[PATCH v11 0/4] add debugfs to migration driver

[PATCH v11 0/4] add debugfs to migration driver

[liulongfang]

Add a debugfs function to the migration driver in VFIO to provide
a step-by-step test function for the migration driver.

When the execution of live migration fails, the user can view the
status and data during the migration process separately from the
source and the destination, which is convenient for users to analyze
and locate problems.

Changes v10 -> v11
	Delete the device restore function in debugfs.

Changes v9 -> v10
	Update the debugfs file of the live migration driver.

Changes v8 -> v9
	Update the debugfs directory structure of vfio.

Changes v7 -> v8
	Add support for platform devices.

Changes v6 -> v7
	Fix some code style issues.

Changes v5 -> v6
	Control the creation of debugfs through the CONFIG_DEBUG_FS.

Changes v4 -> v5
	Remove the newly added vfio_migration_ops and use seq_printf
	to optimize the implementation of debugfs.

Changes v3 -> v4
	Change the migration_debug_operate interface to debug_root file.

Changes v2 -> v3
	Extend the debugfs function from hisilicon device to vfio.

Changes v1 -> v2
	Change the registration method of root_debugfs to register
	with module initialization. 

Longfang Liu (4):
  vfio/migration: Add debugfs to live migration driver
  hisi_acc_vfio_pci: extract public functions for container_of
  hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
  Documentation: add debugfs description for vfio

 .../ABI/testing/debugfs-hisi-migration        |  32 +++
 Documentation/ABI/testing/debugfs-vfio        |  25 +++
 MAINTAINERS                                   |   2 +
 drivers/vfio/Makefile                         |   1 +
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 203 +++++++++++++++++-
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
 drivers/vfio/vfio.h                           |  14 ++
 drivers/vfio/vfio_debugfs.c                   |  78 +++++++
 drivers/vfio/vfio_main.c                      |   9 +-
 include/linux/vfio.h                          |   7 +
 10 files changed, 371 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
 create mode 100644 Documentation/ABI/testing/debugfs-vfio
 create mode 100644 drivers/vfio/vfio_debugfs.c

-- 
2.24.0

[PATCH v11 1/4] vfio/migration: Add debugfs to live migration driver

[liulongfang]

From: Longfang Liu <liulongfang@huawei.com>

There are multiple devices, software and operational steps involved
in the process of live migration. An error occurred on any node may
cause the live migration operation to fail.
This complex process makes it very difficult to locate and analyze
the cause when the function fails.

In order to quickly locate the cause of the problem when the
live migration fails, I added a set of debugfs to the vfio
live migration driver.

    +-------------------------------------------+
    |                                           |
    |                                           |
    |                  QEMU                     |
    |                                           |
    |                                           |
    +---+----------------------------+----------+
        |      ^                     |      ^
        |      |                     |      |
        |      |                     |      |
        v      |                     v      |
     +---------+--+               +---------+--+
     |src vfio_dev|               |dst vfio_dev|
     +--+---------+               +--+---------+
        |      ^                     |      ^
        |      |                     |      |
        v      |                     |      |
   +-----------+----+           +-----------+----+
   |src dev debugfs |           |dst dev debugfs |
   +----------------+           +----------------+

The entire debugfs directory will be based on the definition of
the CONFIG_DEBUG_FS macro. If this macro is not enabled, the
interfaces in vfio.h will be empty definitions, and the creation
and initialization of the debugfs directory will not be executed.

   vfio
    |
    +---<dev_name1>
    |    +---migration
    |        +--state
    |        +--hisi_acc
    |            +--attr
    |            +--data
    |            +--save
    |            +--io_test
    |
    +---<dev_name2>
         +---migration
             +--state
             +--hisi_acc
                 +--attr
                 +--data
                 +--save
                 +--io_test

debugfs will create a public root directory "vfio" file.
then create a dev_name() file for each live migration device.
First, create a unified state acquisition file of "migration"
in this device directory.
Then, create a public live migration state lookup file "state"
Finally, create a directory file based on the device type,
and then create the device's own debugging files under
this directory file.

Here, HiSilicon accelerator creates three debug files:
attr: used to export the attribute parameters of the
current live migration device.
data: used to export the live migration data of the current
live migration device.
save: used to read the current live migration device's data
and save it to the driver.
io_test: used to test the IO read and write for the driver.

The live migration function of the current device can be tested by
operating the debug files, and the functional status of the equipment
and software at each stage can be tested step by step without
performing the complete live migration function. And after the live
migration is performed, the migration device data of the live migration
can be obtained through the debug files.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 drivers/vfio/Makefile       |  1 +
 drivers/vfio/vfio.h         | 14 +++++++
 drivers/vfio/vfio_debugfs.c | 78 +++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_main.c    |  9 ++++-
 include/linux/vfio.h        |  7 ++++
 5 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 drivers/vfio/vfio_debugfs.c

diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 66f418aef5a9..6829c58210dc 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -7,6 +7,7 @@ vfio-y += vfio_main.o \
 vfio-$(CONFIG_IOMMUFD) += iommufd.o
 vfio-$(CONFIG_VFIO_CONTAINER) += container.o
 vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
+vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o
 
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index 7b19c621e0e6..729c52ef579a 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -264,4 +264,18 @@ static inline void vfio_device_put_kvm(struct vfio_device *device)
 }
 #endif
 
+#ifdef CONFIG_DEBUG_FS
+void vfio_debugfs_create_root(void);
+void vfio_debugfs_remove_root(void);
+
+void vfio_device_debugfs_init(struct vfio_device *vdev);
+void vfio_device_debugfs_exit(struct vfio_device *vdev);
+#else
+static inline void vfio_debugfs_create_root(void) { }
+static inline void vfio_debugfs_remove_root(void) { }
+
+static inline void vfio_device_debugfs_init(struct vfio_device *vdev) { }
+static inline void vfio_device_debugfs_exit(struct vfio_device *vdev) { }
+#endif /* CONFIG_DEBUG_FS */
+
 #endif
diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c
new file mode 100644
index 000000000000..7bff30f76bd9
--- /dev/null
+++ b/drivers/vfio/vfio_debugfs.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023, HiSilicon Ltd.
+ */
+
+#include <linux/device.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/vfio.h>
+#include "vfio.h"
+
+static struct dentry *vfio_debugfs_root;
+
+static int vfio_device_state_read(struct seq_file *seq, void *data)
+{
+	struct device *vf_dev = seq->private;
+	struct vfio_device *vdev = container_of(vf_dev, struct vfio_device, device);
+	enum vfio_device_mig_state state;
+	int ret;
+
+	ret = vdev->mig_ops->migration_get_state(vdev, &state);
+	if (ret)
+		return -EINVAL;
+
+	switch (state) {
+	case VFIO_DEVICE_STATE_RUNNING:
+		seq_printf(seq, "%s\n", "RUNNING");
+		break;
+	case VFIO_DEVICE_STATE_STOP_COPY:
+		seq_printf(seq, "%s\n", "STOP_COPY");
+		break;
+	case VFIO_DEVICE_STATE_STOP:
+		seq_printf(seq, "%s\n", "STOP");
+		break;
+	case VFIO_DEVICE_STATE_RESUMING:
+		seq_printf(seq, "%s\n", "RESUMING");
+		break;
+	case VFIO_DEVICE_STATE_RUNNING_P2P:
+		seq_printf(seq, "%s\n", "RESUMING_P2P");
+		break;
+	case VFIO_DEVICE_STATE_ERROR:
+		seq_printf(seq, "%s\n", "ERROR");
+		break;
+	default:
+		seq_printf(seq, "%s\n", "Invalid");
+	}
+
+	return 0;
+}
+
+void vfio_device_debugfs_init(struct vfio_device *vdev)
+{
+	struct dentry *vfio_dev_migration = NULL;
+	struct device *dev = &vdev->device;
+
+	vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
+	vfio_dev_migration = debugfs_create_dir("migration", vdev->debug_root);
+
+	debugfs_create_devm_seqfile(dev, "state", vfio_dev_migration,
+				  vfio_device_state_read);
+}
+
+void vfio_device_debugfs_exit(struct vfio_device *vdev)
+{
+	debugfs_remove_recursive(vdev->debug_root);
+}
+
+void vfio_debugfs_create_root(void)
+{
+	vfio_debugfs_root = debugfs_create_dir("vfio", NULL);
+}
+
+void vfio_debugfs_remove_root(void)
+{
+	debugfs_remove_recursive(vfio_debugfs_root);
+	vfio_debugfs_root = NULL;
+}
+
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index f0ca33b2e1df..18d050ec9a12 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -282,7 +282,8 @@ static int __vfio_register_dev(struct vfio_device *device,
 
 	/* Refcounting can't start until the driver calls register */
 	refcount_set(&device->refcount, 1);
-
+	if (device->mig_ops)
+		vfio_device_debugfs_init(device);
 	vfio_device_group_register(device);
 
 	return 0;
@@ -339,6 +340,8 @@ void vfio_unregister_group_dev(struct vfio_device *device)
 		}
 	}
 
+	if (device->mig_ops)
+		vfio_device_debugfs_exit(device);
 	vfio_device_group_unregister(device);
 
 	/* Balances device_add in register path */
@@ -1415,7 +1418,10 @@ static int __init vfio_init(void)
 		goto err_dev_class;
 	}
 
+
+	vfio_debugfs_create_root();
 	pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
+
 	return 0;
 
 err_dev_class:
@@ -1433,6 +1439,7 @@ static void __exit vfio_cleanup(void)
 	vfio_virqfd_exit();
 	vfio_group_cleanup();
 	xa_destroy(&vfio_device_set_xa);
+	vfio_debugfs_remove_root();
 }
 
 module_init(vfio_init);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 2c137ea94a3e..a114b430be31 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -62,6 +62,13 @@ struct vfio_device {
 	struct iommufd_device *iommufd_device;
 	bool iommufd_attached;
 #endif
+#ifdef CONFIG_DEBUG_FS
+	/*
+	 * debug_root is a static property of the vfio_device
+	 * which must be set prior to registering the vfio_device.
+	 */
+	struct dentry *debug_root;
+#endif
 };
 
 /**
-- 
2.24.0

Re: [PATCH v11 1/4] vfio/migration: Add debugfs to live migration driver

[Cédric Le Goater]

On 6/30/23 11:24, liulongfang wrote:
> From: Longfang Liu <liulongfang@huawei.com>
> 
> There are multiple devices, software and operational steps involved
> in the process of live migration. An error occurred on any node may
> cause the live migration operation to fail.
> This complex process makes it very difficult to locate and analyze
> the cause when the function fails.
> 
> In order to quickly locate the cause of the problem when the
> live migration fails, I added a set of debugfs to the vfio
> live migration driver.
> 
>      +-------------------------------------------+
>      |                                           |
>      |                                           |
>      |                  QEMU                     |
>      |                                           |
>      |                                           |
>      +---+----------------------------+----------+
>          |      ^                     |      ^
>          |      |                     |      |
>          |      |                     |      |
>          v      |                     v      |
>       +---------+--+               +---------+--+
>       |src vfio_dev|               |dst vfio_dev|
>       +--+---------+               +--+---------+
>          |      ^                     |      ^
>          |      |                     |      |
>          v      |                     |      |
>     +-----------+----+           +-----------+----+
>     |src dev debugfs |           |dst dev debugfs |
>     +----------------+           +----------------+
> 
> The entire debugfs directory will be based on the definition of
> the CONFIG_DEBUG_FS macro. If this macro is not enabled, the
> interfaces in vfio.h will be empty definitions, and the creation
> and initialization of the debugfs directory will not be executed.
> 
>     vfio
>      |
>      +---<dev_name1>
>      |    +---migration
>      |        +--state
>      |        +--hisi_acc
>      |            +--attr
>      |            +--data
>      |            +--save
>      |            +--io_test
>      |
>      +---<dev_name2>
>           +---migration
>               +--state
>               +--hisi_acc
>                   +--attr
>                   +--data
>                   +--save
>                   +--io_test
> 
> debugfs will create a public root directory "vfio" file.
> then create a dev_name() file for each live migration device.
> First, create a unified state acquisition file of "migration"
> in this device directory.
> Then, create a public live migration state lookup file "state"
> Finally, create a directory file based on the device type,
> and then create the device's own debugging files under
> this directory file.
> 
> Here, HiSilicon accelerator creates three debug files:
> attr: used to export the attribute parameters of the
> current live migration device.
> data: used to export the live migration data of the current
> live migration device.
> save: used to read the current live migration device's data
> and save it to the driver.
> io_test: used to test the IO read and write for the driver.
> 
> The live migration function of the current device can be tested by
> operating the debug files, and the functional status of the equipment
> and software at each stage can be tested step by step without
> performing the complete live migration function. And after the live
> migration is performed, the migration device data of the live migration
> can be obtained through the debug files.
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>   drivers/vfio/Makefile       |  1 +
>   drivers/vfio/vfio.h         | 14 +++++++
>   drivers/vfio/vfio_debugfs.c | 78 +++++++++++++++++++++++++++++++++++++
>   drivers/vfio/vfio_main.c    |  9 ++++-
>   include/linux/vfio.h        |  7 ++++
>   5 files changed, 108 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/vfio/vfio_debugfs.c
> 
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index 66f418aef5a9..6829c58210dc 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -7,6 +7,7 @@ vfio-y += vfio_main.o \
>   vfio-$(CONFIG_IOMMUFD) += iommufd.o
>   vfio-$(CONFIG_VFIO_CONTAINER) += container.o
>   vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
> +vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o
>   
>   obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
>   obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index 7b19c621e0e6..729c52ef579a 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -264,4 +264,18 @@ static inline void vfio_device_put_kvm(struct vfio_device *device)
>   }
>   #endif
>   
> +#ifdef CONFIG_DEBUG_FS
> +void vfio_debugfs_create_root(void);
> +void vfio_debugfs_remove_root(void);
> +
> +void vfio_device_debugfs_init(struct vfio_device *vdev);
> +void vfio_device_debugfs_exit(struct vfio_device *vdev);
> +#else
> +static inline void vfio_debugfs_create_root(void) { }
> +static inline void vfio_debugfs_remove_root(void) { }
> +
> +static inline void vfio_device_debugfs_init(struct vfio_device *vdev) { }
> +static inline void vfio_device_debugfs_exit(struct vfio_device *vdev) { }
> +#endif /* CONFIG_DEBUG_FS */
> +
>   #endif
> diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c
> new file mode 100644
> index 000000000000..7bff30f76bd9
> --- /dev/null
> +++ b/drivers/vfio/vfio_debugfs.c
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2023, HiSilicon Ltd.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/debugfs.h>
> +#include <linux/seq_file.h>
> +#include <linux/vfio.h>
> +#include "vfio.h"
> +
> +static struct dentry *vfio_debugfs_root;

This could be external to all VFIO. See comment below.
  
