Add a debugfs function to the migration driver in VFIO to provide
a step-by-step debugfs information for the migration driver.
Changes v15 -> v16
Update the calling order of functions to maintain symmetry
Changes v14 -> v15
Update the output status value of live migration.
Changes v13 -> v14
Split the patchset and keep the vfio debugfs frame.
Changes v12 -> v13
Solve the problem of open and close competition to debugfs.
Changes v11 -> v12
Update loading conditions of vfio debugfs.
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 (2):
vfio/migration: Add debugfs to live migration driver
Documentation: add debugfs description for vfio
Documentation/ABI/testing/debugfs-vfio | 25 ++++++++
MAINTAINERS | 1 +
drivers/vfio/Makefile | 1 +
drivers/vfio/vfio.h | 14 +++++
drivers/vfio/vfio_debugfs.c | 87 ++++++++++++++++++++++++++
drivers/vfio/vfio_main.c | 14 ++++-
include/linux/vfio.h | 7 +++
7 files changed, 147 insertions(+), 2 deletions(-)
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
|
+---<dev_name2>
+---migration
+--state
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.
Signed-off-by: Longfang Liu <[email protected]>
---
drivers/vfio/Makefile | 1 +
drivers/vfio/vfio.h | 14 ++++++
drivers/vfio/vfio_debugfs.c | 87 +++++++++++++++++++++++++++++++++++++
drivers/vfio/vfio_main.c | 14 +++++-
include/linux/vfio.h | 7 +++
5 files changed, 121 insertions(+), 2 deletions(-)
create mode 100644 drivers/vfio/vfio_debugfs.c
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index c82ea032d352..7934ac829989 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -8,6 +8,7 @@ vfio-$(CONFIG_VFIO_GROUP) += group.o
vfio-$(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 307e3f29b527..09b00757d0bb 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -448,4 +448,18 @@ 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..b79bdef08357
--- /dev/null
+++ b/drivers/vfio/vfio_debugfs.c
@@ -0,0 +1,87 @@
+// 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_STOP:
+ seq_printf(seq, "%s\n", "STOP");
+ break;
+ 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_RESUMING:
+ seq_printf(seq, "%s\n", "RESUMING");
+ break;
+ case VFIO_DEVICE_STATE_RUNNING_P2P:
+ seq_printf(seq, "%s\n", "RUNNING_P2P");
+ break;
+ case VFIO_DEVICE_STATE_PRE_COPY:
+ seq_printf(seq, "%s\n", "PRE_COPY");
+ break;
+ case VFIO_DEVICE_STATE_PRE_COPY_P2P:
+ seq_printf(seq, "%s\n", "PRE_COPY_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 device *dev = &vdev->device;
+
+ vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
+
+ if (vdev->mig_ops) {
+ struct dentry *vfio_dev_migration = NULL;
+
+ 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 cfad824d9aa2..4e3ced20d2d1 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -309,7 +309,6 @@ static int __vfio_register_dev(struct vfio_device *device,
/* Refcounting can't start until the driver calls register */
refcount_set(&device->refcount, 1);
-
vfio_device_group_register(device);
return 0;
@@ -320,7 +319,15 @@ static int __vfio_register_dev(struct vfio_device *device,
int vfio_register_group_dev(struct vfio_device *device)
{
- return __vfio_register_dev(device, VFIO_IOMMU);
+ int ret;
+
+ ret = __vfio_register_dev(device, VFIO_IOMMU);
+ if (ret)
+ return ret;
+
+ vfio_device_debugfs_init(device);
+
+ return 0;
}
EXPORT_SYMBOL_GPL(vfio_register_group_dev);
@@ -378,6 +385,7 @@ void vfio_unregister_group_dev(struct vfio_device *device)
}
}
+ vfio_device_debugfs_exit(device);
/* Balances vfio_device_set_group in register path */
vfio_device_remove_group(device);
}
@@ -1662,6 +1670,7 @@ static int __init vfio_init(void)
if (ret)
goto err_alloc_dev_chrdev;
+ vfio_debugfs_create_root();
pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
return 0;
@@ -1677,6 +1686,7 @@ static int __init vfio_init(void)
static void __exit vfio_cleanup(void)
{
+ vfio_debugfs_remove_root();
ida_destroy(&vfio.device_ida);
vfio_cdev_cleanup();
class_destroy(vfio.device_class);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 454e9295970c..769d7af86225 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -69,6 +69,13 @@ struct vfio_device {
u8 iommufd_attached:1;
#endif
u8 cdev_opened:1;
+#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 an 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]>
---
Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 26 insertions(+)
create mode 100644 Documentation/ABI/testing/debugfs-vfio
diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
new file mode 100644
index 000000000000..7959ec5ac445
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-vfio
@@ -0,0 +1,25 @@
+What: /sys/kernel/debug/vfio
+Date: Sep 2023
+KernelVersion: 6.7
+Contact: Longfang Liu <[email protected]>
+Description: This debugfs file directory is used for debugging
+ of vfio devices, it's a common directory for all vfio devices.
