From: Alex Williamson <alex.williamson@redhat.com>
To: liulongfang <liulongfang@huawei.com>
Cc: <jgg@nvidia.com>, <shameerali.kolothum.thodi@huawei.com>,
<jonathan.cameron@huawei.com>, <cohuck@redhat.com>,
<linux-kernel@vger.kernel.org>, <linuxarm@openeuler.org>
Subject: Re: [PATCH v7 1/5] vfio/migration: Add debugfs to live migration driver
Date: Wed, 1 Feb 2023 09:36:44 -0700 [thread overview]
Message-ID: <20230201093644.4983db0d.alex.williamson@redhat.com> (raw)
In-Reply-To: <add8f068-3aaa-0707-bfe6-27fd8bf9e10c@huawei.com>
On Wed, 1 Feb 2023 11:20:08 +0800
liulongfang <liulongfang@huawei.com> wrote:
> On 2023/1/27 3:27, Alex Williamson wrote:
> > On Fri, 20 Jan 2023 11:29:26 +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 |
> >> | |
> >> | |
> >> +-----+-------------------------+----------+
> >> | ^ | ^
> >> v | v |
> >> +-----+--+ +-----+--+
> >> | src VF | | dst VF |
> >> +-+------+ +-+------+
> >> | ^ | ^
> >> v | v |
> >> +-------+-+------+ +-------+-+------+
> >> |Debugfs|state | |Debugfs|state |
> >> +-------+--------+ +-------+--------+
> >> | debug_root | | debug_root |
> >> +-------+--------+ +-------+--------+
> >>
> >> 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_pci_debugfs.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_mig" file.
> >> then create a "debug_root" file for each live migration VF device.
> >
> > s/VF // In practice it may be VFs, but I don't think we want to
> > artificially imply that the device must be a VF. In fact, I'm not sure
>
> Yes, the description should be modified here, and it should not be limited
> to only support VF.
>
> > why any of this code lives in vfio/pci/ vs vfio/, there's nothing PCI
> > specific here. Why isn't all of this done in vfio_main to be shared
> > with both pci and non-pci vfio drivers and devices?
> >
>
> Combined with your observations below, I think it is more appropriate to
> create a "vfio-pci" directory here, because the current live migration
> function is still used on pci devices.
>
> For non-pci devices, if there is a device that needs to add debugfs,
> then it can create a similar directory.
But live migration itself is not specific to vfio-pci, it's device
agnostic. We'd certainly expect to see mdev devices supporting
migration in the near term. Thanks,
Alex
next prev parent reply other threads:[~2023-02-01 16:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 3:29 [PATCH v7 0/5] add debugfs to migration driver Longfang Liu
2023-01-20 3:29 ` [PATCH v7 1/5] vfio/migration: Add debugfs to live " Longfang Liu
2023-01-26 19:27 ` Alex Williamson
2023-02-01 3:20 ` liulongfang
2023-02-01 16:36 ` Alex Williamson [this message]
2023-01-20 3:29 ` [PATCH v7 2/5] hisi_acc_vfio_pci: extract public functions for container_of Longfang Liu
2023-01-20 3:29 ` [PATCH v7 3/5] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver Longfang Liu
2023-01-26 19:28 ` Alex Williamson
2023-02-01 3:24 ` liulongfang
2023-01-20 3:29 ` [PATCH v7 4/5] Documentation: add debugfs description for hisi_acc_vfio_pci Longfang Liu
2023-01-26 19:28 ` Alex Williamson
2023-02-01 3:26 ` liulongfang
2023-01-20 3:29 ` [PATCH v7 5/5] vfio: update live migration device status Longfang Liu
2023-01-26 19:28 ` Alex Williamson
2023-02-01 3:36 ` liulongfang
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