[PATCH v7 0/5] add debugfs to migration driver

[PATCH v7 0/5] add debugfs to migration driver

[Longfang Liu]

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 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 (5):
  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 hisi_acc_vfio_pci
  vfio: update live migration device status

 .../ABI/testing/debugfs-hisi-migration        |  32 ++
 drivers/vfio/pci/Makefile                     |   1 +
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 306 +++++++++++++++++-
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
 drivers/vfio/pci/mlx5/main.c                  |   3 +
 drivers/vfio/pci/vfio_pci_core.c              |   3 +
 drivers/vfio/pci/vfio_pci_debugfs.c           |  80 +++++
 drivers/vfio/pci/vfio_pci_debugfs.h           |  28 ++
 include/linux/vfio.h                          |   8 +
 9 files changed, 462 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
 create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.c
 create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.h

-- 
2.24.0

[PATCH v7 1/5] vfio/migration: Add debugfs to live migration driver

[Longfang Liu]

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 VF |                | dst VF |
     +-+------+                +-+------+
       |   ^                     |   ^
       v   |                     v   |
 +-------+-+------+        +-------+-+------+
 |Debugfs|state   |        |Debugfs|state   |
 +-------+--------+        +-------+--------+
 |   debug_root   |        |   debug_root   |
 +-------+--------+        +-------+--------+

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_pci_debugfs.h will be empty definitions,
and the creation and initialization of the debugfs directory
will not be executed.

debugfs will create a public root directory "vfio_mig" file.
then create a "debug_root" file for each live migration VF device.
state file: used to get the status of the live migration device.
debug_root: used to create your own custom debug files for live
migration device drivers.

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/pci/Makefile           |  1 +
 drivers/vfio/pci/vfio_pci_core.c    |  3 ++
 drivers/vfio/pci/vfio_pci_debugfs.c | 80 +++++++++++++++++++++++++++++
 drivers/vfio/pci/vfio_pci_debugfs.h | 28 ++++++++++
 include/linux/vfio.h                |  8 +++
 5 files changed, 120 insertions(+)
 create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.c
 create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.h

diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
index 24c524224da5..75fe37e72e8d 100644
--- a/drivers/vfio/pci/Makefile
+++ b/drivers/vfio/pci/Makefile
@@ -2,6 +2,7 @@
 
 vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
 vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o
+vfio-pci-core-$(CONFIG_DEBUG_FS) += vfio_pci_debugfs.o
 obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o
 
 vfio-pci-y := vfio_pci.o
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index f9365a5bc961..e85df2deb8e6 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -31,6 +31,7 @@
 #include <asm/eeh.h>
 #endif
 
+#include "vfio_pci_debugfs.h"
 #include "vfio_pci_priv.h"
 
 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
@@ -2555,11 +2556,13 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_set_params);
 
 static void vfio_pci_core_cleanup(void)
 {
+	vfio_pci_debugfs_remove_root();
 	vfio_pci_uninit_perm_bits();
 }
 
 static int __init vfio_pci_core_init(void)
 {
+	vfio_pci_debugfs_create_root();
 	/* Allocate shared config space permission data used by all devices */
 	return vfio_pci_init_perm_bits();
 }
diff --git a/drivers/vfio/pci/vfio_pci_debugfs.c b/drivers/vfio/pci/vfio_pci_debugfs.c
new file mode 100644
index 000000000000..0bcf0bf034e5
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_debugfs.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023, HiSilicon Ltd.
+ */
+
+#include <linux/pci.h>
+#include <linux/vfio_pci_core.h>
+
+#include "vfio_pci_debugfs.h"
+
+static struct dentry *vfio_pci_debugfs_root;
+
+static int vfio_pci_vf_state_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;
+	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_pci_vf_debugfs_init(struct vfio_device *vdev)
+{
+	struct device *dev = vdev->dev;
+
+	vdev->debug_root = debugfs_create_dir(dev_name(dev), vfio_pci_debugfs_root);
+
+	debugfs_create_devm_seqfile(dev, "state", vdev->debug_root,
+				  vfio_pci_vf_state_read);
+}
+EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_init);
+
+void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev)
+{
+	debugfs_remove_recursive(vdev->debug_root);
+}
+EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_exit);
+
+void  vfio_pci_debugfs_create_root(void)
+{
+	vfio_pci_debugfs_root = debugfs_create_dir("vfio_mig", NULL);
+}
+EXPORT_SYMBOL_GPL(vfio_pci_debugfs_create_root);
+
+void  vfio_pci_debugfs_remove_root(void)
+{
+	debugfs_remove_recursive(vfio_pci_debugfs_root);
+	vfio_pci_debugfs_root = NULL;
+}
+EXPORT_SYMBOL_GPL(vfio_pci_debugfs_remove_root);
+
diff --git a/drivers/vfio/pci/vfio_pci_debugfs.h b/drivers/vfio/pci/vfio_pci_debugfs.h
new file mode 100644
index 000000000000..beaaa709725e
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_debugfs.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * vfio_pci_debugfs.h - VFIO migration debugfs interface
+ *
+ * Copyright (c) 2023, HiSilicon Ltd.
+ *
+ * Author: Longfang Liu <liulongfang@huawei.com>
+ */
+
+#ifndef __VFIO_PCI_DEBUGFS_H
+#define __VFIO_PCI_DEBUGFS_H
+
+#include <linux/debugfs.h>
+#include <linux/vfio.h>
+
+#ifdef CONFIG_DEBUG_FS
+void vfio_pci_debugfs_create_root(void);
+void vfio_pci_debugfs_remove_root(void);
+void vfio_pci_vf_debugfs_init(struct vfio_device *vdev);
+void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev);
+#else
+static inline void vfio_pci_debugfs_create_root(void) {}
+static inline void vfio_pci_debugfs_remove_root(void) {}
+static inline void vfio_pci_vf_debugfs_init(struct vfio_device *vdev) {}
+static inline void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev) {}
+#endif /* CONFIG_DEBUG_FS */
+
+#endif /* __VFIO_PCI_DEBUGFS_H */
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index b4d5d4ca3d7d..b4bc8dfe8413 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -54,6 +54,14 @@ struct vfio_device {
 	struct completion comp;
 	struct list_head group_next;
 	struct list_head iommu_entry;
+
+#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

[PATCH v7 2/5] hisi_acc_vfio_pci: extract public functions for container_of

[Longfang Liu]

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>
---
 .../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 51941bb4f31f..6a219b01c965 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 v7 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Longfang Liu]

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

On the basis of the original public debug function, a private debug
function is added:

mig_data file: used to get the migration data of the live migration device
mig_attr file: used to get device attributes of the live migration device
debug file: used to test for acquiring and writing device state data
for VF device.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 282 ++++++++++++++++++
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
 2 files changed, 293 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index 6a219b01c965..96e2a021a956 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_pci_debugfs.h"
 
 /* Return 0 on VM acc device ready, -ETIMEDOUT hardware timeout */
 static int qm_wait_dev_not_ready(struct hisi_qm *qm)
@@ -606,6 +607,18 @@ hisi_acc_check_int_state(struct hisi_acc_vf_core_device *hisi_acc_vdev)
 	}
 }
 
+static void hisi_acc_vf_migf_save(struct hisi_acc_vf_migration_file *src_migf,
+	struct hisi_acc_vf_migration_file *dst_migf)
+{
+	if (!dst_migf)
+		return;
+
+	dst_migf->disabled = false;
+	dst_migf->total_length = src_migf->total_length;
+	memcpy(&dst_migf->vf_data, &src_migf->vf_data,
+		    sizeof(struct acc_vf_data));
+}
+
 static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
 {
 	mutex_lock(&migf->lock);
@@ -618,12 +631,16 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
 static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
 {
 	if (hisi_acc_vdev->resuming_migf) {
+		hisi_acc_vf_migf_save(hisi_acc_vdev->resuming_migf,
+						hisi_acc_vdev->debug_migf);
 		hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf);
 		fput(hisi_acc_vdev->resuming_migf->filp);
 		hisi_acc_vdev->resuming_migf = NULL;
 	}
 
 	if (hisi_acc_vdev->saving_migf) {
+		hisi_acc_vf_migf_save(hisi_acc_vdev->saving_migf,
+						hisi_acc_vdev->debug_migf);
 		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
 		fput(hisi_acc_vdev->saving_migf->filp);
 		hisi_acc_vdev->saving_migf = NULL;
@@ -1303,6 +1320,265 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
 	return vfio_pci_core_ioctl(core_vdev, cmd, arg);
 }
 
