When userspace opts into VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2, the driver may report the VFIO_PRECOPY_INFO_REINIT output flag in response to the VFIO_MIG_GET_PRECOPY_INFO ioctl, along with a new initial_bytes value. The presence of the VFIO_PRECOPY_INFO_REINIT flag indicates to the caller that new initial data is available in the migration stream. If the firmware reports a new initial-data chunk, any previously dirty bytes in memory are treated as initial bytes, since the caller must read both sets before reaching the end of the initial-data region. In this case, the driver issues a new SAVE command to fetch the data and prepare it for a subsequent read() from userspace. Signed-off-by: Yishai Hadas --- drivers/vfio/pci/mlx5/cmd.c | 20 ++++++-- drivers/vfio/pci/mlx5/cmd.h | 5 +- drivers/vfio/pci/mlx5/main.c | 97 +++++++++++++++++++++++------------- 3 files changed, 83 insertions(+), 39 deletions(-) diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c index 18b8d8594070..5fe0621b5fbd 100644 --- a/drivers/vfio/pci/mlx5/cmd.c +++ b/drivers/vfio/pci/mlx5/cmd.c @@ -87,7 +87,7 @@ int mlx5vf_cmd_resume_vhca(struct mlx5vf_pci_core_device *mvdev, u16 op_mod) int mlx5vf_cmd_query_vhca_migration_state(struct mlx5vf_pci_core_device *mvdev, size_t *state_size, u64 *total_size, - u8 query_flags) + u8 *mig_state, u8 query_flags) { u32 out[MLX5_ST_SZ_DW(query_vhca_migration_state_out)] = {}; u32 in[MLX5_ST_SZ_DW(query_vhca_migration_state_in)] = {}; @@ -152,6 +152,10 @@ int mlx5vf_cmd_query_vhca_migration_state(struct mlx5vf_pci_core_device *mvdev, MLX5_GET64(query_vhca_migration_state_out, out, remaining_total_size) : *state_size; + if (mig_state && mvdev->mig_state_cap) + *mig_state = MLX5_GET(query_vhca_migration_state_out, out, + migration_state); + return 0; } @@ -277,6 +281,9 @@ void mlx5vf_cmd_set_migratable(struct mlx5vf_pci_core_device *mvdev, if (MLX5_CAP_GEN_2(mvdev->mdev, migration_in_chunks)) mvdev->chunk_mode = 1; + if (MLX5_CAP_GEN_2(mvdev->mdev, migration_state)) + mvdev->mig_state_cap = 1; + end: mlx5_vf_put_core_dev(mvdev->mdev); } @@ -555,6 +562,7 @@ void mlx5vf_put_data_buffer(struct mlx5_vhca_data_buffer *buf) { spin_lock_irq(&buf->migf->list_lock); buf->stop_copy_chunk_num = 0; + buf->pre_copy_init_bytes_chunk = false; list_add_tail(&buf->buf_elm, &buf->migf->avail_list); spin_unlock_irq(&buf->migf->list_lock); } @@ -689,7 +697,8 @@ static void mlx5vf_save_callback(int status, struct mlx5_async_work *context) !next_required_umem_size; if (async_data->header_buf) { status = add_buf_header(async_data->header_buf, image_size, - initial_pre_copy); + initial_pre_copy || + async_data->buf->pre_copy_init_bytes_chunk); if (status) goto err; } @@ -708,9 +717,12 @@ static void mlx5vf_save_callback(int status, struct mlx5_async_work *context) } } spin_unlock_irqrestore(&migf->list_lock, flags); - if (initial_pre_copy) { + if (initial_pre_copy || async_data->buf->pre_copy_init_bytes_chunk) { migf->pre_copy_initial_bytes += image_size; - migf->state = MLX5_MIGF_STATE_PRE_COPY; + if (initial_pre_copy) + migf->state = MLX5_MIGF_STATE_PRE_COPY; + if (async_data->buf->pre_copy_init_bytes_chunk) + async_data->buf->pre_copy_init_bytes_chunk = false; } if (stop_copy_last_chunk) migf->state = MLX5_MIGF_STATE_COMPLETE; diff --git