+ Vfio core will create a device subdirectory under this
+ directory.
+
+What: /sys/kernel/debug/vfio/<device>/migration
+Date: Sep 2023
+KernelVersion: 6.7
+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: Sep 2023
+KernelVersion: 6.7
+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 7b1306615fc0..bd01ca674c60 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22304,6 +22304,7 @@ 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
--
2.24.0
On Tue, 26 Sep 2023 17:33:55 +0800
liulongfang <[email protected]> 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
> |
> +---<dev_name2>
> +---migration
> +--state
>
> 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.
We don't actually do the thing claimed in this last statement.
> Signed-off-by: Longfang Liu <[email protected]>
> ---
> drivers/vfio/Makefile | 1 +
> drivers/vfio/vfio.h | 14 ++++++
> drivers/vfio/vfio_debugfs.c | 87 +++++++++++++++++++++++++++++++++++++
> drivers/vfio/vfio_main.c | 14 +++++-
> include/linux/vfio.h | 7 +++
> 5 files changed, 121 insertions(+), 2 deletions(-)
> create mode 100644 drivers/vfio/vfio_debugfs.c
>
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index c82ea032d352..7934ac829989 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -8,6 +8,7 @@ vfio-$(CONFIG_VFIO_GROUP) += group.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
I see that other subsystems create Kconfig entries allowing more fine
grained control of DEBUGFS support. Wouldn't it make sense to have a
VFIO_DEBUGFS config option, similar to IOMMU_DEBUGFS?
Also, with our trend towards less redundant file naming, this could
just be debugfs.[co].
> 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 307e3f29b527..09b00757d0bb 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -448,4 +448,18 @@ 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..b79bdef08357
> --- /dev/null
> +++ b/drivers/vfio/vfio_debugfs.c
> @@ -0,0 +1,87 @@
> +// 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_STOP:
> + seq_printf(seq, "%s\n", "STOP");
> + break;
> + 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_RESUMING:
> + seq_printf(seq, "%s\n", "RESUMING");
> + break;
> + case VFIO_DEVICE_STATE_RUNNING_P2P:
> + seq_printf(seq, "%s\n", "RUNNING_P2P");
> + break;
> + case VFIO_DEVICE_STATE_PRE_COPY:
> + seq_printf(seq, "%s\n", "PRE_COPY");
> + break;
> + case VFIO_DEVICE_STATE_PRE_COPY_P2P:
> + seq_printf(seq, "%s\n", "PRE_COPY_P2P");
> + break;
> + case VFIO_DEVICE_STATE_ERROR:
^^^^^^^^^^^^^^^^^^^^^^^
> + seq_printf(seq, "%s\n", "ERROR");
> + break;
> + default:
> + seq_printf(seq, "%s\n", "Invalid");
> + }
Not exactly in the order they're defined:
enum vfio_device_mig_state {
VFIO_DEVICE_STATE_ERROR = 0,
^^^^^^^^^^^^^^^^^^^^^^^
VFIO_DEVICE_STATE_STOP = 1,
VFIO_DEVICE_STATE_RUNNING = 2,
...