+static int hisi_acc_vf_debug_io(struct vfio_device *vdev)
+{
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
+	struct device *dev = vdev->dev;
+	u64 data;
+	int ret;
+
+	ret = qm_wait_dev_not_ready(vf_qm);
+	if (ret)
+		dev_err(dev, "VF device not ready!\n");
+
+	data = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
+	dev_info(dev, "debug mailbox val: 0x%llx\n", data);
+
+	return ret;
+}
+
+static int hisi_acc_vf_debug_resume(struct vfio_device *vdev)
+{
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
+	struct device *dev = vdev->dev;
+	int ret;
+
+	ret = vf_qm_state_save(hisi_acc_vdev, migf);
+	if (ret) {
+		dev_err(dev, "failed to save device data!\n");
+		return -EINVAL;
+	}
+
+	ret = vf_qm_check_match(hisi_acc_vdev, migf);
+	if (ret) {
+		dev_err(dev, "failed to match the VF!\n");
+		return -EINVAL;
+	}
+
+	ret = vf_qm_load_data(hisi_acc_vdev, migf);
+	if (ret) {
+		dev_err(dev, "failed to recover the VF!\n");
+		return -EINVAL;
+	}
+
+	vf_qm_fun_reset(&hisi_acc_vdev->vf_qm);
+	dev_info(dev, "successful to resume device data!\n");
+
+	return 0;
+}
+
+static int hisi_acc_vf_debug_save(struct vfio_device *vdev)
+{
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
+	struct device *dev = vdev->dev;
+	int ret;
+
+	ret = vf_qm_state_save(hisi_acc_vdev, migf);
+	if (ret) {
+		dev_err(dev, "failed to save device data!\n");
+		return -EINVAL;
+	}
+	dev_info(dev, "successful to save device data!\n");
+
+	return 0;
+}
+
+static int
+hisi_acc_vf_debug_operate(struct vfio_device *vdev, unsigned int cmd)
+{
+	int ret;
+
+	switch (cmd) {
+	case STATE_SAVE:
+		ret = hisi_acc_vf_debug_save(vdev);
+		if (ret)
+			return ret;
+		break;
+	case STATE_RESUME:
+		ret = hisi_acc_vf_debug_resume(vdev);
+		if (ret)
+			return ret;
+		break;
+	case RW_IO_TEST:
+		ret = hisi_acc_vf_debug_io(vdev);
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int hisi_acc_vf_debug_check(struct vfio_device *vdev)
+{
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
+	enum vfio_device_mig_state state;
+
+	if (!vdev->mig_ops || !migf) {
+		dev_err(vdev->dev, "device not support debugfs!\n");
+		return -EINVAL;
+	}
+
+	/* If device not opened, the debugfs operation will trigger calltrace */
+	(void)vdev->mig_ops->migration_get_state(vdev, &state);
+	if (state == VFIO_DEVICE_STATE_ERROR ||
+	    state == VFIO_DEVICE_STATE_STOP) {
+		dev_err(vdev->dev, "device not opened!\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static ssize_t hisi_acc_vf_debug_write(struct file *filp, const char __user *buffer,
+			    size_t count, loff_t *pos)
+{
+	struct vfio_device	*vdev = filp->private_data;
+	char tbuf[VFIO_DEV_DBG_LEN];
+	unsigned long cmd;
+	int len, ret;
+
+	if (*pos)
+		return 0;
+
+	if (count >= VFIO_DEV_DBG_LEN)
+		return -ENOSPC;
+
+	ret = hisi_acc_vf_debug_check(vdev);
+	if (ret)
+		return -EINVAL;
+
+	len = simple_write_to_buffer(tbuf, VFIO_DEV_DBG_LEN - 1,
+					pos, buffer, count);
+	if (len < 0 || len > VFIO_DEV_DBG_LEN - 1)
+		return -EINVAL;
+	tbuf[len] = '\0';
+	if (kstrtoul(tbuf, 0, &cmd))
+		return -EFAULT;
+
+	ret = hisi_acc_vf_debug_operate(vdev, cmd);
+	if (ret) {
+		dev_err(vdev->dev, "device debug test failed!\n");
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static const struct file_operations hisi_acc_vf_debug_fops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.write = hisi_acc_vf_debug_write,
+};
+
+static void seq_print_hex_data(struct seq_file *seq, const void *buf, size_t len)
+{
+#define HEX_LINE_SIZE		131
+#define HEX_ROW_SIZE		16
+	unsigned char linebuf[HEX_LINE_SIZE];
+	int i, linelen, remaining = len;
+	const u8 *ptr = buf;
+
+	for (i = 0; i < len; i += HEX_ROW_SIZE) {
+		linelen = min(remaining, HEX_ROW_SIZE);
+		remaining -= HEX_ROW_SIZE;
+
+		hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE, 1,
+					linebuf, sizeof(linebuf), false);
+
+		seq_printf(seq, "%s%.8x: %s\n", "Mig Data:", i, linebuf);
+	}
+}
+
+static int hisi_acc_vf_data_read(struct seq_file *seq, void *data)
+{
+	struct device *vf_dev = seq->private;
+	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
+	struct vfio_device	*vdev = &core_device->vdev;
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
+	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
+
+	if (debug_migf && debug_migf->total_length)
+		seq_print_hex_data(seq, (unsigned char *)&debug_migf->vf_data,
+				vf_data_sz);
+	else
+		seq_printf(seq, "%s\n", "device not migrated!");
+
+	return 0;
+}
+
+static int hisi_acc_vf_attr_read(struct seq_file *seq, void *data)
+{
+	struct device *vf_dev = seq->private;
+	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
+	struct vfio_device	*vdev = &core_device->vdev;
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
+	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
+
+	if (debug_migf && debug_migf->total_length) {
+		seq_printf(seq,
+			 "acc device:\n"
+			 "device  state: %d\n"
+			 "device  ready: %u\n"
+			 "data    valid: %d\n"
+			 "data     size: %lu\n",
+			 hisi_acc_vdev->mig_state,
+			 hisi_acc_vdev->vf_qm_state,
+			 debug_migf->disabled,
+			 debug_migf->total_length);
+	} else {
+		seq_printf(seq, "%s\n", "device not migrated!");
+	}
+
+	return 0;
+}
+
+static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev)
+{
+	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
+	struct device *dev = vdev->dev;
+	void *migf = NULL;
+
+	if (!debugfs_initialized())
+		return 0;
+
+	vfio_pci_vf_debugfs_init(vdev);
+
+	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
+	if (!migf)
+		return -ENOMEM;
+
+	hisi_acc_vdev->debug_migf = migf;
+
+	debugfs_create_devm_seqfile(dev, "mig_data", vdev->debug_root,
+				  hisi_acc_vf_data_read);
+	debugfs_create_devm_seqfile(dev, "mig_attr", vdev->debug_root,
+				  hisi_acc_vf_attr_read);
+
+	debugfs_create_file("debug", 0200, vdev->debug_root,
+				  vdev, &hisi_acc_vf_debug_fops);
+
+	return 0;
+}
+
+static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
+{
+	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
+
+	if (!debugfs_initialized())
+		return;
+
+	kfree(hisi_acc_vdev->debug_migf);
+	vfio_pci_vf_debugfs_exit(vdev);
+}
+
 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);
@@ -1410,6 +1686,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 	if (IS_ERR(hisi_acc_vdev))
 		return PTR_ERR(hisi_acc_vdev);
 
+	if (ops == &hisi_acc_vfio_pci_migrn_ops)
+		hisi_acc_vfio_debug_init(hisi_acc_vdev);
+
 	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
 	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
 	if (ret)
@@ -1417,6 +1696,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 	return 0;
 
 out_put_vdev:
+	if (ops == &hisi_acc_vfio_pci_migrn_ops)
+		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
 	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
 	return ret;
 }
@@ -1425,6 +1706,7 @@ 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

[PATCH v7 4/5] Documentation: add debugfs description for hisi_acc_vfio_pci

[Longfang Liu]

