Date:   Sat, 18 Mar 2023 17:07:38 +0800
From:   liulongfang <liulongfang@...wei.com>
To:     Alex Williamson <alex.williamson@...hat.com>
CC:     <jgg@...dia.com>, <shameerali.kolothum.thodi@...wei.com>,
        <jonathan.cameron@...wei.com>, <cohuck@...hat.com>,
        <linux-kernel@...r.kernel.org>, <linuxarm@...neuler.org>
Subject: Re: [PATCH v8 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon
 migration driver

On 2023/3/14 23:17, Alex Williamson wrote:
> On Tue, 14 Mar 2023 19:21:29 +0800
> liulongfang <liulongfang@...wei.com> wrote:
> 
>> On 2023/3/14 19:04, liulongfang wrote:
>>> On 2023/3/11 7:40, Alex Williamson wrote:  
>>>> On Fri, 17 Feb 2023 16:48:29 +0800
>>>> Longfang Liu <liulongfang@...wei.com> wrote:
>>>>  
>>>>> On the debugfs framework of VFIO, if the CONFIG_DEBUG_FS macro is
>>>>> enabled, the debug function is registered for the live migration driver
>>>>> of the HiSilicon accelerator device.
>>>>>
>>>>> On the basis of the original public debug function, a private debug
>>>>> function is added:
>>>>>
>>>>> mig_data file: used to get the migration data of the live migration device
>>>>> mig_attr file: used to get device attributes of the live migration device
>>>>> debug file: used to test for acquiring and writing device state data
>>>>> for VF device.
>>>>>
>>>>> Signed-off-by: Longfang Liu <liulongfang@...wei.com>
>>>>> ---
>>>>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 282 ++++++++++++++++++
>>>>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
>>>>>  2 files changed, 293 insertions(+)
>>>>>
>>>>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>>>> index a1589947e721..a0ecb1cd5707 100644
>>>>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>>>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>>>> @@ -15,6 +15,7 @@
>>>>>  #include <linux/anon_inodes.h>
>>>>>  
>>>>>  #include "hisi_acc_vfio_pci.h"
>>>>> +#include "../../vfio.h"
>>>>>  
>>>>>  /* Return 0 on VM acc device ready, -ETIMEDOUT hardware timeout */
>>>>>  static int qm_wait_dev_not_ready(struct hisi_qm *qm)
>>>>> @@ -606,6 +607,18 @@ hisi_acc_check_int_state(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>>>>  	}
>>>>>  }
>>>>>  
>>>>> +static void hisi_acc_vf_migf_save(struct hisi_acc_vf_migration_file *src_migf,
>>>>> +	struct hisi_acc_vf_migration_file *dst_migf)
>>>>> +{
>>>>> +	if (!dst_migf)
>>>>> +		return;
>>>>> +
>>>>> +	dst_migf->disabled = false;
>>>>> +	dst_migf->total_length = src_migf->total_length;
>>>>> +	memcpy(&dst_migf->vf_data, &src_migf->vf_data,
>>>>> +		    sizeof(struct acc_vf_data));
>>>>> +}
>>>>> +
>>>>>  static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>>>>  {
>>>>>  	mutex_lock(&migf->lock);
>>>>> @@ -618,12 +631,16 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>>>>  static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>>>>  {
>>>>>  	if (hisi_acc_vdev->resuming_migf) {
>>>>> +		hisi_acc_vf_migf_save(hisi_acc_vdev->resuming_migf,
>>>>> +						hisi_acc_vdev->debug_migf);
>>>>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf);
>>>>>  		fput(hisi_acc_vdev->resuming_migf->filp);
>>>>>  		hisi_acc_vdev->resuming_migf = NULL;
>>>>>  	}
>>>>>  
>>>>>  	if (hisi_acc_vdev->saving_migf) {
>>>>> +		hisi_acc_vf_migf_save(hisi_acc_vdev->saving_migf,
>>>>> +						hisi_acc_vdev->debug_migf);
>>>>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>>>>>  		fput(hisi_acc_vdev->saving_migf->filp);
>>>>>  		hisi_acc_vdev->saving_migf = NULL;
>>>>> @@ -1303,6 +1320,265 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
>>>>>  	return vfio_pci_core_ioctl(core_vdev, cmd, arg);
>>>>>  }
>>>>>  
>>>>> +static int hisi_acc_vf_debug_io(struct vfio_device *vdev)
>>>>> +{
