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

[Yishai Hadas via Virtualization <virtualization@lists.linux-foundation.org>]

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On 25/10/2023 0:01, Michael S. Tsirkin wrote:
> 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.

The VF was given to let the function gets the PF from it.

For now, the only existing 'group_type' in the spec is SRIOV, this is 
why we hard-coded it internally to match the VF PCI.

Alternatively,
We can change the API to get the PF and 'group_type' from the caller to 
better match future usage.
However, this will require to export the virtio_pci_vf_get_pf_dev() API 
outside virtio-pci.

Do you prefer to change to the latter option ?

>
>> +
>> +/*
>> + * 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.
>
OK.

We'll export the below 2 APIs [1] which internally will call 
virtio_pci_admin_legacy_io_write() with the proper op code hard-coded.

[1]virtio_pci_admin_legacy_device_io_write()
      virtio_pci_admin_legacy_common_io_write()

Yishai

>
>
>> + * @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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