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 };

/**

.

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 */

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.

.

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