Add a debugfs document description file to help users understand
how to use the accelerator live migration driver's debugfs.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration

diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
new file mode 100644
index 000000000000..d644a497c464
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-hisi-migration
@@ -0,0 +1,32 @@
+What:		/sys/kernel/debug/vfio_mig/<bdf>/state
+Date:		Jan 2023
+Contact:	linux-kernel@vger.kernel.org
+Description:	Read the live migration status of the VF device.
+		The status of these live migrations includes:
+		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.
+
+What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_data
+Date:		Jan 2023
+Contact:	linux-kernel@vger.kernel.org
+Description:	Read the live migration data of the VF device.
+		The output format of the data is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_attr
+Date:		Jan 2023
+Contact:	linux-kernel@vger.kernel.org
+Description:	Read the live migration attributes of the VF device.
+		The output format of the attributes is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio_mig/<bdf>/debug
+Date:		Jan 2023
+Contact:	linux-kernel@vger.kernel.org
+Description:	This debug file supports "echo" command	write operations.
+		The command is actually represented by an integer number, and the
+		specific meaning is defined by the corresponding device driver.
+		For example, three commands are defined in the HiSilicon accelerator
+		live migration driver:
+		0: State save
+		1: State resume
+		2: IO test
-- 
2.24.0

[PATCH v7 5/5] vfio: update live migration device status

[Longfang Liu]

migration debugfs needs to perform debug operations based on the
status of the current device. If the device is not loaded or has
stopped, debugfs does not allow operations.

so, after the live migration function is executed and the device is
turned off, the device no longer needs to be accessed. At this time,
the status of the device needs to be set to stop.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 3 +++
 drivers/vfio/pci/mlx5/main.c                   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index 96e2a021a956..bdb9043f88f1 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -1607,6 +1607,9 @@ 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;
 
+	if (core_vdev->mig_ops)
+		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_STOP;
+
 	iounmap(vf_qm->io_base);
 	vfio_pci_core_close_device(core_vdev);
 }
diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
index 031ac8cc215d..64b2fe58355a 100644
--- a/drivers/vfio/pci/mlx5/main.c
+++ b/drivers/vfio/pci/mlx5/main.c
@@ -1092,6 +1092,9 @@ static void mlx5vf_pci_close_device(struct vfio_device *core_vdev)
 	struct mlx5vf_pci_core_device *mvdev = container_of(
 		core_vdev, struct mlx5vf_pci_core_device, core_device.vdev);
 
+	if (mvdev->migrate_cap)
+		mvdev->mig_state = VFIO_DEVICE_STATE_STOP;
+
 	mlx5vf_cmd_close_migratable(mvdev);
 	vfio_pci_core_close_device(core_vdev);
 }
-- 
2.24.0

Re: [PATCH v7 1/5] vfio/migration: Add debugfs to live migration driver

[Alex Williamson]

On Fri, 20 Jan 2023 11:29:26 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> 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 VF |                | dst VF |
>      +-+------+                +-+------+
>        |   ^                     |   ^
>        v   |                     v   |
>  +-------+-+------+        +-------+-+------+
>  |Debugfs|state   |        |Debugfs|state   |
>  +-------+--------+        +-------+--------+
>  |   debug_root   |        |   debug_root   |
>  +-------+--------+        +-------+--------+
> 
> 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_pci_debugfs.h will be empty definitions,
> and the creation and initialization of the debugfs directory
> will not be executed.
> 
> debugfs will create a public root directory "vfio_mig" file.
> then create a "debug_root" file for each live migration VF device.

s/VF // In practice it may be VFs, but I don't think we want to
artificially imply that the device must be a VF.  In fact, I'm not sure
why any of this code lives in vfio/pci/ vs vfio/, there's nothing PCI
specific here.  Why isn't all of this done in vfio_main to be shared
with both pci and non-pci vfio drivers and devices?

> state file: used to get the status of the live migration device.
> debug_root: used to create your own custom debug files for live
> migration device drivers.
> 
> 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/pci/Makefile           |  1 +
>  drivers/vfio/pci/vfio_pci_core.c    |  3 ++
>  drivers/vfio/pci/vfio_pci_debugfs.c | 80 +++++++++++++++++++++++++++++
>  drivers/vfio/pci/vfio_pci_debugfs.h | 28 ++++++++++
>  include/linux/vfio.h                |  8 +++
>  5 files changed, 120 insertions(+)
>  create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.c
>  create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.h
> 
> diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
> index 24c524224da5..75fe37e72e8d 100644
> --- a/drivers/vfio/pci/Makefile
> +++ b/drivers/vfio/pci/Makefile
> @@ -2,6 +2,7 @@
>  
>  vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
>  vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o
> +vfio-pci-core-$(CONFIG_DEBUG_FS) += vfio_pci_debugfs.o
>  obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o
>  
>  vfio-pci-y := vfio_pci.o
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index f9365a5bc961..e85df2deb8e6 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -31,6 +31,7 @@
>  #include <asm/eeh.h>
>  #endif
>  
> +#include "vfio_pci_debugfs.h"
>  #include "vfio_pci_priv.h"
>  
>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
> @@ -2555,11 +2556,13 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_set_params);
>  
>  static void vfio_pci_core_cleanup(void)
>  {
> +	vfio_pci_debugfs_remove_root();
>  	vfio_pci_uninit_perm_bits();
>  }
>  
>  static int __init vfio_pci_core_init(void)
>  {
> +	vfio_pci_debugfs_create_root();
>  	/* Allocate shared config space permission data used by all devices */
>  	return vfio_pci_init_perm_bits();
>  }
> diff --git a/drivers/vfio/pci/vfio_pci_debugfs.c b/drivers/vfio/pci/vfio_pci_debugfs.c
> new file mode 100644
> index 000000000000..0bcf0bf034e5
> --- /dev/null
> +++ b/drivers/vfio/pci/vfio_pci_debugfs.c
> @@ -0,0 +1,80 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2023, HiSilicon Ltd.
> + */
> +
> +#include <linux/pci.h>
> +#include <linux/vfio_pci_core.h>
> +
> +#include "vfio_pci_debugfs.h"
> +
> +static struct dentry *vfio_pci_debugfs_root;
> +
> +static int vfio_pci_vf_state_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;
> +	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_pci_vf_debugfs_init(struct vfio_device *vdev)
> +{
> +	struct device *dev = vdev->dev;
> +
> +	vdev->debug_root = debugfs_create_dir(dev_name(dev), vfio_pci_debugfs_root);
> +
> +	debugfs_create_devm_seqfile(dev, "state", vdev->debug_root,
> +				  vfio_pci_vf_state_read);
> +}
> +EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_init);
> +
> +void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev)
> +{
> +	debugfs_remove_recursive(vdev->debug_root);
> +}
> +EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_exit);
> +
> +void  vfio_pci_debugfs_create_root(void)
> +{
> +	vfio_pci_debugfs_root = debugfs_create_dir("vfio_mig", NULL);

Is this hierarchical, ie. should we have "vfio/migration/" such that we
can introduce other debugfs entries w/o creating vfio_foo, vfio_bar,
vfio_baz, etc.  Otherwise the core or pci-core should only initialize a
"vfio" or "vfio-pci" root and the above init and exit interfaces should
be migration specific, creating "migrations_state" and only removing
the entries on exit that their companion init function created.

> +}
> +EXPORT_SYMBOL_GPL(vfio_pci_debugfs_create_root);
> +
> +void  vfio_pci_debugfs_remove_root(void)
> +{
> +	debugfs_remove_recursive(vfio_pci_debugfs_root);
> +	vfio_pci_debugfs_root = NULL;
> +}
> +EXPORT_SYMBOL_GPL(vfio_pci_debugfs_remove_root);
> +
> diff --git a/drivers/vfio/pci/vfio_pci_debugfs.h b/drivers/vfio/pci/vfio_pci_debugfs.h
> new file mode 100644
> index 000000000000..beaaa709725e
> --- /dev/null
> +++ b/drivers/vfio/pci/vfio_pci_debugfs.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * vfio_pci_debugfs.h - VFIO migration debugfs interface
> + *
> + * Copyright (c) 2023, HiSilicon Ltd.
> + *
> + * Author: Longfang Liu <liulongfang@huawei.com>
> + */
> +
> +#ifndef __VFIO_PCI_DEBUGFS_H
> +#define __VFIO_PCI_DEBUGFS_H
> +
> +#include <linux/debugfs.h>
> +#include <linux/vfio.h>
> +
> +#ifdef CONFIG_DEBUG_FS
> +void vfio_pci_debugfs_create_root(void);
> +void vfio_pci_debugfs_remove_root(void);
> +void vfio_pci_vf_debugfs_init(struct vfio_device *vdev);
> +void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev);
> +#else
> +static inline void vfio_pci_debugfs_create_root(void) {}
> +static inline void vfio_pci_debugfs_remove_root(void) {}
> +static inline void vfio_pci_vf_debugfs_init(struct vfio_device *vdev) {}
> +static inline void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev) {}
> +#endif /* CONFIG_DEBUG_FS */
> +
> +#endif /* __VFIO_PCI_DEBUGFS_H */

