Messages in this thread Patch in this message | | | Date | Fri, 10 Mar 2023 16:40:07 -0700 | From | Alex Williamson <> | Subject | Re: [PATCH v8 1/5] vfio/migration: Add debugfs to live migration driver |
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On Fri, 17 Feb 2023 16:48:27 +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 | > | | > | | > +---+----------------------------+----------+ > | ^ | ^ > | | | | > +--------+ | | | | > | vfio | v | v | > +--------+ +---------+--+ +---------+--+ > ^ |src vfio_dev| |dst vfio_dev| > | +--+---------+ +--+---------+ > | | ^ | ^ > | | | | | > | v | | | > | +-----------+ +-----------+----+ | | > +--+<bdf>file_x+<----+---+migration_attr | | | > | +-----------+ | +----------------+ | | > | +---+migration_data | | | > | | +----------------+ | | > | +---+migration_debug | | | > | | +----------------+ | | > | | +----------------+ | | > | +---+migration_state | | | > | +----------------+ | | > | | | > | +-----------+ +----------------+ | | > +--+<bdf>file_y|<----+---+migration_attr | | | > +-----------+ | +----------------+ | | > +---+migration_data | | | > | +----------------+<---------------+ | > +---+migration_debug | | > | +----------------+ | > | +----------------+ | > +---+migration_state +-----------------------+ > +----------------+ > > 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.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" file. > then create a device <bdf> named file for each live migration device.
dev_name(), it's only <sbdf> for PCI devices.
> First, create a unified state acquisition file of "migration_state" > in this device directory. > Then, create your own debugging files independently according to > the functional requirements of each device. > > Here, HiSilicon accelerator creates three debug files: > migration_attr: used to obtain the attribute parameters of the > current live migration device. > migration_data: used to get the live migration data of the current > live migration device. > migration_debug: Used to debug the current live migration device > through commands. > > 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/Makefile | 2 +- > drivers/vfio/vfio.h | 14 +++++++ > drivers/vfio/vfio_debugfs.c | 82 +++++++++++++++++++++++++++++++++++++ > drivers/vfio/vfio_main.c | 5 +++ > include/linux/vfio.h | 8 ++++ > 5 files changed, 110 insertions(+), 1 deletion(-) > create mode 100644 drivers/vfio/vfio_debugfs.c > > diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile > index 70e7dcb302ef..1debcff31d30 100644 > --- a/drivers/vfio/Makefile > +++ b/drivers/vfio/Makefile > @@ -7,7 +7,7 @@ vfio-y += vfio_main.o \ > vfio-$(CONFIG_IOMMUFD) += iommufd.o > vfio-$(CONFIG_VFIO_CONTAINER) += container.o > vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o > - > +vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o > obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o > obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o > obj-$(CONFIG_VFIO_PCI) += pci/ > diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h > index e9721d8424bc..66c00f97e9cc 100644 > --- a/drivers/vfio/vfio.h > +++ b/drivers/vfio/vfio.h > @@ -258,4 +258,18 @@ static inline void vfio_device_put_kvm(struct vfio_device *device) > } > #endif > > +#ifdef CONFIG_DEBUG_FS > +void vfio_debugfs_create_root(void); > +void vfio_debugfs_remove_root(void); > + > +void vfio_vf_debugfs_init(struct vfio_device *vdev); > +void vfio_vf_debugfs_exit(struct vfio_device *vdev);
s/vf_// throughout.
> +#else > +static inline void vfio_debugfs_create_root(void) { } > +static inline void vfio_debugfs_remove_root(void) { } > + > +static inline void vfio_vf_debugfs_init(struct vfio_device *vdev) { } > +static inline void vfio_vf_debugfs_exit(struct vfio_device *vdev) { } > +#endif /* CONFIG_DEBUG_FS */ > + > #endif > diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c > new file mode 100644 > index 000000000000..c5df1496fe0e > --- /dev/null > +++ b/drivers/vfio/vfio_debugfs.c > @@ -0,0 +1,82 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2023, HiSilicon Ltd. > + */ > + > +#include <linux/device.h> > +#include <linux/debugfs.h> > +#include <linux/seq_file.h> > +#include <linux/vfio.h> > +#include "vfio.h" > + > +static struct dentry *vfio_debugfs_root; > + > +static int vfio_vf_state_read(struct seq_file *seq, void *data) > +{ > + struct device *vf_dev = seq->private; > + struct vfio_device *vdev = container_of(vf_dev, struct vfio_device, device); > + enum vfio_device_mig_state state; > + int ret; > + > + ret = vdev->mig_ops->migration_get_state(vdev, &state); > + if (ret) { > + dev_err(vf_dev, "failed to get device migration state"); Isn't the errno below sufficient? No need to add the ability to fill logs as well.
> + 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_vf_debugfs_init(struct vfio_device *vdev) > +{ > + struct device *dev = &vdev->device; > + > + vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root); > + > + debugfs_create_devm_seqfile(dev, "migration_state", vdev->debug_root, > + vfio_vf_state_read); > +} > +EXPORT_SYMBOL_GPL(vfio_vf_debugfs_init); > + > +void vfio_vf_debugfs_exit(struct vfio_device *vdev) > +{ > + debugfs_remove_recursive(vdev->debug_root); > +} > +EXPORT_SYMBOL_GPL(vfio_vf_debugfs_exit);
The above two should probably be vfio_device_debugfs_{init,exit}(). > + > +void vfio_debugfs_create_root(void) > +{ > + vfio_debugfs_root = debugfs_create_dir("vfio", NULL); > +} > +EXPORT_SYMBOL_GPL(vfio_debugfs_create_root); > + > +void vfio_debugfs_remove_root(void) > +{ > + debugfs_remove_recursive(vfio_debugfs_root); > + vfio_debugfs_root = NULL; > +} > +EXPORT_SYMBOL_GPL(vfio_debugfs_remove_root);
As Jason notes, this becomes part of the vfio module, these latter two don't need to be exported to be called by vfio_main.
Thanks, Alex
> + > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > index 3a597e799918..09772fd3a396 100644 > --- a/drivers/vfio/vfio_main.c > +++ b/drivers/vfio/vfio_main.c > @@ -1408,6 +1408,9 @@ static int __init vfio_init(void) > } > > pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n"); > + > + vfio_debugfs_create_root(); > + > return 0; > > err_dev_class: > @@ -1425,6 +1428,8 @@ static void __exit vfio_cleanup(void) > vfio_virqfd_exit(); > vfio_group_cleanup(); > xa_destroy(&vfio_device_set_xa); > + > + vfio_debugfs_remove_root(); > } > > module_init(vfio_init); > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 93134b023968..fa6b898ebb58 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -63,6 +63,14 @@ struct vfio_device { > struct iommufd_ctx *iommufd_ictx; > bool iommufd_attached; > #endif > + > +#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 > }; > > /**
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