Implements two callbacks related to the current state of a vfio-ap device: * The callback that sets a new migration state of a vfio-ap device during live migration of guests with pass-through access to AP devices. This callback is mandatory for VFIO_DEVICE_FEATURE_MIGRATION support. The function pointer for this callback is specified via the 'migration_set_state' field of the 'vfio_migration_ops' structure which is stored with the VFIO device when the 'vfio_device' structure representing the mediated device is initialized. * The callback that returns the current vfio device migration state during live migration of guests with pass-through access to AP devices. The function pointer for this callback is specified via the 'migration_get_state' field of the 'vfio_migration_ops' structure which is stored with the VFIO device when the 'vfio_device' structure representing the mediated device is initialized. Signed-off-by: Anthony Krowiak --- drivers/s390/crypto/vfio_ap_migration.c | 130 +++++++++++++++++++++++- 1 file changed, 127 insertions(+), 3 deletions(-) diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c index c7c71980bdbb..8274e7b65eea 100644 --- a/drivers/s390/crypto/vfio_ap_migration.c +++ b/drivers/s390/crypto/vfio_ap_migration.c @@ -5,6 +5,7 @@ * Copyright IBM Corp. 2025 */ #include +#include "ap_bus.h" #include "vfio_ap_private.h" /** @@ -56,16 +57,140 @@ struct vfio_ap_config { struct vfio_ap_queue_info qinfo[] __counted_by(num_queues); }; +static struct file * +vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev, + enum vfio_device_mig_state new_state) +{ + struct vfio_ap_migration_data *mig_data; + enum vfio_device_mig_state cur_state; + + lockdep_assert_held(&matrix_dev->mdevs_lock); + mig_data = matrix_mdev->mig_data; + cur_state = mig_data->mig_state; + dev_dbg(matrix_mdev->vdev.dev, "%s: %d -> %d\n", __func__, cur_state, + new_state); + + if (cur_state == VFIO_DEVICE_STATE_STOP && + new_state == VFIO_DEVICE_STATE_STOP_COPY) { + /* TODO */ + return ERR_PTR(-EOPNOTSUPP); + } + + if (cur_state == VFIO_DEVICE_STATE_STOP && + new_state == VFIO_DEVICE_STATE_RESUMING) { + /* TODO */ + return ERR_PTR(-EOPNOTSUPP); + } + + if ((cur_state == VFIO_DEVICE_STATE_RESUMING && + new_state == VFIO_DEVICE_STATE_STOP) || + (cur_state == VFIO_DEVICE_STATE_STOP_COPY && + new_state == VFIO_DEVICE_STATE_STOP)) { + /* TODO */ + return ERR_PTR(-EOPNOTSUPP); + } + + if ((cur_state == VFIO_DEVICE_STATE_STOP && + new_state == VFIO_DEVICE_STATE_RUNNING) || + (cur_state == VFIO_DEVICE_STATE_RUNNING && + new_state == VFIO_DEVICE_STATE_STOP)) { + /* TODO */ + return ERR_PTR(-EOPNOTSUPP); + } + + /* vfio_mig_get_next_state() does not use arcs other than the above */ + WARN_ON(true); + + return ERR_PTR(-EINVAL); +} + static struct file *vfio_ap_set_state(struct vfio_device *vdev, enum vfio_device_mig_state new_state) { - return NULL; + int ret; + struct file *filp = NULL; + struct ap_matrix_mdev *matrix_mdev; + enum vfio_device_mig_state next_state; + struct vfio_ap_migration_data *mig_data; + + matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev); + + mutex_lock(&matrix_dev->mdevs_lock); + if (ap_is_se_guest()) { + dev_err(matrix_mdev->vdev.dev, + "Migration not allowed from or to a Secure Execution guest\n"); + mutex_unlock(&matrix_dev->mdevs_lock); + return ERR_PTR(-EPERM); + } + + mig_data = matrix_mdev->mig_data; + + /* + * The mig_data pointer is set in the vfio_ap_init_migration_data + * function which is called when the vfio-ap device fd is opened. + * Since the implicit pre-open state is RUNNING, a request to set + * RUNNING is a no-op. Any other state transition is invalid before + * open_device. + */ + if (!mig_data) { + mutex_unlock(&matrix_dev->mdevs_lock); + if (new_state == VFIO_DEVICE_STATE_RUNNING) + return NULL; + return ERR_PTR(-ENODEV); + } + + dev_dbg(vdev->dev, "%s -> %d\n", __func__, new_state); + + while (mig_data->mig_state != new_state) { + ret = vfio_mig_get_next_state(vdev, mig_data->mig_state, + new_state, &next_state); + if (ret) { + filp = ERR_PTR(ret); + break; + } + + filp = vfio_ap_transition_to_state(matrix_mdev, next_state); + if (IS_ERR(filp)) + break; + + mig_data->mig_state = next_state; + + if (WARN_ON(filp && new_state != next_state)) { + fput(filp); + filp = ERR_PTR(-EINVAL); + break; + } + } + + mutex_unlock(&matrix_dev->mdevs_lock); + + return filp; } static int vfio_ap_get_state(struct vfio_device *vdev, enum vfio_device_mig_state *current_state) { - return -EOPNOTSUPP; + struct ap_matrix_mdev *matrix_mdev; + struct vfio_ap_migration_data *mig_data; + + mutex_lock(&matrix_dev->mdevs_lock); + + matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev); + mig_data = matrix_mdev->mig_data; + + /* + * The mig_data pointer is set in the vfio_ap_init_migration_data + * function which is called when the vfio-ap device fd is opened. + * If mig_data is NULL, report RUNNING as the implicit pre-open state + * so userspace doesn't need to perform any state transition before the + * device becomes active. + */ + *current_state = (mig_data) ? mig_data->mig_state : + VFIO_DEVICE_STATE_RUNNING; + + mutex_unlock(&matrix_dev->mdevs_lock); + + return 0; } static int vfio_ap_get_data_size(struct vfio_device *vdev, @@ -146,6 +271,5 @@ void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev) if (!matrix_mdev->mig_data) return; - vfio_ap_release_mig_files(matrix_mdev); matrix_mdev->mig_data->mig_state = VFIO_DEVICE_STATE_RUNNING; } -- 2.53.0