Re: [PATCH v7 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
From: Alex Williamson
Date: Thu Jan 26 2023 - 14:29:08 EST
On Fri, 20 Jan 2023 11:29:28 +0800
Longfang Liu <liulongfang@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> .../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 */