From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5232BCD37B2 for ; Fri, 15 Sep 2023 21:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237825AbjIOVDH (ORCPT ); Fri, 15 Sep 2023 17:03:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237756AbjIOVCi (ORCPT ); Fri, 15 Sep 2023 17:02:38 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1458CE6D for ; Fri, 15 Sep 2023 14:00:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694811631; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/+DYMbVRs8xDCtF10EOXfbPaBUn/i3lpJXJRzM5wjU8=; b=TDIao2OSmt3/hbYnEI6zpayIhv7WET41JtbuHGWCqFBsjeQzXoUkuWx7OKSszBPXpGWUpA EaZS9S5wzAtDObNYh29Q9lHne7PArr+Uvm3X8bCaqs8n3XXG004Rp1uc8q9ckoW89PoTrr 8uYlQq/2U9QgLhEKOpzA1tIcJ2240eI= Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-658-bTFxoKsMPqOzirUeho08jw-1; Fri, 15 Sep 2023 17:00:29 -0400 X-MC-Unique: bTFxoKsMPqOzirUeho08jw-1 Received: by mail-io1-f69.google.com with SMTP id ca18e2360f4ac-797f63d1760so241894739f.1 for ; Fri, 15 Sep 2023 14:00:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694811629; x=1695416429; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/+DYMbVRs8xDCtF10EOXfbPaBUn/i3lpJXJRzM5wjU8=; b=CjJTJJesQnlAma9EB8A8FBD02+b5Xwq/Yt9X/IPZ/+scp6pqgpBGpjih4weWBYs9kV 4+3qlDX51NUr2/aDDEVK5X3s9CruXi89lzM+SvEuzN7Kh3JxjpsRMzmNQhngQsBSGsUE V9s/Xg8Rrh6uaW4FBMOwAtlmYtBJ97v4NDAunYp4yTEwNIwgTkK9sWanXi1TjQaZ/UPs OMaQwLcc184uMe2uJbBHWwdv0jth63cZEBa51UYCaEPXUiv9M2sLK7BOo8mKRmVXTdhw DWEDEwcECUmP0xOVc9B0AuGpW9NNF3LsaoB+EmSEUQfDyhKfTpIght8b0wvdHFJ/wtlA qYcQ== X-Gm-Message-State: AOJu0Yyc272g5quqec9v1GJWfUwqpPJYqjSFbSR/nTUNF4Hxcqira3iu TVH1ENyP6dz0K91gvH+5pN3kUfKtRj6aEdaaJYr88QikPoS9obcHltKvcSpYC3fW60pfrVtEhpM Sj5I8IS/y6fRLwWst4H/+67J8O2L0h3Uy X-Received: by 2002:a5d:84c5:0:b0:790:f866:d71b with SMTP id z5-20020a5d84c5000000b00790f866d71bmr2760283ior.13.1694811628767; Fri, 15 Sep 2023 14:00:28 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFE+/7b23ZVRSvv5lHFNO4h2ccvzwGYKSWfaFtCFygGCrGuaa4xKbx1/uqLbQv6HC7qWqXDvw== X-Received: by 2002:a5d:84c5:0:b0:790:f866:d71b with SMTP id z5-20020a5d84c5000000b00790f866d71bmr2760269ior.13.1694811628471; Fri, 15 Sep 2023 14:00:28 -0700 (PDT) Received: from redhat.com ([38.15.60.12]) by smtp.gmail.com with ESMTPSA id f4-20020a5d8144000000b00790d81167a7sm1326279ioo.2.2023.09.15.14.00.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Sep 2023 14:00:27 -0700 (PDT) Date: Fri, 15 Sep 2023 15:00:26 -0600 From: Alex Williamson To: liulongfang Cc: , , , , , , Subject: Re: [PATCH v15 1/2] vfio/migration: Add debugfs to live migration driver Message-ID: <20230915150026.06bea533.alex.williamson@redhat.com> In-Reply-To: <20230901023606.47587-2-liulongfang@huawei.com> References: <20230901023606.47587-1-liulongfang@huawei.com> <20230901023606.47587-2-liulongfang@huawei.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 1 Sep 2023 10:36:05 +0800 liulongfang wrote: > From: Longfang Liu > > 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 > | > +--- > | +---migration > | +--state > | > +--- > +---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 > --- > drivers/vfio/Makefile | 1 + > drivers/vfio/vfio.h | 14 +++++++ > drivers/vfio/vfio_debugfs.c | 80 +++++++++++++++++++++++++++++++++++++ > drivers/vfio/vfio_main.c | 5 ++- > include/linux/vfio.h | 7 ++++ > 5 files changed, 106 insertions(+), 1 deletion(-) > 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..cd6c01437475 > --- /dev/null > +++ b/drivers/vfio/vfio_debugfs.c > @@ -0,0 +1,80 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2023, HiSilicon Ltd. > + */ > + > +#include > +#include > +#include > +#include > +#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_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", "RUNNING_P2P"); > + break; > + case VFIO_DEVICE_STATE_ERROR: > + seq_printf(seq, "%s\n", "ERROR"); Please order these the same as enum vfio_device_mig_state, we're also missing a couple states, ie. PRE_COPY and PRE_COPY_P2P. Can we use any compiler tricks to create a build error when these are out of sync? > + break; > + default: > + seq_printf(seq, "%s\n", "Invalid"); > + } > + > + return 0; > +} > + > +void vfio_device_debugfs_init(struct vfio_device *vdev) > +{ > + struct dentry *vfio_dev_migration = NULL; > + struct device *dev = &vdev->device; Nit, both of these could be defined within the scope of the mig_ops test below. > + > + vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root); > + > + if (vdev->mig_ops) { > + 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..8a7456f89842 100644 > --- a/drivers/vfio/vfio_main.c > +++ b/drivers/vfio/vfio_main.c > @@ -309,7 +309,7 @@ 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_debugfs_init(device); > vfio_device_group_register(device); > > return 0; > @@ -378,6 +378,7 @@ 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); > } init/exit calls should try to be symmetric, if we call init before vfio_device_group_register() then we should call exit after vfio_device_group_unregister(). In this case, why shouldn't init be the last call in __vfio_register_dev() and exit the first call in vfio_unregister_group_dev()? > @@ -1662,6 +1663,7 @@ 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; > > @@ -1684,6 +1686,7 @@ static void __exit vfio_cleanup(void) > vfio_virqfd_exit(); > vfio_group_cleanup(); > xa_destroy(&vfio_device_set_xa); > + vfio_debugfs_remove_root(); > } Same, if we create it last, let's remove it first. The above creates it last and removes it last. Thanks, Alex > > module_init(vfio_init); > 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 > }; > > /**