Commit 0e7caa65 authored by Yishai Hadas's avatar Yishai Hadas Committed by Alex Williamson
Browse files

vfio/mlx5: Enforce a single SAVE command at a time 



Enforce a single SAVE command at a time.

As the SAVE command is an asynchronous one, we must enforce running only
a single command at a time.

This will preserve ordering between multiple calls and protect from
races on the migration file data structure.

This is a must for the next patches from the series where as part of
PRE_COPY we may have multiple images to be saved and multiple SAVE
commands may be issued from different flows.

Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarYishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20221206083438.37807-4-yishaih@nvidia.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 4db52602

drivers/vfio/pci/mlx5/cmd.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -281,6 +281,7 @@ void mlx5vf_mig_file_cleanup_cb(struct work_struct *_work) 
	dma_unmap_sgtable(mdev->device, &migf->table.sgt, DMA_FROM_DEVICE, 0);

	dma_unmap_sgtable(mdev->device, &migf->table.sgt, DMA_FROM_DEVICE, 0);

	mlx5_core_dealloc_pd(mdev, async_data->pdn);

	mlx5_core_dealloc_pd(mdev, async_data->pdn);

	kvfree(async_data->out);

	kvfree(async_data->out);

	complete(&migf->save_comp);

	fput(migf->filp);

	fput(migf->filp);

}

}
@@ -321,6 +322,10 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev, 
		return -ENOTCONN;

		return -ENOTCONN;





	mdev = mvdev->mdev;

	mdev = mvdev->mdev;

	err = wait_for_completion_interruptible(&migf->save_comp);

	if (err)

		return err;



	err = mlx5_core_alloc_pd(mdev, &pdn);

	err = mlx5_core_alloc_pd(mdev, &pdn);

	if (err)

	if (err)

		return err;

		return err;
@@ -371,6 +376,7 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev, 
	dma_unmap_sgtable(mdev->device, &migf->table.sgt, DMA_FROM_DEVICE, 0);

	dma_unmap_sgtable(mdev->device, &migf->table.sgt, DMA_FROM_DEVICE, 0);

err_dma_map:

err_dma_map:

	mlx5_core_dealloc_pd(mdev, pdn);

	mlx5_core_dealloc_pd(mdev, pdn);

	complete(&migf->save_comp);

	return err;

	return err;

}

}

drivers/vfio/pci/mlx5/cmd.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -37,6 +37,7 @@ struct mlx5_vf_migration_file { 
	unsigned long last_offset;

	unsigned long last_offset;

	struct mlx5vf_pci_core_device *mvdev;

	struct mlx5vf_pci_core_device *mvdev;

	wait_queue_head_t poll_wait;

	wait_queue_head_t poll_wait;

	struct completion save_comp;

	struct mlx5_async_ctx async_ctx;

	struct mlx5_async_ctx async_ctx;

	struct mlx5vf_async_data async_data;

	struct mlx5vf_async_data async_data;

};

};

drivers/vfio/pci/mlx5/main.c

+7 −0
Original line number Original line Diff line number Diff line
@@ -245,6 +245,13 @@ mlx5vf_pci_save_device_data(struct mlx5vf_pci_core_device *mvdev) 
	stream_open(migf->filp->f_inode, migf->filp);

	stream_open(migf->filp->f_inode, migf->filp);

	mutex_init(&migf->lock);

	mutex_init(&migf->lock);

	init_waitqueue_head(&migf->poll_wait);

	init_waitqueue_head(&migf->poll_wait);

	init_completion(&migf->save_comp);

	/*

	 * save_comp is being used as a binary semaphore built from

	 * a completion. A normal mutex cannot be used because the lock is

	 * passed between kernel threads and lockdep can't model this.

	 */

	complete(&migf->save_comp);

	mlx5_cmd_init_async_ctx(mvdev->mdev, &migf->async_ctx);

	mlx5_cmd_init_async_ctx(mvdev->mdev, &migf->async_ctx);

	INIT_WORK(&migf->async_data.work, mlx5vf_mig_file_cleanup_cb);

	INIT_WORK(&migf->async_data.work, mlx5vf_mig_file_cleanup_cb);

	ret = mlx5vf_cmd_query_vhca_migration_state(mvdev,

	ret = mlx5vf_cmd_query_vhca_migration_state(mvdev,