I also suggested last time some means to keep this in sync with the set
of states defined. Maybe there are better suggestions, but one way to
do that could be:
diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c
index ee6b1831b3e5..1ec90b90d150 100644
--- a/drivers/vfio/vfio_debugfs.c
+++ b/drivers/vfio/vfio_debugfs.c
@@ -18,6 +18,9 @@ static int vfio_device_state_read(struct seq_file *seq, void *data)
enum vfio_device_mig_state state;
int ret;
+ BUILD_BUG_ON(VFIO_DEVICE_STATE_NR !=
+ VFIO_DEVICE_STATE_PRE_COPY_P2P + 1);
+
ret = vdev->mig_ops->migration_get_state(vdev, &state);
if (ret)
return -EINVAL;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 7f5fb010226d..2b68e6cdf190 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1219,6 +1219,7 @@ enum vfio_device_mig_state {
VFIO_DEVICE_STATE_RUNNING_P2P = 5,
VFIO_DEVICE_STATE_PRE_COPY = 6,
VFIO_DEVICE_STATE_PRE_COPY_P2P = 7,
+ VFIO_DEVICE_STATE_NR,
};
/**
Thanks,
Alex
> +
> + return 0;
> +}
> +
> +void vfio_device_debugfs_init(struct vfio_device *vdev)
> +{
> + struct device *dev = &vdev->device;
> +
> + vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
> +
> + if (vdev->mig_ops) {
> + struct dentry *vfio_dev_migration = NULL;
> +
> + 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 cfad824d9aa2..4e3ced20d2d1 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -309,7 +309,6 @@ static int __vfio_register_dev(struct vfio_device *device,
>
> /* Refcounting can't start until the driver calls register */
> refcount_set(&device->refcount, 1);
> -
> vfio_device_group_register(device);
>
> return 0;
> @@ -320,7 +319,15 @@ static int __vfio_register_dev(struct vfio_device *device,
>
> int vfio_register_group_dev(struct vfio_device *device)
> {
> - return __vfio_register_dev(device, VFIO_IOMMU);
> + int ret;
> +
> + ret = __vfio_register_dev(device, VFIO_IOMMU);
> + if (ret)
> + return ret;
> +
> + vfio_device_debugfs_init(device);
> +
> + return 0;
> }
> EXPORT_SYMBOL_GPL(vfio_register_group_dev);
>
> @@ -378,6 +385,7 @@ void vfio_unregister_group_dev(struct vfio_device *device)
> }
> }
>
> + vfio_device_debugfs_exit(device);
> /* Balances vfio_device_set_group in register path */
> vfio_device_remove_group(device);
> }
> @@ -1662,6 +1670,7 @@ static int __init vfio_init(void)
> if (ret)
> goto err_alloc_dev_chrdev;
>
> + vfio_debugfs_create_root();
> pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
> return 0;
>
> @@ -1677,6 +1686,7 @@ static int __init vfio_init(void)
>
> static void __exit vfio_cleanup(void)
> {
> + vfio_debugfs_remove_root();
> ida_destroy(&vfio.device_ida);
> vfio_cdev_cleanup();
> class_destroy(vfio.device_class);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 454e9295970c..769d7af86225 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -69,6 +69,13 @@ struct vfio_device {
> u8 iommufd_attached:1;
> #endif
> u8 cdev_opened:1;
> +#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 Tue, 26 Sep 2023 17:33:56 +0800
liulongfang <[email protected]> wrote:
> From: Longfang Liu <[email protected]>
>
> 1.Add an 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]>
> ---
> Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++
> MAINTAINERS | 1 +
> 2 files changed, 26 insertions(+)
> create mode 100644 Documentation/ABI/testing/debugfs-vfio
>
> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
> new file mode 100644
> index 000000000000..7959ec5ac445
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-vfio
> @@ -0,0 +1,25 @@
> +What: /sys/kernel/debug/vfio
> +Date: Sep 2023
> +KernelVersion: 6.7
> +Contact: Longfang Liu <[email protected]>
> +Description: This debugfs file directory is used for debugging
> + of vfio devices, it's a common directory for all vfio devices.
> + Vfio core will create a device subdirectory under this
> + directory.
> +
> +What: /sys/kernel/debug/vfio/<device>/migration
> +Date: Sep 2023
> +KernelVersion: 6.7
> +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: Sep 2023
> +KernelVersion: 6.7
> +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.
This is another area that's doomed to be out of sync, it's already not
updated for P2P states. Better to avoid the problem and say something
like "The contents of the state file reflects the migration state
relative to those defined in the vfio_device_mig_state enum".
Also, as suggested last time, October is a more realistic date. Thanks,
Alex
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7b1306615fc0..bd01ca674c60 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22304,6 +22304,7 @@ 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
On 2023/10/4 3:26, Alex Williamson wrote:
> On Tue, 26 Sep 2023 17:33:55 +0800
> liulongfang <[email protected]> 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
>> |
>> +---<dev_name2>
>> +---migration
>> +--state
>>
>> 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.
