* [PATCH v16 0/2] add debugfs to migration driver @ 2023-09-26 9:33 liulongfang 2023-09-26 9:33 ` [PATCH v16 1/2] vfio/migration: Add debugfs to live " liulongfang 2023-09-26 9:33 ` [PATCH v16 2/2] Documentation: add debugfs description for vfio liulongfang 0 siblings, 2 replies; 7+ messages in thread From: liulongfang @ 2023-09-26 9:33 UTC (permalink / raw) To: alex.williamson, jgg, shameerali.kolothum.thodi, jonathan.cameron Cc: bcreeley, kvm, linux-kernel, linuxarm, liulongfang Add a debugfs function to the migration driver in VFIO to provide a step-by-step debugfs information for the migration driver. Changes v15 -> v16 Update the calling order of functions to maintain symmetry Changes v14 -> v15 Update the output status value of live migration. Changes v13 -> v14 Split the patchset and keep the vfio debugfs frame. Changes v12 -> v13 Solve the problem of open and close competition to debugfs. Changes v11 -> v12 Update loading conditions of vfio debugfs. Changes v10 -> v11 Delete the device restore function in debugfs. Changes v9 -> v10 Update the debugfs file of the live migration driver. Changes v8 -> v9 Update the debugfs directory structure of vfio. Changes v7 -> v8 Add support for platform devices. Changes v6 -> v7 Fix some code style issues. Changes v5 -> v6 Control the creation of debugfs through the CONFIG_DEBUG_FS. Changes v4 -> v5 Remove the newly added vfio_migration_ops and use seq_printf to optimize the implementation of debugfs. Changes v3 -> v4 Change the migration_debug_operate interface to debug_root file. Changes v2 -> v3 Extend the debugfs function from hisilicon device to vfio. Changes v1 -> v2 Change the registration method of root_debugfs to register with module initialization. Longfang Liu (2): vfio/migration: Add debugfs to live migration driver Documentation: add debugfs description for vfio Documentation/ABI/testing/debugfs-vfio | 25 ++++++++ MAINTAINERS | 1 + 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 +++ 7 files changed, 147 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/debugfs-vfio create mode 100644 drivers/vfio/vfio_debugfs.c -- 2.24.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v16 1/2] vfio/migration: Add debugfs to live migration driver 2023-09-26 9:33 [PATCH v16 0/2] add debugfs to migration driver liulongfang @ 2023-09-26 9:33 ` liulongfang 2023-10-03 19:26 ` Alex Williamson 2023-09-26 9:33 ` [PATCH v16 2/2] Documentation: add debugfs description for vfio liulongfang 1 sibling, 1 reply; 7+ messages in thread From: liulongfang @ 2023-09-26 9:33 UTC (permalink / raw) To: alex.williamson, jgg, shameerali.kolothum.thodi, jonathan.cameron Cc: bcreeley, kvm, linux-kernel, linuxarm, liulongfang From: Longfang Liu <liulongfang@huawei.com> 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. Signed-off-by: Longfang Liu <liulongfang@huawei.com> --- 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-$(CONFIG_DEBUG_FS) += vfio_debugfs.o obj-$(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"); + } + + 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 }; /** -- 2.24.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 1/2] vfio/migration: Add debugfs to live migration driver 2023-09-26 9:33 ` [PATCH v16 1/2] vfio/migration: Add debugfs to live " liulongfang @ 2023-10-03 19:26 ` Alex Williamson 2023-10-13 8:09 ` liulongfang 0 siblings, 1 reply; 7+ messages in thread From: Alex Williamson @ 2023-10-03 19:26 UTC (permalink / raw) To: liulongfang Cc: jgg, shameerali.kolothum.thodi, jonathan.cameron, bcreeley, kvm, linux-kernel, linuxarm On Tue, 26 Sep 2023 17:33:55 +0800 liulongfang <liulongfang@huawei.com> wrote: > From: Longfang Liu <liulongfang@huawei.com> > > 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. > Signed-off-by: Longfang Liu <liulongfang@huawei.com> > --- > 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? Also, with our trend towards less redundant file naming, this could just be debugfs.[co]. > 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 > + > + 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 > }; > > /** ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 1/2] vfio/migration: Add debugfs to live migration driver 2023-10-03 19:26 ` Alex Williamson @ 2023-10-13 8:09 ` liulongfang 0 siblings, 0 replies; 7+ messages in thread From: liulongfang @ 2023-10-13 8:09 UTC (permalink / raw) To: Alex Williamson Cc: jgg, shameerali.kolothum.thodi, jonathan.cameron, bcreeley, kvm, linux-kernel, linuxarm On 2023/10/4 3:26, Alex Williamson wrote: > On Tue, 26 Sep 2023 17:33:55 +0800 > liulongfang <liulongfang@huawei.com> wrote: > >> From: Longfang Liu <liulongfang@huawei.com> >> >> 