doing but instead of getting it from notifier data get it from the vfio_device) > but thought I should point it out. Previously, this function was called > by the > notifier handler which did not have access to the KVM pointer which is > why it > was retrieved from matrix_mdev->kvm. Even if the vdev->kvm and > matrix_mdev->kvm did not match, we should probably go ahead and call > the unset function anyway to remove access to AP resources for the guest > and > reset the queues. > ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2022-05-19 16:35 UTC | newest] Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-05-18 21:26 [PATCH v2 0/1] vfio: remove VFIO_GROUP_NOTIFY_SET_KVM Matthew Rosato 2022-05-18 21:26 ` [PATCH v2 1/1] " Matthew Rosato 2022-05-19 6:43 ` Tian, Kevin 2022-05-19 6:43 ` [Intel-gfx] " Tian, Kevin 2022-05-19 6:48 ` hch 2022-05-19 6:48 ` [Intel-gfx] " hch 2022-05-19 6:52 ` Tian, Kevin 2022-05-19 6:52 ` [Intel-gfx] " Tian, Kevin 2022-05-19 12:33 ` Jason Gunthorpe 2022-05-19 12:33 ` [Intel-gfx] " Jason Gunthorpe 2022-05-19 16:23 ` Tony Krowiak 2022-05-19 16:35 ` Matthew Rosato
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