vfio/mlx5: Let firmware knows upon leaving PRE_COPY back to RUNNING

Let firmware knows upon leaving PRE_COPY back to RUNNING as of some
error in the target/migration cancellation.

This will let firmware cleaning its internal resources that were turned
on upon PRE_COPY.

The flow is based on the device specification in this area.

Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Leon Romanovsky <leon@kernel.org>
Link: https://lore.kernel.org/r/20240205124828.232701-6-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: Yishai Hadas

drivers/vfio/pci/mlx5/cmd.c

@@ -108,8 +108,9 @@ int mlx5vf_cmd_query_vhca_migration_state(struct mlx5vf_pci_core_device *mvdev,
 		ret = wait_for_completion_interruptible(&mvdev->saving_migf->save_comp);
 		if (ret)
 			return ret;
-		if (mvdev->saving_migf->state ==
-		    MLX5_MIGF_STATE_PRE_COPY_ERROR) {
+		/* Upon cleanup, ignore previous pre_copy error state */
+		if (mvdev->saving_migf->state == MLX5_MIGF_STATE_PRE_COPY_ERROR &&
+		    !(query_flags & MLX5VF_QUERY_CLEANUP)) {
 			/*
 			 * In case we had a PRE_COPY error, only query full
 			 * image for final image
@@ -200,7 +201,7 @@ void mlx5vf_cmd_close_migratable(struct mlx5vf_pci_core_device *mvdev)
 	/* Must be done outside the lock to let it progress */
 	set_tracker_error(mvdev);
 	mutex_lock(&mvdev->state_mutex);
-	mlx5vf_disable_fds(mvdev);
+	mlx5vf_disable_fds(mvdev, NULL);
 	_mlx5vf_free_page_tracker_resources(mvdev);
 	mlx5vf_state_mutex_unlock(mvdev);
 }
@@ -639,6 +640,7 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev,
 	u32 in[MLX5_ST_SZ_DW(save_vhca_state_in)] = {};
 	struct mlx5_vhca_data_buffer *header_buf = NULL;
 	struct mlx5vf_async_data *async_data;
+	bool pre_copy_cleanup = false;
 	int err;
 
 	lockdep_assert_held(&mvdev->state_mutex);
@@ -649,6 +651,10 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev,
 	if (err)
 		return err;
 
+	if ((migf->state == MLX5_MIGF_STATE_PRE_COPY ||
+	     migf->state == MLX5_MIGF_STATE_PRE_COPY_ERROR) && !track && !inc)
+		pre_copy_cleanup = true;
+
 	if (migf->state == MLX5_MIGF_STATE_PRE_COPY_ERROR)
 		/*
 		 * In case we had a PRE_COPY error, SAVE is triggered only for
@@ -667,7 +673,7 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev,
 
 	async_data = &migf->async_data;
 	async_data->buf = buf;
-	async_data->stop_copy_chunk = !track;
+	async_data->stop_copy_chunk = (!track && !pre_copy_cleanup);
 	async_data->out = kvzalloc(out_size, GFP_KERNEL);
 	if (!async_data->out) {
 		err = -ENOMEM;

drivers/vfio/pci/mlx5/cmd.h

@@ -197,6 +197,7 @@ struct mlx5vf_pci_core_device {
 enum {
 	MLX5VF_QUERY_INC = (1UL << 0),
 	MLX5VF_QUERY_FINAL = (1UL << 1),
+	MLX5VF_QUERY_CLEANUP = (1UL << 2),
 };
 
 int mlx5vf_cmd_suspend_vhca(struct mlx5vf_pci_core_device *mvdev, u16 op_mod);
@@ -232,7 +233,8 @@ int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,
 struct page *mlx5vf_get_migration_page(struct mlx5_vhca_data_buffer *buf,
 				       unsigned long offset);
 void mlx5vf_state_mutex_unlock(struct mlx5vf_pci_core_device *mvdev);
-void mlx5vf_disable_fds(struct mlx5vf_pci_core_device *mvdev);
+void mlx5vf_disable_fds(struct mlx5vf_pci_core_device *mvdev,
+			enum mlx5_vf_migf_state *last_save_state);
 void mlx5vf_mig_file_cleanup_cb(struct work_struct *_work);
 void mlx5vf_mig_file_set_save_work(struct mlx5_vf_migration_file *migf,
 				   u8 chunk_num, size_t next_required_umem_size);

drivers/vfio/pci/mlx5/main.c

@@ -1146,7 +1146,8 @@ mlx5vf_pci_resume_device_data(struct mlx5vf_pci_core_device *mvdev)
 	return ERR_PTR(ret);
 }
 
