On 2023/10/4 3:26, Alex Williamson wrote: > On Tue, 26 Sep 2023 17:33:55 +0800 > liulongfang <liulongfang@xxxxxxxxxx> wrote: > >> From: Longfang Liu <liulongfang@xxxxxxxxxx> >> >> 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 | >> | | >> | | >> +---+----------------------------+----------+ >> | ^ | ^ >> | | | | >> | | | | >> v | v | >> +---------+--+ +---------+--+ >> |src vfio_dev| |dst vfio_dev| >> +--+---------+ +--+---------+ >> | ^ | ^ >> | | | | >> v | | | >> +-----------+----+ +-----------+----+ >> |src dev debugfs | |dst dev debugfs | >> +----------------+ +----------------+ >> >> 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. >> >> vfio >> | >> +---<dev_name1> >> | +---migration >> | +--state >> | >> +---<dev_name2> >> +---migration >> +--state >> >> debugfs will create a public root directory "vfio" file. >> then create a dev_name() file for each live migration device. >> First, create a unified state acquisition file of "migration" >> in this device directory. >> Then, create a public live migration state lookup file "state" >> Finally, create a directory file based on the device type, >> and then create the device's own debugging files under >> this directory file. > > We don't actually do the thing claimed in this last statement. > OK, I will modify it in the next version. >> Signed-off-by: Longfang Liu <liulongfang@xxxxxxxxxx> >> --- >> drivers/vfio/Makefile | 1 + >> drivers/vfio/vfio.h | 14 ++++++ >> drivers/vfio/vfio_debugfs.c | 87 +++++++++++++++++++++++++++++++++++++ >> drivers/vfio/vfio_main.c | 14 +++++- >> include/linux/vfio.h | 7 +++ >> 5 files changed, 121 insertions(+), 2 deletions(-) >> create mode 100644 drivers/vfio/vfio_debugfs.c >> >> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile >> index c82ea032d352..7934ac829989 100644 >> --- a/drivers/vfio/Makefile >> +++ b/drivers/vfio/Makefile >> @@ -8,6 +8,7 @@ vfio-$(CONFIG_VFIO_GROUP) += group.o >> vfio-$(CONFIG_IOMMUFD) += iommufd.o >> vfio-$(CONFIG_VFIO_CONTAINER) += container.o >> vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o >> +vfio-$(CONFIG_DEBUG_FS) += vfio_debugfs.o > > I see that other subsystems create Kconfig entries allowing more fine > grained control of DEBUGFS support. Wouldn't it make sense to have a > VFIO_DEBUGFS config option, similar to IOMMU_DEBUGFS? > OK, I create a version with VFIO_DEBUGFS > Also, with our trend towards less redundant file naming, this could > just be debugfs.[co]. > OK. >> obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o >> obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o >> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h >> index 307e3f29b527..09b00757d0bb 100644 >> --- a/drivers/vfio/vfio.h >> +++ b/drivers/vfio/vfio.h >> @@ -448,4 +448,18 @@ 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_device_debugfs_init(struct vfio_device *vdev); >> +void vfio_device_debugfs_exit(struct vfio_device *vdev); >> +#else >> +static inline void vfio_debugfs_create_root(void) { } >> +static inline void vfio_debugfs_remove_root(void) { } >> + >> +static inline void vfio_device_debugfs_init(struct vfio_device *vdev) { } >> +static inline void vfio_device_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..b79bdef08357 >> --- /dev/null >> +++ b/drivers/vfio/vfio_debugfs.c >> @@ -0,0 +1,87 @@ >> +// 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_device_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) >> + return -EINVAL; >> + >> + switch (state) { >> + case VFIO_DEVICE_STATE_STOP: >> + seq_printf(seq, "%s\n", "STOP"); >> + break; >> + 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_RESUMING: >> + seq_printf(seq, "%s\n", "RESUMING"); >> + break; >> + case VFIO_DEVICE_STATE_RUNNING_P2P: >> + seq_printf(seq, "%s\n", "RUNNING_P2P"); >> + break; >> + case VFIO_DEVICE_STATE_PRE_COPY: >> + seq_printf(seq, "%s\n", "PRE_COPY"); >> + break; >> + case VFIO_DEVICE_STATE_PRE_COPY_P2P: >> + seq_printf(seq, "%s\n", "PRE_COPY_P2P"); >> + break; >> + case VFIO_DEVICE_STATE_ERROR: > ^^^^^^^^^^^^^^^^^^^^^^^ > >> + seq_printf(seq, "%s\n", "ERROR"); >> + break; >> + default: >> + seq_printf(seq, "%s\n", "Invalid"); >> + } > > Not exactly in the order they're defined: > > enum vfio_device_mig_state { > VFIO_DEVICE_STATE_ERROR = 0, > ^^^^^^^^^^^^^^^^^^^^^^^ > VFIO_DEVICE_STATE_STOP = 1, > VFIO_DEVICE_STATE_RUNNING = 2, > ... > > I also suggested last time some means to keep this in sync with the set > of states defined. Maybe there are better suggestions, but one way to > do that could be: > > diff --git a/drivers/vfio/vfio_debugfs.c b/drivers/vfio/vfio_debugfs.c > index ee6b1831b3e5..1ec90b90d150 100644 > --- a/drivers/vfio/vfio_debugfs.c > +++ b/drivers/vfio/vfio_debugfs.c > @@ -18,6 +18,9 @@ static int vfio_device_state_read(struct seq_file *seq, void *data) > enum vfio_device_mig_state state; > int ret; > > + BUILD_BUG_ON(VFIO_DEVICE_STATE_NR != > + VFIO_DEVICE_STATE_PRE_COPY_P2P + 1); > + > ret = vdev->mig_ops->migration_get_state(vdev, &state); > if (ret) > return -EINVAL; > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 7f5fb010226d..2b68e6cdf190 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1219,6 +1219,7 @@ enum vfio_device_mig_state { > VFIO_DEVICE_STATE_RUNNING_P2P = 5, > VFIO_DEVICE_STATE_PRE_COPY = 6, > VFIO_DEVICE_STATE_PRE_COPY_P2P = 7, > + VFIO_DEVICE_STATE_NR, > }; > > /** > > Thanks, > Alex > OK, I will modify it in the next version Thanks, Longfang > >> + >> + return 0; >> +} >> + >> +void vfio_device_debugfs_init(struct vfio_device *vdev) >> +{ >> + struct device *dev = &vdev->device; >> + >> + vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root); >> + >> + if (vdev->mig_ops) { >> + struct dentry *vfio_dev_migration = NULL; >> + >> + vfio_dev_migration = debugfs_create_dir("migration", vdev->debug_root); >> + debugfs_create_devm_seqfile(dev, "state", vfio_dev_migration, >> + vfio_device_state_read); >> + } >> +} >> + >> +void vfio_device_debugfs_exit(struct vfio_device *vdev) >> +{ >> + debugfs_remove_recursive(vdev->debug_root); >> +} >> + >> +void vfio_debugfs_create_root(void) >> +{ >> + vfio_debugfs_root = debugfs_create_dir("vfio", NULL); >> +} >> + >> +void vfio_debugfs_remove_root(void) >> +{ >> + debugfs_remove_recursive(vfio_debugfs_root); >> + vfio_debugfs_root = NULL; >> +} >> + >> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c >> index cfad824d9aa2..4e3ced20d2d1 100644 >> --- a/drivers/vfio/vfio_main.c >> +++ b/drivers/vfio/vfio_main.c >> @@ -309,7 +309,6 @@ static int __vfio_register_dev(struct vfio_device *device, >> >> /* Refcounting can't start until the driver calls register */ >> refcount_set(&device->refcount, 1); >> - >> vfio_device_group_register(device); >> >> return 0; >> @@ -320,7 +319,15 @@ static int __vfio_register_dev(struct vfio_device *device, >> >> int vfio_register_group_dev(struct vfio_device *device) >> { >> - return __vfio_register_dev(device, VFIO_IOMMU); >> + int ret; >> + >> + ret = __vfio_register_dev(device, VFIO_IOMMU); >> + if (ret) >> + return ret; >> + >> + vfio_device_debugfs_init(device); >> + >> + return 0; >> } >> EXPORT_SYMBOL_GPL(vfio_register_group_dev); >> >> @@ -378,6 +385,7 @@ void vfio_unregister_group_dev(struct vfio_device *device) >> } >> } >> >> + vfio_device_debugfs_exit(device); >> /* Balances vfio_device_set_group in register path */ >> vfio_device_remove_group(device); >> } >> @@ -1662,6 +1670,7 @@ static int __init vfio_init(void) >> if (ret) >> goto err_alloc_dev_chrdev; >> >> + vfio_debugfs_create_root(); >> pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n"); >> return 0; >> >> @@ -1677,6 +1686,7 @@ static int __init vfio_init(void) >> >> static void __exit vfio_cleanup(void) >> { >> + vfio_debugfs_remove_root(); >> ida_destroy(&vfio.device_ida); >> vfio_cdev_cleanup(); >> class_destroy(vfio.device_class); >> diff --git a/include/linux/vfio.h b/include/linux/vfio.h >> index 454e9295970c..769d7af86225 100644 >> --- a/include/linux/vfio.h >> +++ b/include/linux/vfio.h >> @@ -69,6 +69,13 @@ struct vfio_device { >> u8 iommufd_attached:1; >> #endif >> u8 cdev_opened:1; >> +#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 >> }; >> >> /** > > . >