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Message-ID: <20240503112120.3740da24.alex.williamson@redhat.com>
Date: Fri, 3 May 2024 11:21:20 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: Longfang Liu <liulongfang@...wei.com>
Cc: <jgg@...dia.com>, <shameerali.kolothum.thodi@...wei.com>,
<jonathan.cameron@...wei.com>, <kvm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linuxarm@...neuler.org>
Subject: Re: [PATCH v6 4/5] hisi_acc_vfio_pci: register debugfs for
hisilicon migration driver
On Thu, 25 Apr 2024 21:23:21 +0800
Longfang Liu <liulongfang@...wei.com> wrote:
> 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_mif | | 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 real-time status data
> of the device through the "dev_data" file. It will directly read
> the device status data and will not affect the live migration
> function. Its data is stored in the allocated memory buffer,
> and the memory is released after data returning to user mode.
>
> To obtain the data of the last complete migration, user need to
> obtain it through the "migf_data" file. Since the live migration
> data only exists during the migration process, it is destroyed
> after the migration is completed.
> In order to save this data, a debug_migf file is created in the
> driver. At the end of the live migration process, copy the data
> to debug_migf.
>
> Signed-off-by: Longfang Liu <liulongfang@...wei.com>
> ---
> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 225 ++++++++++++++++++
> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 7 +
> 2 files changed, 232 insertions(+)
>
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index bf358ba94b5d..656b3d975940 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -627,15 +627,33 @@ 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;
> +
> + mutex_lock(&hisi_acc_vdev->enable_mutex);
> + dst_migf->disabled = src_migf->disabled;
> + dst_migf->total_length = src_migf->total_length;
> + memcpy(&dst_migf->vf_data, &src_migf->vf_data,
> + sizeof(struct acc_vf_data));
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> +}
> +
> 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;
> @@ -1144,6 +1162,7 @@ static int hisi_acc_vf_qm_init(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> if (!vf_qm->io_base)
> return -EIO;
>
> + mutex_init(&hisi_acc_vdev->enable_mutex);
> vf_qm->fun_type = QM_HW_VF;
> vf_qm->pdev = vf_dev;
> mutex_init(&vf_qm->mailbox_lock);
> @@ -1294,6 +1313,203 @@ 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;
> + struct device *dev = vdev->dev;
> + int ret;
> +
> + if (!vdev->mig_ops) {
> + dev_err(dev, "device does not support live migration!\n");
Sorry, every error path should not spam dmesg with dev_err(). I'm
going to wait until your co-maintainer approves this before looking at
any further iterations of this series. Thanks,
Alex
> + return -EINVAL;
> + }
> +
> + /**
> + * When the device is not opened, the io_base is not mapped.
> + * The driver cannot perform device read and write operations.
> + */
> + if (!hisi_acc_vdev->dev_opened) {
> + dev_err(dev, "device not opened!\n");
> + return -EINVAL;
> + }
> +
> + ret = qm_wait_dev_not_ready(vf_qm);
> + if (ret) {
> + dev_err(dev, "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->enable_mutex);
> + ret = hisi_acc_vf_debug_check(seq, vdev);
> + if (ret) {
> + mutex_unlock(&hisi_acc_vdev->enable_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->enable_mutex);
> + dev_err(vf_dev, "mailbox cmd channel not ready!\n");
> + return -EINVAL;
> + }
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> + dev_err(vf_dev, "mailbox cmd channel state is OK!\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 hisi_acc_vf_migration_file *migf = NULL;
> + int ret;
> +
> + migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL);
> + if (!migf)
> + return -ENOMEM;
> +
> + mutex_lock(&hisi_acc_vdev->enable_mutex);
> + ret = hisi_acc_vf_debug_check(seq, vdev);
> + if (ret) {
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> + goto migf_err;
> + }
> +
> + migf->vf_data.vf_qm_state = hisi_acc_vdev->vf_qm_state;
> + ret = vf_qm_read_data(&hisi_acc_vdev->vf_qm, &migf->vf_data);
> + if (ret) {
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> + dev_err(vf_dev, "failed to read device data!\n");
> + goto migf_err;
> + }
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> +
> + if (hisi_acc_vdev->resuming_migf)
> + migf->disabled = hisi_acc_vdev->resuming_migf->disabled;
> + else if (hisi_acc_vdev->saving_migf)
> + migf->disabled = hisi_acc_vdev->saving_migf->disabled;
> + else
> + migf->disabled = true;
> + migf->total_length = sizeof(struct acc_vf_data);
> +
> + seq_hex_dump(seq, "Dev Data:", DUMP_PREFIX_OFFSET, 16, 1,
> + (unsigned char *)&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,
> + migf->disabled,
> + migf->total_length);
> +
> +migf_err:
> + kfree(migf);
> +
> + 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 < vf_data_sz) {
> + dev_err(vf_dev, "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 +1527,11 @@ 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 +1540,10 @@ 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;
>
> + hisi_acc_vdev->dev_opened = false;
> + mutex_lock(&hisi_acc_vdev->enable_mutex);
> iounmap(vf_qm->io_base);
> + mutex_unlock(&hisi_acc_vdev->enable_mutex);
> vfio_pci_core_close_device(core_vdev);
> }
>
> @@ -1413,6 +1634,9 @@ 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 +1649,7 @@ 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 f887ab98581c..93ee8bef32a1 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
> @@ -114,5 +115,11 @@ 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 enabled */
> + struct mutex enable_mutex;
> + bool dev_opened;
> + /* To save migration data */
> + struct hisi_acc_vf_migration_file *debug_migf;
> };
> #endif /* HISI_ACC_VFIO_PCI_H */
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