Re: [PATCH V1 vfio 6/9] virtio-pci: Introduce APIs to execute legacy IO admin commands

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Oct 17, 2023 at 04:42:14PM +0300, Yishai Hadas wrote:
> Introduce APIs to execute legacy IO admin commands.
> 
> It includes: list_query/use, io_legacy_read/write,
> io_legacy_notify_info.
> 
> Those APIs will be used by the next patches from this series.
> 
> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
> ---
>  drivers/virtio/virtio_pci_common.c |  11 ++
>  drivers/virtio/virtio_pci_common.h |   2 +
>  drivers/virtio/virtio_pci_modern.c | 206 +++++++++++++++++++++++++++++
>  include/linux/virtio_pci_admin.h   |  18 +++
>  4 files changed, 237 insertions(+)
>  create mode 100644 include/linux/virtio_pci_admin.h
> 
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index 6b4766d5abe6..212d68401d2c 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -645,6 +645,17 @@ static struct pci_driver virtio_pci_driver = {
>  	.sriov_configure = virtio_pci_sriov_configure,
>  };
>  
> +struct virtio_device *virtio_pci_vf_get_pf_dev(struct pci_dev *pdev)
> +{
> +	struct virtio_pci_device *pf_vp_dev;
> +
> +	pf_vp_dev = pci_iov_get_pf_drvdata(pdev, &virtio_pci_driver);
> +	if (IS_ERR(pf_vp_dev))
> +		return NULL;
> +
> +	return &pf_vp_dev->vdev;
> +}
> +
>  module_pci_driver(virtio_pci_driver);
>  
>  MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> index a21b9ba01a60..2785e61ed668 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -155,4 +155,6 @@ static inline void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
>  int virtio_pci_modern_probe(struct virtio_pci_device *);
>  void virtio_pci_modern_remove(struct virtio_pci_device *);
>  
> +struct virtio_device *virtio_pci_vf_get_pf_dev(struct pci_dev *pdev);
> +
>  #endif
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index cc159a8e6c70..00b65e20b2f5 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -719,6 +719,212 @@ static void vp_modern_destroy_avq(struct virtio_device *vdev)
>  	vp_dev->del_vq(&vp_dev->admin_vq.info);
>  }
>  
> +/*
> + * virtio_pci_admin_list_query - Provides to driver list of commands
> + * supported for the PCI VF.
> + * @dev: VF pci_dev
> + * @buf: buffer to hold the returned list
> + * @buf_size: size of the given buffer
> + *
> + * Returns 0 on success, or negative on failure.
> + */
> +int virtio_pci_admin_list_query(struct pci_dev *pdev, u8 *buf, int buf_size)
> +{
> +	struct virtio_device *virtio_dev = virtio_pci_vf_get_pf_dev(pdev);
> +	struct virtio_admin_cmd cmd = {};
> +	struct scatterlist result_sg;
> +
> +	if (!virtio_dev)
> +		return -ENODEV;
> +
> +	sg_init_one(&result_sg, buf, buf_size);
> +	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_QUERY);
> +	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
> +	cmd.result_sg = &result_sg;
> +
> +	return vp_modern_admin_cmd_exec(virtio_dev, &cmd);
> +}
> +EXPORT_SYMBOL_GPL(virtio_pci_admin_list_query);
> +
> +/*
> + * virtio_pci_admin_list_use - Provides to device list of commands
> + * used for the PCI VF.
> + * @dev: VF pci_dev
> + * @buf: buffer which holds the list
> + * @buf_size: size of the given buffer
> + *
> + * Returns 0 on success, or negative on failure.
> + */
> +int virtio_pci_admin_list_use(struct pci_dev *pdev, u8 *buf, int buf_size)
> +{
> +	struct virtio_device *virtio_dev = virtio_pci_vf_get_pf_dev(pdev);
> +	struct virtio_admin_cmd cmd = {};
> +	struct scatterlist data_sg;
> +
> +	if (!virtio_dev)
> +		return -ENODEV;
> +
> +	sg_init_one(&data_sg, buf, buf_size);
> +	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_USE);
> +	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
> +	cmd.data_sg = &data_sg;
> +
> +	return vp_modern_admin_cmd_exec(virtio_dev, &cmd);
> +}
> +EXPORT_SYMBOL_GPL(virtio_pci_admin_list_use);

list commands are actually for a group, not for the VF.

> +
> +/*
> + * virtio_pci_admin_legacy_io_write - Write legacy registers of a member device
> + * @dev: VF pci_dev
> + * @opcode: op code of the io write command

opcode is actually either VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_WRITE
or VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_WRITE correct?

So please just add 2 APIs for this so users don't need to care.
Could be wrappers around these two things.