> +
> +static int vfio_device_state_read(struct seq_file *seq, void *data)
> +{
> +	struct device *vf_dev = seq->private;
> +	struct vfio_device *vdev = container_of(vf_dev, struct vfio_device, device);
> +	enum vfio_device_mig_state state;
> +	int ret;
> +
> +	ret = vdev->mig_ops->migration_get_state(vdev, &state);
> +	if (ret)
> +		return -EINVAL;
> +
> +	switch (state) {
> +	case VFIO_DEVICE_STATE_RUNNING:
> +		seq_printf(seq, "%s\n", "RUNNING");
> +		break;
> +	case VFIO_DEVICE_STATE_STOP_COPY:
> +		seq_printf(seq, "%s\n", "STOP_COPY");
> +		break;
> +	case VFIO_DEVICE_STATE_STOP:
> +		seq_printf(seq, "%s\n", "STOP");
> +		break;
> +	case VFIO_DEVICE_STATE_RESUMING:
> +		seq_printf(seq, "%s\n", "RESUMING");
> +		break;
> +	case VFIO_DEVICE_STATE_RUNNING_P2P:
> +		seq_printf(seq, "%s\n", "RESUMING_P2P");
> +		break;
> +	case VFIO_DEVICE_STATE_ERROR:
> +		seq_printf(seq, "%s\n", "ERROR");
> +		break;
> +	default:
> +		seq_printf(seq, "%s\n", "Invalid");
> +	}
> +
> +	return 0;
> +}
> +
> +void vfio_device_debugfs_init(struct vfio_device *vdev)
> +{
> +	struct dentry *vfio_dev_migration = NULL;
> +	struct device *dev = &vdev->device;
> +
> +	vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
> +	vfio_dev_migration = debugfs_create_dir("migration", vdev->debug_root);
> +
> +	debugfs_create_devm_seqfile(dev, "state", vfio_dev_migration,
> +				  vfio_device_state_read);
> +}
> +
> +void vfio_device_debugfs_exit(struct vfio_device *vdev)
> +{
> +	debugfs_remove_recursive(vdev->debug_root);
> +}

I would simply use :

	if (IS_ENABLED(CONFIG_DEBUG_FS))
		debugfs_remove_recursive(vdev->debug_root);

where vfio_device_debugfs_exit() is called.

> +
> +void vfio_debugfs_create_root(void)
> +{
> +	vfio_debugfs_root = debugfs_create_dir("vfio", NULL);
> +}
> +
> +void vfio_debugfs_remove_root(void)
> +{
> +	debugfs_remove_recursive(vfio_debugfs_root);
> +	vfio_debugfs_root = NULL;
ditto.

> +}
> +
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index f0ca33b2e1df..18d050ec9a12 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -282,7 +282,8 @@ static int __vfio_register_dev(struct vfio_device *device,
>   
>   	/* Refcounting can't start until the driver calls register */
>   	refcount_set(&device->refcount, 1);
> -
> +	if (device->mig_ops)
> +		vfio_device_debugfs_init(device);

I think we should prepare ground for more debugfs files than just migration
related things. Migration is clearly a very good candidate, but there could
be more. I have a couple out of tree patches to collect statistics on VMA
usage and resets for instance which could be included.


Thanks,

C.

>   	vfio_device_group_register(device);
>   
>   	return 0;
> @@ -339,6 +340,8 @@ void vfio_unregister_group_dev(struct vfio_device *device)
>   		}
>   	}
>   
> +	if (device->mig_ops)
> +		vfio_device_debugfs_exit(device);
>   	vfio_device_group_unregister(device);
>   
>   	/* Balances device_add in register path */
> @@ -1415,7 +1418,10 @@ static int __init vfio_init(void)
>   		goto err_dev_class;
>   	}
>   
> +
> +	vfio_debugfs_create_root();
>   	pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
> +
>   	return 0;
>   
>   err_dev_class:
> @@ -1433,6 +1439,7 @@ static void __exit vfio_cleanup(void)
>   	vfio_virqfd_exit();
>   	vfio_group_cleanup();
>   	xa_destroy(&vfio_device_set_xa);
> +	vfio_debugfs_remove_root();
>   }
>   
>   module_init(vfio_init);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 2c137ea94a3e..a114b430be31 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -62,6 +62,13 @@ struct vfio_device {
>   	struct iommufd_device *iommufd_device;
>   	bool iommufd_attached;
>   #endif
> +#ifdef CONFIG_DEBUG_FS
> +	/*
> +	 * debug_root is a static property of the vfio_device
> +	 * which must be set prior to registering the vfio_device.
> +	 */
> +	struct dentry *debug_root;
> +#endif
>   };
>   
>   /**

Re: [PATCH v11 1/4] vfio/migration: Add debugfs to live migration driver

[liulongfang]

On 2023/7/19 1:45, Cédric Le Goater Wrote:
> On 6/30/23 11:24, liulongfang wrote:
>> From: Longfang Liu <liulongfang@huawei.com>
>>
>> There are multiple devices, software and operational steps involved
>> in the process of live migration. An error occurred on any node may
>> cause the live migration operation to fail.
>> This complex process makes it very difficult to locate and analyze
>> the cause when the function fails.
>>
>> In order to quickly locate the cause of the problem when the
>> live migration fails, I added a set of debugfs to the vfio
>> live migration driver.
>>
>>      +-------------------------------------------+
>>      |                                           |
>>      |                                           |
>>      |                  QEMU                     |
>>      |                                           |
>>      |                                           |
>>      +---+----------------------------+----------+
>>          |      ^                     |      ^
>>          |      |                     |      |
>>          |      |                     |      |
>>          v      |                     v      |
>>       +---------+--+               +---------+--+
>>       |src vfio_dev|               |dst vfio_dev|
>>       +--+---------+               +--+---------+
>>          |      ^                     |      ^
>>          |      |                     |      |
>>          v      |                     |      |
>>     +-----------+----+           +-----------+----+
>>     |src dev debugfs |           |dst dev debugfs |
>>     +----------------+           +----------------+
>>
>> The entire debugfs directory will be based on the definition of
>> the CONFIG_DEBUG_FS macro. If this macro is not enabled, the
>> interfaces in vfio.h will be empty definitions, and the creation
>> and initialization of the debugfs directory will not be executed.
>>
>>     vfio
>>      |
>>      +---<dev_name1>
>>      |    +---migration
>>      |        +--state
>>      |        +--hisi_acc
>>      |            +--attr
>>      |            +--data
>>      |            +--save
>>      |            +--io_test
>>      |
>>      +---<dev_name2>
>>           +---migration
>>               +--state
>>               +--hisi_acc
>>                   +--attr
>>                   +--data
>>                   +--save
>>                   +--io_test
>>
>> debugfs will create a public root directory "vfio" file.
>> then create a dev_name() file for each live migration device.
>> First, create a unified state acquisition file of "migration"
>> in this device directory.
>> Then, create a public live migration state lookup file "state"
>> Finally, create a directory file based on the device type,
>> and then create the device's own debugging files under
>> this directory file.
>>
>> Here, HiSilicon accelerator creates three debug files:
>> attr: used to export the attribute parameters of the
>> current live migration device.
>> data: used to export the live migration data of the current
>> live migration device.
>> save: used to read the current live migration device's data
>> and save it to the driver.
>> io_test: used to test the IO read and write for the driver.
>>
>> The live migration function of the current device can be tested by
>> operating the debug files, and the functional status of the equipment
>> and software at each stage can be tested step by step without
>> performing the complete live migration function. And after the live
>> migration is performed, the migration device data of the live migration
>> can be obtained through the debug files.
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>   drivers/vfio/Makefile       |  1 +
>>   drivers/vfio/vfio.h         | 14 +++++++
>>   drivers/vfio/vfio_debugfs.c | 78 +++++++++++++++++++++++++++++++++++++
>>   drivers/vfio/vfio_main.c    |  9 ++++-
>>   include/linux/vfio.h        |  7 ++++
>>   5 files changed, 108 insertions(+), 1 deletion(-)
>>   create mode 100644 drivers/vfio/vfio_debugfs.c
>>
>> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
>> index 66f418aef5a9..6829c58210dc 100644
>> --- a/drivers/vfio/Makefile
>> +++ b/drivers/vfio/Makefile
>> @@ -7,6 +7,7 @@ vfio-y += vfio_main.o \
>>   vfio-$(CONFIG_IOMMUFD) += iommufd.o
>>   vfio-$(CONFIG_VFIO_CONTAINER) += container.o
>>   vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
>> +vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o
>>     obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
>>   obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
>> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
>> index 7b19c621e0e6..729c52ef579a 100644
>> --- a/drivers/vfio/vfio.h
>> +++ b/drivers/vfio/vfio.h
>> @@ -264,4 +264,18 @@ static inline void vfio_device_put_kvm(struct vfio_device *device)
>>   }
>>   #endif
>>   +#ifdef CONFIG_DEBUG_FS
>> +void vfio_debugfs_create_root(void);
>> +void vfio_debugfs_remove_root(void);
>> +
>> +void vfio_device_debugfs_init(struct vfio_device *vdev);
>> +void vfio_device_debugfs_exit(struct vfio_device *vdev);
>> +#else
>> +static inline void vfio_debugfs_create_root(void) { }
>> +static inline void vfio_debugfs_remove_root(void) { }
>> +
>> +static inline void vfio_device_debugfs_init(struct vfio_device *vdev) { }
>> +static inline void vfio_device_debugfs_exit(struct vfio_device *vdev) { }
>> +#endif /* CONFIG_DEBUG_FS */
>> +
>>   #endif
>> diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c
>> new file mode 100644
>> index 000000000000..7bff30f76bd9
>> --- /dev/null
>> +++ b/drivers/vfio/vfio_debugfs.c
>> @@ -0,0 +1,78 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2023, HiSilicon Ltd.
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/debugfs.h>
>> +#include <linux/seq_file.h>
>> +#include <linux/vfio.h>
>> +#include "vfio.h"
>> +
>> +static struct dentry *vfio_debugfs_root;
> 
> This could be external to all VFIO. See comment below.
>  
>> +
>> +static int vfio_device_state_read(struct seq_file *seq, void *data)
>> +{
>> +    struct device *vf_dev = seq->private;
>> +    struct vfio_device *vdev = container_of(vf_dev, struct vfio_device, device);
>> +    enum vfio_device_mig_state state;
>> +    int ret;
>> +
>> +    ret = vdev->mig_ops->migration_get_state(vdev, &state);
>> +    if (ret)
>> +        return -EINVAL;
>> +
>> +    switch (state) {
>> +    case VFIO_DEVICE_STATE_RUNNING:
>> +        seq_printf(seq, "%s\n", "RUNNING");
>> +        break;
>> +    case VFIO_DEVICE_STATE_STOP_COPY:
>> +        seq_printf(seq, "%s\n", "STOP_COPY");
>> +        break;
>> +    case VFIO_DEVICE_STATE_STOP:
>> +        seq_printf(seq, "%s\n", "STOP");
>> +        break;
>> +    case VFIO_DEVICE_STATE_RESUMING:
>> +        seq_printf(seq, "%s\n", "RESUMING");
>> +        break;
>> +    case VFIO_DEVICE_STATE_RUNNING_P2P:
>> +        seq_printf(seq, "%s\n", "RESUMING_P2P");
>> +        break;
>> +    case VFIO_DEVICE_STATE_ERROR:
>> +        seq_printf(seq, "%s\n", "ERROR");
>> +        break;
>> +    default:
>> +        seq_printf(seq, "%s\n", "Invalid");
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +void vfio_device_debugfs_init(struct vfio_device *vdev)
>> +{
>> +    struct dentry *vfio_dev_migration = NULL;
>> +    struct device *dev = &vdev->device;
>> +
>> +    vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
>> +    vfio_dev_migration = debugfs_create_dir("migration", vdev->debug_root);
>> +
>> +    debugfs_create_devm_seqfile(dev, "state", vfio_dev_migration,
>> +                  vfio_device_state_read);
>> +}
>> +
>> +void vfio_device_debugfs_exit(struct vfio_device *vdev)
>> +{
>> +    debugfs_remove_recursive(vdev->debug_root);
>> +}
> 
> I would simply use :
> 
>     if (IS_ENABLED(CONFIG_DEBUG_FS))
>         debugfs_remove_recursive(vdev->debug_root);
> 
> where vfio_device_debugfs_exit() is called.
> 
These functions have been processed by CONFIG_DEBUG_FS in vfio.h.
The effect is almost the same.

>> +
>> +void vfio_debugfs_create_root(void)
>> +{
>> +    vfio_debugfs_root = debugfs_create_dir("vfio", NULL);
>> +}
>> +
>> +void vfio_debugfs_remove_root(void)
>> +{
>> +    debugfs_remove_recursive(vfio_debugfs_root);
>> +    vfio_debugfs_root = NULL;
> ditto.
>
ditto.

>> +}
>> +
>> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
>> index f0ca33b2e1df..18d050ec9a12 100644
>> --- a/drivers/vfio/vfio_main.c
>> +++ b/drivers/vfio/vfio_main.c
>> @@ -282,7 +282,8 @@ static int __vfio_register_dev(struct vfio_device *device,
>>         /* Refcounting can't start until the driver calls register */
>>       refcount_set(&device->refcount, 1);
>> -
>> +    if (device->mig_ops)
>> +        vfio_device_debugfs_init(device);
> 
> I think we should prepare ground for more debugfs files than just migration
> related things. Migration is clearly a very good candidate, but there could
> be more. I have a couple out of tree patches to collect statistics on VMA
> usage and resets for instance which could be included.
> 
> 
> Thanks,
> 
> C.

OK, this suggestion of yours is very good.
I can put this judgment processing into vfio_device_debugfs_init().
If your patch needs to add debugfs, you can add it in vfio_device_debugfs_init().

