diff options
Diffstat (limited to 'gitlab/issues_text/target_missing/host_missing/accel_missing/1577')
| -rw-r--r-- | gitlab/issues_text/target_missing/host_missing/accel_missing/1577 | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/gitlab/issues_text/target_missing/host_missing/accel_missing/1577 b/gitlab/issues_text/target_missing/host_missing/accel_missing/1577 deleted file mode 100644 index f24609089..000000000 --- a/gitlab/issues_text/target_missing/host_missing/accel_missing/1577 +++ /dev/null @@ -1,84 +0,0 @@ -device_del return is already in the process of unplug frequently -Description of problem: -recently we update qemu 6.1.1 to qemu 7.1.0, and run into an issue with the following error: - -command '{ "execute": "device_del", "arguments": { "id": "virtio-diskX" } }' for VM "id" failed ({ "return": {"class": "GenericError", "desc": "Device virtio-diskX is already in the process of unplug"} }). - -The issue is reproducible. With a few seconds delay before hot-unplug, hot-unplug just works fine. - -After a few digging, we found that the commit 9323f892b39 may incur the issue. ------------------- - failover: fix unplug pending detection - - Failover needs to detect the end of the PCI unplug to start migration - after the VFIO card has been unplugged. - - To do that, a flag is set in pcie_cap_slot_unplug_request_cb() and reset in - pcie_unplug_device(). - - But since - 17858a169508 ("hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35") - we have switched to ACPI unplug and these functions are not called anymore - and the flag not set. So failover migration is not able to detect if card - is really unplugged and acts as it's done as soon as it's started. So it - doesn't wait the end of the unplug to start the migration. We don't see any - problem when we test that because ACPI unplug is faster than PCIe native - hotplug and when the migration really starts the unplug operation is - already done. - - See c000a9bd06ea ("pci: mark device having guest unplug request pending") - a99c4da9fc2a ("pci: mark devices partially unplugged") - - Signed-off-by: Laurent Vivier <lvivier@redhat.com> - Reviewed-by: Ani Sinha <ani@anisinha.ca> - Message-Id: <20211118133225.324937-4-lvivier@redhat.com> - Reviewed-by: Michael S. Tsirkin <mst@redhat.com> - Signed-off-by: Michael S. Tsirkin <mst@redhat.com> ------------------- -The purpose is for detecting the end of the PCI device hot-unplug. However, we feel the error confusing. How is it possible that a disk "is already in the process of unplug" during the first hot-unplug attempt? So far as I know, the issue was also encountered by libvirt, but they simply ignored it: - - https://bugzilla.redhat.com/show_bug.cgi?id=1878659 - -Hence, a question is: should we have the line below in acpi_pcihp_device_unplug_request_cb()? - - pdev->qdev.pending_deleted_event = true; - -It would be great if you as the author could give us a few hints. - -Thank you very much for your reply! - -Sincerely, - -Yu Zhang @ Compute Platform IONOS - - -The issue is reproducible in our own stack, which is not quite easy to describe in a few command lines. We simplified it a bit by a script instead. Although it's not able to reproduce, it could be somewhat helpful to understand the issue. - -``` -#!/bin/bash - -HOME=~ -QEMU=$HOME/qemu/bin/qemu-system-x86_64 -DISK1=$HOME/img/disk1.qcow2 -DISK4=$HOME/img/disk4.qcow2 -DISK5=$HOME/img/disk5.qcow2 - -$QEMU \ - -cpu host -enable-kvm -m 2048 -smp 2 \ - -object iothread,id=iothread1 \ - -drive file=$DISK1,if=none,id=drive-virtio-disk1,format=qcow2,snapshot=off,discard=on,cache=none \ - -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk1,iothread=iothread1,num-queues=1,discard=on,id=virtio-disk1 \ - -object iothread,id=iothread4 \ - -drive file=$DISK4,if=none,id=drive-virtio-disk4,format=qcow2,snapshot=off,discard=on,cache=none \ - -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk4,iothread=iothread4,num-queues=1,discard=on,id=virtio-disk4 \ - -object iothread,id=iothread5 \ - -drive file=$DISK5,if=none,id=drive-virtio-disk5,format=qcow2,snapshot=off,discard=on,cache=none \ - -device virtio-blk-pci,bus=pci.0,addr=0x6,drive=drive-virtio-disk5,iothread=iothread5,num-queues=1,discard=on,id=virtio-disk5 \ - -qmp unix:./qmp-sock,server,nowait & - -sleep 5 - -echo '{"execute":"qmp_capabilities"}{"execute": "device_del","arguments": { "id": "virtio-disk5"}}{"execute": "query-block"}' | nc -U -w 1 ./qmp-sock -echo '{"execute":"qmp_capabilities"}{"execute": "device_del","arguments": { "id": "virtio-disk5"}}{"execute": "query-block"}' | nc -U -w 1 ./qmp-sock``` -Additional information: -Possible workaround: https://lore.kernel.org/qemu-devel/20230403131833-mutt-send-email-mst@kernel.org/T/#t |