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
From: Longfang Liu <[email protected]>
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 <[email protected]>
---
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
From: Longfang Liu <[email protected]>
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 <[email protected]>
---
.../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 <[email protected]>
+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 <[email protected]>
+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 <[email protected]>
+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 <[email protected]>
+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 <[email protected]>
+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 <[email protected]>
+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 <[email protected]>
+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: [email protected]
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 <[email protected]>
M: Shameer Kolothum <[email protected]>
L: [email protected]
S: Maintained
+F: Documentation/ABI/testing/debugfs-hisi-migration
F: drivers/vfio/pci/hisilicon/
VFIO MEDIATED DEVICE DRIVERS
--
2.24.0
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.
On Fri, 30 Jun 2023 17:24:57 +0800
liulongfang <[email protected]> wrote:
> From: Longfang Liu <[email protected]>
>
> 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 <[email protected]>
> ---
> .../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 <[email protected]>
> +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 <[email protected]>
> +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 <[email protected]>
> +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 <[email protected]>
> +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 <[email protected]>
> +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 <[email protected]>
> +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 <[email protected]>
> +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: [email protected]
> 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 <[email protected]>
> M: Shameer Kolothum <[email protected]>
> L: [email protected]
> S: Maintained
> +F: Documentation/ABI/testing/debugfs-hisi-migration
> F: drivers/vfio/pci/hisilicon/
>
> VFIO MEDIATED DEVICE DRIVERS
On 6/30/23 11:24, liulongfang wrote:
> From: Longfang Liu <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
> };
>
> /**
On 2023/7/19 1:45, Cédric Le Goater Wrote:
> On 6/30/23 11:24, liulongfang wrote:
>> From: Longfang Liu <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>> 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
>> };
>> /**
>
> .
>
On 2023/7/15 6:07, Alex Williamson write:
> On Fri, 30 Jun 2023 17:24:57 +0800
> liulongfang <[email protected]> wrote:
>
>> From: Longfang Liu <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>> .../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 <[email protected]>
>> +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 <[email protected]>
>> +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 <[email protected]>
>> +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 <[email protected]>
>> +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 <[email protected]>
>> +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 <[email protected]>
>> +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 <[email protected]>
>> +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: [email protected]
>> 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 <[email protected]>
>> M: Shameer Kolothum <[email protected]>
>> L: [email protected]
>> S: Maintained
>> +F: Documentation/ABI/testing/debugfs-hisi-migration
>> F: drivers/vfio/pci/hisilicon/
>>
>> VFIO MEDIATED DEVICE DRIVERS
>
> .
>