-void mlx5vf_disable_fds(struct mlx5vf_pci_core_device *mvdev)
+void mlx5vf_disable_fds(struct mlx5vf_pci_core_device *mvdev,
+			enum mlx5_vf_migf_state *last_save_state)
 {
 	if (mvdev->resuming_migf) {
 		mlx5vf_disable_fd(mvdev->resuming_migf);
@@ -1157,6 +1158,8 @@ void mlx5vf_disable_fds(struct mlx5vf_pci_core_device *mvdev)
 	if (mvdev->saving_migf) {
 		mlx5_cmd_cleanup_async_ctx(&mvdev->saving_migf->async_ctx);
 		cancel_work_sync(&mvdev->saving_migf->async_data.work);
+		if (last_save_state)
+			*last_save_state = mvdev->saving_migf->state;
 		mlx5vf_disable_fd(mvdev->saving_migf);
 		wake_up_interruptible(&mvdev->saving_migf->poll_wait);
 		mlx5fv_cmd_clean_migf_resources(mvdev->saving_migf);
@@ -1217,12 +1220,34 @@ mlx5vf_pci_step_device_state_locked(struct mlx5vf_pci_core_device *mvdev,
 		return migf->filp;
 	}
 
-	if ((cur == VFIO_DEVICE_STATE_STOP_COPY && new == VFIO_DEVICE_STATE_STOP) ||
-	    (cur == VFIO_DEVICE_STATE_PRE_COPY && new == VFIO_DEVICE_STATE_RUNNING) ||
+	if (cur == VFIO_DEVICE_STATE_STOP_COPY && new == VFIO_DEVICE_STATE_STOP) {
+		mlx5vf_disable_fds(mvdev, NULL);
+		return NULL;
+	}
+
+	if ((cur == VFIO_DEVICE_STATE_PRE_COPY && new == VFIO_DEVICE_STATE_RUNNING) ||
 	    (cur == VFIO_DEVICE_STATE_PRE_COPY_P2P &&
 	     new == VFIO_DEVICE_STATE_RUNNING_P2P)) {
-		mlx5vf_disable_fds(mvdev);
-		return NULL;
+		struct mlx5_vf_migration_file *migf = mvdev->saving_migf;
+		struct mlx5_vhca_data_buffer *buf;
+		enum mlx5_vf_migf_state state;
+		size_t size;
+
+		ret = mlx5vf_cmd_query_vhca_migration_state(mvdev, &size, NULL,
+					MLX5VF_QUERY_INC | MLX5VF_QUERY_CLEANUP);
+		if (ret)
+			return ERR_PTR(ret);
+		buf = mlx5vf_get_data_buffer(migf, size, DMA_FROM_DEVICE);
+		if (IS_ERR(buf))
+			return ERR_CAST(buf);
+		/* pre_copy cleanup */
+		ret = mlx5vf_cmd_save_vhca_state(mvdev, migf, buf, false, false);
+		if (ret) {
+			mlx5vf_put_data_buffer(buf);
+			return ERR_PTR(ret);
+		}
+		mlx5vf_disable_fds(mvdev, &state);
+		return (state != MLX5_MIGF_STATE_ERROR) ? NULL : ERR_PTR(-EIO);
 	}
 
 	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RESUMING) {
@@ -1244,7 +1269,7 @@ mlx5vf_pci_step_device_state_locked(struct mlx5vf_pci_core_device *mvdev,
 			if (ret)
 				return ERR_PTR(ret);
 		}
-		mlx5vf_disable_fds(mvdev);
+		mlx5vf_disable_fds(mvdev, NULL);
 		return NULL;
 	}
 
@@ -1289,7 +1314,7 @@ void mlx5vf_state_mutex_unlock(struct mlx5vf_pci_core_device *mvdev)
 		mvdev->deferred_reset = false;
 		spin_unlock(&mvdev->reset_lock);
 		mvdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
-		mlx5vf_disable_fds(mvdev);
+		mlx5vf_disable_fds(mvdev, NULL);
 		goto again;
 	}
 	mutex_unlock(&mvdev->state_mutex);