Thanks,
Longfang.
> 
>>       vfio_device_group_register(device);
>>         return 0;
>> @@ -339,6 +340,8 @@ void vfio_unregister_group_dev(struct vfio_device *device)
>>           }
>>       }
>>   +    if (device->mig_ops)
>> +        vfio_device_debugfs_exit(device);
>>       vfio_device_group_unregister(device);
>>         /* Balances device_add in register path */
>> @@ -1415,7 +1418,10 @@ static int __init vfio_init(void)
>>           goto err_dev_class;
>>       }
>>   +
>> +    vfio_debugfs_create_root();
>>       pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
>> +
>>       return 0;
>>     err_dev_class:
>> @@ -1433,6 +1439,7 @@ static void __exit vfio_cleanup(void)
>>       vfio_virqfd_exit();
>>       vfio_group_cleanup();
>>       xa_destroy(&vfio_device_set_xa);
>> +    vfio_debugfs_remove_root();
>>   }
>>     module_init(vfio_init);
>> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
>> index 2c137ea94a3e..a114b430be31 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -62,6 +62,13 @@ struct vfio_device {
>>       struct iommufd_device *iommufd_device;
>>       bool iommufd_attached;
>>   #endif
>> +#ifdef CONFIG_DEBUG_FS
>> +    /*
>> +     * debug_root is a static property of the vfio_device
>> +     * which must be set prior to registering the vfio_device.
>> +     */
>> +    struct dentry *debug_root;
>> +#endif
>>   };
>>     /**
> 
> .
> 

[PATCH v11 2/4] hisi_acc_vfio_pci: extract public functions for container_of

[liulongfang]

From: Longfang Liu <liulongfang@huawei.com>

In the current driver, vdev is obtained from struct
hisi_acc_vf_core_device through the container_of function.
This method is used in many places in the driver. In order to
reduce this repetitive operation, I extracted a public function
to replace it.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index a117eaf21c14..a1589947e721 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -630,6 +630,12 @@ static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vde
 	}
 }
 
+static struct hisi_acc_vf_core_device *hisi_acc_get_vf_dev(struct vfio_device *vdev)
+{
+	return container_of(vdev, struct hisi_acc_vf_core_device,
+			    core_device.vdev);
+}
+
 /*
  * This function is called in all state_mutex unlock cases to
  * handle a 'deferred_reset' if exists.
@@ -1042,8 +1048,7 @@ static struct file *
 hisi_acc_vfio_pci_set_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state new_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 	enum vfio_device_mig_state next_state;
 	struct file *res = NULL;
 	int ret;
@@ -1084,8 +1089,7 @@ static int
 hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state *curr_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 
 	mutex_lock(&hisi_acc_vdev->state_mutex);
 	*curr_state = hisi_acc_vdev->mig_state;
@@ -1301,8 +1305,7 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
 
 static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct vfio_pci_core_device *vdev = &hisi_acc_vdev->core_device;
 	int ret;
 
@@ -1325,8 +1328,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 
 static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
 
 	iounmap(vf_qm->io_base);
@@ -1341,8 +1343,7 @@ static const struct vfio_migration_ops hisi_acc_vfio_pci_migrn_state_ops = {
 
 static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
 	struct hisi_qm *pf_qm = hisi_acc_get_pf_qm(pdev);
 
-- 
2.24.0

[PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

From: Longfang Liu <liulongfang@huawei.com>

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.

After registering the HiSilicon accelerator device on the debugfs
framework of live migration of vfio, a directory file "hisi_acc"
of debugfs is created, and then three debug function files are
created in this directory:

data file: used to get the migration data from the driver
attr file: used to get device attributes parameters from the driver
save file: used to read the data of the live migration device and save
it to the driver.
io_test: used to test IO read and write for the driver.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 182 ++++++++++++++++++
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 ++
 2 files changed, 193 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..a6f5e94bfaf2 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 +1320,164 @@ 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_check(struct seq_file *seq, 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;
+
+	if (!vdev->mig_ops || !migf) {
+		seq_printf(seq, "%s\n", "device not support debugfs!");
+		return -EINVAL;
+	}
+
+	/* If device not opened, the debugfs operation will trigger calltrace */
+	if (!vdev->open_count) {
+		seq_printf(seq, "%s\n", "device not opened!");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int hisi_acc_vf_debug_io(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_qm *vf_qm = &hisi_acc_vdev->vf_qm;
+	u64 value;
+	int ret;
+
+	ret = hisi_acc_vf_debug_check(seq, vdev);
+	if (ret)
+		goto io_err;
+
+	ret = qm_wait_dev_not_ready(vf_qm);
+	if (ret) {
+		seq_printf(seq, "%s\n", "VF device not ready!");
+		goto io_err;
+	}
+
+	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
+	seq_printf(seq, "%s:0x%llx\n", "debug mailbox val", value);
+
+io_err:
+	return 0;
+}
+
+static int hisi_acc_vf_debug_save(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 *migf = hisi_acc_vdev->debug_migf;
+	int ret;
+
+	ret = hisi_acc_vf_debug_check(seq, vdev);
+	if (ret)
+		goto save_err;
+
+	ret = vf_qm_state_save(hisi_acc_vdev, migf);
+	if (ret) {
+		seq_printf(seq, "%s\n", "failed to save device data!");
+		goto save_err;
+	}
+	seq_printf(seq, "%s\n", "successful to save device data!");
+
+save_err:
+	return 0;
+}
+
+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_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
+				(unsigned char *)&debug_migf->vf_data,
+				vf_data_sz, false);
+	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 dentry *vfio_dev_migration = NULL;
+	struct dentry *vfio_hisi_acc = NULL;
+	struct device *dev = vdev->dev;
+	void *migf = NULL;
+
+	if (!debugfs_initialized())
+		return 0;
+
+	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
+	if (!migf)
+		return -ENOMEM;
+	hisi_acc_vdev->debug_migf = migf;
+
+	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
+	if (!vfio_dev_migration) {
+		dev_err(dev, "failed to lookup migration debugfs file!\n");
+		return -ENODEV;
+	}
+
+	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
+	debugfs_create_devm_seqfile(dev, "data", vfio_hisi_acc,
+				  hisi_acc_vf_data_read);
+	debugfs_create_devm_seqfile(dev, "attr", vfio_hisi_acc,
+				  hisi_acc_vf_attr_read);
+	debugfs_create_devm_seqfile(dev, "io_test", vfio_hisi_acc,
+				  hisi_acc_vf_debug_io);
+	debugfs_create_devm_seqfile(dev, "save", vfio_hisi_acc,
+				  hisi_acc_vf_debug_save);
+
+	return 0;
+}
+
+static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
+{
+	if (!debugfs_initialized())
+		return;
+
+	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);
@@ -1323,6 +1498,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 	}
 
 	vfio_pci_core_finish_enable(vdev);
+
 	return 0;
 }
 
@@ -1420,9 +1596,14 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
 	if (ret)
 		goto out_put_vdev;
+
+	if (ops == &hisi_acc_vfio_pci_migrn_ops)
+		hisi_acc_vfio_debug_init(hisi_acc_vdev);
 	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 +1612,7 @@ 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 */
-- 
2.24.0

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Alex Williamson]

On Fri, 30 Jun 2023 17:24:56 +0800
liulongfang <liulongfang@huawei.com> wrote:

> From: Longfang Liu <liulongfang@huawei.com>
> 
> 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.
> 
> After registering the HiSilicon accelerator device on the debugfs
> framework of live migration of vfio, a directory file "hisi_acc"
> of debugfs is created, and then three debug function files are
> created in this directory:
> 
> data file: used to get the migration data from the driver
> attr file: used to get device attributes parameters from the driver
> save file: used to read the data of the live migration device and save
> it to the driver.
> io_test: used to test IO read and write for the driver.
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 182 ++++++++++++++++++
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 ++
>  2 files changed, 193 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..a6f5e94bfaf2 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)

Consider swapping the args to be more consistent with functions like
memcpy() where the destination is the first arg and source is the
second.

> +{
> +	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 +1320,164 @@ 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_check(struct seq_file *seq, 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;
> +
> +	if (!vdev->mig_ops || !migf) {
> +		seq_printf(seq, "%s\n", "device not support debugfs!");

"device does not support debugfs"?

> +		return -EINVAL;
> +	}
> +
> +	/* If device not opened, the debugfs operation will trigger calltrace */
> +	if (!vdev->open_count) {
> +		seq_printf(seq, "%s\n", "device not opened!");
> +		return -EINVAL;
> +	}

What prevents this from racing release of the device?

> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_debug_io(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;

A tab sneaked in here.

> +	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;
> +	u64 value;
> +	int ret;
> +
> +	ret = hisi_acc_vf_debug_check(seq, vdev);
> +	if (ret)
> +		goto io_err;
> +
> +	ret = qm_wait_dev_not_ready(vf_qm);
> +	if (ret) {
> +		seq_printf(seq, "%s\n", "VF device not ready!");
> +		goto io_err;
> +	}
> +
> +	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
> +	seq_printf(seq, "%s:0x%llx\n", "debug mailbox val", value);
> +
> +io_err:
> +	return 0;

A goto that simply returns seems unnecessary vs return at the error
condition.  Also why don't we return the errno for error cases?  Do we
even need seq_printf() calls for error cases?

> +}
> +
> +static int hisi_acc_vf_debug_save(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;

Another tab.

> +	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;
> +	int ret;
> +
> +	ret = hisi_acc_vf_debug_check(seq, vdev);
> +	if (ret)
> +		goto save_err;
> +
> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
> +	if (ret) {
> +		seq_printf(seq, "%s\n", "failed to save device data!");
> +		goto save_err;
> +	}
> +	seq_printf(seq, "%s\n", "successful to save device data!");
> +
> +save_err:
> +	return 0;
> +}
> +
> +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;

Tab.

> +	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_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
> +				(unsigned char *)&debug_migf->vf_data,
> +				vf_data_sz, false);
> +	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;

Tab.

> +	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 dentry *vfio_dev_migration = NULL;
> +	struct dentry *vfio_hisi_acc = NULL;
> +	struct device *dev = vdev->dev;
> +	void *migf = NULL;
> +
> +	if (!debugfs_initialized())
> +		return 0;
> +
> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
> +	if (!migf)
> +		return -ENOMEM;
> +	hisi_acc_vdev->debug_migf = migf;
> +
> +	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
> +	if (!vfio_dev_migration) {
> +		dev_err(dev, "failed to lookup migration debugfs file!\n");
> +		return -ENODEV;
> +	}
> +
> +	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
> +	debugfs_create_devm_seqfile(dev, "data", vfio_hisi_acc,
> +				  hisi_acc_vf_data_read);
> +	debugfs_create_devm_seqfile(dev, "attr", vfio_hisi_acc,
> +				  hisi_acc_vf_attr_read);
> +	debugfs_create_devm_seqfile(dev, "io_test", vfio_hisi_acc,
> +				  hisi_acc_vf_debug_io);
> +	debugfs_create_devm_seqfile(dev, "save", vfio_hisi_acc,
> +				  hisi_acc_vf_debug_save);
> +
> +	return 0;
> +}
> +
> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> +{
> +	if (!debugfs_initialized())
> +		return;
> +
> +	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);
> @@ -1323,6 +1498,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>  	}
>  
>  	vfio_pci_core_finish_enable(vdev);
> +
>  	return 0;
>  }
>  
> @@ -1420,9 +1596,14 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>  	if (ret)
>  		goto out_put_vdev;
> +
> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
> +		hisi_acc_vfio_debug_init(hisi_acc_vdev);
>  	return 0;
>  
>  out_put_vdev:
> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
> +		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);

Why do we need this?  There's no case where debug_init occurs before
this goto.

>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>  	return ret;
>  }
> @@ -1431,6 +1612,7 @@ 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,
> +};

Unused.

Thanks,
Alex

> +
>  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 */

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2023/7/15 6:07, Alex Williamson wrote:
> On Fri, 30 Jun 2023 17:24:56 +0800
> liulongfang <liulongfang@huawei.com> wrote:
> 
>> From: Longfang Liu <liulongfang@huawei.com>
>>
>> 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.
>>
>> After registering the HiSilicon accelerator device on the debugfs
>> framework of live migration of vfio, a directory file "hisi_acc"
>> of debugfs is created, and then three debug function files are
>> created in this directory:
>>
>> data file: used to get the migration data from the driver
>> attr file: used to get device attributes parameters from the driver
>> save file: used to read the data of the live migration device and save
>> it to the driver.
>> io_test: used to test IO read and write for the driver.
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 182 ++++++++++++++++++
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 ++
>>  2 files changed, 193 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..a6f5e94bfaf2 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)
> 
> Consider swapping the args to be more consistent with functions like
> memcpy() where the destination is the first arg and source is the
> second.>
OK, These two parameters can be swapped.

>> +{
>> +	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 +1320,164 @@ 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_check(struct seq_file *seq, 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;
>> +
>> +	if (!vdev->mig_ops || !migf) {
>> +		seq_printf(seq, "%s\n", "device not support debugfs!");
> 
> "device does not support debugfs"?
> 
OK,"device does not support live migration"

>> +		return -EINVAL;
>> +	}
>> +
>> +	/* If device not opened, the debugfs operation will trigger calltrace */
>> +	if (!vdev->open_count) {
>> +		seq_printf(seq, "%s\n", "device not opened!");
>> +		return -EINVAL;
>> +	}
> 
> What prevents this from racing release of the device?
>
Now there are only read operations for debugfs. The open_count here only needs
to be used to prevent read operations when the device is not opened.
There is no need to deal with competition issues.

>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_debug_io(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;
> 
> A tab sneaked in here.
> 
Thanks.

>> +	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;
>> +	u64 value;
>> +	int ret;
>> +
>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>> +	if (ret)
>> +		goto io_err;
>> +
>> +	ret = qm_wait_dev_not_ready(vf_qm);
>> +	if (ret) {
>> +		seq_printf(seq, "%s\n", "VF device not ready!");
>> +		goto io_err;
>> +	}
>> +
>> +	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
>> +	seq_printf(seq, "%s:0x%llx\n", "debug mailbox val", value);
>> +
>> +io_err:
>> +	return 0;
> 
> A goto that simply returns seems unnecessary vs return at the error
Ok, no need to use goto here. The following one is also handled in the same way.

> condition.  Also why don't we return the errno for error cases?  Do we> even need seq_printf() calls for error cases?
>

Added logging of seq_printf only on critical steps.

>> +}
>> +
>> +static int hisi_acc_vf_debug_save(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;
> 
> Another tab.
> 
OK.

