[Linuxarm] Re: [PATCH v7 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

-----Original Message----- From: liulongfang liulongfang@huawei.com Sent: Tuesday, July 30, 2024 1:15 PM To: alex.williamson@redhat.com; jgg@nvidia.com; Shameerali Kolothum Thodi shameerali.kolothum.thodi@huawei.com; Jonathan Cameron jonathan.cameron@huawei.com Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; linuxarm@openeuler.org; liulongfang liulongfang@huawei.com Subject: [PATCH v7 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

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

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

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

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

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

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

Signed-off-by: Longfang Liu liulongfang@huawei.com

.../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 220 ++++++++++++++++++ .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 6 + 2 files changed, 226 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index a8c53952d82e..ae8946901e73 100644 --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -627,15 +627,31 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf) mutex_unlock(&migf->lock); }

+static void hisi_acc_debug_migf_copy(struct hisi_acc_vf_core_device *hisi_acc_vdev,

• struct hisi_acc_vf_migration_file *src_migf)

+{

• struct hisi_acc_vf_migration_file *dst_migf = hisi_acc_vdev-

...

debug_migf;

• if (!dst_migf)

• return;
  

• dst_migf->disabled = true;

This is always set to true, then why bother printing this as part of migf_data below?. See also comments on "disabled" below. Is there any value in giving this info to user?

• dst_migf->total_length = src_migf->total_length;
• memcpy(&dst_migf->vf_data, &src_migf->vf_data,

• sizeof(struct acc_vf_data));
  

+}

static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev) { if (hisi_acc_vdev->resuming_migf) {

• hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev-
  

...

resuming_migf);

hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf);
fput(hisi_acc_vdev->resuming_migf->filp);
hisi_acc_vdev->resuming_migf = NULL;

}

if (hisi_acc_vdev->saving_migf) {

• hisi_acc_debug_migf_copy(hisi_acc_vdev, hisi_acc_vdev-
  

...

saving_migf);

hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf);
fput(hisi_acc_vdev->saving_migf->filp);
hisi_acc_vdev->saving_migf = NULL;

@@ -1294,6 +1310,201 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int return vfio_pci_core_ioctl(core_vdev, cmd, arg); }

+static int hisi_acc_vf_debug_check(struct seq_file *seq, struct vfio_device *vdev) +{

• struct hisi_acc_vf_core_device *hisi_acc_vdev =

hisi_acc_get_vf_dev(vdev);

• struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
• int ret;
• if (!vdev->mig_ops) {

• seq_printf(seq, "%s\n", "device does not support live
  

migration!\n");

• return -EINVAL;
  

• }
• /*

• * When the device is not opened, the io_base is not mapped.
  

• * The driver cannot perform device read and write operations.
  

• */
  

I think it is better you make sure the lock is held in this function before checking this. Use lockdep_assert_held(lock).

• if (!hisi_acc_vdev->dev_opened) {

• seq_printf(seq, "%s\n", "device not opened!\n");
  

• return -EINVAL;
  

• }
• ret = qm_wait_dev_not_ready(vf_qm);
• if (ret) {

• seq_printf(seq, "%s\n", "VF device not ready!\n");
  

• return -EBUSY;
  

• }
• return 0;

+}

+static int hisi_acc_vf_debug_cmd(struct seq_file *seq, void *data) +{

• struct device *vf_dev = seq->private;
• struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
• struct vfio_device *vdev = &core_device->vdev;
• struct hisi_acc_vf_core_device *hisi_acc_vdev =

hisi_acc_get_vf_dev(vdev);

• struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;
• u64 value;
• int ret;
• mutex_lock(&hisi_acc_vdev->state_mutex);
• ret = hisi_acc_vf_debug_check(seq, vdev);
• if (ret) {

• mutex_unlock(&hisi_acc_vdev->state_mutex);
  

• return ret;
  

• }
• value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
• if (value == QM_MB_CMD_NOT_READY) {

• mutex_unlock(&hisi_acc_vdev->state_mutex);
  

• seq_printf(seq, "mailbox cmd channel not ready!\n");
  

• return -EINVAL;
  

• }
• mutex_unlock(&hisi_acc_vdev->state_mutex);
• seq_printf(seq, "mailbox cmd channel ready!\n");
• return 0;

+}

+static int hisi_acc_vf_dev_read(struct seq_file *seq, void *data) +{

• struct device *vf_dev = seq->private;
• struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
• struct vfio_device *vdev = &core_device->vdev;
• struct hisi_acc_vf_core_device *hisi_acc_vdev =

hisi_acc_get_vf_dev(vdev);

• size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
• struct acc_vf_data *vf_data = NULL;
• bool migf_state;
• int ret;
• vf_data = kzalloc(sizeof(struct acc_vf_data), GFP_KERNEL);
• if (!vf_data)

• return -ENOMEM;
  

• mutex_lock(&hisi_acc_vdev->state_mutex);
• ret = hisi_acc_vf_debug_check(seq, vdev);
• if (ret) {

• mutex_unlock(&hisi_acc_vdev->state_mutex);
  

• goto migf_err;
  

• }
• vf_data->vf_qm_state = hisi_acc_vdev->vf_qm_state;
• ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, vf_data);
• if (ret) {

• mutex_unlock(&hisi_acc_vdev->state_mutex);
  

• goto migf_err;
  

• }
• if (hisi_acc_vdev->resuming_migf)

• migf_state = hisi_acc_vdev->resuming_migf->disabled;
  

• else if (hisi_acc_vdev->saving_migf)

• migf_state = hisi_acc_vdev->saving_migf->disabled;
  

• else

• migf_state = true;
  

I am still not sure what information we are getting from this "disabled". The value "true" means the migf file is released, isn't it? How is that equivalent to report as "data valid" below? Also "migf_state" is misleading here.