With the above changes, declarations should probably just exist in
drivers/vfio/vfio.h.  Thanks,

Alex

> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index b4d5d4ca3d7d..b4bc8dfe8413 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -54,6 +54,14 @@ struct vfio_device {
>  	struct completion comp;
>  	struct list_head group_next;
>  	struct list_head iommu_entry;
> +
> +#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 v7 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Alex Williamson]

On Fri, 20 Jan 2023 11:29:28 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> On the debugfs framework of VFIO, if the CONFIG_DEBUG_FS macro is
> enabled, the debug function is registered for the live migration driver
> of the HiSilicon accelerator device.
> 
> On the basis of the original public debug function, a private debug
> function is added:
> 
> mig_data file: used to get the migration data of the live migration device
> mig_attr file: used to get device attributes of the live migration device
> debug file: used to test for acquiring and writing device state data
> for VF device.
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 282 ++++++++++++++++++
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
>  2 files changed, 293 insertions(+)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 6a219b01c965..96e2a021a956 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_pci_debugfs.h"
>  
>  /* Return 0 on VM acc device ready, -ETIMEDOUT hardware timeout */
>  static int qm_wait_dev_not_ready(struct hisi_qm *qm)
> @@ -606,6 +607,18 @@ hisi_acc_check_int_state(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>  	}
>  }
>  
> +static void hisi_acc_vf_migf_save(struct hisi_acc_vf_migration_file *src_migf,
> +	struct hisi_acc_vf_migration_file *dst_migf)
> +{
> +	if (!dst_migf)
> +		return;
> +
> +	dst_migf->disabled = false;
> +	dst_migf->total_length = src_migf->total_length;
> +	memcpy(&dst_migf->vf_data, &src_migf->vf_data,
> +		    sizeof(struct acc_vf_data));
> +}
> +
>  static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>  {
>  	mutex_lock(&migf->lock);
> @@ -618,12 +631,16 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>  static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>  {
>  	if (hisi_acc_vdev->resuming_migf) {
> +		hisi_acc_vf_migf_save(hisi_acc_vdev->resuming_migf,
> +						hisi_acc_vdev->debug_migf);
>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf);
>  		fput(hisi_acc_vdev->resuming_migf->filp);
>  		hisi_acc_vdev->resuming_migf = NULL;
>  	}
>  
>  	if (hisi_acc_vdev->saving_migf) {
> +		hisi_acc_vf_migf_save(hisi_acc_vdev->saving_migf,
> +						hisi_acc_vdev->debug_migf);
>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>  		fput(hisi_acc_vdev->saving_migf->filp);
>  		hisi_acc_vdev->saving_migf = NULL;
> @@ -1303,6 +1320,265 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
>  	return vfio_pci_core_ioctl(core_vdev, cmd, arg);
>  }
>  
> +static int hisi_acc_vf_debug_io(struct vfio_device *vdev)
> +{
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
> +	struct device *dev = vdev->dev;
> +	u64 data;
> +	int ret;
> +
> +	ret = qm_wait_dev_not_ready(vf_qm);
> +	if (ret)
> +		dev_err(dev, "VF device not ready!\n");
> +
> +	data = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
> +	dev_info(dev, "debug mailbox val: 0x%llx\n", data);
> +
> +	return ret;
> +}
> +
> +static int hisi_acc_vf_debug_resume(struct vfio_device *vdev)
> +{
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
> +	struct device *dev = vdev->dev;
> +	int ret;
> +
> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
> +	if (ret) {
> +		dev_err(dev, "failed to save device data!\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = vf_qm_check_match(hisi_acc_vdev, migf);
> +	if (ret) {
> +		dev_err(dev, "failed to match the VF!\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = vf_qm_load_data(hisi_acc_vdev, migf);
> +	if (ret) {
> +		dev_err(dev, "failed to recover the VF!\n");
> +		return -EINVAL;
> +	}
> +
> +	vf_qm_fun_reset(&hisi_acc_vdev->vf_qm);
> +	dev_info(dev, "successful to resume device data!\n");
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_debug_save(struct vfio_device *vdev)
> +{
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
> +	struct device *dev = vdev->dev;
> +	int ret;
> +
> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
> +	if (ret) {
> +		dev_err(dev, "failed to save device data!\n");
> +		return -EINVAL;
> +	}
> +	dev_info(dev, "successful to save device data!\n");
> +
> +	return 0;
> +}
> +
> +static int
> +hisi_acc_vf_debug_operate(struct vfio_device *vdev, unsigned int cmd)
> +{
> +	int ret;
> +
> +	switch (cmd) {
> +	case STATE_SAVE:
> +		ret = hisi_acc_vf_debug_save(vdev);
> +		if (ret)
> +			return ret;
> +		break;
> +	case STATE_RESUME:
> +		ret = hisi_acc_vf_debug_resume(vdev);
> +		if (ret)
> +			return ret;
> +		break;
> +	case RW_IO_TEST:
> +		ret = hisi_acc_vf_debug_io(vdev);
> +		if (ret)
> +			return ret;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_debug_check(struct vfio_device *vdev)
> +{
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
> +	enum vfio_device_mig_state state;
> +
> +	if (!vdev->mig_ops || !migf) {
> +		dev_err(vdev->dev, "device not support debugfs!\n");
> +		return -EINVAL;
> +	}
> +
> +	/* If device not opened, the debugfs operation will trigger calltrace */
> +	(void)vdev->mig_ops->migration_get_state(vdev, &state);
> +	if (state == VFIO_DEVICE_STATE_ERROR ||
> +	    state == VFIO_DEVICE_STATE_STOP) {
> +		dev_err(vdev->dev, "device not opened!\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static ssize_t hisi_acc_vf_debug_write(struct file *filp, const char __user *buffer,
> +			    size_t count, loff_t *pos)
> +{
> +	struct vfio_device	*vdev = filp->private_data;
> +	char tbuf[VFIO_DEV_DBG_LEN];
> +	unsigned long cmd;
> +	int len, ret;
> +
> +	if (*pos)
> +		return 0;
> +
> +	if (count >= VFIO_DEV_DBG_LEN)
> +		return -ENOSPC;
> +
> +	ret = hisi_acc_vf_debug_check(vdev);
> +	if (ret)
> +		return -EINVAL;
> +
> +	len = simple_write_to_buffer(tbuf, VFIO_DEV_DBG_LEN - 1,
> +					pos, buffer, count);
> +	if (len < 0 || len > VFIO_DEV_DBG_LEN - 1)
> +		return -EINVAL;
> +	tbuf[len] = '\0';
> +	if (kstrtoul(tbuf, 0, &cmd))
> +		return -EFAULT;
> +
> +	ret = hisi_acc_vf_debug_operate(vdev, cmd);
> +	if (ret) {
> +		dev_err(vdev->dev, "device debug test failed!\n");
> +		return -EINVAL;
> +	}
> +
> +	return count;
> +}
> +
> +static const struct file_operations hisi_acc_vf_debug_fops = {
> +	.owner = THIS_MODULE,
> +	.open = simple_open,
> +	.write = hisi_acc_vf_debug_write,
> +};
> +
> +static void seq_print_hex_data(struct seq_file *seq, const void *buf, size_t len)
> +{
> +#define HEX_LINE_SIZE		131
> +#define HEX_ROW_SIZE		16
> +	unsigned char linebuf[HEX_LINE_SIZE];
> +	int i, linelen, remaining = len;
> +	const u8 *ptr = buf;
> +
> +	for (i = 0; i < len; i += HEX_ROW_SIZE) {
> +		linelen = min(remaining, HEX_ROW_SIZE);
> +		remaining -= HEX_ROW_SIZE;
> +
> +		hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE, 1,
> +					linebuf, sizeof(linebuf), false);
> +
> +		seq_printf(seq, "%s%.8x: %s\n", "Mig Data:", i, linebuf);
> +	}
> +}
> +
> +static int hisi_acc_vf_data_read(struct seq_file *seq, void *data)
> +{
> +	struct device *vf_dev = seq->private;
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
> +	struct vfio_device	*vdev = &core_device->vdev;
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
> +
> +	if (debug_migf && debug_migf->total_length)
> +		seq_print_hex_data(seq, (unsigned char *)&debug_migf->vf_data,
> +				vf_data_sz);
> +	else
> +		seq_printf(seq, "%s\n", "device not migrated!");
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vf_attr_read(struct seq_file *seq, void *data)
> +{
> +	struct device *vf_dev = seq->private;
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
> +	struct vfio_device	*vdev = &core_device->vdev;
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
> +
> +	if (debug_migf && debug_migf->total_length) {
> +		seq_printf(seq,
> +			 "acc device:\n"
> +			 "device  state: %d\n"
> +			 "device  ready: %u\n"
> +			 "data    valid: %d\n"
> +			 "data     size: %lu\n",
> +			 hisi_acc_vdev->mig_state,
> +			 hisi_acc_vdev->vf_qm_state,
> +			 debug_migf->disabled,
> +			 debug_migf->total_length);
> +	} else {
> +		seq_printf(seq, "%s\n", "device not migrated!");
> +	}
> +
> +	return 0;
> +}
> +
> +static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> +{
> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
> +	struct device *dev = vdev->dev;
> +	void *migf = NULL;
> +
> +	if (!debugfs_initialized())
> +		return 0;
> +
> +	vfio_pci_vf_debugfs_init(vdev);
> +
> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
> +	if (!migf)
> +		return -ENOMEM;
> +
> +	hisi_acc_vdev->debug_migf = migf;
> +
> +	debugfs_create_devm_seqfile(dev, "mig_data", vdev->debug_root,
> +				  hisi_acc_vf_data_read);
> +	debugfs_create_devm_seqfile(dev, "mig_attr", vdev->debug_root,
> +				  hisi_acc_vf_attr_read);
> +
> +	debugfs_create_file("debug", 0200, vdev->debug_root,
> +				  vdev, &hisi_acc_vf_debug_fops);