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@huawei.com> >> --- >> 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 >> }; >> >> /** > > . > ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v16 2/2] Documentation: add debugfs description for vfio 2023-09-26 9:33 [PATCH v16 0/2] add debugfs to migration driver liulongfang 2023-09-26 9:33 ` [PATCH v16 1/2] vfio/migration: Add debugfs to live " liulongfang @ 2023-09-26 9:33 ` liulongfang 2023-10-03 19:26 ` Alex Williamson 1 sibling, 1 reply; 7+ messages in thread From: liulongfang @ 2023-09-26 9:33 UTC (permalink / raw) To: alex.williamson, jgg, shameerali.kolothum.thodi, jonathan.cameron Cc: bcreeley, kvm, linux-kernel, linuxarm, liulongfang From: Longfang Liu <liulongfang@huawei.com> 1.Add an debugfs document description file to help users understand how to use the accelerator live migration driver's debugfs. 2.Update the file paths that need to be maintained in MAINTAINERS Signed-off-by: Longfang Liu <liulongfang@huawei.com> --- Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 26 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-vfio diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio new file mode 100644 index 000000000000..7959ec5ac445 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-vfio @@ -0,0 +1,25 @@ +What: /sys/kernel/debug/vfio +Date: Sep 2023 +KernelVersion: 6.7 +Contact: Longfang Liu <liulongfang@huawei.com> +Description: This debugfs file directory is used for debugging + of vfio devices, it's a common directory for all vfio devices. + Vfio core will create a device subdirectory under this + directory. + +What: /sys/kernel/debug/vfio/<device>/migration +Date: Sep 2023 +KernelVersion: 6.7 +Contact: Longfang Liu <liulongfang@huawei.com> +Description: This debugfs file directory is used for debugging + of vfio devices that support live migration. + The debugfs of each vfio device that supports live migration + could be created under this directory. + +What: /sys/kernel/debug/vfio/<device>/migration/state +Date: Sep 2023 +KernelVersion: 6.7 +Contact: Longfang Liu <liulongfang@huawei.com> +Description: Read the live migration status of the vfio device. + The status of these live migrations includes: + ERROR, RUNNING, STOP, STOP_COPY, RESUMING. diff --git a/MAINTAINERS b/MAINTAINERS index 7b1306615fc0..bd01ca674c60 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -22304,6 +22304,7 @@ L: kvm@vger.kernel.org S: Maintained T: git https://github.com/awilliam/linux-vfio.git F: Documentation/ABI/testing/sysfs-devices-vfio-dev +F: Documentation/ABI/testing/debugfs-vfio F: Documentation/driver-api/vfio.rst F: drivers/vfio/ F: include/linux/vfio.h -- 2.24.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 2/2] Documentation: add debugfs description for vfio 2023-09-26 9:33 ` [PATCH v16 2/2] Documentation: add debugfs description for vfio liulongfang @ 2023-10-03 19:26 ` Alex Williamson 2023-10-13 8:16 ` liulongfang 0 siblings, 1 reply; 7+ messages in thread From: Alex Williamson @ 2023-10-03 19:26 UTC (permalink / raw) To: liulongfang Cc: jgg, shameerali.kolothum.thodi, jonathan.cameron, bcreeley, kvm, linux-kernel, linuxarm On Tue, 26 Sep 2023 17:33:56 +0800 liulongfang <liulongfang@huawei.com> wrote: > From: Longfang Liu <liulongfang@huawei.com> > > 1.Add an debugfs document description file to help users understand > how to use the accelerator live migration driver's debugfs. > 2.Update the file paths that need to be maintained in MAINTAINERS > > Signed-off-by: Longfang Liu <liulongfang@huawei.com> > --- > Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++ > MAINTAINERS | 1 + > 2 files changed, 26 insertions(+) > create mode 100644 Documentation/ABI/testing/debugfs-vfio > > diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio > new file mode 100644 > index 000000000000..7959ec5ac445 > --- /dev/null > +++ b/Documentation/ABI/testing/debugfs-vfio > @@ -0,0 +1,25 @@ > +What: /sys/kernel/debug/vfio > +Date: Sep 2023 > +KernelVersion: 6.7 > +Contact: Longfang Liu <liulongfang@huawei.com> > +Description: This debugfs file directory is used for debugging > + of vfio devices, it's a common directory for all vfio devices. > + Vfio core will create a device subdirectory under this > + directory. > + > +What: /sys/kernel/debug/vfio/<device>/migration > +Date: Sep 2023 > +KernelVersion: 6.7 > +Contact: Longfang Liu <liulongfang@huawei.com> > +Description: This debugfs file directory is used for debugging > + of vfio devices that support live migration. > + The debugfs of each vfio device that supports live migration > + could be created under this directory. > + > +What: /sys/kernel/debug/vfio/<device>/migration/state > +Date: Sep 2023 > +KernelVersion: 6.7 > +Contact: Longfang Liu <liulongfang@huawei.com> > +Description: Read the live migration status of the vfio device. > + The status of these live migrations includes: > + ERROR, RUNNING, STOP, STOP_COPY, RESUMING. This is another area that's doomed to be out of sync, it's already not updated for P2P states. Better to avoid the problem and say something like "The contents of the state file reflects the migration state relative to those defined in the vfio_device_mig_state enum". Also, as suggested last time, October is a more realistic date. Thanks, Alex > diff --git a/MAINTAINERS b/MAINTAINERS > index 7b1306615fc0..bd01ca674c60 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -22304,6 +22304,7 @@ L: kvm@vger.kernel.org > S: Maintained > T: git https://github.com/awilliam/linux-vfio.git > F: Documentation/ABI/testing/sysfs-devices-vfio-dev > +F: Documentation/ABI/testing/debugfs-vfio > F: Documentation/driver-api/vfio.rst > F: drivers/vfio/ > F: include/linux/vfio.h ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 2/2] Documentation: add debugfs description for vfio 2023-10-03 19:26 ` Alex Williamson @ 2023-10-13 8:16 ` liulongfang 0 siblings, 0 replies; 7+ messages in thread From: liulongfang @ 2023-10-13 8:16 UTC (permalink / raw) To: Alex Williamson Cc: jgg, shameerali.kolothum.thodi, jonathan.cameron, bcreeley, kvm, linux-kernel, linuxarm On 2023/10/4 3:26, Alex Williamson wrote: > On Tue, 26 Sep 2023 17:33:56 +0800 > liulongfang <liulongfang@huawei.com> wrote: > >> From: Longfang Liu <liulongfang@huawei.com> >> >> 1.Add an debugfs document description file to help users understand >> how to use the accelerator live migration driver's debugfs. >> 2.Update the file paths that need to be maintained in MAINTAINERS >> >> Signed-off-by: Longfang Liu <liulongfang@huawei.com> >> --- >> Documentation/ABI/testing/debugfs-vfio | 25 +++++++++++++++++++++++++ >> MAINTAINERS | 1 + >> 2 files changed, 26 insertions(+) >> create mode 100644 Documentation/ABI/testing/debugfs-vfio >> >> diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio >> new file mode 100644 >> index 000000000000..7959ec5ac445 >> --- /dev/null >> +++ b/Documentation/ABI/testing/debugfs-vfio >> @@ -0,0 +1,25 @@ >> +What: /sys/kernel/debug/vfio >> +Date: Sep 2023 >> +KernelVersion: 6.7 >> +Contact: Longfang Liu <liulongfang@huawei.com> >> +Description: This debugfs file directory is used for debugging >> + of vfio devices, it's a common directory for all vfio devices. >> + Vfio core will create a device subdirectory under this >> + directory. >> + >> +What: /sys/kernel/debug/vfio/<device>/migration >> +Date: Sep 2023 >> +KernelVersion: 6.7 >> +Contact: Longfang Liu <liulongfang@huawei.com> >> +Description: This debugfs file directory is used for debugging >> + of vfio devices that support live migration. >> + The debugfs of each vfio device that supports live migration >> + could be created under this directory. >> + >> +What: /sys/kernel/debug/vfio/<device>/migration/state >> +Date: Sep 2023 >> +KernelVersion: 6.7 >> +Contact: Longfang Liu <liulongfang@huawei.com> >> +Description: Read the live migration status of the vfio device. >> + The status of these live migrations includes: >> + ERROR, RUNNING, STOP, STOP_COPY, RESUMING. > > This is another area that's doomed to be out of sync, it's already not > updated for P2P states. Better to avoid the problem and say something > like "The contents of the state file reflects the migration state > relative to those defined in the vfio_device_mig_state enum". > > Also, as suggested last time, October is a more realistic date. Thanks, > OK, I will modify it in the next version Thanks Longfang. > Alex > >> diff --git a/MAINTAINERS b/MAINTAINERS >> index 7b1306615fc0..bd01ca674c60 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -22304,6 +22304,7 @@ L: kvm@vger.kernel.org >> S: Maintained >> T: git https://github.com/awilliam/linux-vfio.git >> F: Documentation/ABI/testing/sysfs-devices-vfio-dev >> +F: Documentation/ABI/testing/debugfs-vfio >> F: Documentation/driver-api/vfio.rst >> F: drivers/vfio/ >> F: include/linux/vfio.h > > . > ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-10-13 8:16 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-09-26 9:33 [PATCH v16 0/2] add debugfs to migration driver liulongfang 2023-09-26 9:33 ` [PATCH v16 1/2] vfio/migration: Add debugfs to live " liulongfang 2023-10-03 19:26 ` Alex Williamson 2023-10-13 8:09 ` liulongfang 2023-09-26 9:33 ` [PATCH v16 2/2] Documentation: add debugfs description for vfio liulongfang 2023-10-03 19:26 ` Alex Williamson 2023-10-13 8:16 ` liulongfang
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