>
> We don't actually do the thing claimed in this last statement.
>
OK, I will modify it in the next version.
>> Signed-off-by: Longfang Liu <[email protected]>
>> ---
>> drivers/vfio/Makefile | 1 +
>> drivers/vfio/vfio.h | 14 ++++++
>> drivers/vfio/vfio_debugfs.c | 87 +++++++++++++++++++++++++++++++++++++
>> drivers/vfio/vfio_main.c | 14 +++++-
>> include/linux/vfio.h | 7 +++
>> 5 files changed, 121 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/vfio/vfio_debugfs.c
>>
>> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
>> index c82ea032d352..7934ac829989 100644
>> --- a/drivers/vfio/Makefile
>> +++ b/drivers/vfio/Makefile
>> @@ -8,6 +8,7 @@ vfio-$(CONFIG_VFIO_GROUP) += group.o
>> vfio-$(CONFIG_IOMMUFD) += iommufd.o
>> vfio-$(CONFIG_VFIO_CONTAINER) += container.o
>> vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
>> +vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o
>
> I see that other subsystems create Kconfig entries allowing more fine
> grained control of DEBUGFS support. Wouldn't it make sense to have a
> VFIO_DEBUGFS config option, similar to IOMMU_DEBUGFS?
>
OK, I create a version with VFIO_DEBUGFS
> Also, with our trend towards less redundant file naming, this could
> just be debugfs.[co].
>
OK.
>> obj-$(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 307e3f29b527..09b00757d0bb 100644
>> --- a/drivers/vfio/vfio.h
>> +++ b/drivers/vfio/vfio.h
>> @@ -448,4 +448,18 @@ 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..b79bdef08357
>> --- /dev/null
>> +++ b/drivers/vfio/vfio_debugfs.c
>> @@ -0,0 +1,87 @@
>> +// 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_STOP:
>> + seq_printf(seq, "%s\n", "STOP");
>> + break;
>> + 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_RESUMING:
>> + seq_printf(seq, "%s\n", "RESUMING");
>> + break;
>> + case VFIO_DEVICE_STATE_RUNNING_P2P:
>> + seq_printf(seq, "%s\n", "RUNNING_P2P");
>> + break;
>> + case VFIO_DEVICE_STATE_PRE_COPY:
>> + seq_printf(seq, "%s\n", "PRE_COPY");
>> + break;
>> + case VFIO_DEVICE_STATE_PRE_COPY_P2P:
>> + seq_printf(seq, "%s\n", "PRE_COPY_P2P");
>> + break;
>> + case VFIO_DEVICE_STATE_ERROR:
> ^^^^^^^^^^^^^^^^^^^^^^^
>
>> + seq_printf(seq, "%s\n", "ERROR");
>> + break;
>> + default:
>> + seq_printf(seq, "%s\n", "Invalid");
>> + }
>
> Not exactly in the order they're defined:
>
> enum vfio_device_mig_state {
> VFIO_DEVICE_STATE_ERROR = 0,
> ^^^^^^^^^^^^^^^^^^^^^^^
> VFIO_DEVICE_STATE_STOP = 1,
> VFIO_DEVICE_STATE_RUNNING = 2,
> ...
