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vfio: remove VFIO_GROUP_NOTIFY_SET_KVM
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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.

Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20220519183311.582380-2-mjrosato@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Matthew Rosato authored and Alex Williamson committed May 24, 2022
1 parent c490513 commit 421cfe6
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Showing 7 changed files with 57 additions and 159 deletions.
4 changes: 2 additions & 2 deletions drivers/gpu/drm/i915/gvt/gtt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand Down Expand Up @@ -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));
Expand Down
3 changes: 0 additions & 3 deletions drivers/gpu/drm/i915/gvt/gvt.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
82 changes: 18 additions & 64 deletions drivers/gpu/drm/i915/gvt/kvmgt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand Down Expand Up @@ -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;
Expand All @@ -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;
}
Expand All @@ -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,
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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;

Expand All @@ -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)
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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;

Expand Down
35 changes: 6 additions & 29 deletions drivers/s390/crypto/vfio_ap_ops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1284,25 +1284,6 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev)
}
}

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;
}

static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)
{
struct device *dev;
Expand Down Expand Up @@ -1402,11 +1383,10 @@ 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 -EINVAL;

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;

Expand All @@ -1415,12 +1395,11 @@ 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;
}

Expand All @@ -1431,8 +1410,6 @@ 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);
}

Expand Down
3 changes: 0 additions & 3 deletions drivers/s390/crypto/vfio_ap_private.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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;
Expand Down
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