Naming is rather haphazard.  I think this results in vfio_mig/state,
vfio_mig/mig_data, vfio_mig/mig_attr, vfio_mig/debug.  If would be much
cleaner if we had either {state,data,attr,debug} under vfio/migration/
or migration_{state,data,attr,debug} under vfio/

> +
> +	return 0;
> +}
> +
> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> +{
> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
> +
> +	if (!debugfs_initialized())
> +		return;
> +
> +	kfree(hisi_acc_vdev->debug_migf);
> +	vfio_pci_vf_debugfs_exit(vdev);

Ordering is suspect here, we're freeing data used by the debugfs
entries before removing the entries themselves, which suggests a
use-after-free issue.  Thanks,

Alex

> +}
> +
>  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);
> @@ -1410,6 +1686,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  	if (IS_ERR(hisi_acc_vdev))
>  		return PTR_ERR(hisi_acc_vdev);
>  
> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
> +		hisi_acc_vfio_debug_init(hisi_acc_vdev);
> +
>  	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>  	if (ret)
> @@ -1417,6 +1696,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  	return 0;
>  
>  out_put_vdev:
> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
> +		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>  	return ret;
>  }
> @@ -1425,6 +1706,7 @@ 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 */

Re: [PATCH v7 4/5] Documentation: add debugfs description for hisi_acc_vfio_pci

[Alex Williamson]

On Fri, 20 Jan 2023 11:29:29 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> Add a debugfs document description file to help users understand
> how to use the accelerator live migration driver's debugfs.
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
> 
> diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
> new file mode 100644
> index 000000000000..d644a497c464
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-hisi-migration
> @@ -0,0 +1,32 @@
> +What:		/sys/kernel/debug/vfio_mig/<bdf>/state
> +Date:		Jan 2023
> +Contact:	linux-kernel@vger.kernel.org
> +Description:	Read the live migration status of the VF device.
> +		The status of these live migrations includes:
> +		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.

state is added by vfio-pci-core in this series, so the documentation
can't be limited to hisi_acc.

> +
> +What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_data
> +Date:		Jan 2023
> +Contact:	linux-kernel@vger.kernel.org
> +Description:	Read the live migration data of the VF device.
> +		The output format of the data is defined by the live
> +		migration driver.
> +
> +What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_attr
> +Date:		Jan 2023
> +Contact:	linux-kernel@vger.kernel.org
> +Description:	Read the live migration attributes of the VF device.
> +		The output format of the attributes is defined by the live
> +		migration driver.
> +
> +What:		/sys/kernel/debug/vfio_mig/<bdf>/debug
> +Date:		Jan 2023
> +Contact:	linux-kernel@vger.kernel.org
> +Description:	This debug file supports "echo" command	write operations.
> +		The command is actually represented by an integer number, and the
> +		specific meaning is defined by the corresponding device driver.
> +		For example, three commands are defined in the HiSilicon accelerator
> +		live migration driver:
> +		0: State save
> +		1: State resume
> +		2: IO test

I think the goal here is to create some sort of standard interface for
migration, so these should also be documented for all devices, and any
device specific behavior noted.  Otherwise these should all be prefixed
hisi_acc_ to denote them as device specific implementations.  Thanks,

Alex

Re: [PATCH v7 5/5] vfio: update live migration device status

[Alex Williamson]

On Fri, 20 Jan 2023 11:29:30 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> migration debugfs needs to perform debug operations based on the
> status of the current device. If the device is not loaded or has
> stopped, debugfs does not allow operations.
> 
> so, after the live migration function is executed and the device is
> turned off, the device no longer needs to be accessed. At this time,
> the status of the device needs to be set to stop.
> 
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 3 +++
>  drivers/vfio/pci/mlx5/main.c                   | 3 +++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 96e2a021a956..bdb9043f88f1 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1607,6 +1607,9 @@ 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;
>  
> +	if (core_vdev->mig_ops)
> +		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_STOP;
> +
>  	iounmap(vf_qm->io_base);
>  	vfio_pci_core_close_device(core_vdev);
>  }
> diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
> index 031ac8cc215d..64b2fe58355a 100644
> --- a/drivers/vfio/pci/mlx5/main.c
> +++ b/drivers/vfio/pci/mlx5/main.c
> @@ -1092,6 +1092,9 @@ static void mlx5vf_pci_close_device(struct vfio_device *core_vdev)
>  	struct mlx5vf_pci_core_device *mvdev = container_of(
>  		core_vdev, struct mlx5vf_pci_core_device, core_device.vdev);
>  
> +	if (mvdev->migrate_cap)
> +		mvdev->mig_state = VFIO_DEVICE_STATE_STOP;
> +
>  	mlx5vf_cmd_close_migratable(mvdev);
>  	vfio_pci_core_close_device(core_vdev);
>  }

It seems prone to issues to manipulate the migration state outside of
the driver state machine.  If the device is closed, shouldn't the
debugfs state interface return -EINVAL?  Thanks,

Alex

Re: [PATCH v7 1/5] vfio/migration: Add debugfs to live migration driver

[liulongfang]

On 2023/1/27 3:27, Alex Williamson wrote:
> On Fri, 20 Jan 2023 11:29:26 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> 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 VF |                | dst VF |
>>      +-+------+                +-+------+
>>        |   ^                     |   ^
>>        v   |                     v   |
>>  +-------+-+------+        +-------+-+------+
>>  |Debugfs|state   |        |Debugfs|state   |
>>  +-------+--------+        +-------+--------+
>>  |   debug_root   |        |   debug_root   |
>>  +-------+--------+        +-------+--------+
>>
>> 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_pci_debugfs.h will be empty definitions,
>> and the creation and initialization of the debugfs directory
>> will not be executed.
>>
>> debugfs will create a public root directory "vfio_mig" file.
>> then create a "debug_root" file for each live migration VF device.
> 
> s/VF // In practice it may be VFs, but I don't think we want to
> artificially imply that the device must be a VF.  In fact, I'm not sure

Yes, the description should be modified here, and it should not be limited
to only support VF.

> why any of this code lives in vfio/pci/ vs vfio/, there's nothing PCI
> specific here.  Why isn't all of this done in vfio_main to be shared
> with both pci and non-pci vfio drivers and devices?
>

Combined with your observations below, I think it is more appropriate to
create a "vfio-pci" directory here, because the current live migration
function is still used on pci devices.

For non-pci devices, if there is a device that needs to add debugfs,
then it can create a similar directory.