>> +	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;
>> +	int ret;
>> +
>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>> +	if (ret)
>> +		goto save_err;
>> +
>> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
>> +	if (ret) {
>> +		seq_printf(seq, "%s\n", "failed to save device data!");
>> +		goto save_err;
>> +	}
>> +	seq_printf(seq, "%s\n", "successful to save device data!");
>> +
>> +save_err:
>> +	return 0;
>> +}
>> +
>> +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;
> 
> Tab.
> 
OK.
>> +	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_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
>> +				(unsigned char *)&debug_migf->vf_data,
>> +				vf_data_sz, false);
>> +	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;
> 
> Tab.
> 
OK.
>> +	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 dentry *vfio_dev_migration = NULL;
>> +	struct dentry *vfio_hisi_acc = NULL;
>> +	struct device *dev = vdev->dev;
>> +	void *migf = NULL;
>> +
>> +	if (!debugfs_initialized())
>> +		return 0;
>> +
>> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
>> +	if (!migf)
>> +		return -ENOMEM;
>> +	hisi_acc_vdev->debug_migf = migf;
>> +
>> +	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
>> +	if (!vfio_dev_migration) {
>> +		dev_err(dev, "failed to lookup migration debugfs file!\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
>> +	debugfs_create_devm_seqfile(dev, "data", vfio_hisi_acc,
>> +				  hisi_acc_vf_data_read);
>> +	debugfs_create_devm_seqfile(dev, "attr", vfio_hisi_acc,
>> +				  hisi_acc_vf_attr_read);
>> +	debugfs_create_devm_seqfile(dev, "io_test", vfio_hisi_acc,
>> +				  hisi_acc_vf_debug_io);
>> +	debugfs_create_devm_seqfile(dev, "save", vfio_hisi_acc,
>> +				  hisi_acc_vf_debug_save);
>> +
>> +	return 0;
>> +}
>> +
>> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>> +{
>> +	if (!debugfs_initialized())
>> +		return;
>> +
>> +	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);
>> @@ -1323,6 +1498,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>>  	}
>>  
>>  	vfio_pci_core_finish_enable(vdev);
>> +
>>  	return 0;
>>  }
>>  
>> @@ -1420,9 +1596,14 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>>  	if (ret)
>>  		goto out_put_vdev;
>> +
>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>> +		hisi_acc_vfio_debug_init(hisi_acc_vdev);
>>  	return 0;
>>  
>>  out_put_vdev:
>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>> +		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
> 
> Why do we need this?  There's no case where debug_init occurs before
> this goto.
>

Yes. These two lines are not needed here.

>>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>>  	return ret;
>>  }
>> @@ -1431,6 +1612,7 @@ 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,
>> +};
> 
> Unused.
> 
OK.

> Thanks,
> Alex
> 
Thanks,
Longfang.
>> +
>>  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 */
> 
> .
> 

[PATCH v11 4/4] Documentation: add debugfs description for vfio

[liulongfang]

From: Longfang Liu <liulongfang@huawei.com>

1.Add two debugfs document description file to help users understand
how to use the accelerator live migration driver's debugfs.
2.Update the file paths that need to be maintained in MAINTAINERS

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
 Documentation/ABI/testing/debugfs-vfio        | 25 +++++++++++++++
 MAINTAINERS                                   |  2 ++
 3 files changed, 59 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
 create mode 100644 Documentation/ABI/testing/debugfs-vfio

diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
new file mode 100644
index 000000000000..0dfc7008a3e1
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-hisi-migration
@@ -0,0 +1,32 @@
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/data
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration data of the vfio device.
+		The output format of the data is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/attr
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration attributes of the vfio device.
+		The output format of the attributes is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/io_test
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Trigger the HiSilicon accelerator device to perform
+		the io test through the read operation, and directly output
+		the test result.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/save
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Trigger the Hisilicon accelerator device to perform
+		the state saving operation of live migration through the read
+		operation, and directly output the operation result.
+
diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
new file mode 100644
index 000000000000..e2132a2f602b
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-vfio
@@ -0,0 +1,25 @@
+What:		/sys/kernel/debug/vfio
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	This debugfs file directory is used for debugging
+		of vfio devices.
+		Each device can create a device subdirectory under this
+		directory by referencing the public registration interface.
+
+What:		/sys/kernel/debug/vfio/<device>/migration
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	This debugfs file directory is used for debugging
+		of vfio devices that support live migration.
+		The debugfs of each vfio device that supports live migration
+		could be created under this directory.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/state
+Date:		June 2023
+KernelVersion:  6.4
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration status of the vfio device.
+		The status of these live migrations includes:
+		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.
diff --git a/MAINTAINERS b/MAINTAINERS
index ce6ac552d8f6..bdd6a5e7350f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22098,6 +22098,7 @@ L:	kvm@vger.kernel.org
 S:	Maintained
 T:	git https://github.com/awilliam/linux-vfio.git
 F:	Documentation/ABI/testing/sysfs-devices-vfio-dev
+F:	Documentation/ABI/testing/debugfs-vfio
 F:	Documentation/driver-api/vfio.rst
 F:	drivers/vfio/
 F:	include/linux/vfio.h
@@ -22115,6 +22116,7 @@ M:	Longfang Liu <liulongfang@huawei.com>
 M:	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
 L:	kvm@vger.kernel.org
 S:	Maintained
+F:	Documentation/ABI/testing/debugfs-hisi-migration
 F:	drivers/vfio/pci/hisilicon/
 
 VFIO MEDIATED DEVICE DRIVERS
-- 
2.24.0

Re: [PATCH v11 4/4] Documentation: add debugfs description for vfio

[Alex Williamson]

On Fri, 30 Jun 2023 17:24:57 +0800
liulongfang <liulongfang@huawei.com> wrote:

> From: Longfang Liu <liulongfang@huawei.com>
> 
> 1.Add two debugfs document description file to help users understand
> how to use the accelerator live migration driver's debugfs.
> 2.Update the file paths that need to be maintained in MAINTAINERS
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
>  Documentation/ABI/testing/debugfs-vfio        | 25 +++++++++++++++
>  MAINTAINERS                                   |  2 ++
>  3 files changed, 59 insertions(+)
>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
>  create mode 100644 Documentation/ABI/testing/debugfs-vfio
> 
> diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
> new file mode 100644
> index 000000000000..0dfc7008a3e1
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-hisi-migration
> @@ -0,0 +1,32 @@
> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/data
> +Date:		June 2023
> +KernelVersion:  6.4

At best we'd be looking at introducing this for 6.6, where it might get
into mainline in late August for all of these.

> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	Read the live migration data of the vfio device.
> +		The output format of the data is defined by the live
> +		migration driver.

This attribute is specific to the hisi_acc driver, so should the data
be detailed here?

> +
> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/attr
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	Read the live migration attributes of the vfio device.
> +		The output format of the attributes is defined by the live
> +		migration driver.

Same here.

> +
> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/io_test
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	Trigger the HiSilicon accelerator device to perform
> +		the io test through the read operation, and directly output
> +		the test result.

This has essentially been reduced to reading the mailbox value AIUI,
should this simply document that and the resulting possible values?

> +
> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/save
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	Trigger the Hisilicon accelerator device to perform
> +		the state saving operation of live migration through the read
> +		operation, and directly output the operation result.

It's unclear to me why we need to parse a returned string from the
debugfs seq file rather than read returns zero on success or errno on
failure.

> +
> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
> new file mode 100644
> index 000000000000..e2132a2f602b
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-vfio
> @@ -0,0 +1,25 @@
> +What:		/sys/kernel/debug/vfio
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	This debugfs file directory is used for debugging
> +		of vfio devices.
> +		Each device can create a device subdirectory under this
> +		directory by referencing the public registration interface.

This suggests it's the device driver's responsibility to create those
subdirectories, but we've delegated that to the core currently.  Maybe
this is suggesting that each driver can create a driver subdirectory
under the core created device directory?

Thanks,
Alex

> +
> +What:		/sys/kernel/debug/vfio/<device>/migration
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	This debugfs file directory is used for debugging
> +		of vfio devices that support live migration.
> +		The debugfs of each vfio device that supports live migration
> +		could be created under this directory.
> +
> +What:		/sys/kernel/debug/vfio/<device>/migration/state
> +Date:		June 2023
> +KernelVersion:  6.4
> +Contact:	Longfang Liu <liulongfang@huawei.com>
> +Description:	Read the live migration status of the vfio device.
> +		The status of these live migrations includes:
> +		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ce6ac552d8f6..bdd6a5e7350f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22098,6 +22098,7 @@ L:	kvm@vger.kernel.org
>  S:	Maintained
>  T:	git https://github.com/awilliam/linux-vfio.git
>  F:	Documentation/ABI/testing/sysfs-devices-vfio-dev
> +F:	Documentation/ABI/testing/debugfs-vfio
>  F:	Documentation/driver-api/vfio.rst
>  F:	drivers/vfio/
>  F:	include/linux/vfio.h
> @@ -22115,6 +22116,7 @@ M:	Longfang Liu <liulongfang@huawei.com>
>  M:	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>  L:	kvm@vger.kernel.org
>  S:	Maintained
> +F:	Documentation/ABI/testing/debugfs-hisi-migration
>  F:	drivers/vfio/pci/hisilicon/
>  
>  VFIO MEDIATED DEVICE DRIVERS

Re: [PATCH v11 4/4] Documentation: add debugfs description for vfio

[liulongfang]

On 2023/7/15 6:07, Alex Williamson write:
> On Fri, 30 Jun 2023 17:24:57 +0800
> liulongfang <liulongfang@huawei.com> wrote:
> 
>> From: Longfang Liu <liulongfang@huawei.com>
>>
>> 1.Add two debugfs document description file to help users understand
>> how to use the accelerator live migration driver's debugfs.
>> 2.Update the file paths that need to be maintained in MAINTAINERS
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
>>  Documentation/ABI/testing/debugfs-vfio        | 25 +++++++++++++++
>>  MAINTAINERS                                   |  2 ++
>>  3 files changed, 59 insertions(+)
>>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
>>  create mode 100644 Documentation/ABI/testing/debugfs-vfio
>>
>> diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
>> new file mode 100644
>> index 000000000000..0dfc7008a3e1
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-hisi-migration
>> @@ -0,0 +1,32 @@
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/data
>> +Date:		June 2023
>> +KernelVersion:  6.4
> 
> At best we'd be looking at introducing this for 6.6, where it might get
> into mainline in late August for all of these.
>
OK, so does this KernelVersion need to be marked as 6.6?

>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Read the live migration data of the vfio device.
>> +		The output format of the data is defined by the live
>> +		migration driver.
> 
> This attribute is specific to the hisi_acc driver, so should the data
> be detailed here?
> 
OK I'll add a description of the role type of the data.

>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/attr
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Read the live migration attributes of the vfio device.
>> +		The output format of the attributes is defined by the live
>> +		migration driver.
> 
> Same here.
> 
OK.

>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/io_test
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Trigger the HiSilicon accelerator device to perform
>> +		the io test through the read operation, and directly output
>> +		the test result.
> 
> This has essentially been reduced to reading the mailbox value AIUI,
> should this simply document that and the resulting possible values?
>
OK,This can add information.

>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/save
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Trigger the Hisilicon accelerator device to perform
>> +		the state saving operation of live migration through the read
>> +		operation, and directly output the operation result.
> 
> It's unclear to me why we need to parse a returned string from the
> debugfs seq file rather than read returns zero on success or errno on
> failure.
>
It is impossible to know the reason for the failure just by returning true or false.
Through the string obtained by seq_printf, the user can know the cause of the error.

>> +
>> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
>> new file mode 100644
>> index 000000000000..e2132a2f602b
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-vfio
>> @@ -0,0 +1,25 @@
>> +What:		/sys/kernel/debug/vfio
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	This debugfs file directory is used for debugging
>> +		of vfio devices.
>> +		Each device can create a device subdirectory under this
>> +		directory by referencing the public registration interface.
> 
> This suggests it's the device driver's responsibility to create those
> subdirectories, but we've delegated that to the core currently.  Maybe
> this is suggesting that each driver can create a driver subdirectory
> under the core created device directory?
>
OK This vfio directory file is added in vfio_main. All vfio devices share this
device directory.
Then each device creates its own device directory with its own dev_name.

Thanks.
Longfang.
> Thanks,
> Alex
> 
>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	This debugfs file directory is used for debugging
>> +		of vfio devices that support live migration.
>> +		The debugfs of each vfio device that supports live migration
>> +		could be created under this directory.
>> +
>> +What:		/sys/kernel/debug/vfio/<device>/migration/state
>> +Date:		June 2023
>> +KernelVersion:  6.4
>> +Contact:	Longfang Liu <liulongfang@huawei.com>
>> +Description:	Read the live migration status of the vfio device.
>> +		The status of these live migrations includes:
>> +		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index ce6ac552d8f6..bdd6a5e7350f 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -22098,6 +22098,7 @@ L:	kvm@vger.kernel.org
>>  S:	Maintained
>>  T:	git https://github.com/awilliam/linux-vfio.git
>>  F:	Documentation/ABI/testing/sysfs-devices-vfio-dev
>> +F:	Documentation/ABI/testing/debugfs-vfio
>>  F:	Documentation/driver-api/vfio.rst
>>  F:	drivers/vfio/
>>  F:	include/linux/vfio.h
>> @@ -22115,6 +22116,7 @@ M:	Longfang Liu <liulongfang@huawei.com>
>>  M:	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>>  L:	kvm@vger.kernel.org
>>  S:	Maintained
>> +F:	Documentation/ABI/testing/debugfs-hisi-migration
>>  F:	drivers/vfio/pci/hisilicon/
>>  
>>  VFIO MEDIATED DEVICE DRIVERS
> 
> .
> 

Re: [PATCH v11 0/4] add debugfs to migration driver

[liulongfang]

On 2023/6/30 17:24, liulongfang wrote:
> Add a debugfs function to the migration driver in VFIO to provide
> a step-by-step test function for the migration driver.
> 
> When the execution of live migration fails, the user can view the
> status and data during the migration process separately from the
> source and the destination, which is convenient for users to analyze
> and locate problems.
> 
> Changes v10 -> v11
> 	Delete the device restore function in debugfs.
> 
> Changes v9 -> v10
> 	Update the debugfs file of the live migration driver.
> 
> Changes v8 -> v9
> 	Update the debugfs directory structure of vfio.
> 
> Changes v7 -> v8
> 	Add support for platform devices.
> 
> Changes v6 -> v7
> 	Fix some code style issues.
> 
> Changes v5 -> v6
> 	Control the creation of debugfs through the CONFIG_DEBUG_FS.
> 
> Changes v4 -> v5
> 	Remove the newly added vfio_migration_ops and use seq_printf
> 	to optimize the implementation of debugfs.
> 
> Changes v3 -> v4
> 	Change the migration_debug_operate interface to debug_root file.
> 
> Changes v2 -> v3
> 	Extend the debugfs function from hisilicon device to vfio.
> 
> Changes v1 -> v2
> 	Change the registration method of root_debugfs to register
> 	with module initialization. 
> 
> Longfang Liu (4):
>   vfio/migration: Add debugfs to live migration driver
>   hisi_acc_vfio_pci: extract public functions for container_of
>   hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
>   Documentation: add debugfs description for vfio
> 
>  .../ABI/testing/debugfs-hisi-migration        |  32 +++
>  Documentation/ABI/testing/debugfs-vfio        |  25 +++
>  MAINTAINERS                                   |   2 +
>  drivers/vfio/Makefile                         |   1 +
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 203 +++++++++++++++++-
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
>  drivers/vfio/vfio.h                           |  14 ++
>  drivers/vfio/vfio_debugfs.c                   |  78 +++++++
>  drivers/vfio/vfio_main.c                      |   9 +-
>  include/linux/vfio.h                          |   7 +
>  10 files changed, 371 insertions(+), 11 deletions(-)
>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
>  create mode 100644 Documentation/ABI/testing/debugfs-vfio
>  create mode 100644 drivers/vfio/vfio_debugfs.c
> 

Hi, Alex
Can you help me to review these patches ?