> + * @offset: starting byte offset within the registers to write to
> + * @size: size of the data to write
> + * @buf: buffer which holds the data
> + *
> + * Returns 0 on success, or negative on failure.
> + */
> +int virtio_pci_admin_legacy_io_write(struct pci_dev *pdev, u16 opcode,
> +				     u8 offset, u8 size, u8 *buf)
> +{
> +	struct virtio_device *virtio_dev = virtio_pci_vf_get_pf_dev(pdev);
> +	struct virtio_admin_cmd_legacy_wr_data *data;
> +	struct virtio_admin_cmd cmd = {};
> +	struct scatterlist data_sg;
> +	int vf_id;
> +	int ret;
> +
> +	if (!virtio_dev)
> +		return -ENODEV;
> +
> +	vf_id = pci_iov_vf_id(pdev);
> +	if (vf_id < 0)
> +		return vf_id;
> +
> +	data = kzalloc(sizeof(*data) + size, GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->offset = offset;
> +	memcpy(data->registers, buf, size);
> +	sg_init_one(&data_sg, data, sizeof(*data) + size);
> +	cmd.opcode = cpu_to_le16(opcode);
> +	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
> +	cmd.group_member_id = cpu_to_le64(vf_id + 1);
> +	cmd.data_sg = &data_sg;
> +	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
> +
> +	kfree(data);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_pci_admin_legacy_io_write);
> +
> +/*
> + * virtio_pci_admin_legacy_io_read - Read legacy registers of a member device
> + * @dev: VF pci_dev
> + * @opcode: op code of the io read command
> + * @offset: starting byte offset within the registers to read from
> + * @size: size of the data to be read
> + * @buf: buffer to hold the returned data
> + *
> + * Returns 0 on success, or negative on failure.
> + */
> +int virtio_pci_admin_legacy_io_read(struct pci_dev *pdev, u16 opcode,
> +				    u8 offset, u8 size, u8 *buf)
> +{
> +	struct virtio_device *virtio_dev = virtio_pci_vf_get_pf_dev(pdev);
> +	struct virtio_admin_cmd_legacy_rd_data *data;
> +	struct scatterlist data_sg, result_sg;
> +	struct virtio_admin_cmd cmd = {};
> +	int vf_id;
> +	int ret;
> +
> +	if (!virtio_dev)
> +		return -ENODEV;
> +
> +	vf_id = pci_iov_vf_id(pdev);
> +	if (vf_id < 0)
> +		return vf_id;
> +
> +	data = kzalloc(sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->offset = offset;
> +	sg_init_one(&data_sg, data, sizeof(*data));
> +	sg_init_one(&result_sg, buf, size);
> +	cmd.opcode = cpu_to_le16(opcode);
> +	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
> +	cmd.group_member_id = cpu_to_le64(vf_id + 1);
> +	cmd.data_sg = &data_sg;
> +	cmd.result_sg = &result_sg;
> +	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
> +
> +	kfree(data);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_pci_admin_legacy_io_read);
> +
> +/*
> + * virtio_pci_admin_legacy_io_notify_info - Read the queue notification
> + * information for legacy interface
> + * @dev: VF pci_dev
> + * @req_bar_flags: requested bar flags
> + * @bar: on output the BAR number of the member device
> + * @bar_offset: on output the offset within bar
> + *
> + * Returns 0 on success, or negative on failure.
> + */
> +int virtio_pci_admin_legacy_io_notify_info(struct pci_dev *pdev,
> +					   u8 req_bar_flags, u8 *bar,
> +					   u64 *bar_offset)
> +{
> +	struct virtio_device *virtio_dev = virtio_pci_vf_get_pf_dev(pdev);
> +	struct virtio_admin_cmd_notify_info_result *result;
> +	struct virtio_admin_cmd cmd = {};
> +	struct scatterlist result_sg;
> +	int vf_id;
> +	int ret;
> +
> +	if (!virtio_dev)
> +		return -ENODEV;
> +
> +	vf_id = pci_iov_vf_id(pdev);
> +	if (vf_id < 0)
> +		return vf_id;
> +
> +	result = kzalloc(sizeof(*result), GFP_KERNEL);
> +	if (!result)
> +		return -ENOMEM;
> +
> +	sg_init_one(&result_sg, result, sizeof(*result));
> +	cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO);
> +	cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV);
> +	cmd.group_member_id = cpu_to_le64(vf_id + 1);
> +	cmd.result_sg = &result_sg;
> +	ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd);
> +	if (!ret) {
> +		struct virtio_admin_cmd_notify_info_data *entry;
> +		int i;
> +
> +		ret = -ENOENT;
> +		for (i = 0; i < VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO; i++) {
> +			entry = &result->entries[i];
> +			if (entry->flags == VIRTIO_ADMIN_CMD_NOTIFY_INFO_FLAGS_END)
> +				break;
> +			if (entry->flags != req_bar_flags)
> +				continue;
> +			*bar = entry->bar;
> +			*bar_offset = le64_to_cpu(entry->offset);
> +			ret = 0;
> +			break;
> +		}
> +	}
> +
> +	kfree(result);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_pci_admin_legacy_io_notify_info);
> +
>  static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
>  	.get		= NULL,
>  	.set		= NULL,
> diff --git a/include/linux/virtio_pci_admin.h b/include/linux/virtio_pci_admin.h
> new file mode 100644
> index 000000000000..cb916a4bc1b1
> --- /dev/null
> +++ b/include/linux/virtio_pci_admin.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_VIRTIO_PCI_ADMIN_H
> +#define _LINUX_VIRTIO_PCI_ADMIN_H
> +
> +#include <linux/types.h>
> +#include <linux/pci.h>
> +
> +int virtio_pci_admin_list_use(struct pci_dev *pdev, u8 *buf, int buf_size);
> +int virtio_pci_admin_list_query(struct pci_dev *pdev, u8 *buf, int buf_size);
> +int virtio_pci_admin_legacy_io_write(struct pci_dev *pdev, u16 opcode,
> +				     u8 offset, u8 size, u8 *buf);
> +int virtio_pci_admin_legacy_io_read(struct pci_dev *pdev, u16 opcode,
> +				    u8 offset, u8 size, u8 *buf);
> +int virtio_pci_admin_legacy_io_notify_info(struct pci_dev *pdev,
> +					   u8 req_bar_flags, u8 *bar,
> +					   u64 *bar_offset);
> +
> +#endif /* _LINUX_VIRTIO_PCI_ADMIN_H */
> -- 
> 2.27.0

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