>> state file: used to get the status of the live migration device.
>> debug_root: used to create your own custom debug files for live
>> migration device drivers.
>>
>> 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/pci/Makefile           |  1 +
>>  drivers/vfio/pci/vfio_pci_core.c    |  3 ++
>>  drivers/vfio/pci/vfio_pci_debugfs.c | 80 +++++++++++++++++++++++++++++
>>  drivers/vfio/pci/vfio_pci_debugfs.h | 28 ++++++++++
>>  include/linux/vfio.h                |  8 +++
>>  5 files changed, 120 insertions(+)
>>  create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.c
>>  create mode 100644 drivers/vfio/pci/vfio_pci_debugfs.h
>>
>> diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
>> index 24c524224da5..75fe37e72e8d 100644
>> --- a/drivers/vfio/pci/Makefile
>> +++ b/drivers/vfio/pci/Makefile
>> @@ -2,6 +2,7 @@
>>  
>>  vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
>>  vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o
>> +vfio-pci-core-$(CONFIG_DEBUG_FS) += vfio_pci_debugfs.o
>>  obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o
>>  
>>  vfio-pci-y := vfio_pci.o
>> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
>> index f9365a5bc961..e85df2deb8e6 100644
>> --- a/drivers/vfio/pci/vfio_pci_core.c
>> +++ b/drivers/vfio/pci/vfio_pci_core.c
>> @@ -31,6 +31,7 @@
>>  #include <asm/eeh.h>
>>  #endif
>>  
>> +#include "vfio_pci_debugfs.h"
>>  #include "vfio_pci_priv.h"
>>  
>>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
>> @@ -2555,11 +2556,13 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_set_params);
>>  
>>  static void vfio_pci_core_cleanup(void)
>>  {
>> +	vfio_pci_debugfs_remove_root();
>>  	vfio_pci_uninit_perm_bits();
>>  }
>>  
>>  static int __init vfio_pci_core_init(void)
>>  {
>> +	vfio_pci_debugfs_create_root();
>>  	/* Allocate shared config space permission data used by all devices */
>>  	return vfio_pci_init_perm_bits();
>>  }
>> diff --git a/drivers/vfio/pci/vfio_pci_debugfs.c b/drivers/vfio/pci/vfio_pci_debugfs.c
>> new file mode 100644
>> index 000000000000..0bcf0bf034e5
>> --- /dev/null
>> +++ b/drivers/vfio/pci/vfio_pci_debugfs.c
>> @@ -0,0 +1,80 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2023, HiSilicon Ltd.
>> + */
>> +
>> +#include <linux/pci.h>
>> +#include <linux/vfio_pci_core.h>
>> +
>> +#include "vfio_pci_debugfs.h"
>> +
>> +static struct dentry *vfio_pci_debugfs_root;
>> +
>> +static int vfio_pci_vf_state_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;
>> +	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_pci_vf_debugfs_init(struct vfio_device *vdev)
>> +{
>> +	struct device *dev = vdev->dev;
>> +
>> +	vdev->debug_root = debugfs_create_dir(dev_name(dev), vfio_pci_debugfs_root);
>> +
>> +	debugfs_create_devm_seqfile(dev, "state", vdev->debug_root,
>> +				  vfio_pci_vf_state_read);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_init);
>> +
>> +void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev)
>> +{
>> +	debugfs_remove_recursive(vdev->debug_root);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_pci_vf_debugfs_exit);
>> +
>> +void  vfio_pci_debugfs_create_root(void)
>> +{
>> +	vfio_pci_debugfs_root = debugfs_create_dir("vfio_mig", NULL);
> 
> Is this hierarchical, ie. should we have "vfio/migration/" such that we
> can introduce other debugfs entries w/o creating vfio_foo, vfio_bar,
> vfio_baz, etc.  Otherwise the core or pci-core should only initialize a
> "vfio" or "vfio-pci" root and the above init and exit interfaces should
> be migration specific, creating "migrations_state" and only removing
> the entries on exit that their companion init function created.
>

Yes, your suggestion is very good. Here I also agree to create a "vfio-pci"
directory.In addition, it is not easy to create a "migration" subdirectory
internally,because there is no valid basis for judging whether to create a
"migration" directory when creating a vfio-pci directory.
Therefore, it is simpler to create migration_state directly with migration
as a prefix.

>> +}
>> +EXPORT_SYMBOL_GPL(vfio_pci_debugfs_create_root);
>> +
>> +void  vfio_pci_debugfs_remove_root(void)
>> +{
>> +	debugfs_remove_recursive(vfio_pci_debugfs_root);
>> +	vfio_pci_debugfs_root = NULL;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_pci_debugfs_remove_root);
>> +
>> diff --git a/drivers/vfio/pci/vfio_pci_debugfs.h b/drivers/vfio/pci/vfio_pci_debugfs.h
>> new file mode 100644
>> index 000000000000..beaaa709725e
>> --- /dev/null
>> +++ b/drivers/vfio/pci/vfio_pci_debugfs.h
>> @@ -0,0 +1,28 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * vfio_pci_debugfs.h - VFIO migration debugfs interface
>> + *
>> + * Copyright (c) 2023, HiSilicon Ltd.
>> + *
>> + * Author: Longfang Liu <liulongfang@huawei.com>
>> + */
>> +
>> +#ifndef __VFIO_PCI_DEBUGFS_H
>> +#define __VFIO_PCI_DEBUGFS_H
>> +
>> +#include <linux/debugfs.h>
>> +#include <linux/vfio.h>
>> +
>> +#ifdef CONFIG_DEBUG_FS
>> +void vfio_pci_debugfs_create_root(void);
>> +void vfio_pci_debugfs_remove_root(void);
>> +void vfio_pci_vf_debugfs_init(struct vfio_device *vdev);
>> +void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev);
>> +#else
>> +static inline void vfio_pci_debugfs_create_root(void) {}
>> +static inline void vfio_pci_debugfs_remove_root(void) {}
>> +static inline void vfio_pci_vf_debugfs_init(struct vfio_device *vdev) {}
>> +static inline void vfio_pci_vf_debugfs_exit(struct vfio_device *vdev) {}
>> +#endif /* CONFIG_DEBUG_FS */
>> +
>> +#endif /* __VFIO_PCI_DEBUGFS_H */
> 
> With the above changes, declarations should probably just exist in
> drivers/vfio/vfio.h.  Thanks,
> 

Ok, then I'll delete this header file and put them directly in vfio.h

> Alex
> 
Thanks,
Longfang.

>> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
>> index b4d5d4ca3d7d..b4bc8dfe8413 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -54,6 +54,14 @@ struct vfio_device {
>>  	struct completion comp;
>>  	struct list_head group_next;
>>  	struct list_head iommu_entry;
>> +
>> +#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 v7 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2023/1/27 3:28, Alex Williamson wrote:
> On Fri, 20 Jan 2023 11:29:28 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> On the debugfs framework of VFIO, if the CONFIG_DEBUG_FS macro is
>> enabled, the debug function is registered for the live migration driver
>> of the HiSilicon accelerator device.
>>
>> On the basis of the original public debug function, a private debug
>> function is added:
>>
>> mig_data file: used to get the migration data of the live migration device
>> mig_attr file: used to get device attributes of the live migration device
>> debug file: used to test for acquiring and writing device state data
>> for VF device.
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 282 ++++++++++++++++++
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  11 +
>>  2 files changed, 293 insertions(+)
>>
>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> index 6a219b01c965..96e2a021a956 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_pci_debugfs.h"
>>  
>>  /* Return 0 on VM acc device ready, -ETIMEDOUT hardware timeout */
>>  static int qm_wait_dev_not_ready(struct hisi_qm *qm)
>> @@ -606,6 +607,18 @@ hisi_acc_check_int_state(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>  	}
>>  }
>>  
>> +static void hisi_acc_vf_migf_save(struct hisi_acc_vf_migration_file *src_migf,
>> +	struct hisi_acc_vf_migration_file *dst_migf)
>> +{
>> +	if (!dst_migf)
>> +		return;
>> +
>> +	dst_migf->disabled = false;
>> +	dst_migf->total_length = src_migf->total_length;
>> +	memcpy(&dst_migf->vf_data, &src_migf->vf_data,
>> +		    sizeof(struct acc_vf_data));
>> +}
>> +
>>  static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>  {
>>  	mutex_lock(&migf->lock);
>> @@ -618,12 +631,16 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf)
>>  static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>>  {
>>  	if (hisi_acc_vdev->resuming_migf) {
>> +		hisi_acc_vf_migf_save(hisi_acc_vdev->resuming_migf,
>> +						hisi_acc_vdev->debug_migf);
>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf);
>>  		fput(hisi_acc_vdev->resuming_migf->filp);
>>  		hisi_acc_vdev->resuming_migf = NULL;
>>  	}
>>  
>>  	if (hisi_acc_vdev->saving_migf) {
>> +		hisi_acc_vf_migf_save(hisi_acc_vdev->saving_migf,
>> +						hisi_acc_vdev->debug_migf);
>>  		hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
>>  		fput(hisi_acc_vdev->saving_migf->filp);
>>  		hisi_acc_vdev->saving_migf = NULL;
>> @@ -1303,6 +1320,265 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
>>  	return vfio_pci_core_ioctl(core_vdev, cmd, arg);
>>  }
>>  
>> +static int hisi_acc_vf_debug_io(struct vfio_device *vdev)
>> +{
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
>> +	struct device *dev = vdev->dev;
>> +	u64 data;
>> +	int ret;
>> +
>> +	ret = qm_wait_dev_not_ready(vf_qm);
>> +	if (ret)
>> +		dev_err(dev, "VF device not ready!\n");
>> +
>> +	data = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
>> +	dev_info(dev, "debug mailbox val: 0x%llx\n", data);
>> +
>> +	return ret;
>> +}
>> +
>> +static int hisi_acc_vf_debug_resume(struct vfio_device *vdev)
>> +{
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>> +	struct device *dev = vdev->dev;
>> +	int ret;
>> +
>> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
>> +	if (ret) {
>> +		dev_err(dev, "failed to save device data!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = vf_qm_check_match(hisi_acc_vdev, migf);
>> +	if (ret) {
>> +		dev_err(dev, "failed to match the VF!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = vf_qm_load_data(hisi_acc_vdev, migf);
>> +	if (ret) {
>> +		dev_err(dev, "failed to recover the VF!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	vf_qm_fun_reset(&hisi_acc_vdev->vf_qm);
>> +	dev_info(dev, "successful to resume device data!\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_debug_save(struct vfio_device *vdev)
>> +{
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>> +	struct device *dev = vdev->dev;
>> +	int ret;
>> +
>> +	ret = vf_qm_state_save(hisi_acc_vdev, migf);
>> +	if (ret) {
>> +		dev_err(dev, "failed to save device data!\n");
>> +		return -EINVAL;
>> +	}
>> +	dev_info(dev, "successful to save device data!\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static int
>> +hisi_acc_vf_debug_operate(struct vfio_device *vdev, unsigned int cmd)
>> +{
>> +	int ret;
>> +
>> +	switch (cmd) {
>> +	case STATE_SAVE:
>> +		ret = hisi_acc_vf_debug_save(vdev);
>> +		if (ret)
>> +			return ret;
>> +		break;
>> +	case STATE_RESUME:
>> +		ret = hisi_acc_vf_debug_resume(vdev);
>> +		if (ret)
>> +			return ret;
>> +		break;
>> +	case RW_IO_TEST:
>> +		ret = hisi_acc_vf_debug_io(vdev);
>> +		if (ret)
>> +			return ret;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_debug_check(struct vfio_device *vdev)
>> +{
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf;
>> +	enum vfio_device_mig_state state;
>> +
>> +	if (!vdev->mig_ops || !migf) {
>> +		dev_err(vdev->dev, "device not support debugfs!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* If device not opened, the debugfs operation will trigger calltrace */
>> +	(void)vdev->mig_ops->migration_get_state(vdev, &state);
>> +	if (state == VFIO_DEVICE_STATE_ERROR ||
>> +	    state == VFIO_DEVICE_STATE_STOP) {
>> +		dev_err(vdev->dev, "device not opened!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static ssize_t hisi_acc_vf_debug_write(struct file *filp, const char __user *buffer,
>> +			    size_t count, loff_t *pos)
>> +{
>> +	struct vfio_device	*vdev = filp->private_data;
>> +	char tbuf[VFIO_DEV_DBG_LEN];
>> +	unsigned long cmd;
>> +	int len, ret;
>> +
>> +	if (*pos)
>> +		return 0;
>> +
>> +	if (count >= VFIO_DEV_DBG_LEN)
>> +		return -ENOSPC;
>> +
>> +	ret = hisi_acc_vf_debug_check(vdev);
>> +	if (ret)
>> +		return -EINVAL;
>> +
>> +	len = simple_write_to_buffer(tbuf, VFIO_DEV_DBG_LEN - 1,
>> +					pos, buffer, count);
>> +	if (len < 0 || len > VFIO_DEV_DBG_LEN - 1)
>> +		return -EINVAL;
>> +	tbuf[len] = '\0';
>> +	if (kstrtoul(tbuf, 0, &cmd))
>> +		return -EFAULT;
>> +
>> +	ret = hisi_acc_vf_debug_operate(vdev, cmd);
>> +	if (ret) {
>> +		dev_err(vdev->dev, "device debug test failed!\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	return count;
>> +}
>> +
>> +static const struct file_operations hisi_acc_vf_debug_fops = {
>> +	.owner = THIS_MODULE,
>> +	.open = simple_open,
>> +	.write = hisi_acc_vf_debug_write,
>> +};
>> +
>> +static void seq_print_hex_data(struct seq_file *seq, const void *buf, size_t len)
>> +{
>> +#define HEX_LINE_SIZE		131
>> +#define HEX_ROW_SIZE		16
>> +	unsigned char linebuf[HEX_LINE_SIZE];
>> +	int i, linelen, remaining = len;
>> +	const u8 *ptr = buf;
>> +
>> +	for (i = 0; i < len; i += HEX_ROW_SIZE) {
>> +		linelen = min(remaining, HEX_ROW_SIZE);
>> +		remaining -= HEX_ROW_SIZE;
>> +
>> +		hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE, 1,
>> +					linebuf, sizeof(linebuf), false);
>> +
>> +		seq_printf(seq, "%s%.8x: %s\n", "Mig Data:", i, linebuf);
>> +	}
>> +}
>> +
>> +static int hisi_acc_vf_data_read(struct seq_file *seq, void *data)
>> +{
>> +	struct device *vf_dev = seq->private;
>> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
>> +	struct vfio_device	*vdev = &core_device->vdev;
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>> +	size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
>> +
>> +	if (debug_migf && debug_migf->total_length)
>> +		seq_print_hex_data(seq, (unsigned char *)&debug_migf->vf_data,
>> +				vf_data_sz);
>> +	else
>> +		seq_printf(seq, "%s\n", "device not migrated!");
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vf_attr_read(struct seq_file *seq, void *data)
>> +{
>> +	struct device *vf_dev = seq->private;
>> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
>> +	struct vfio_device	*vdev = &core_device->vdev;
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
>> +	struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf;
>> +
>> +	if (debug_migf && debug_migf->total_length) {
>> +		seq_printf(seq,
>> +			 "acc device:\n"
>> +			 "device  state: %d\n"
>> +			 "device  ready: %u\n"
>> +			 "data    valid: %d\n"
>> +			 "data     size: %lu\n",
>> +			 hisi_acc_vdev->mig_state,
>> +			 hisi_acc_vdev->vf_qm_state,
>> +			 debug_migf->disabled,
>> +			 debug_migf->total_length);
>> +	} else {
>> +		seq_printf(seq, "%s\n", "device not migrated!");
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>> +{
>> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
>> +	struct device *dev = vdev->dev;
>> +	void *migf = NULL;
>> +
>> +	if (!debugfs_initialized())
>> +		return 0;
>> +
>> +	vfio_pci_vf_debugfs_init(vdev);
>> +
>> +	migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
>> +	if (!migf)
>> +		return -ENOMEM;
>> +
>> +	hisi_acc_vdev->debug_migf = migf;
>> +
>> +	debugfs_create_devm_seqfile(dev, "mig_data", vdev->debug_root,
>> +				  hisi_acc_vf_data_read);
>> +	debugfs_create_devm_seqfile(dev, "mig_attr", vdev->debug_root,
>> +				  hisi_acc_vf_attr_read);
>> +
>> +	debugfs_create_file("debug", 0200, vdev->debug_root,
>> +				  vdev, &hisi_acc_vf_debug_fops);
> 
> Naming is rather haphazard.  I think this results in vfio_mig/state,
> vfio_mig/mig_data, vfio_mig/mig_attr, vfio_mig/debug.  If would be much
> cleaner if we had either {state,data,attr,debug} under vfio/migration/
> or migration_{state,data,attr,debug} under vfio/
> 

Following the previous instructions, I will change these to
vfio-pci/migration_{state,data,attr,debug}.