Thanks,
Longfang.

[PATCH v11 0/4] debugfs to hisilicon migration driver

[Longfang Liu]

Add a debugfs function to the hisilicon migration driver in VFIO to
provide intermediate state values and data during device migration.

When the execution of live migration fails, the user can view the
status and data during the migration process separately from the
source and the destination, which is convenient for users to analyze
and locate problems.

Changes v10 -> v11
	Update conditions for debugfs registration

Changes v9 -> v10
	Optimize symmetry processing of mutex

Changes v8 -> v9
	Added device enable mutex

Changes v7 -> v8
	Delete unnecessary information

Changes v6 -> v7
	Remove redundant kernel error log printing and
	remove unrelated bugfix code

Changes v5 -> v6
	Modify log output calling error

Changes v4 -> v5
	Adjust the descriptioniptionbugfs file directory

Changes v3 -> v4
	Rebased on kernel6.9

Changes 2 -> v3
	Solve debugfs serialization problem.

Changes v1 -> v2
	Solve the racy problem of io_base.

Longfang Liu (4):
  hisi_acc_vfio_pci: extract public functions for container_of
  hisi_acc_vfio_pci: create subfunction for data reading
  hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
  Documentation: add debugfs description for hisi migration

 .../ABI/testing/debugfs-hisi-migration        |  25 ++
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 279 ++++++++++++++++--
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   7 +
 3 files changed, 280 insertions(+), 31 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration

-- 
2.24.0

[PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Longfang Liu]

On the debugfs framework of VFIO, if the CONFIG_VFIO_DEBUGFS macro is
enabled, the debug function is registered for the live migration driver
of the HiSilicon accelerator device.

After registering the HiSilicon accelerator device on the debugfs
framework of live migration of vfio, a directory file "hisi_acc"
of debugfs is created, and then three debug function files are
created in this directory:

   vfio
    |
    +---<dev_name1>
    |    +---migration
    |        +--state
    |        +--hisi_acc
    |            +--dev_data
    |            +--migf_data
    |            +--cmd_state
    |
    +---<dev_name2>
         +---migration
             +--state
             +--hisi_acc
                 +--dev_data
                 +--migf_data
                 +--cmd_state

dev_data file: read device data that needs to be migrated from the
current device in real time
migf_data file: read the migration data of the last live migration
from the current driver.
cmd_state: used to get the cmd channel state for the device.

+----------------+        +--------------+       +---------------+
| migration dev  |        |   src  dev   |       |   dst  dev    |
+-------+--------+        +------+-------+       +-------+-------+
        |                        |                       |
        |                 +------v-------+       +-------v-------+
        |                 |  saving_migf |       | resuming_migf |
  read  |                 |     file     |       |     file      |
        |                 +------+-------+       +-------+-------+
        |                        |          copy         |
        |                        +------------+----------+
        |                                     |
+-------v--------+                    +-------v--------+
|   data buffer  |                    |   debug_migf   |
+-------+--------+                    +-------+--------+
        |                                     |
   cat  |                                 cat |
+-------v--------+                    +-------v--------+
|   dev_data     |                    |   migf_data    |
+----------------+                    +----------------+

When accessing debugfs, user can obtain the most recent status data
of the device through the "dev_data" file. It can read recent
complete status data of the device. If the current device is being
migrated, it will wait for it to complete.
The data for the last completed migration function will be stored
in debug_migf. Users can read it via "migf_data".

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 204 ++++++++++++++++++
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   7 +
 2 files changed, 211 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index a8c53952d82e..0577d4ddfb34 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -627,15 +627,30 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
 	mutex_unlock(&migf->lock);
 }
 
+static void hisi_acc_debug_migf_copy(struct hisi_acc_vf_core_device *hisi_acc_vdev,
+	struct hisi_acc_vf_migration_file *src_migf)
+{
+	struct hisi_acc_vf_migration_file *dst_migf = hisi_acc_vdev->debug_migf;
+
+	if (!dst_migf)
+		return;
+
+	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_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
 {
 	if (hisi_acc_vdev->resuming_migf) {
+		hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->resuming_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_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->saving_migf);
 		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
 		fput(hisi_acc_vdev->saving_migf->filp);
 		hisi_acc_vdev->saving_migf = NULL;
@@ -1294,6 +1309,140 @@ 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_check(struct seq_file *seq, 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;
+	int ret;
+
+	lockdep_assert_held(&hisi_acc_vdev->open_mutex);
+	/*
+	 * When the device is not opened, the io_base is not mapped.
+	 * The driver cannot perform device read and write operations.
+	 */
+	if (!hisi_acc_vdev->dev_opened) {
+		seq_printf(seq, "device not opened!\n");
+		return -EINVAL;
+	}
+
+	ret = qm_wait_dev_not_ready(vf_qm);
+	if (ret) {
+		seq_printf(seq, "VF device not ready!\n");
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int hisi_acc_vf_debug_cmd(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_qm *vf_qm = &hisi_acc_vdev->vf_qm;
+	u64 value;
+	int ret;
+
+	mutex_lock(&hisi_acc_vdev->open_mutex);
+	ret = hisi_acc_vf_debug_check(seq, vdev);
+	if (ret) {
+		mutex_unlock(&hisi_acc_vdev->open_mutex);
+		return ret;
+	}
+
+	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
+	if (value == QM_MB_CMD_NOT_READY) {
+		mutex_unlock(&hisi_acc_vdev->open_mutex);
+		seq_printf(seq, "mailbox cmd channel not ready!\n");
+		return -EINVAL;
+	}
+	mutex_unlock(&hisi_acc_vdev->open_mutex);
+	seq_printf(seq, "mailbox cmd channel ready!\n");
+
+	return 0;
+}
+
+static int hisi_acc_vf_dev_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);
+	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
+	struct acc_vf_data *vf_data = NULL;
+	int ret;
+
+	mutex_lock(&hisi_acc_vdev->open_mutex);
+	ret = hisi_acc_vf_debug_check(seq, vdev);
+	if (ret) {
+		mutex_unlock(&hisi_acc_vdev->open_mutex);
+		return ret;
+	}
+
+	mutex_lock(&hisi_acc_vdev->state_mutex);
+	vf_data = kzalloc(sizeof(struct acc_vf_data), GFP_KERNEL);
+	if (!vf_data) {
+		ret = -ENOMEM;
+		goto mutex_release;
+	}
+
+	vf_data->vf_qm_state = hisi_acc_vdev->vf_qm_state;
+	ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, vf_data);
+	if (ret)
+		goto migf_err;
+
+	seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,
+			(unsigned char *)vf_data,
+			vf_data_sz, false);
+
+	seq_printf(seq,
+		 "acc device:\n"
+		 "guest driver load: %u\n"
+		 "data size: %lu\n",
+		 hisi_acc_vdev->vf_qm_state,
+		 sizeof(struct acc_vf_data));
+
+migf_err:
+	kfree(vf_data);
+mutex_release:
+	mutex_unlock(&hisi_acc_vdev->open_mutex);
+	mutex_unlock(&hisi_acc_vdev->state_mutex);
+
+	return ret;
+}
+
+static int hisi_acc_vf_migf_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);
+	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
+	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
+
+	/* Check whether the live migration operation has been performed */
+	if (debug_migf->total_length < QM_MATCH_SIZE) {
+		seq_printf(seq, "device not migrated!\n");
+		return -EAGAIN;
+	}
+
+	seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
+			(unsigned char *)&debug_migf->vf_data,
+			vf_data_sz, false);
+
+	seq_printf(seq,
+		 "acc device:\n"
+		 "guest driver load: %u\n"
+		 "device opened: %d\n"
+		 "migrate data length: %lu\n",
+		 hisi_acc_vdev->vf_qm_state,
+		 hisi_acc_vdev->dev_opened,
+		 debug_migf->total_length);
+
+	return 0;
+}
+
 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);
@@ -1305,12 +1454,16 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 		return ret;
 
 	if (core_vdev->mig_ops) {
+		mutex_lock(&hisi_acc_vdev->open_mutex);
 		ret = hisi_acc_vf_qm_init(hisi_acc_vdev);
 		if (ret) {
+			mutex_unlock(&hisi_acc_vdev->open_mutex);
 			vfio_pci_core_disable(vdev);
 			return ret;
 		}
 		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
+		hisi_acc_vdev->dev_opened = true;
+		mutex_unlock(&hisi_acc_vdev->open_mutex);
 	}
 
 	vfio_pci_core_finish_enable(vdev);
@@ -1322,7 +1475,10 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
 	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
 
+	mutex_lock(&hisi_acc_vdev->open_mutex);
+	hisi_acc_vdev->dev_opened = false;
 	iounmap(vf_qm->io_base);
+	mutex_unlock(&hisi_acc_vdev->open_mutex);
 	vfio_pci_core_close_device(core_vdev);
 }
 
@@ -1342,6 +1498,7 @@ static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
 	hisi_acc_vdev->pf_qm = pf_qm;
 	hisi_acc_vdev->vf_dev = pdev;
 	mutex_init(&hisi_acc_vdev->state_mutex);
+	mutex_init(&hisi_acc_vdev->open_mutex);
 
 	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY;
 	core_vdev->mig_ops = &hisi_acc_vfio_pci_migrn_state_ops;
@@ -1387,6 +1544,50 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
 	.detach_ioas = vfio_iommufd_physical_detach_ioas,
 };
 
+static void 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 dentry *vfio_dev_migration = NULL;
+	struct dentry *vfio_hisi_acc = NULL;
+	struct device *dev = vdev->dev;
+	void *migf = NULL;
+
+	if (!debugfs_initialized() ||
+	    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
+		return;
+
+	if (vdev->ops != &hisi_acc_vfio_pci_migrn_ops)
+		return;
+
+	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
+	if (!vfio_dev_migration) {
+		dev_err(dev, "failed to lookup migration debugfs file!\n");
+		return;
+	}
+
+	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
+	if (!migf)
+		return;
+	hisi_acc_vdev->debug_migf = migf;
+
+	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
+	debugfs_create_devm_seqfile(dev, "dev_data", vfio_hisi_acc,
+				  hisi_acc_vf_dev_read);
+	debugfs_create_devm_seqfile(dev, "migf_data", vfio_hisi_acc,
+				  hisi_acc_vf_migf_read);
+	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
+				  hisi_acc_vf_debug_cmd);
+}
+
+static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
+{
+	/* If migrn_ops is not used, debug_migf is NULL */
+	if (hisi_acc_vdev->debug_migf) {
+		kfree(hisi_acc_vdev->debug_migf);
+		hisi_acc_vdev->debug_migf = NULL;
+	}
+}
+
 static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct hisi_acc_vf_core_device *hisi_acc_vdev;
@@ -1413,6 +1614,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
 	if (ret)
 		goto out_put_vdev;
+
+	hisi_acc_vfio_debug_init(hisi_acc_vdev);
 	return 0;
 
 out_put_vdev:
@@ -1425,6 +1628,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
 	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
 
 	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
+	hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
 	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 5bab46602fad..2a78ffd060c3 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
@@ -32,6 +32,7 @@
 #define QM_SQC_VFT_BASE_MASK_V2		GENMASK(15, 0)
 #define QM_SQC_VFT_NUM_SHIFT_V2		45
 #define QM_SQC_VFT_NUM_MASK_V2		GENMASK(9, 0)
+#define QM_MB_CMD_NOT_READY	0xffffffff
 
 /* RW regs */
 #define QM_REGS_MAX_LEN		7
@@ -99,6 +100,8 @@ struct hisi_acc_vf_migration_file {
 struct hisi_acc_vf_core_device {
 	struct vfio_pci_core_device core_device;
 	u8 match_done;
+	/* To make sure the device is opened */
+	bool dev_opened;
 
 	/* For migration state */
 	struct mutex state_mutex;
@@ -111,5 +114,9 @@ struct hisi_acc_vf_core_device {
 	int vf_id;
 	struct hisi_acc_vf_migration_file *resuming_migf;
 	struct hisi_acc_vf_migration_file *saving_migf;
+
+	/* To save migration data */
+	struct hisi_acc_vf_migration_file *debug_migf;
+	struct mutex open_mutex;
 };
 #endif /* HISI_ACC_VFIO_PCI_H */
-- 
2.24.0

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Alex Williamson]

