Commit 821b8f6b authored by Yishai Hadas's avatar Yishai Hadas Committed by Alex Williamson
Browse files

vfio/mlx5: Enforce PRE_COPY support 



Enable live migration only once the firmware supports PRE_COPY.

PRE_COPY has been supported by the firmware for a long time already [1]
and is required to achieve a low downtime upon live migration.

This lets us clean up some old code that is not applicable those days
while PRE_COPY is fully supported by the firmware.

[1] The minimum firmware version that supports PRE_COPY is 28.36.1010,
it was released in January 2023.

No firmware without PRE_COPY support ever available to users.

Signed-off-by: default avatarYishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20240306105624.114830-1-yishaih@nvidia.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 626f534d

drivers/vfio/pci/mlx5/cmd.c

+63 −20
Original line number Diff line number Diff line
@@ -233,6 +233,10 @@ void mlx5vf_cmd_set_migratable(struct mlx5vf_pci_core_device *mvdev, 
	if (!MLX5_CAP_GEN(mvdev->mdev, migration))

		goto end;



	if (!(MLX5_CAP_GEN_2(mvdev->mdev, migration_multi_load) &&

	      MLX5_CAP_GEN_2(mvdev->mdev, migration_tracking_state)))

		goto end;



	mvdev->vf_id = pci_iov_vf_id(pdev);

	if (mvdev->vf_id < 0)

		goto end;
@@ -262,17 +266,14 @@ void mlx5vf_cmd_set_migratable(struct mlx5vf_pci_core_device *mvdev, 
	mvdev->migrate_cap = 1;

	mvdev->core_device.vdev.migration_flags =

		VFIO_MIGRATION_STOP_COPY |

		VFIO_MIGRATION_P2P;

		VFIO_MIGRATION_P2P |

		VFIO_MIGRATION_PRE_COPY;



	mvdev->core_device.vdev.mig_ops = mig_ops;

	init_completion(&mvdev->tracker_comp);

	if (MLX5_CAP_GEN(mvdev->mdev, adv_virtualization))

		mvdev->core_device.vdev.log_ops = log_ops;



	if (MLX5_CAP_GEN_2(mvdev->mdev, migration_multi_load) &&

	    MLX5_CAP_GEN_2(mvdev->mdev, migration_tracking_state))

		mvdev->core_device.vdev.migration_flags |=

			VFIO_MIGRATION_PRE_COPY;



	if (MLX5_CAP_GEN_2(mvdev->mdev, migration_in_chunks))

		mvdev->chunk_mode = 1;
@@ -414,6 +415,50 @@ void mlx5vf_free_data_buffer(struct mlx5_vhca_data_buffer *buf) 
	kfree(buf);

}



static int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,

				      unsigned int npages)

{

	unsigned int to_alloc = npages;

	struct page **page_list;

	unsigned long filled;

	unsigned int to_fill;

	int ret;



	to_fill = min_t(unsigned int, npages, PAGE_SIZE / sizeof(*page_list));

	page_list = kvzalloc(to_fill * sizeof(*page_list), GFP_KERNEL_ACCOUNT);

	if (!page_list)

		return -ENOMEM;



	do {

		filled = alloc_pages_bulk_array(GFP_KERNEL_ACCOUNT, to_fill,

						page_list);

		if (!filled) {

			ret = -ENOMEM;

			goto err;

		}

		to_alloc -= filled;

		ret = sg_alloc_append_table_from_pages(

			&buf->table, page_list, filled, 0,

			filled << PAGE_SHIFT, UINT_MAX, SG_MAX_SINGLE_ALLOC,

			GFP_KERNEL_ACCOUNT);



		if (ret)

			goto err;

		buf->allocated_length += filled * PAGE_SIZE;

		/* clean input for another bulk allocation */

		memset(page_list, 0, filled * sizeof(*page_list));

		to_fill = min_t(unsigned int, to_alloc,

				PAGE_SIZE / sizeof(*page_list));

	} while (to_alloc > 0);



	kvfree(page_list);

	return 0;



err:

	kvfree(page_list);

	return ret;

}



struct mlx5_vhca_data_buffer *

mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf,

			 size_t length,
@@ -680,7 +725,6 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev, 
		goto err_out;

	}



	if (MLX5VF_PRE_COPY_SUPP(mvdev)) {

	if (async_data->stop_copy_chunk) {

		u8 header_idx = buf->stop_copy_chunk_num ?

			buf->stop_copy_chunk_num - 1 : 0;
@@ -697,7 +741,6 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev, 
			goto err_free;

		}

	}

	}



	if (async_data->stop_copy_chunk)

		migf->state = MLX5_MIGF_STATE_SAVE_STOP_COPY_CHUNK;

drivers/vfio/pci/mlx5/cmd.h

+0 −6
Original line number Diff line number Diff line
@@ -13,9 +13,6 @@ 
#include <linux/mlx5/cq.h>

#include <linux/mlx5/qp.h>



#define MLX5VF_PRE_COPY_SUPP(mvdev) \

	((mvdev)->core_device.vdev.migration_flags & VFIO_MIGRATION_PRE_COPY)



enum mlx5_vf_migf_state {

	MLX5_MIGF_STATE_ERROR = 1,

	MLX5_MIGF_STATE_PRE_COPY_ERROR,
@@ -25,7 +22,6 @@ enum mlx5_vf_migf_state { 
};



enum mlx5_vf_load_state {

	MLX5_VF_LOAD_STATE_READ_IMAGE_NO_HEADER,

	MLX5_VF_LOAD_STATE_READ_HEADER,

	MLX5_VF_LOAD_STATE_PREP_HEADER_DATA,

	MLX5_VF_LOAD_STATE_READ_HEADER_DATA,
@@ -228,8 +224,6 @@ struct mlx5_vhca_data_buffer * 
mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf,

		       size_t length, enum dma_data_direction dma_dir);

void mlx5vf_put_data_buffer(struct mlx5_vhca_data_buffer *buf);

int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,

			       unsigned int npages);

