On 11/27/25 01:39, Michał Winiarski wrote:
[snip]
+static void xe_vfio_pci_reset_done(struct pci_dev *pdev)
+{
+ struct xe_vfio_pci_core_device *xe_vdev = pci_get_drvdata(pdev);
+ int ret;
+
+ if (!pdev->is_virtfn)
+ return;
+
+ /*
+ * VF FLR requires additional processing done by PF driver.
+ * The processing is done after FLR is already finished from PCIe
+ * perspective.
+ * In order to avoid a scenario where VF is used while PF processing
+ * is still in progress, additional synchronization point is needed.
+ */
+ ret = xe_sriov_vfio_wait_flr_done(xe_vdev->xe, xe_vdev->vfid);
+ if (ret)
+ dev_err(&pdev->dev, "Failed to wait for FLR: %d\n", ret);
+
+ if (!xe_vdev->vfid)
+ return;
+
+ /*
+ * As the higher VFIO layers are holding locks across reset and using
+ * those same locks with the mm_lock we need to prevent ABBA deadlock
+ * with the state_mutex and mm_lock.
+ * In case the state_mutex was taken already we defer the cleanup work
+ * to the unlock flow of the other running context.
+ */
+ spin_lock(&xe_vdev->reset_lock);
+ xe_vdev->deferred_reset = true;
+ if (!mutex_trylock(&xe_vdev->state_mutex)) {
+ spin_unlock(&xe_vdev->reset_lock);
+ return;
+ }
+ spin_unlock(&xe_vdev->reset_lock);
+ xe_vfio_pci_state_mutex_unlock(xe_vdev);
+
+ xe_vfio_pci_reset(xe_vdev);
+}
[snip]
My first KVM review :)
I think xe_vfio_pci_reset(xe_vdev) need be protected by state_mutex. So,
we should move xe_vfio_pci_state_mutex_unlock(xe_vdev) after
xe_vfio_pci_reset(xe_vdev). Thoughts?
Thanks,
Angela
