[libvirt] [PATCH v3 REBASE 2 00/12] hostdev: handle usb detach/attach on node

Dave Allan libvirt at dpallan.com
Thu Oct 31 16:50:28 UTC 2019


On Thu, Oct 31, 2019 at 10:40:42AM +0000, Nikolay Shirokovskiy wrote:
>
>
>On 30.10.2019 23:21, Dave Allan wrote:
>> On Tue, Oct 29, 2019 at 11:17:51AM +0300, Nikolay Shirokovskiy wrote:
>>> Diff to v2[1] version:
>>> - add 'replug' attribute for hostdev element to allow replug semantics
>>> - avoid accuiring domain lock in event loop thread on udev events as
>>>  suggested by Peter
>>> - nit picks after review by Daniel Henrique Barboza
>>>
>>> * is used to mark patches that were 'Reviewed-by' by Daniel (sometimes
>>>  with very minor changes to take into account new replug flag).
>>
>> I did some basic testing today, and I'm seeing the device appear and disappear in the guest, which is great and much nicer than my ugly udev rule hack.  I did find what I think is a bug though: if the USB device is plugged in at domain start, unplugging it while the domain is running does not cause it to disappear, and subsqeuently replugging it into the host causes a second instance of the device to appear in the guest.
>
>Hi.
>
>Hmm. Looks like you're using startupPolicy=optional otherwise it is not
>possible to start domain without a device. But in this case the whole replug thing
>is disabled and further I don't understand how the second instance of the device can appear.
>
>If device is present at domain start then replug is in play. And I cannot reproduce the bug.

I am using startupPolicy optional, and I'm seeing the device attached and detached 100% of the time.  I can start the domain with or without the device attached to the host, plug and unplug it and it appears and disappears from the guest, which is exactly the behavior I want.  My domain XML is attached.

I tested a few more times just now, and I saw the duplicate device appear in the guest the first time I tried, but I have not been able to reproduce it again after that.

>Can you clarify on you use case?

My usecase is that I'm flashing the USB device with a program running in the VM.  I keep the VM running, and when I need to reflash, I connect the device, so having the startupPolicy optional is useful.

>Nikolay
>
>>
>>> Can be applied on:
>>>
>>> commit bf0e7bdeeb790bc6ba5732623be0d9ff26a5961a
>>> Author: Peter Krempa <pkrempa at redhat.com>
>>> Date:   Thu Oct 24 15:50:50 2019 +0200
>>>
>>>    util: xml: Make virXMLFormatElement void
>>> [1] https://www.redhat.com/archives/libvir-list/2019-September/msg00321.html
>>>
>>> Nikolay Shirokovskiy (12):
>>>  conf: add replug option for usb hostdev
>>>  qemu: track hostdev delete intention
>>>  *qemu: support host usb device unplug
>>>  *qemu: support usb hostdev plugging back
>>>  qemu: handle host usb device add/del udev events
>>>  *qemu: handle libvirtd restart after host usb device unplug
>>>  *qemu: handle race on device deletion and usb host device plugging
>>>  qemu: hotplug: update device list on device deleted event
>>>  *qemu: handle host usb device plug/unplug when libvirtd is down
>>>  *qemu: don't mess with non mandatory hostdevs on reattaching
>>>  qemu: handle detaching of unplugged hostdev
>>>  *conf: parse hostdev missing flag
>>>
>>> docs/formatdomain.html.in                     |  10 +-
>>> docs/schemas/domaincommon.rng                 |   5 +
>>> src/conf/domain_conf.c                        |  62 +++
>>> src/conf/domain_conf.h                        |  17 +
>>> src/qemu/Makefile.inc.am                      |   2 +
>>> src/qemu/qemu_conf.h                          |   3 +
>>> src/qemu/qemu_domain.c                        |   2 +
>>> src/qemu/qemu_domain.h                        |   2 +
>>> src/qemu/qemu_driver.c                        | 404 +++++++++++++++++-
>>> src/qemu/qemu_hotplug.c                       | 104 ++++-
>>> src/qemu/qemu_hotplug.h                       |   3 +-
>>> src/qemu/qemu_process.c                       |  60 +++
>>> src/util/virhostdev.c                         |   2 +
>>> tests/qemuhotplugtest.c                       |   2 +-
>>> tests/qemuxml2argvdata/hostdev-usb-replug.xml |  36 ++
>>> .../qemuxml2xmloutdata/hostdev-usb-replug.xml |  40 ++
>>> tests/qemuxml2xmltest.c                       |   1 +
>>> 17 files changed, 733 insertions(+), 22 deletions(-)
>>> create mode 100644 tests/qemuxml2argvdata/hostdev-usb-replug.xml
>>> create mode 100644 tests/qemuxml2xmloutdata/hostdev-usb-replug.xml
>>>
>>> -- 
>>> 2.23.0
>>>
>>> --
>>> libvir-list mailing list
>>> libvir-list at redhat.com
>>> https://www.redhat.com/mailman/listinfo/libvir-list
>>>
>>>
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