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);

drivers/vfio/pci/mlx5/main.c

+8 −101
Original line number Diff line number Diff line
@@ -65,50 +65,6 @@ mlx5vf_get_migration_page(struct mlx5_vhca_data_buffer *buf, 
	return NULL;

}



int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,

			       unsigned int npages)

{

	unsigned int to_alloc = npages;

	struct page **page_list;

	unsigned long filled;

	unsigned int to_fill;

	int ret;



	to_fill = min_t(unsigned int, npages, PAGE_SIZE / sizeof(*page_list));

	page_list = kvzalloc(to_fill * sizeof(*page_list), GFP_KERNEL_ACCOUNT);

	if (!page_list)

		return -ENOMEM;



	do {

		filled = alloc_pages_bulk_array(GFP_KERNEL_ACCOUNT, to_fill,

						page_list);

		if (!filled) {

			ret = -ENOMEM;

			goto err;

		}

		to_alloc -= filled;

		ret = sg_alloc_append_table_from_pages(

			&buf->table, page_list, filled, 0,

			filled << PAGE_SHIFT, UINT_MAX, SG_MAX_SINGLE_ALLOC,

			GFP_KERNEL_ACCOUNT);



		if (ret)

			goto err;

		buf->allocated_length += filled * PAGE_SIZE;

		/* clean input for another bulk allocation */

		memset(page_list, 0, filled * sizeof(*page_list));

		to_fill = min_t(unsigned int, to_alloc,

				PAGE_SIZE / sizeof(*page_list));

	} while (to_alloc > 0);



	kvfree(page_list);

	return 0;



err:

	kvfree(page_list);

	return ret;

}



static void mlx5vf_disable_fd(struct mlx5_vf_migration_file *migf)

{

	mutex_lock(&migf->lock);
@@ -777,36 +733,6 @@ mlx5vf_append_page_to_mig_buf(struct mlx5_vhca_data_buffer *vhca_buf, 
	return 0;

}



static int

mlx5vf_resume_read_image_no_header(struct mlx5_vhca_data_buffer *vhca_buf,

				   loff_t requested_length,

				   const char __user **buf, size_t *len,

				   loff_t *pos, ssize_t *done)

{

	int ret;



	if (requested_length > MAX_LOAD_SIZE)

		return -ENOMEM;



	if (vhca_buf->allocated_length < requested_length) {

		ret = mlx5vf_add_migration_pages(

			vhca_buf,

			DIV_ROUND_UP(requested_length - vhca_buf->allocated_length,

				     PAGE_SIZE));

		if (ret)

			return ret;

	}



	while (*len) {

		ret = mlx5vf_append_page_to_mig_buf(vhca_buf, buf, len, pos,

						    done);

		if (ret)

			return ret;

	}



	return 0;

}



static ssize_t

mlx5vf_resume_read_image(struct mlx5_vf_migration_file *migf,

			 struct mlx5_vhca_data_buffer *vhca_buf,
@@ -1038,13 +964,6 @@ static ssize_t mlx5vf_resume_write(struct file *filp, const char __user *buf, 
			migf->load_state = MLX5_VF_LOAD_STATE_READ_IMAGE;

			break;

		}

		case MLX5_VF_LOAD_STATE_READ_IMAGE_NO_HEADER:

			ret = mlx5vf_resume_read_image_no_header(vhca_buf,

						requested_length,

						&buf, &len, pos, &done);

			if (ret)

				goto out_unlock;

			break;

		case MLX5_VF_LOAD_STATE_READ_IMAGE:

			ret = mlx5vf_resume_read_image(migf, vhca_buf,

						migf->record_size,
@@ -1114,7 +1033,6 @@ mlx5vf_pci_resume_device_data(struct mlx5vf_pci_core_device *mvdev) 
	}



	migf->buf[0] = buf;

	if (MLX5VF_PRE_COPY_SUPP(mvdev)) {

	buf = mlx5vf_alloc_data_buffer(migf,

		sizeof(struct mlx5_vf_migration_header), DMA_NONE);

	if (IS_ERR(buf)) {
@@ -1124,10 +1042,6 @@ mlx5vf_pci_resume_device_data(struct mlx5vf_pci_core_device *mvdev) 


	migf->buf_header[0] = buf;

	migf->load_state = MLX5_VF_LOAD_STATE_READ_HEADER;

	} else {

		/* Initial state will be to read the image */

		migf->load_state = MLX5_VF_LOAD_STATE_READ_IMAGE_NO_HEADER;

	}



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

	mutex_init(&migf->lock);
@@ -1262,13 +1176,6 @@ mlx5vf_pci_step_device_state_locked(struct mlx5vf_pci_core_device *mvdev, 
	}



	if (cur == VFIO_DEVICE_STATE_RESUMING && new == VFIO_DEVICE_STATE_STOP) {

		if (!MLX5VF_PRE_COPY_SUPP(mvdev)) {

			ret = mlx5vf_cmd_load_vhca_state(mvdev,

							 mvdev->resuming_migf,

							 mvdev->resuming_migf->buf[0]);

			if (ret)

				return ERR_PTR(ret);

		}

		mlx5vf_disable_fds(mvdev, NULL);

		return NULL;

	}