>> +
>> +	return 0;
>> +}
>> +
>> +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
>> +{
>> +	struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
>> +
>> +	if (!debugfs_initialized())
>> +		return;
>> +
>> +	kfree(hisi_acc_vdev->debug_migf);
>> +	vfio_pci_vf_debugfs_exit(vdev);
> 
> Ordering is suspect here, we're freeing data used by the debugfs
> entries before removing the entries themselves, which suggests a
> use-after-free issue.  Thanks,
> 

Yes, this is a problem, I will fix it in the next version.

> Alex
> 

Thanks,
Longfang.

>> +}
>> +
>>  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);
>> @@ -1410,6 +1686,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>  	if (IS_ERR(hisi_acc_vdev))
>>  		return PTR_ERR(hisi_acc_vdev);
>>  
>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>> +		hisi_acc_vfio_debug_init(hisi_acc_vdev);
>> +
>>  	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
>>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>>  	if (ret)
>> @@ -1417,6 +1696,8 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>>  	return 0;
>>  
>>  out_put_vdev:
>> +	if (ops == &hisi_acc_vfio_pci_migrn_ops)
>> +		hisi_acc_vf_debugfs_exit(hisi_acc_vdev);
>>  	vfio_put_device(&hisi_acc_vdev->core_device.vdev);
>>  	return ret;
>>  }
>> @@ -1425,6 +1706,7 @@ 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 */
> 
> .
> 

Re: [PATCH v7 4/5] Documentation: add debugfs description for hisi_acc_vfio_pci

[liulongfang]

On 2023/1/27 3:28, Alex Williamson wrote:
> On Fri, 20 Jan 2023 11:29:29 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> Add a debugfs document description file to help users understand
>> how to use the accelerator live migration driver's debugfs.
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../ABI/testing/debugfs-hisi-migration        | 32 +++++++++++++++++++
>>  1 file changed, 32 insertions(+)
>>  create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration
>>
>> diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
>> new file mode 100644
>> index 000000000000..d644a497c464
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-hisi-migration
>> @@ -0,0 +1,32 @@
>> +What:		/sys/kernel/debug/vfio_mig/<bdf>/state
>> +Date:		Jan 2023
>> +Contact:	linux-kernel@vger.kernel.org
>> +Description:	Read the live migration status of the VF device.
>> +		The status of these live migrations includes:
>> +		ERROR, RUNNING, STOP, STOP_COPY, RESUMING.
> 
> state is added by vfio-pci-core in this series, so the documentation
> can't be limited to hisi_acc.
> 
>> +
>> +What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_data
>> +Date:		Jan 2023
>> +Contact:	linux-kernel@vger.kernel.org
>> +Description:	Read the live migration data of the VF device.
>> +		The output format of the data is defined by the live
>> +		migration driver.
>> +
>> +What:		/sys/kernel/debug/vfio_mig/<bdf>/mig_attr
>> +Date:		Jan 2023
>> +Contact:	linux-kernel@vger.kernel.org
>> +Description:	Read the live migration attributes of the VF device.
>> +		The output format of the attributes is defined by the live
>> +		migration driver.
>> +
>> +What:		/sys/kernel/debug/vfio_mig/<bdf>/debug
>> +Date:		Jan 2023
>> +Contact:	linux-kernel@vger.kernel.org
>> +Description:	This debug file supports "echo" command	write operations.
>> +		The command is actually represented by an integer number, and the
>> +		specific meaning is defined by the corresponding device driver.
>> +		For example, three commands are defined in the HiSilicon accelerator
>> +		live migration driver:
>> +		0: State save
>> +		1: State resume
>> +		2: IO test
> 
> I think the goal here is to create some sort of standard interface for
> migration, so these should also be documented for all devices, and any
> device specific behavior noted.  Otherwise these should all be prefixed
> hisi_acc_ to denote them as device specific implementations.  Thanks,
> 

Ok, the ABI file name needs to be changed, and the internal description needs
to be updated, not limited to hisi_acc.

> Alex
> 
Thansk,
Longfang.
> .
> 

Re: [PATCH v7 5/5] vfio: update live migration device status

[liulongfang]

On 2023/1/27 3:28, Alex Williamson wrote:
> On Fri, 20 Jan 2023 11:29:30 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> migration debugfs needs to perform debug operations based on the
>> status of the current device. If the device is not loaded or has
>> stopped, debugfs does not allow operations.
>>
>> so, after the live migration function is executed and the device is
>> turned off, the device no longer needs to be accessed. At this time,
>> the status of the device needs to be set to stop.
>>
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 3 +++
>>  drivers/vfio/pci/mlx5/main.c                   | 3 +++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> index 96e2a021a956..bdb9043f88f1 100644
>> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> @@ -1607,6 +1607,9 @@ 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;
>>  
>> +	if (core_vdev->mig_ops)
>> +		hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_STOP;
>> +
>>  	iounmap(vf_qm->io_base);
>>  	vfio_pci_core_close_device(core_vdev);
>>  }
>> diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
>> index 031ac8cc215d..64b2fe58355a 100644
>> --- a/drivers/vfio/pci/mlx5/main.c
>> +++ b/drivers/vfio/pci/mlx5/main.c
>> @@ -1092,6 +1092,9 @@ static void mlx5vf_pci_close_device(struct vfio_device *core_vdev)
>>  	struct mlx5vf_pci_core_device *mvdev = container_of(
>>  		core_vdev, struct mlx5vf_pci_core_device, core_device.vdev);
>>  
>> +	if (mvdev->migrate_cap)
>> +		mvdev->mig_state = VFIO_DEVICE_STATE_STOP;
>> +
>>  	mlx5vf_cmd_close_migratable(mvdev);
>>  	vfio_pci_core_close_device(core_vdev);
>>  }
> 
> It seems prone to issues to manipulate the migration state outside of
> the driver state machine.  If the device is closed, shouldn't the
> debugfs state interface return -EINVAL?  Thanks,
> 

This operation itself should be paired with the operation of setting mig_state to
the VFIO_DEVICE_STATE_RUNNING state in the open_device of vfio_device_ops.
It's just that this problem was not found when the debugfs function was not added.
In addition, this setting mig_state to VFIO_DEVICE_STATE_STOP state will be used
in hisi_acc_vf_debug_check, which is to prevent the wrong operation of debugfs
through this state, and return -EINVAL.

> Alex
> 
Thanks,
Longfang.
> .
> 

Re: [PATCH v7 1/5] vfio/migration: Add debugfs to live migration driver

[Alex Williamson]

On Wed, 1 Feb 2023 11:20:08 +0800
liulongfang <liulongfang@huawei.com> wrote:

> On 2023/1/27 3:27, Alex Williamson wrote:
> > On Fri, 20 Jan 2023 11:29:26 +0800
> > Longfang Liu <liulongfang@huawei.com> wrote:
> >   
> >> 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 VF |                | dst VF |
> >>      +-+------+                +-+------+
> >>        |   ^                     |   ^
> >>        v   |                     v   |
> >>  +-------+-+------+        +-------+-+------+
> >>  |Debugfs|state   |        |Debugfs|state   |
> >>  +-------+--------+        +-------+--------+
> >>  |   debug_root   |        |   debug_root   |
> >>  +-------+--------+        +-------+--------+
> >>
> >> 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_pci_debugfs.h will be empty definitions,
> >> and the creation and initialization of the debugfs directory
> >> will not be executed.
> >>
> >> debugfs will create a public root directory "vfio_mig" file.
> >> then create a "debug_root" file for each live migration VF device.  
> > 
> > s/VF // In practice it may be VFs, but I don't think we want to
> > artificially imply that the device must be a VF.  In fact, I'm not sure  
> 
> Yes, the description should be modified here, and it should not be limited
> to only support VF.
> 
> > why any of this code lives in vfio/pci/ vs vfio/, there's nothing PCI
> > specific here.  Why isn't all of this done in vfio_main to be shared
> > with both pci and non-pci vfio drivers and devices?
> >  
> 
> Combined with your observations below, I think it is more appropriate to
> create a "vfio-pci" directory here, because the current live migration
> function is still used on pci devices.
> 
> For non-pci devices, if there is a device that needs to add debugfs,
> then it can create a similar directory.

But live migration itself is not specific to vfio-pci, it's device
agnostic.  We'd certainly expect to see mdev devices supporting
migration in the near term.  Thanks,

Alex