>
> I also suggested last time some means to keep this in sync with the set
> of states defined. Maybe there are better suggestions, but one way to
> do that could be:
>
> diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c
> index ee6b1831b3e5..1ec90b90d150 100644
> --- a/drivers/vfio/vfio_debugfs.c
> +++ b/drivers/vfio/vfio_debugfs.c
> @@ -18,6 +18,9 @@ static int vfio_device_state_read(struct seq_file *seq, void *data)
> enum vfio_device_mig_state state;
> int ret;
>
> + BUILD_BUG_ON(VFIO_DEVICE_STATE_NR !=
> + VFIO_DEVICE_STATE_PRE_COPY_P2P + 1);
> +
> ret = vdev->mig_ops->migration_get_state(vdev, &state);
> if (ret)
> return -EINVAL;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 7f5fb010226d..2b68e6cdf190 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -1219,6 +1219,7 @@ enum vfio_device_mig_state {
> VFIO_DEVICE_STATE_RUNNING_P2P = 5,
> VFIO_DEVICE_STATE_PRE_COPY = 6,
> VFIO_DEVICE_STATE_PRE_COPY_P2P = 7,
> + VFIO_DEVICE_STATE_NR,
> };
>
> /**
>
> Thanks,
> Alex
>
OK, I will modify it in the next version
Thanks,
Longfang
>
>> +
>> + return 0;
>> +}
>> +
>> +void vfio_device_debugfs_init(struct vfio_device *vdev)
>> +{
>> + struct device *dev = &vdev->device;
>> +
>> + vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
>> +
>> + if (vdev->mig_ops) {
>> + struct dentry *vfio_dev_migration = NULL;
>> +
>> + 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 cfad824d9aa2..4e3ced20d2d1 100644
>> --- a/drivers/vfio/vfio_main.c
>> +++ b/drivers/vfio/vfio_main.c
>> @@ -309,7 +309,6 @@ static int __vfio_register_dev(struct vfio_device *device,
>>
>> /* Refcounting can't start until the driver calls register */
>> refcount_set(&device->refcount, 1);
>> -
>> vfio_device_group_register(device);
>>
>> return 0;
>> @@ -320,7 +319,15 @@ static int __vfio_register_dev(struct vfio_device *device,
>>
>> int vfio_register_group_dev(struct vfio_device *device)
>> {
>> - return __vfio_register_dev(device, VFIO_IOMMU);
>> + int ret;
>> +
>> + ret = __vfio_register_dev(device, VFIO_IOMMU);
>> + if (ret)
>> + return ret;
>> +
>> + vfio_device_debugfs_init(device);
>> +
>> + return 0;
>> }
>> EXPORT_SYMBOL_GPL(vfio_register_group_dev);
>>
>> @@ -378,6 +385,7 @@ void vfio_unregister_group_dev(struct vfio_device *device)
>> }
>> }
>>
>> + vfio_device_debugfs_exit(device);
>> /* Balances vfio_device_set_group in register path */
>> vfio_device_remove_group(device);
>> }
>> @@ -1662,6 +1670,7 @@ static int __init vfio_init(void)
>> if (ret)
>> goto err_alloc_dev_chrdev;
>>
>> + vfio_debugfs_create_root();
>> pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
>> return 0;
>>
>> @@ -1677,6 +1686,7 @@ static int __init vfio_init(void)
>>
>> static void __exit vfio_cleanup(void)
>> {
>> + vfio_debugfs_remove_root();
>> ida_destroy(&vfio.device_ida);
>> vfio_cdev_cleanup();
>> class_destroy(vfio.device_class);
>> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
>> index 454e9295970c..769d7af86225 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -69,6 +69,13 @@ struct vfio_device {
>> u8 iommufd_attached:1;
>> #endif
>> u8 cdev_opened:1;
>> +#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 2023/10/4 3:26, Alex Williamson wrote:
> On Tue, 26 Sep 2023 17:33:56 +0800
> liulongfang <[email protected]> wrote:
>
>> From: Longfang Liu <[email protected]>
>>
>> 1.Add an 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]>
>> ---
>> Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++
>> MAINTAINERS | 1 +
>> 2 files changed, 26 insertions(+)
>> create mode 100644 Documentation/ABI/testing/debugfs-vfio
>>
>> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
>> new file mode 100644
>> index 000000000000..7959ec5ac445
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-vfio
>> @@ -0,0 +1,25 @@
>> +What: /sys/kernel/debug/vfio
>> +Date: Sep 2023
>> +KernelVersion: 6.7
>> +Contact: Longfang Liu <[email protected]>
>> +Description: This debugfs file directory is used for debugging
>> + of vfio devices, it's a common directory for all vfio devices.
>> + Vfio core will create a device subdirectory under this
>> + directory.
>> +
>> +What: /sys/kernel/debug/vfio/<device>/migration
>> +Date: Sep 2023
>> +KernelVersion: 6.7
>> +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: Sep 2023
>> +KernelVersion: 6.7
>> +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.
>
> This is another area that's doomed to be out of sync, it's already not
> updated for P2P states. Better to avoid the problem and say something
> like "The contents of the state file reflects the migration state
> relative to those defined in the vfio_device_mig_state enum".
>
> Also, as suggested last time, October is a more realistic date. Thanks,
>
OK, I will modify it in the next version
Thanks
Longfang.
> Alex
>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 7b1306615fc0..bd01ca674c60 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -22304,6 +22304,7 @@ 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
>
> .
>