Thanks, Shameer

• mutex_unlock(&hisi_acc_vdev->state_mutex);
• seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,

• 	(unsigned char *)vf_data,
  

• 	vf_data_sz, false);
  

• seq_printf(seq,

•  "acc device:\n"
  

•  "device  ready: %u\n"
  

•  "device  opened: %d\n"
  

•  "data    valid: %d\n"
  

•  "data     size: %lu\n",
  

•  hisi_acc_vdev->vf_qm_state,
  

•  hisi_acc_vdev->dev_opened,
  

•  migf_state,
  

•  sizeof(struct acc_vf_data));
  

+migf_err:

• kfree(vf_data);
• return ret;

+}

+static int hisi_acc_vf_migf_read(struct seq_file *seq, void *data) +{

• struct device *vf_dev = seq->private;
• struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev);
• struct vfio_device *vdev = &core_device->vdev;
• struct hisi_acc_vf_core_device *hisi_acc_vdev =

hisi_acc_get_vf_dev(vdev);

• size_t vf_data_sz = offsetofend(struct acc_vf_data, padding);
• struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev-

...

debug_migf;

• /* Check whether the live migration operation has been performed

*/

• if (debug_migf->total_length < QM_MATCH_SIZE) {

• seq_printf(seq, "%s\n", "device not migrated!\n");
  

• return -EAGAIN;
  

• }
• seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1,

• 	(unsigned char *)&debug_migf->vf_data,
  

• 	vf_data_sz, false);
  

• seq_printf(seq,

•  "acc device:\n"
  

•  "device  ready: %u\n"
  

•  "device  opened: %d\n"
  

•  "data    valid: %d\n"
  

•  "data     size: %lu\n",
  

•  hisi_acc_vdev->vf_qm_state,
  

•  hisi_acc_vdev->dev_opened,
  

•  debug_migf->disabled,
  

•  debug_migf->total_length);
  

• return 0;

+}

+static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev) +{

• struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev;
• struct dentry *vfio_dev_migration = NULL;
• struct dentry *vfio_hisi_acc = NULL;
• struct device *dev = vdev->dev;
• void *migf = NULL;
• if (!debugfs_initialized() ||

•    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
  

• return 0;
  

• migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
• if (!migf)

• return -ENOMEM;
  

• hisi_acc_vdev->debug_migf = migf;
• vfio_dev_migration = debugfs_lookup("migration", vdev-

...

debug_root);

• if (!vfio_dev_migration) {

• kfree(migf);
  

• hisi_acc_vdev->debug_migf = NULL;
  

• dev_err(dev, "failed to lookup migration debugfs file!\n");
  

• return -ENODEV;
  

• }
• vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
• debugfs_create_devm_seqfile(dev, "dev_data", vfio_hisi_acc,

• 		  hisi_acc_vf_dev_read);
  

• debugfs_create_devm_seqfile(dev, "migf_data", vfio_hisi_acc,

• 		  hisi_acc_vf_migf_read);
  

• debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,

• 		  hisi_acc_vf_debug_cmd);
  

• return 0;

+}

+static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev) +{

• if (!debugfs_initialized() ||

•    !IS_ENABLED(CONFIG_VFIO_DEBUGFS))
  

• return;
  

• if (hisi_acc_vdev->debug_migf)

• kfree(hisi_acc_vdev->debug_migf);
  

+}

static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev) { struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev); @@ -1311,9 +1522,11 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev) return ret; } hisi_acc_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;

• hisi_acc_vdev->dev_opened = true;
  

  }

  vfio_pci_core_finish_enable(vdev);

• return 0;

}

@@ -1322,7 +1535,10 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev) struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev); struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm;

• mutex_lock(&hisi_acc_vdev->state_mutex);
• hisi_acc_vdev->dev_opened = false; iounmap(vf_qm->io_base);
• mutex_unlock(&hisi_acc_vdev->state_mutex); vfio_pci_core_close_device(core_vdev);

}

@@ -1413,6 +1629,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device); if (ret) goto out_put_vdev;

• if (ops == &hisi_acc_vfio_pci_migrn_ops)

• hisi_acc_vfio_debug_init(hisi_acc_vdev);
  

  return 0;

out_put_vdev: @@ -1425,6 +1644,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev) struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);

vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);

• hisi_acc_vf_debugfs_exit(hisi_acc_vdev); vfio_put_device(&hisi_acc_vdev->core_device.vdev);

}

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h index 5bab46602fad..f86f3b88b09e 100644 --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h @@ -32,6 +32,7 @@ #define QM_SQC_VFT_BASE_MASK_V2 GENMASK(15, 0) #define QM_SQC_VFT_NUM_SHIFT_V2 45 #define QM_SQC_VFT_NUM_MASK_V2 GENMASK(9, 0) +#define QM_MB_CMD_NOT_READY 0xffffffff

/* RW regs */ #define QM_REGS_MAX_LEN 7 @@ -111,5 +112,10 @@ struct hisi_acc_vf_core_device { int vf_id; struct hisi_acc_vf_migration_file *resuming_migf; struct hisi_acc_vf_migration_file *saving_migf;

• /* To make sure the device is opened */
• bool dev_opened;
• /* To save migration data */
• struct hisi_acc_vf_migration_file *debug_migf;

};

#endif /* HISI_ACC_VFIO_PCI_H */

2.24.0