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>>>>> +	struct device *dev = vdev->dev;
>>>>> +	u64 data;
>>>>> +	int ret;
>>>>> +
>>>>> +	ret = qm_wait_dev_not_ready(vf_qm);
>>>>> +	if (ret)
>>>>> +		dev_err(dev, "VF device not ready!\n");
>>>>> +
>>>>> +	data = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
>>>>> +	dev_info(dev, "debug mailbox val: 0x%llx\n", data);
>>>>> +
>>>>> +	return ret;
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vf_debug_resume(struct vfio_device *vdev)
>>>>> +{
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>>>>> +	struct device *dev = vdev->dev;
>>>>> +	int ret;
>>>>> +
>>>>> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
>>>>> +	if (ret) {
>>>>> +		dev_err(dev, "failed to save device data!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	ret = vf_qm_check_match(hisi_acc_vdev, migf);
>>>>> +	if (ret) {
>>>>> +		dev_err(dev, "failed to match the VF!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	ret = vf_qm_load_data(hisi_acc_vdev, migf);
>>>>> +	if (ret) {
>>>>> +		dev_err(dev, "failed to recover the VF!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	vf_qm_fun_reset(&hisi_acc_vdev->vf_qm);
>>>>> +	dev_info(dev, "successful to resume device data!\n");
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vf_debug_save(struct vfio_device *vdev)
>>>>> +{
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>>>>> +	struct device *dev = vdev->dev;
>>>>> +	int ret;
>>>>> +
>>>>> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
>>>>> +	if (ret) {
>>>>> +		dev_err(dev, "failed to save device data!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +	dev_info(dev, "successful to save device data!\n");
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int
>>>>> +hisi_acc_vf_debug_operate(struct vfio_device *vdev, unsigned int cmd)
>>>>> +{
>>>>> +	int ret;
>>>>> +
>>>>> +	switch (cmd) {
>>>>> +	case STATE_SAVE:
>>>>> +		ret = hisi_acc_vf_debug_save(vdev);
>>>>> +		if (ret)
>>>>> +			return ret;
>>>>> +		break;
>>>>> +	case STATE_RESUME:
>>>>> +		ret = hisi_acc_vf_debug_resume(vdev);
>>>>> +		if (ret)
>>>>> +			return ret;
>>>>> +		break;
>>>>> +	case RW_IO_TEST:
>>>>> +		ret = hisi_acc_vf_debug_io(vdev);
>>>>> +		if (ret)
>>>>> +			return ret;
>>>>> +		break;
>>>>> +	default:
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vf_debug_check(struct vfio_device *vdev)
>>>>> +{
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>>>>> +	enum vfio_device_mig_state state;
>>>>> +
>>>>> +	if (!vdev->mig_ops || !migf) {
>>>>> +		dev_err(vdev->dev, "device not support debugfs!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	/* If device not opened, the debugfs operation will trigger calltrace */
>>>>> +	(void)vdev->mig_ops->migration_get_state(vdev, &state);
>>>>> +	if (state == VFIO_DEVICE_STATE_ERROR ||
>>>>> +	    state == VFIO_DEVICE_STATE_STOP) {
>>>>> +		dev_err(vdev->dev, "device not opened!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static ssize_t hisi_acc_vf_debug_write(struct file *filp, const char __user *buffer,
>>>>> +			    size_t count, loff_t *pos)
>>>>> +{
>>>>> +	struct vfio_device	*vdev = filp->private_data;
>>>>> +	char tbuf[VFIO_DEV_DBG_LEN];
>>>>> +	unsigned long cmd;
>>>>> +	int len, ret;
>>>>> +
>>>>> +	if (*pos)
>>>>> +		return 0;
>>>>> +
>>>>> +	if (count >= VFIO_DEV_DBG_LEN)
>>>>> +		return -ENOSPC;
>>>>> +
>>>>> +	ret = hisi_acc_vf_debug_check(vdev);
>>>>> +	if (ret)
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	len = simple_write_to_buffer(tbuf, VFIO_DEV_DBG_LEN - 1,
>>>>> +					pos, buffer, count);
>>>>> +	if (len < 0 || len > VFIO_DEV_DBG_LEN - 1)
>>>>> +		return -EINVAL;
>>>>> +	tbuf[len] = '\0';
>>>>> +	if (kstrtoul(tbuf, 0, &cmd))
