[Linuxarm] Re: [PATCH v4 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

On 2022/12/2 23:21, Jason Gunthorpe wrote:

On Fri, Dec 02, 2022 at 05:26:23PM +0800, Longfang Liu wrote:

...

On the debugfs framework of VFIO, register the debug function 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, so that the single-step debugging function during live migration can be realized.

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

.../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 250 ++++++++++++++++++ .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 9 + drivers/vfio/pci/vfio_pci_debugfs.c | 10 +- 3 files changed, 268 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index eb18edffbd5f..0f35cde6e8ec 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) @@ -609,6 +610,18 @@ 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); @@ -621,12 +634,16 @@ 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;

@@ -1188,6 +1205,231 @@ 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;
• data = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE);
• dev_info(dev, "debug mailbox val: 0x%llx\n", data);
• ret = qm_wait_dev_not_ready(vf_qm);
• if (ret)

• dev_err(dev, "VF device not ready!\n");
  

debugfs has helpers for this, you should use debugfs_print_regs32()

Yes, it is now possible to use this public interface in debugfs to implement this read register function.

Thanks, Longfang.

...

+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;

+}

This doesn't seem like it belongs in debugfs at all, please just write a test progam using normal vfio ioctls to do these steps and put in the kernel selftests directory.

...

+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;

+}

Ditto, I don't think debugfs should be accessing the device state independently of the main FSM.

Jason .