On Fri, 25 Oct 2024 17:01:42 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> On the debugfs framework of VFIO, if the CONFIG_VFIO_DEBUGFS macro is
> enabled, the debug function is registered for the live migration driver
> of the HiSilicon accelerator device.
> 
> After registering the HiSilicon accelerator device on the debugfs
> framework of live migration of vfio, a directory file "hisi_acc"
> of debugfs is created, and then three debug function files are
> created in this directory:
> 
>    vfio
>     |
>     +---<dev_name1>
>     |    +---migration
>     |        +--state
>     |        +--hisi_acc
>     |            +--dev_data
>     |            +--migf_data
>     |            +--cmd_state
>     |
>     +---<dev_name2>
>          +---migration
>              +--state
>              +--hisi_acc
>                  +--dev_data
>                  +--migf_data
>                  +--cmd_state
> 
> dev_data file: read device data that needs to be migrated from the
> current device in real time
> migf_data file: read the migration data of the last live migration
> from the current driver.
> cmd_state: used to get the cmd channel state for the device.
> 
> +----------------+        +--------------+       +---------------+
> | migration dev  |        |   src  dev   |       |   dst  dev    |
> +-------+--------+        +------+-------+       +-------+-------+
>         |                        |                       |
>         |                 +------v-------+       +-------v-------+
>         |                 |  saving_migf |       | resuming_migf |
>   read  |                 |     file     |       |     file      |
>         |                 +------+-------+       +-------+-------+
>         |                        |          copy         |
>         |                        +------------+----------+
>         |                                     |
> +-------v--------+                    +-------v--------+
> |   data buffer  |                    |   debug_migf   |
> +-------+--------+                    +-------+--------+
>         |                                     |
>    cat  |                                 cat |
> +-------v--------+                    +-------v--------+
> |   dev_data     |                    |   migf_data    |
> +----------------+                    +----------------+
> 
> When accessing debugfs, user can obtain the most recent status data
> of the device through the "dev_data" file. It can read recent
> complete status data of the device. If the current device is being
> migrated, it will wait for it to complete.
> The data for the last completed migration function will be stored
> in debug_migf. Users can read it via "migf_data".
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 204 ++++++++++++++++++
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   7 +
>  2 files changed, 211 insertions(+)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index a8c53952d82e..0577d4ddfb34 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -627,15 +627,30 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>  	mutex_unlock(&migf->lock);
>  }
>  
> +static void hisi_acc_debug_migf_copy(struct hisi_acc_vf_core_device *hisi_acc_vdev,
> +	struct hisi_acc_vf_migration_file *src_migf)
> +{
> +	struct hisi_acc_vf_migration_file *dst_migf = hisi_acc_vdev->debug_migf;
> +
> +	if (!dst_migf)
> +		return;
> +
> +	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_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>  {
>  	if (hisi_acc_vdev->resuming_migf) {
> +		hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->resuming_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_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->saving_migf);
>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>  		fput(hisi_acc_vdev->saving_migf->filp);
>  		hisi_acc_vdev->saving_migf = NULL;
> @@ -1294,6 +1309,140 @@ 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_check(struct seq_file *seq, 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;
> +	int ret;
> +
> +	lockdep_assert_held(&hisi_acc_vdev->open_mutex);
> +	/*
> +	 * When the device is not opened, the io_base is not mapped.
> +	 * The driver cannot perform device read and write operations.
> +	 */
> +	if (!hisi_acc_vdev->dev_opened) {
> +		seq_printf(seq, "device not opened!\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = qm_wait_dev_not_ready(vf_qm);
> +	if (ret) {
> +		seq_printf(seq, "VF device not ready!\n");
> +		return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_debug_cmd(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_qm *vf_qm = &hisi_acc_vdev->vf_qm;
> +	u64 value;
> +	int ret;
> +
> +	mutex_lock(&hisi_acc_vdev->open_mutex);
> +	ret = hisi_acc_vf_debug_check(seq, vdev);
> +	if (ret) {
> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
> +		return ret;
> +	}
> +
> +	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
> +	if (value == QM_MB_CMD_NOT_READY) {
> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
> +		seq_printf(seq, "mailbox cmd channel not ready!\n");
> +		return -EINVAL;
> +	}
> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
> +	seq_printf(seq, "mailbox cmd channel ready!\n");
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_dev_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);
> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
> +	struct acc_vf_data *vf_data = NULL;

Nit, this initialization is unnecessary.

> +	int ret;
> +
> +	mutex_lock(&hisi_acc_vdev->open_mutex);
> +	ret = hisi_acc_vf_debug_check(seq, vdev);
> +	if (ret) {
> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
> +		return ret;
> +	}
> +
> +	mutex_lock(&hisi_acc_vdev->state_mutex);
> +	vf_data = kzalloc(sizeof(struct acc_vf_data), GFP_KERNEL);
> +	if (!vf_data) {
> +		ret = -ENOMEM;
> +		goto mutex_release;
> +	}
> +
> +	vf_data->vf_qm_state = hisi_acc_vdev->vf_qm_state;
> +	ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, vf_data);
> +	if (ret)
> +		goto migf_err;
> +
> +	seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,
> +			(unsigned char *)vf_data,

Casting to (const void *) would match the prototype.  This line should
also wrap to just inside the opening parenthesis of the previous line, 2
tabs, 5 spaces.

> +			vf_data_sz, false);
> +
> +	seq_printf(seq,
> +		 "acc device:\n"
> +		 "guest driver load: %u\n"
> +		 "data size: %lu\n",
> +		 hisi_acc_vdev->vf_qm_state,
> +		 sizeof(struct acc_vf_data));

Same here and throughout, wrap aligned to the relevant parenthesis.

I know you've described vf_qm_state as indicating whether or not the
guest driver is loaded, but I still can't figure out how to discern
that from the code.  It's largely only set based on the return value of
qm_wait_dev_not_ready(), which tests QM_VF_STATE, and describes the
function as testing if the device is ready.  Improved comments would
help future reviews.

What's the purpose of the "acc device:" prefix?

> +
> +migf_err:
> +	kfree(vf_data);
> +mutex_release:
> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
> +	mutex_unlock(&hisi_acc_vdev->state_mutex);

Locks should be released in the reverse order they were acquired.

> +
> +	return ret;
> +}
> +
> +static int hisi_acc_vf_migf_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);
> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
> +
> +	/* Check whether the live migration operation has been performed */
> +	if (debug_migf->total_length < QM_MATCH_SIZE) {
> +		seq_printf(seq, "device not migrated!\n");
> +		return -EAGAIN;
> +	}
> +
> +	seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
> +			(unsigned char *)&debug_migf->vf_data,
> +			vf_data_sz, false);
> +
> +	seq_printf(seq,
> +		 "acc device:\n"
> +		 "guest driver load: %u\n"
> +		 "device opened: %d\n"
> +		 "migrate data length: %lu\n",
> +		 hisi_acc_vdev->vf_qm_state,
> +		 hisi_acc_vdev->dev_opened,
> +		 debug_migf->total_length);

This debugfs entry is described as returning the data from the last
migration, but vf_qm_state and dev_opened are relative to the current
device/guest driver state.  Both seem to have no relevance to the data
in debug_migf.

> +
> +	return 0;
> +}
> +
>  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);
> @@ -1305,12 +1454,16 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>  		return ret;
>  
>  	if (core_vdev->mig_ops) {
> +		mutex_lock(&hisi_acc_vdev->open_mutex);
>  		ret = hisi_acc_vf_qm_init(hisi_acc_vdev);
>  		if (ret) {
> +			mutex_unlock(&hisi_acc_vdev->open_mutex);
>  			vfio_pci_core_disable(vdev);
>  			return ret;
>  		}
>  		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
> +		hisi_acc_vdev->dev_opened = true;
> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>  	}
>  
>  	vfio_pci_core_finish_enable(vdev);
> @@ -1322,7 +1475,10 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>  
> +	mutex_lock(&hisi_acc_vdev->open_mutex);
> +	hisi_acc_vdev->dev_opened = false;
>  	iounmap(vf_qm->io_base);
> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>  	vfio_pci_core_close_device(core_vdev);
>  }
>  
> @@ -1342,6 +1498,7 @@ static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
>  	hisi_acc_vdev->pf_qm = pf_qm;
>  	hisi_acc_vdev->vf_dev = pdev;
>  	mutex_init(&hisi_acc_vdev->state_mutex);
> +	mutex_init(&hisi_acc_vdev->open_mutex);
>  
>  	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY;
>  	core_vdev->mig_ops = &hisi_acc_vfio_pci_migrn_state_ops;
> @@ -1387,6 +1544,50 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
>  	.detach_ioas = vfio_iommufd_physical_detach_ioas,
>  };
>  
> +static void 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 dentry *vfio_dev_migration = NULL;
> +	struct dentry *vfio_hisi_acc = NULL;
> +	struct device *dev = vdev->dev;
> +	void *migf = NULL;
> +
> +	if (!debugfs_initialized() ||
> +	    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
> +		return;
> +
> +	if (vdev->ops != &hisi_acc_vfio_pci_migrn_ops)
> +		return;
> +
> +	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
> +	if (!vfio_dev_migration) {
> +		dev_err(dev, "failed to lookup migration debugfs file!\n");
> +		return;
> +	}
> +
> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
> +	if (!migf)
> +		return;
> +	hisi_acc_vdev->debug_migf = migf;
> +
> +	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
> +	debugfs_create_devm_seqfile(dev, "dev_data", vfio_hisi_acc,
> +				  hisi_acc_vf_dev_read);
> +	debugfs_create_devm_seqfile(dev, "migf_data", vfio_hisi_acc,
> +				  hisi_acc_vf_migf_read);
> +	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
> +				  hisi_acc_vf_debug_cmd);
> +}
> +
> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> +{
> +	/* If migrn_ops is not used, debug_migf is NULL */
> +	if (hisi_acc_vdev->debug_migf) {

This test is unnecessary, kfree(NULL) is valid.

> +		kfree(hisi_acc_vdev->debug_migf);
> +		hisi_acc_vdev->debug_migf = NULL;
> +	}
> +}
> +
>  static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  {
>  	struct hisi_acc_vf_core_device *hisi_acc_vdev;
> @@ -1413,6 +1614,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>  	if (ret)
>  		goto out_put_vdev;
> +
> +	hisi_acc_vfio_debug_init(hisi_acc_vdev);
>  	return 0;
>  
>  out_put_vdev:
> @@ -1425,6 +1628,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
>  
>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
> +	hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>  	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 5bab46602fad..2a78ffd060c3 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> @@ -32,6 +32,7 @@
>  #define QM_SQC_VFT_BASE_MASK_V2		GENMASK(15, 0)
>  #define QM_SQC_VFT_NUM_SHIFT_V2		45
>  #define QM_SQC_VFT_NUM_MASK_V2		GENMASK(9, 0)
> +#define QM_MB_CMD_NOT_READY	0xffffffff
>  
>  /* RW regs */
>  #define QM_REGS_MAX_LEN		7
> @@ -99,6 +100,8 @@ struct hisi_acc_vf_migration_file {
>  struct hisi_acc_vf_core_device {
>  	struct vfio_pci_core_device core_device;
>  	u8 match_done;
> +	/* To make sure the device is opened */

We can infer that from the field name, it would be more useful to
comment that io_base is only valid when dev_opened, which is protected
by open_mutex.

> +	bool dev_opened;

Seems like open_mutex would fit just as well here and have better
proximity to the data it protects.

>  
>  	/* For migration state */
>  	struct mutex state_mutex;
> @@ -111,5 +114,9 @@ struct hisi_acc_vf_core_device {
>  	int vf_id;
>  	struct hisi_acc_vf_migration_file *resuming_migf;
>  	struct hisi_acc_vf_migration_file *saving_migf;
> +
> +	/* To save migration data */

Clearly.  Describing it as an extra buffer for reporting migration data
through debugfs might be more useful.  Thanks,

Alex

> +	struct hisi_acc_vf_migration_file *debug_migf;
> +	struct mutex open_mutex;
>  };
>  #endif /* HISI_ACC_VFIO_PCI_H */

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2024/11/1 6:04, Alex Williamson wrote:
> On Fri, 25 Oct 2024 17:01:42 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> On the debugfs framework of VFIO, if the CONFIG_VFIO_DEBUGFS macro is
>> enabled, the debug function is registered for the live migration driver
>> of the HiSilicon accelerator device.
>>
>> After registering the HiSilicon accelerator device on the debugfs
>> framework of live migration of vfio, a directory file "hisi_acc"
>> of debugfs is created, and then three debug function files are
>> created in this directory:
>>
>>    vfio
>>     |
>>     +---<dev_name1>
>>     |    +---migration
>>     |        +--state
>>     |        +--hisi_acc
>>     |            +--dev_data
>>     |            +--migf_data
>>     |            +--cmd_state
>>     |
>>     +---<dev_name2>
>>          +---migration
>>              +--state
>>              +--hisi_acc
>>                  +--dev_data
>>                  +--migf_data
>>                  +--cmd_state
>>
>> dev_data file: read device data that needs to be migrated from the
>> current device in real time
>> migf_data file: read the migration data of the last live migration
>> from the current driver.
>> cmd_state: used to get the cmd channel state for the device.
>>
>> +----------------+        +--------------+       +---------------+
>> | migration dev  |        |   src  dev   |       |   dst  dev    |
>> +-------+--------+        +------+-------+       +-------+-------+
>>         |                        |                       |
>>         |                 +------v-------+       +-------v-------+
>>         |                 |  saving_migf |       | resuming_migf |
>>   read  |                 |     file     |       |     file      |
>>         |                 +------+-------+       +-------+-------+
>>         |                        |          copy         |
>>         |                        +------------+----------+
>>         |                                     |
>> +-------v--------+                    +-------v--------+
>> |   data buffer  |                    |   debug_migf   |
>> +-------+--------+                    +-------+--------+
>>         |                                     |
>>    cat  |                                 cat |
>> +-------v--------+                    +-------v--------+
>> |   dev_data     |                    |   migf_data    |
>> +----------------+                    +----------------+
>>
>> When accessing debugfs, user can obtain the most recent status data
>> of the device through the "dev_data" file. It can read recent
>> complete status data of the device. If the current device is being
>> migrated, it will wait for it to complete.
>> The data for the last completed migration function will be stored
>> in debug_migf. Users can read it via "migf_data".
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>> ---
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 204 ++++++++++++++++++
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   7 +
>>  2 files changed, 211 insertions(+)
>>
>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> index a8c53952d82e..0577d4ddfb34 100644
>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> @@ -627,15 +627,30 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>  	mutex_unlock(&migf->lock);
>>  }
>>  
>> +static void hisi_acc_debug_migf_copy(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>> +	struct hisi_acc_vf_migration_file *src_migf)
>> +{
>> +	struct hisi_acc_vf_migration_file *dst_migf = hisi_acc_vdev->debug_migf;
>> +
>> +	if (!dst_migf)
>> +		return;
>> +
>> +	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_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>  {
>>  	if (hisi_acc_vdev->resuming_migf) {
>> +		hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->resuming_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_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->saving_migf);
>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>>  		fput(hisi_acc_vdev->saving_migf->filp);
>>  		hisi_acc_vdev->saving_migf = NULL;
>> @@ -1294,6 +1309,140 @@ 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_check(struct seq_file *seq, 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;
>> +	int ret;
>> +
>> +	lockdep_assert_held(&hisi_acc_vdev->open_mutex);
>> +	/*
>> +	 * When the device is not opened, the io_base is not mapped.
>> +	 * The driver cannot perform device read and write operations.
>> +	 */
>> +	if (!hisi_acc_vdev->dev_opened) {
>> +		seq_printf(seq, "device not opened!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = qm_wait_dev_not_ready(vf_qm);
>> +	if (ret) {
>> +		seq_printf(seq, "VF device not ready!\n");
>> +		return -EBUSY;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_debug_cmd(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_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>> +	u64 value;
>> +	int ret;
>> +
>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>> +	if (ret) {
>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>> +		return ret;
>> +	}
>> +
>> +	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
>> +	if (value == QM_MB_CMD_NOT_READY) {
>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>> +		seq_printf(seq, "mailbox cmd channel not ready!\n");
>> +		return -EINVAL;
>> +	}
>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>> +	seq_printf(seq, "mailbox cmd channel ready!\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_dev_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);
>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>> +	struct acc_vf_data *vf_data = NULL;
> 
> Nit, this initialization is unnecessary.
>

OK, delete it in next version.