>>>>> +		return -EFAULT;
>>>>> +
>>>>> +	ret = hisi_acc_vf_debug_operate(vdev, cmd);
>>>>> +	if (ret) {
>>>>> +		dev_err(vdev->dev, "device debug test failed!\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	return count;
>>>>> +}
>>>>> +
>>>>> +static const struct file_operations hisi_acc_vf_debug_fops = {
>>>>> +	.owner = THIS_MODULE,
>>>>> +	.open = simple_open,
>>>>> +	.write = hisi_acc_vf_debug_write,
>>>>> +};
>>>>> +
>>>>> +static void seq_print_hex_data(struct seq_file *seq, const void *buf, size_t len)
>>>>> +{
>>>>> +#define HEX_LINE_SIZE		131
>>>>> +#define HEX_ROW_SIZE		16
>>>>> +	unsigned char linebuf[HEX_LINE_SIZE];
>>>>> +	int i, linelen, remaining = len;
>>>>> +	const u8 *ptr = buf;
>>>>> +
>>>>> +	for (i = 0; i < len; i += HEX_ROW_SIZE) {
>>>>> +		linelen = min(remaining, HEX_ROW_SIZE);
>>>>> +		remaining -= HEX_ROW_SIZE;
>>>>> +
>>>>> +		hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE, 1,
>>>>> +					linebuf, sizeof(linebuf), false);
>>>>> +
>>>>> +		seq_printf(seq, "%s%.8x: %s\n", "Mig Data:", i, linebuf);
>>>>> +	}
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vf_data_read(struct seq_file *seq, void *data)
>>>>> +{
>>>>> +	struct device *vf_dev = seq->private;
>>>>> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
>>>>> +	struct vfio_device	*vdev = &core_device->vdev;
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>>>>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>>>>> +
>>>>> +	if (debug_migf && debug_migf->total_length)
>>>>> +		seq_print_hex_data(seq, (unsigned char *)&debug_migf->vf_data,
>>>>> +				vf_data_sz);
>>>>> +	else
>>>>> +		seq_printf(seq, "%s\n", "device not migrated!");
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vf_attr_read(struct seq_file *seq, void *data)
>>>>> +{
>>>>> +	struct device *vf_dev = seq->private;
>>>>> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
>>>>> +	struct vfio_device	*vdev = &core_device->vdev;
>>>>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>>>>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>>>>> +
>>>>> +	if (debug_migf && debug_migf->total_length) {
>>>>> +		seq_printf(seq,
>>>>> +			 "acc device:\n"
>>>>> +			 "device  state: %d\n"
>>>>> +			 "device  ready: %u\n"
>>>>> +			 "data    valid: %d\n"
>>>>> +			 "data     size: %lu\n",
>>>>> +			 hisi_acc_vdev->mig_state,
>>>>> +			 hisi_acc_vdev->vf_qm_state,
>>>>> +			 debug_migf->disabled,
>>>>> +			 debug_migf->total_length);
>>>>> +	} else {
>>>>> +		seq_printf(seq, "%s\n", "device not migrated!");
>>>>> +	}
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>>>> +{
>>>>> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
>>>>> +	struct device *dev = vdev->dev;
>>>>> +	void *migf = NULL;
>>>>> +
>>>>> +	if (!debugfs_initialized())
>>>>> +		return 0;
>>>>> +
>>>>> +	vfio_vf_debugfs_init(vdev);
>>>>> +
>>>>> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
>>>>> +	if (!migf)
>>>>> +		return -ENOMEM;
>>>>> +
>>>>> +	hisi_acc_vdev->debug_migf = migf;
>>>>> +
>>>>> +	debugfs_create_devm_seqfile(dev, "migration_data", vdev->debug_root,
>>>>> +				  hisi_acc_vf_data_read);
>>>>> +	debugfs_create_devm_seqfile(dev, "migration_attr", vdev->debug_root,
>>>>> +				  hisi_acc_vf_attr_read);
>>>>> +
>>>>> +	debugfs_create_file("migration_debug", 0200, vdev->debug_root,
>>>>> +				  vdev, &hisi_acc_vf_debug_fops);
>>>>> +  
>>>>
>>>> All of these are going to be device specific, right?  So do we really
>>>> want a debugfs file structure that looks like:
>>>>
>>>> vfio
>>>> └── migration
>>>>     ├── hisi_acc
>>>>     │   ├── attr
>>>>     │   ├── data
>>>>     │   └── debug
>>>>     └── state
>>>>  
>>>
>>> According to this directory structure, I also need to change.