a/drivers/vfio/pci/mlx5/cmd.h b/drivers/vfio/pci/mlx5/cmd.h index 7d2c10be2e60..deed0f132f39 100644 --- a/drivers/vfio/pci/mlx5/cmd.h +++ b/drivers/vfio/pci/mlx5/cmd.h @@ -62,6 +62,7 @@ struct mlx5_vhca_data_buffer { u32 *mkey_in; enum dma_data_direction dma_dir; u8 stop_copy_chunk_num; + bool pre_copy_init_bytes_chunk; struct list_head buf_elm; struct mlx5_vf_migration_file *migf; }; @@ -97,6 +98,7 @@ struct mlx5_vf_migration_file { u32 record_tag; u64 stop_copy_prep_size; u64 pre_copy_initial_bytes; + u64 pre_copy_initial_bytes_start; size_t next_required_umem_size; u8 num_ready_chunks; /* Upon chunk mode preserve another set of buffers for stop_copy phase */ @@ -175,6 +177,7 @@ struct mlx5vf_pci_core_device { u8 mdev_detach:1; u8 log_active:1; u8 chunk_mode:1; + u8 mig_state_cap:1; struct completion tracker_comp; /* protect migration state */ struct mutex state_mutex; @@ -199,7 +202,7 @@ int mlx5vf_cmd_suspend_vhca(struct mlx5vf_pci_core_device *mvdev, u16 op_mod); int mlx5vf_cmd_resume_vhca(struct mlx5vf_pci_core_device *mvdev, u16 op_mod); int mlx5vf_cmd_query_vhca_migration_state(struct mlx5vf_pci_core_device *mvdev, size_t *state_size, u64 *total_size, - u8 query_flags); + u8 *migration_state, u8 query_flags); void mlx5vf_cmd_set_migratable(struct mlx5vf_pci_core_device *mvdev, const struct vfio_migration_ops *mig_ops, const struct vfio_log_ops *log_ops); diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c index 68e051c48d40..0d4e363a4e3b 100644 --- a/drivers/vfio/pci/mlx5/main.c +++ b/drivers/vfio/pci/mlx5/main.c @@ -464,8 +464,10 @@ static long mlx5vf_precopy_ioctl(struct file *filp, unsigned int cmd, struct mlx5_vhca_data_buffer *buf; struct vfio_precopy_info info = {}; loff_t *pos = &filp->f_pos; + u8 migration_state = 0; size_t inc_length = 0; - bool end_of_data = false; + bool reinit_state; + bool end_of_data; int ret; ret = vfio_check_precopy_ioctl(&mvdev->core_device.vdev, cmd, arg, @@ -492,7 +494,8 @@ static long mlx5vf_precopy_ioctl(struct file *filp, unsigned int cmd, * As so, the other code below is safe with the proper locks. */ ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &inc_length, - NULL, MLX5VF_QUERY_INC); + NULL, &migration_state, + MLX5VF_QUERY_INC); if (ret) goto err_state_unlock; } @@ -503,41 +506,67 @@ static long mlx5vf_precopy_ioctl(struct file *filp, unsigned int cmd, goto err_migf_unlock; } - if (migf->pre_copy_initial_bytes > *pos) { - info.initial_bytes = migf->pre_copy_initial_bytes - *pos; + /* + * opt-in for VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2 serves + * as opt-in for VFIO_PRECOPY_INFO_REINIT as well + */ + reinit_state = mvdev->core_device.vdev.precopy_info_flags_fix && + migration_state == MLX5_QUERY_VHCA_MIG_STATE_OPER_MIGRATION_INIT; + end_of_data = !(migf->max_pos - *pos); + if (reinit_state) { + /* + * Any bytes already present in memory are treated as initial + * bytes, since the caller is required to read them before + * reaching the new initial-bytes region. + */ + migf->pre_copy_initial_bytes_start = *pos; + migf->pre_copy_initial_bytes = migf->max_pos - *pos; + info.initial_bytes = migf->pre_copy_initial_bytes + inc_length; + info.flags |= VFIO_PRECOPY_INFO_REINIT; } else { - info.dirty_bytes = migf->max_pos - *pos; - if (!info.dirty_bytes) - end_of_data = true; - info.dirty_bytes += inc_length; + if (migf->pre_copy_initial_bytes_start + + migf->pre_copy_initial_bytes > *pos) { + WARN_ON_ONCE(end_of_data); + info.initial_bytes = migf->pre_copy_initial_bytes_start + + migf->pre_copy_initial_bytes - *pos; + } else { + info.dirty_bytes = (migf->max_pos - *pos) + inc_length; + } } + mutex_unlock(&migf->lock); - if (!end_of_data || !inc_length) { - mutex_unlock(&migf->lock); - goto done; - } + if ((reinit_state || end_of_data) && inc_length) { + /* + * In case we finished transferring the current state and the + * device has a dirty state, or that the device has a new init + * state, save a new state to be ready for. + */ + buf = mlx5vf_get_data_buffer(migf, DIV_ROUND_UP(inc_length, PAGE_SIZE), + DMA_FROM_DEVICE); + if (IS_ERR(buf)) { + ret = PTR_ERR(buf); + mlx5vf_mark_err(migf); + goto err_state_unlock; + } - mutex_unlock(&migf->lock); - /* - * We finished transferring the current state and the device has a - * dirty state, save a new state to be ready for. - */ - buf = mlx5vf_get_data_buffer(migf, DIV_ROUND_UP(inc_length, PAGE_SIZE), - DMA_FROM_DEVICE); - if (IS_ERR(buf)) { - ret = PTR_ERR(buf); - mlx5vf_mark_err(migf); - goto err_state_unlock; - } + buf->pre_copy_init_bytes_chunk = reinit_state; + ret = mlx5vf_cmd_save_vhca_state(mvdev, migf, buf, true, true); + if (ret) { + mlx5vf_mark_err(migf); + mlx5vf_put_data_buffer(buf); + goto err_state_unlock; + } - ret = mlx5vf_cmd_save_vhca_state(mvdev, migf, buf, true, true); - if (ret) { - mlx5vf_mark_err(migf); - mlx5vf_put_data_buffer(buf); - goto err_state_unlock; + /* + * SAVE appends a header record via add_buf_header(), + * let's account it as well. + */ + if (reinit_state) + info.initial_bytes += sizeof(struct mlx5_vf_migration_header); + else + info.dirty_bytes += sizeof(struct mlx5_vf_migration_header); } -done: mlx5vf_state_mutex_unlock(mvdev); if (copy_to_user((void __user *)arg, &info, offsetofend(struct vfio_precopy_info, dirty_bytes))) @@ -570,7 +599,7 @@ static int mlx5vf_pci_save_device_inc_data(struct mlx5vf_pci_core_device *mvdev) if (migf->state == MLX5_MIGF_STATE_ERROR) return -ENODEV; - ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &length, NULL, + ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &length, NULL, NULL, MLX5VF_QUERY_INC | MLX5VF_QUERY_FINAL); if (ret) goto err; @@ -636,7 +665,7 @@ mlx5vf_pci_save_device_data(struct mlx5vf_pci_core_device *mvdev, bool track) if (ret) goto out; - ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &length, &full_size, 0); + ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &length, &full_size, NULL, 0); if (ret) goto out_pd; @@ -1123,7 +1152,7 @@ mlx5vf_pci_step_device_state_locked(struct mlx5vf_pci_core_device *mvdev, enum mlx5_vf_migf_state state; size_t size; - ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &size, NULL, + ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &size, NULL, NULL, MLX5VF_QUERY_INC | MLX5VF_QUERY_CLEANUP); if (ret) return ERR_PTR(ret); @@ -1248,7 +1277,7 @@ static int mlx5vf_pci_get_data_size(struct vfio_device *vdev, mutex_lock(&mvdev->state_mutex); ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &state_size, - &total_size, 0); + &total_size, NULL, 0); if (!ret) *stop_copy_length = total_size; mlx5vf_state_mutex_unlock(mvdev); -- 2.18.1