>> +	int ret;
>> +
>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>> +	if (ret) {
>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>> +		return ret;
>> +	}
>> +
>> +	mutex_lock(&hisi_acc_vdev->state_mutex);
>> +	vf_data = kzalloc(sizeof(struct acc_vf_data), GFP_KERNEL);
>> +	if (!vf_data) {
>> +		ret = -ENOMEM;
>> +		goto mutex_release;
>> +	}
>> +
>> +	vf_data->vf_qm_state = hisi_acc_vdev->vf_qm_state;
>> +	ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, vf_data);
>> +	if (ret)
>> +		goto migf_err;
>> +
>> +	seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,
>> +			(unsigned char *)vf_data,
> 
> Casting to (const void *) would match the prototype.  This line should
> also wrap to just inside the opening parenthesis of the previous line, 2
> tabs, 5 spaces.
>

OK, I will adjust it in the next version.

>> +			vf_data_sz, false);
>> +
>> +	seq_printf(seq,
>> +		 "acc device:\n"
>> +		 "guest driver load: %u\n"
>> +		 "data size: %lu\n",
>> +		 hisi_acc_vdev->vf_qm_state,
>> +		 sizeof(struct acc_vf_data));
> 
> Same here and throughout, wrap aligned to the relevant parenthesis.
>

OK.

> I know you've described vf_qm_state as indicating whether or not the
> guest driver is loaded, but I still can't figure out how to discern
> that from the code.  It's largely only set based on the return value of
> qm_wait_dev_not_ready(), which tests QM_VF_STATE, and describes the
> function as testing if the device is ready.  Improved comments would
> help future reviews.
>

This QM_VF_STATE register will be written to QM_READY when the acc device
driver is loaded, and QM_NOT_READY will be written after the device
driver is unloaded.

I will add a comment where vf_qm_state is declared.

> What's the purpose of the "acc device:" prefix?
>

OK, it can be deleted.

>> +
>> +migf_err:
>> +	kfree(vf_data);
>> +mutex_release:
>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>> +	mutex_unlock(&hisi_acc_vdev->state_mutex);
> 
> Locks should be released in the reverse order they were acquired.
>

OK.

>> +
>> +	return ret;
>> +}
>> +
>> +static int hisi_acc_vf_migf_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);
>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>> +
>> +	/* Check whether the live migration operation has been performed */
>> +	if (debug_migf->total_length < QM_MATCH_SIZE) {
>> +		seq_printf(seq, "device not migrated!\n");
>> +		return -EAGAIN;
>> +	}
>> +
>> +	seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
>> +			(unsigned char *)&debug_migf->vf_data,
>> +			vf_data_sz, false);
>> +
>> +	seq_printf(seq,
>> +		 "acc device:\n"
>> +		 "guest driver load: %u\n"
>> +		 "device opened: %d\n"
>> +		 "migrate data length: %lu\n",
>> +		 hisi_acc_vdev->vf_qm_state,
>> +		 hisi_acc_vdev->dev_opened,
>> +		 debug_migf->total_length);
> 
> This debugfs entry is described as returning the data from the last
> migration, but vf_qm_state and dev_opened are relative to the current
> device/guest driver state.  Both seem to have no relevance to the data
> in debug_migf.
>

The benefit of dev_opened retention is that user can obtain the device status
during the cat migf_data operation.

And vf_qm_state does need to be retained.
Because adding a driver or not adding a driver to the Guest OS has a great impact
on the results of live migration, it is a key factor. It has a great impact on
the success or failure of live migration.

When adding a driver, live migration will read device status data, and data will
be written back to device after the migration is completed.
When no driver is added, live migration only executes a process. It does not
perform data reading and data recovery operations.

>> +
>> +	return 0;
>> +}
>> +
>>  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);
>> @@ -1305,12 +1454,16 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>>  		return ret;
>>  
>>  	if (core_vdev->mig_ops) {
>> +		mutex_lock(&hisi_acc_vdev->open_mutex);
>>  		ret = hisi_acc_vf_qm_init(hisi_acc_vdev);
>>  		if (ret) {
>> +			mutex_unlock(&hisi_acc_vdev->open_mutex);
>>  			vfio_pci_core_disable(vdev);
>>  			return ret;
>>  		}
>>  		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
>> +		hisi_acc_vdev->dev_opened = true;
>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>>  	}
>>  
>>  	vfio_pci_core_finish_enable(vdev);
>> @@ -1322,7 +1475,10 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>>  
>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>> +	hisi_acc_vdev->dev_opened = false;
>>  	iounmap(vf_qm->io_base);
>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>>  	vfio_pci_core_close_device(core_vdev);
>>  }
>>  
>> @@ -1342,6 +1498,7 @@ static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
>>  	hisi_acc_vdev->pf_qm = pf_qm;
>>  	hisi_acc_vdev->vf_dev = pdev;
>>  	mutex_init(&hisi_acc_vdev->state_mutex);
>> +	mutex_init(&hisi_acc_vdev->open_mutex);
>>  
>>  	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY;
>>  	core_vdev->mig_ops = &hisi_acc_vfio_pci_migrn_state_ops;
>> @@ -1387,6 +1544,50 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
>>  	.detach_ioas = vfio_iommufd_physical_detach_ioas,
>>  };
>>  
>> +static void 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 dentry *vfio_dev_migration = NULL;
>> +	struct dentry *vfio_hisi_acc = NULL;
>> +	struct device *dev = vdev->dev;
>> +	void *migf = NULL;
>> +
>> +	if (!debugfs_initialized() ||
>> +	    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
>> +		return;
>> +
>> +	if (vdev->ops != &hisi_acc_vfio_pci_migrn_ops)
>> +		return;
>> +
>> +	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
>> +	if (!vfio_dev_migration) {
>> +		dev_err(dev, "failed to lookup migration debugfs file!\n");
>> +		return;
>> +	}
>> +
>> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
>> +	if (!migf)
>> +		return;
>> +	hisi_acc_vdev->debug_migf = migf;
>> +
>> +	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
>> +	debugfs_create_devm_seqfile(dev, "dev_data", vfio_hisi_acc,
>> +				  hisi_acc_vf_dev_read);
>> +	debugfs_create_devm_seqfile(dev, "migf_data", vfio_hisi_acc,
>> +				  hisi_acc_vf_migf_read);
>> +	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
>> +				  hisi_acc_vf_debug_cmd);
>> +}
>> +
>> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>> +{
>> +	/* If migrn_ops is not used, debug_migf is NULL */
>> +	if (hisi_acc_vdev->debug_migf) {
> 
> This test is unnecessary, kfree(NULL) is valid.
>

OK, It will be deleted. Comments will also be updated.

>> +		kfree(hisi_acc_vdev->debug_migf);
>> +		hisi_acc_vdev->debug_migf = NULL;
>> +	}
>> +}
>> +
>>  static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>  {
>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev;
>> @@ -1413,6 +1614,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>>  	if (ret)
>>  		goto out_put_vdev;
>> +
>> +	hisi_acc_vfio_debug_init(hisi_acc_vdev);
>>  	return 0;
>>  
>>  out_put_vdev:
>> @@ -1425,6 +1628,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
>>  
>>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
>> +	hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>>  	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 5bab46602fad..2a78ffd060c3 100644
>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>> @@ -32,6 +32,7 @@
>>  #define QM_SQC_VFT_BASE_MASK_V2		GENMASK(15, 0)
>>  #define QM_SQC_VFT_NUM_SHIFT_V2		45
>>  #define QM_SQC_VFT_NUM_MASK_V2		GENMASK(9, 0)
>> +#define QM_MB_CMD_NOT_READY	0xffffffff
>>  
>>  /* RW regs */
>>  #define QM_REGS_MAX_LEN		7
>> @@ -99,6 +100,8 @@ struct hisi_acc_vf_migration_file {
>>  struct hisi_acc_vf_core_device {
>>  	struct vfio_pci_core_device core_device;
>>  	u8 match_done;
>> +	/* To make sure the device is opened */
> 
> We can infer that from the field name, it would be more useful to
> comment that io_base is only valid when dev_opened, which is protected
> by open_mutex.
>

OK, the comments will be updated according to your instructions.

>> +	bool dev_opened;
> 
> Seems like open_mutex would fit just as well here and have better
> proximity to the data it protects.
> 

OK, I'm going to move it over here.

>>  
>>  	/* For migration state */
>>  	struct mutex state_mutex;
>> @@ -111,5 +114,9 @@ struct hisi_acc_vf_core_device {
>>  	int vf_id;
>>  	struct hisi_acc_vf_migration_file *resuming_migf;
>>  	struct hisi_acc_vf_migration_file *saving_migf;
>> +
>> +	/* To save migration data */
> 
> Clearly.  Describing it as an extra buffer for reporting migration data
> through debugfs might be more useful.  Thanks,
>

OK, the comments will be updated according to your instructions.

Thanks.
Longfang.

> Alex
> 
>> +	struct hisi_acc_vf_migration_file *debug_migf;
>> +	struct mutex open_mutex;
>>  };
>>  #endif /* HISI_ACC_VFIO_PCI_H */
> 
> 
> .
> 

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2024/11/4 15:54, liulongfang wrote:
> On 2024/11/1 6:04, Alex Williamson wrote:
>> On Fri, 25 Oct 2024 17:01:42 +0800
>> Longfang Liu <liulongfang@huawei.com> wrote:
>>
>>> On the debugfs framework of VFIO, if the CONFIG_VFIO_DEBUGFS macro is
>>> enabled, the debug function is registered for the live migration driver
>>> of the HiSilicon accelerator device.
>>>
>>> After registering the HiSilicon accelerator device on the debugfs
>>> framework of live migration of vfio, a directory file "hisi_acc"
>>> of debugfs is created, and then three debug function files are
>>> created in this directory:
>>>
>>>    vfio
>>>     |
>>>     +---<dev_name1>
>>>     |    +---migration
>>>     |        +--state
>>>     |        +--hisi_acc
>>>     |            +--dev_data
>>>     |            +--migf_data
>>>     |            +--cmd_state
>>>     |
>>>     +---<dev_name2>
>>>          +---migration
>>>              +--state
>>>              +--hisi_acc
>>>                  +--dev_data
>>>                  +--migf_data
>>>                  +--cmd_state
>>>
>>> dev_data file: read device data that needs to be migrated from the
>>> current device in real time
>>> migf_data file: read the migration data of the last live migration
>>> from the current driver.
>>> cmd_state: used to get the cmd channel state for the device.
>>>
>>> +----------------+        +--------------+       +---------------+
>>> | migration dev  |        |   src  dev   |       |   dst  dev    |
>>> +-------+--------+        +------+-------+       +-------+-------+
>>>         |                        |                       |
>>>         |                 +------v-------+       +-------v-------+
>>>         |                 |  saving_migf |       | resuming_migf |
>>>   read  |                 |     file     |       |     file      |
>>>         |                 +------+-------+       +-------+-------+
>>>         |                        |          copy         |
>>>         |                        +------------+----------+
>>>         |                                     |
>>> +-------v--------+                    +-------v--------+
>>> |   data buffer  |                    |   debug_migf   |
>>> +-------+--------+                    +-------+--------+
>>>         |                                     |
>>>    cat  |                                 cat |
>>> +-------v--------+                    +-------v--------+
>>> |   dev_data     |                    |   migf_data    |
>>> +----------------+                    +----------------+
>>>
>>> When accessing debugfs, user can obtain the most recent status data
>>> of the device through the "dev_data" file. It can read recent
>>> complete status data of the device. If the current device is being
>>> migrated, it will wait for it to complete.
>>> The data for the last completed migration function will be stored
>>> in debug_migf. Users can read it via "migf_data".
>>>
>>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>>> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>>> ---
>>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 204 ++++++++++++++++++
>>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   7 +
>>>  2 files changed, 211 insertions(+)
>>>
>>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>> index a8c53952d82e..0577d4ddfb34 100644
>>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>>> @@ -627,15 +627,30 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>>  	mutex_unlock(&migf->lock);
>>>  }
>>>  
>>> +static void hisi_acc_debug_migf_copy(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>>> +	struct hisi_acc_vf_migration_file *src_migf)
>>> +{
>>> +	struct hisi_acc_vf_migration_file *dst_migf = hisi_acc_vdev->debug_migf;
>>> +
>>> +	if (!dst_migf)
>>> +		return;
>>> +
>>> +	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_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>>  {
>>>  	if (hisi_acc_vdev->resuming_migf) {
>>> +		hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->resuming_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_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev->saving_migf);
>>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>>>  		fput(hisi_acc_vdev->saving_migf->filp);
>>>  		hisi_acc_vdev->saving_migf = NULL;
>>> @@ -1294,6 +1309,140 @@ 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_check(struct seq_file *seq, 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;
>>> +	int ret;
>>> +
>>> +	lockdep_assert_held(&hisi_acc_vdev->open_mutex);
>>> +	/*
>>> +	 * When the device is not opened, the io_base is not mapped.
>>> +	 * The driver cannot perform device read and write operations.
>>> +	 */
>>> +	if (!hisi_acc_vdev->dev_opened) {
>>> +		seq_printf(seq, "device not opened!\n");
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	ret = qm_wait_dev_not_ready(vf_qm);
>>> +	if (ret) {
>>> +		seq_printf(seq, "VF device not ready!\n");
>>> +		return -EBUSY;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int hisi_acc_vf_debug_cmd(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_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>>> +	u64 value;
>>> +	int ret;
>>> +
>>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>>> +	if (ret) {
>>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>>> +		return ret;
>>> +	}
>>> +
>>> +	value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
>>> +	if (value == QM_MB_CMD_NOT_READY) {
>>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>>> +		seq_printf(seq, "mailbox cmd channel not ready!\n");
>>> +		return -EINVAL;
>>> +	}
>>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>>> +	seq_printf(seq, "mailbox cmd channel ready!\n");
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int hisi_acc_vf_dev_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);
>>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>>> +	struct acc_vf_data *vf_data = NULL;
>>
>> Nit, this initialization is unnecessary.
>>
> 
> OK, delete it in next version.
> 
>>> +	int ret;
>>> +
>>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>>> +	ret = hisi_acc_vf_debug_check(seq, vdev);
>>> +	if (ret) {
>>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>>> +		return ret;
>>> +	}
>>> +
>>> +	mutex_lock(&hisi_acc_vdev->state_mutex);
>>> +	vf_data = kzalloc(sizeof(struct acc_vf_data), GFP_KERNEL);
>>> +	if (!vf_data) {
>>> +		ret = -ENOMEM;
>>> +		goto mutex_release;
>>> +	}
>>> +
>>> +	vf_data->vf_qm_state = hisi_acc_vdev->vf_qm_state;
>>> +	ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, vf_data);
>>> +	if (ret)
>>> +		goto migf_err;
>>> +
>>> +	seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,
>>> +			(unsigned char *)vf_data,
>>
>> Casting to (const void *) would match the prototype.  This line should
>> also wrap to just inside the opening parenthesis of the previous line, 2
>> tabs, 5 spaces.
>>
> 
> OK, I will adjust it in the next version.
> 
>>> +			vf_data_sz, false);
>>> +
>>> +	seq_printf(seq,
>>> +		 "acc device:\n"
>>> +		 "guest driver load: %u\n"
>>> +		 "data size: %lu\n",
>>> +		 hisi_acc_vdev->vf_qm_state,
>>> +		 sizeof(struct acc_vf_data));
>>
>> Same here and throughout, wrap aligned to the relevant parenthesis.
>>
> 
> OK.
> 
>> I know you've described vf_qm_state as indicating whether or not the
>> guest driver is loaded, but I still can't figure out how to discern
>> that from the code.  It's largely only set based on the return value of
>> qm_wait_dev_not_ready(), which tests QM_VF_STATE, and describes the
>> function as testing if the device is ready.  Improved comments would
>> help future reviews.
>>
> 
> This QM_VF_STATE register will be written to QM_READY when the acc device
> driver is loaded, and QM_NOT_READY will be written after the device
> driver is unloaded.
>> I will add a comment where vf_qm_state is declared.
> 
>> What's the purpose of the "acc device:" prefix?
>>
> 
> OK, it can be deleted.
> 
>>> +
>>> +migf_err:
>>> +	kfree(vf_data);
>>> +mutex_release:
>>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>>> +	mutex_unlock(&hisi_acc_vdev->state_mutex);
>>
>> Locks should be released in the reverse order they were acquired.
>>
> 
> OK.
> 
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static int hisi_acc_vf_migf_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);
>>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>>> +
>>> +	/* Check whether the live migration operation has been performed */
>>> +	if (debug_migf->total_length < QM_MATCH_SIZE) {
>>> +		seq_printf(seq, "device not migrated!\n");
>>> +		return -EAGAIN;
>>> +	}
>>> +
>>> +	seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,
>>> +			(unsigned char *)&debug_migf->vf_data,
>>> +			vf_data_sz, false);
>>> +
>>> +	seq_printf(seq,
>>> +		 "acc device:\n"
>>> +		 "guest driver load: %u\n"
>>> +		 "device opened: %d\n"
>>> +		 "migrate data length: %lu\n",
>>> +		 hisi_acc_vdev->vf_qm_state,
>>> +		 hisi_acc_vdev->dev_opened,
>>> +		 debug_migf->total_length);
>>
>> This debugfs entry is described as returning the data from the last
>> migration, but vf_qm_state and dev_opened are relative to the current
>> device/guest driver state.  Both seem to have no relevance to the data
>> in debug_migf.
>>
> 
> The benefit of dev_opened retention is that user can obtain the device status
> during the cat migf_data operation.
>