>>>
>>> Thanks
>>> Longfang.  
>>
>> If there are multiple devices participating in live migration, their current directory structure
>> is like this:
>> vfio
>> ├── hisi_acc_1
>> │     ├── attr
>> │     ├── data
>> │     ├── debug
>> │     └── state
>> │
>> └── hisi_acc_2
>>        ├── attr
>>        ├── data
>>        ├── debug
>>        └── state
>>
>>
>> If you want to change to the above directory structure, which directory should the
>> ‘state’ file be placed in the case of multiple devices?
>> vfio
>>  └─ migration
>>      ├── hisi_acc
>>      │     ├── attr
>>      │     ├── data
>>      │     └── debug
>>      └── state
>>
>> Like this or other directory structure?
>> vfio
>> └─ migration
>>     ├── hisi_acc_1
>>     │     ├── attr
>>     │     ├── data
>>     │     └── debug
>>     ├── hisi_acc_2
>>     │     ├── attr
>>     │     ├── data
>>     │     └── debug
>>     └── state
>> 	   ├── hisi_acc_1
>> 	   └── hisi_acc_2> 
> 
> I was thinking:
> 
> vfio
> ├── <name1>
> │   └── migration
> │       ├── hisi_acc
> │       │   ├── attr
> │       │   ├── data
> │       │   └── debug
> │       └── state
> └── <name2>
>     └── migration
>         ├── hisi_acc
>         │   ├── attr
>         │   ├── data
>         │   └── debug
>         └── state
> 
> My concern is that if {attr,data,debug} have driver specific
> definitions, they should have their own driver specific namespace.
> Thanks,
> 

Do <name1> and <name1> refer to dev_name()?
Is the file name "hisi_acc" defined by the driver?

Thanks,
Longfang.
> Alex
> 
>  
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>>>> +{
>>>>> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
>>>>> +
>>>>> +	if (!debugfs_initialized())
>>>>> +		return;
>>>>> +
>>>>> +	vfio_vf_debugfs_exit(vdev);
>>>>> +	kfree(hisi_acc_vdev->debug_migf);
>>>>> +}
>>>>> +
>>>>>  static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>>>>>  {
>>>>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>>>>> @@ -1416,6 +1692,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>>>>  	if (IS_ERR(hisi_acc_vdev))
>>>>>  		return PTR_ERR(hisi_acc_vdev);
>>>>>  
>>>>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>>>>> +		hisi_acc_vfio_debug_init(hisi_acc_vdev);
>>>>> +
>>>>>  	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
>>>>>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>>>>>  	if (ret)
>>>>> @@ -1423,6 +1702,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>>>>  	return 0;
>>>>>  
>>>>>  out_put_vdev:
>>>>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>>>>> +		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>>>>>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>>>>>  	return ret;
>>>>>  }
>>>>> @@ -1431,6 +1712,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>>>>>  {
>>>>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
>>>>>  
>>>>> +	hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>>>>>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
>>>>>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>>>>>  }
>>>>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>>>>> index dcabfeec6ca1..ef50b12f018d 100644
>>>>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>>>>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>>>>> @@ -49,6 +49,14 @@
>>>>>  #define QM_EQC_DW0		0X8000
>>>>>  #define QM_AEQC_DW0		0X8020
>>>>>  
>>>>> +#define VFIO_DEV_DBG_LEN		256
>>>>> +
>>>>> +enum mig_debug_cmd {
>>>>> +	STATE_SAVE,
>>>>> +	STATE_RESUME,
>>>>> +	RW_IO_TEST,
>>>>> +};
>>>>> +
>>>>>  struct acc_vf_data {
>>>>>  #define QM_MATCH_SIZE offsetofend(struct acc_vf_data, qm_rsv_state)
>>>>>  	/* QM match information */
>>>>> @@ -113,5 +121,8 @@ struct hisi_acc_vf_core_device {
>>>>>  	spinlock_t reset_lock;
>>>>>  	struct hisi_acc_vf_migration_file *resuming_migf;
>>>>>  	struct hisi_acc_vf_migration_file *saving_migf;
>>>>> +
>>>>> +	/* For debugfs */
>>>>> +	struct hisi_acc_vf_migration_file *debug_migf;
>>>>>  };
>>>>>  #endif /* HISI_ACC_VFIO_PCI_H */  
>>>>
>>>> .
>>>>  
>>
> 
> .
> 

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