I will remove dev_opened in the next version.
And hisi_acc_vdev->vf_qm_state is changed to debug_migf->vf_data.vf_qm_state
Keep information about whether the device driver in the Guest OS is loaded
when live migration occurs.

Thanks，
Longfang.

> And vf_qm_state does need to be retained.
> Because adding a driver or not adding a driver to the Guest OS has a great impact
> on the results of live migration, it is a key factor. It has a great impact on
> the success or failure of live migration.
> 
> When adding a driver, live migration will read device status data, and data will
> be written back to device after the migration is completed.
> When no driver is added, live migration only executes a process. It does not
> perform data reading and data recovery operations.
> 
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  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);
>>> @@ -1305,12 +1454,16 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
>>>  		return ret;
>>>  
>>>  	if (core_vdev->mig_ops) {
>>> +		mutex_lock(&hisi_acc_vdev->open_mutex);
>>>  		ret = hisi_acc_vf_qm_init(hisi_acc_vdev);
>>>  		if (ret) {
>>> +			mutex_unlock(&hisi_acc_vdev->open_mutex);
>>>  			vfio_pci_core_disable(vdev);
>>>  			return ret;
>>>  		}
>>>  		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
>>> +		hisi_acc_vdev->dev_opened = true;
>>> +		mutex_unlock(&hisi_acc_vdev->open_mutex);
>>>  	}
>>>  
>>>  	vfio_pci_core_finish_enable(vdev);
>>> @@ -1322,7 +1475,10 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
>>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
>>>  	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>>>  
>>> +	mutex_lock(&hisi_acc_vdev->open_mutex);
>>> +	hisi_acc_vdev->dev_opened = false;
>>>  	iounmap(vf_qm->io_base);
>>> +	mutex_unlock(&hisi_acc_vdev->open_mutex);
>>>  	vfio_pci_core_close_device(core_vdev);
>>>  }
>>>  
>>> @@ -1342,6 +1498,7 @@ static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
>>>  	hisi_acc_vdev->pf_qm = pf_qm;
>>>  	hisi_acc_vdev->vf_dev = pdev;
>>>  	mutex_init(&hisi_acc_vdev->state_mutex);
>>> +	mutex_init(&hisi_acc_vdev->open_mutex);
>>>  
>>>  	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY;
>>>  	core_vdev->mig_ops = &hisi_acc_vfio_pci_migrn_state_ops;
>>> @@ -1387,6 +1544,50 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
>>>  	.detach_ioas = vfio_iommufd_physical_detach_ioas,
>>>  };
>>>  
>>> +static void 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 dentry *vfio_dev_migration = NULL;
>>> +	struct dentry *vfio_hisi_acc = NULL;
>>> +	struct device *dev = vdev->dev;
>>> +	void *migf = NULL;
>>> +
>>> +	if (!debugfs_initialized() ||
>>> +	    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
>>> +		return;
>>> +
>>> +	if (vdev->ops != &hisi_acc_vfio_pci_migrn_ops)
>>> +		return;
>>> +
>>> +	vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root);
>>> +	if (!vfio_dev_migration) {
>>> +		dev_err(dev, "failed to lookup migration debugfs file!\n");
>>> +		return;
>>> +	}
>>> +
>>> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
>>> +	if (!migf)
>>> +		return;
>>> +	hisi_acc_vdev->debug_migf = migf;
>>> +
>>> +	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
>>> +	debugfs_create_devm_seqfile(dev, "dev_data", vfio_hisi_acc,
>>> +				  hisi_acc_vf_dev_read);
>>> +	debugfs_create_devm_seqfile(dev, "migf_data", vfio_hisi_acc,
>>> +				  hisi_acc_vf_migf_read);
>>> +	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
>>> +				  hisi_acc_vf_debug_cmd);
>>> +}
>>> +
>>> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>> +{
>>> +	/* If migrn_ops is not used, debug_migf is NULL */
>>> +	if (hisi_acc_vdev->debug_migf) {
>>
>> This test is unnecessary, kfree(NULL) is valid.
>>
> 
> OK, It will be deleted. Comments will also be updated.
> 
>>> +		kfree(hisi_acc_vdev->debug_migf);
>>> +		hisi_acc_vdev->debug_migf = NULL;
>>> +	}
>>> +}
>>> +
>>>  static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>  {
>>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev;
>>> @@ -1413,6 +1614,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>>>  	if (ret)
>>>  		goto out_put_vdev;
>>> +
>>> +	hisi_acc_vfio_debug_init(hisi_acc_vdev);
>>>  	return 0;
>>>  
>>>  out_put_vdev:
>>> @@ -1425,6 +1628,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>>>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
>>>  
>>>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
>>> +	hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>>>  	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 5bab46602fad..2a78ffd060c3 100644
>>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
>>> @@ -32,6 +32,7 @@
>>>  #define QM_SQC_VFT_BASE_MASK_V2		GENMASK(15, 0)
>>>  #define QM_SQC_VFT_NUM_SHIFT_V2		45
>>>  #define QM_SQC_VFT_NUM_MASK_V2		GENMASK(9, 0)
>>> +#define QM_MB_CMD_NOT_READY	0xffffffff
>>>  
>>>  /* RW regs */
>>>  #define QM_REGS_MAX_LEN		7
>>> @@ -99,6 +100,8 @@ struct hisi_acc_vf_migration_file {
>>>  struct hisi_acc_vf_core_device {
>>>  	struct vfio_pci_core_device core_device;
>>>  	u8 match_done;
>>> +	/* To make sure the device is opened */
>>
>> We can infer that from the field name, it would be more useful to
>> comment that io_base is only valid when dev_opened, which is protected
>> by open_mutex.
>>
> 
> OK, the comments will be updated according to your instructions.
> 
>>> +	bool dev_opened;
>>
>> Seems like open_mutex would fit just as well here and have better
>> proximity to the data it protects.
>>
> 
> OK, I'm going to move it over here.
> 
>>>  
>>>  	/* For migration state */
>>>  	struct mutex state_mutex;
>>> @@ -111,5 +114,9 @@ struct hisi_acc_vf_core_device {
>>>  	int vf_id;
>>>  	struct hisi_acc_vf_migration_file *resuming_migf;
>>>  	struct hisi_acc_vf_migration_file *saving_migf;
>>> +
>>> +	/* To save migration data */
>>
>> Clearly.  Describing it as an extra buffer for reporting migration data
>> through debugfs might be more useful.  Thanks,
>>
> 
> OK, the comments will be updated according to your instructions.
> 
> Thanks.
> Longfang.
> 
>> Alex
>>
>>> +	struct hisi_acc_vf_migration_file *debug_migf;
>>> +	struct mutex open_mutex;
>>>  };
>>>  #endif /* HISI_ACC_VFIO_PCI_H */
>>
>>
>> .
>>
> 
> .
> 

RE: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: liulongfang <liulongfang@huawei.com>
> Sent: Monday, November 4, 2024 8:31 AM
> To: Alex Williamson <alex.williamson@redhat.com>
> Cc: jgg@nvidia.com; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>; Jonathan Cameron
> <jonathan.cameron@huawei.com>; kvm@vger.kernel.org; linux-
> kernel@vger.kernel.org; linuxarm@openeuler.org
> Subject: Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon
> migration driver
[...]

> >>> +
> >>> +	seq_printf(seq,
> >>> +		 "acc device:\n"
> >>> +		 "guest driver load: %u\n"
> >>> +		 "device opened: %d\n"
> >>> +		 "migrate data length: %lu\n",
> >>> +		 hisi_acc_vdev->vf_qm_state,
> >>> +		 hisi_acc_vdev->dev_opened,
> >>> +		 debug_migf->total_length);
> >>
> >> This debugfs entry is described as returning the data from the last
> >> migration, but vf_qm_state and dev_opened are relative to the current
> >> device/guest driver state.  Both seem to have no relevance to the data
> >> in debug_migf.
> >>
> >
> > The benefit of dev_opened retention is that user can obtain the device
> status
> > during the cat migf_data operation.
> >
> 
> I will remove dev_opened in the next version.
> And hisi_acc_vdev->vf_qm_state is changed to debug_migf-
> >vf_data.vf_qm_state
> Keep information about whether the device driver in the Guest OS is loaded
> when live migration occurs.

I think you already get that when you dump debug_migf->vf_data.
So not required.

Thanks,
Shameer

Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2024/11/4 16:56, Shameerali Kolothum Thodi wrote:
> 
> 
>> -----Original Message-----
>> From: liulongfang <liulongfang@huawei.com>
>> Sent: Monday, November 4, 2024 8:31 AM
>> To: Alex Williamson <alex.williamson@redhat.com>
>> Cc: jgg@nvidia.com; Shameerali Kolothum Thodi
>> <shameerali.kolothum.thodi@huawei.com>; Jonathan Cameron
>> <jonathan.cameron@huawei.com>; kvm@vger.kernel.org; linux-
>> kernel@vger.kernel.org; linuxarm@openeuler.org
>> Subject: Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon
>> migration driver
> [...]
> 
>>>>> +
>>>>> +	seq_printf(seq,
>>>>> +		 "acc device:\n"
>>>>> +		 "guest driver load: %u\n"
>>>>> +		 "device opened: %d\n"
>>>>> +		 "migrate data length: %lu\n",
>>>>> +		 hisi_acc_vdev->vf_qm_state,
>>>>> +		 hisi_acc_vdev->dev_opened,
>>>>> +		 debug_migf->total_length);
>>>>
>>>> This debugfs entry is described as returning the data from the last
>>>> migration, but vf_qm_state and dev_opened are relative to the current
>>>> device/guest driver state.  Both seem to have no relevance to the data
>>>> in debug_migf.
>>>>
>>>
>>> The benefit of dev_opened retention is that user can obtain the device
>> status
>>> during the cat migf_data operation.
>>>
>>
>> I will remove dev_opened in the next version.
>> And hisi_acc_vdev->vf_qm_state is changed to debug_migf-
>>> vf_data.vf_qm_state
>> Keep information about whether the device driver in the Guest OS is loaded
>> when live migration occurs.
> 
> I think you already get that when you dump debug_migf->vf_data.
> So not required.
>
OK, vf_qm_state still needs to be deleted.

Thanks,
Longfang.

> Thanks,
> Shameer
> 
> .
>