Ubuntu
qemu package

microvm is not the default type for qemu-system-x86_64-microvm >=qemu5.2

Bug #1936894 reported by Christian Ehrhardt 
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
qemu (Ubuntu)
Fix Released
Undecided
Unassigned
Hirsute
Fix Released
Undecided
Christian Ehrhardt 

Bug Description

[Impact]

 * A change of the build system has caused a configuration change
   to be ignored. Due to that the defaults of the machine type are
   no more correct.

 * With the default set (in hirsute) you no more needed -M microvm as an
   argument as this was the default. But by losing this default upgrades
   from there will fail to start the microvm now.

 * The fix is trivial and ensures that the type is known when built
   with meson

[Test Plan]

 * Run this:
   $ qemu-system-x86_64-microvm -M ? | grep -e 'default' -e 'microvm'

  That is the special reduced build for microvms. It currently reports

  microvm microvm (i386)
  pc-i440fx-hirsute Ubuntu 21.04 PC (i440FX + PIIX, 1996) (default)

  But it should report

  microvm microvm (i386) (default)

[Where problems could occur]

 * Of the many things that qemu does this only affects qemu-system-x86_64-
   microvm which is a special build
   (https://cpaelzer.github.io/blogs/009-microvm-in-ubuntu/)
   So the use cases of that could be affected.

[Other Info]

 * Usually examples list to specify the type explicitly, and everyone
   doing so did not have a problem due to that missed default type.

---

In Focal microvm worked and it was a fine addition for those that wanted to try this approach (mature solution of qemu/kvm reduced for a specific use case) to minimal VMs compared to the new projects (very use-case dedicated, but therefore missing quite some features) that spawned.

But it turns out the configuration to make it a default is broken since qemu 5.2.

Correct (Focal)
root@f:~# qemu-system-x86_64-microvm -M ? | grep -e 'default' -e 'microvm'
microvm microvm (i386) (default)

Broken (Groovy and later)
root@i-kvm:~# qemu-system-x86_64-microvm -M ? | grep -e 'default' -e 'microvm'
microvm microvm (i386)
pc-i440fx-impish Ubuntu 21.10 PC (i440FX + PIIX, 1996) (default)

If you follow the guide
  https://cpaelzer.github.io/blogs/009-microvm-in-ubuntu/
It is still usable and that might explain why - even not being the prime use case - we had zero reports of this so far.
The reason for the latter is that explicitly stating -M microvm (common) overcomes the issue and so do a few combinations with -nodefaults.

Thanks to Michael Torkaev for spotting and also fixing this.
But we should backport this as an SRU.

TODOs to call this bug fixed:
- add a testcase to the regression tests
- SRU the fix

See original description

Related branches

~paelzer/ubuntu/+source/qemu:lp-1913421-exec-run-1936894-microvm-HIRSUTE
Utkarsh Gupta (community): Approve
Dan Streetman (community): Abstain
Ubuntu Stable Release Updates Team: Pending requested
Canonical Server packageset reviewers: Pending requested
Canonical Server: Pending requested
Diff: 77 lines (+30/-6)
2 files modified
debian/changelog (+10/-0)
debian/rules (+20/-6)

CVE References

Christian Ehrhardt  (paelzer)
Changed in qemu (Ubuntu):
status: New → Triaged
description: updated
description: updated
tags: added: server-next
Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

Fixed by
commit 3f9e518010693a98f23f50ea45f98837204c597e
Author: Michael Tokarev <email address hidden>
Date: Tue Jul 20 08:56:48 2021 +0300

    fix microvm default machine type for a new build system (LP#1936894)

Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

Working in impish on a PPA, some more testing needed to be released.

Changed in qemu (Ubuntu):
status: Triaged → Fix Committed
Changed in qemu (Ubuntu Hirsute):
status: New → Triaged
Christian Ehrhardt  (paelzer)
description: updated
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (5.3 KiB)

This bug was fixed in the package qemu - 1:6.0+dfsg-2expubuntu1

---------------
qemu (1:6.0+dfsg-2expubuntu1) impish; urgency=medium

  * Merge with Debian experimental, remaining changes:
    - qemu-kvm to systemd unit
      - d/qemu-kvm-init: script for QEMU KVM preparation modules, ksm,
        hugepages and architecture specifics
      - d/qemu-system-common.qemu-kvm.service: systemd unit to call
        qemu-kvm-init
      - d/qemu-system-common.install: install helper script
      - d/qemu-system-common.qemu-kvm.default: defaults for
        /etc/default/qemu-kvm
      - d/rules: call dh_installinit and dh_installsystemd for qemu-kvm
    - Distribution specific machine type
      (LP: 1304107 1621042 1776189 1761372 1761372 1776189)
      - d/p/ubuntu/define-ubuntu-machine-types.patch: define distro machine
        types containing release versioned machine attributes
      - d/qemu-system-x86.NEWS Info on fixed machine type defintions
        for host-phys-bits=true
      - Add an info about -hpb machine type in debian/qemu-system-x86.NEWS
      - ubuntu-q35 alias added to auto-select the most recent q35 ubuntu type
    - Enable nesting by default
      - d/p/ubuntu/enable-svm-by-default.patch: Enable nested svm by default
        in qemu64 on amd
        [ No more strictly needed, but required for backward compatibility ]
    - improved dependencies
      - Make qemu-system-common depend on qemu-block-extra
      - Make qemu-utils depend on qemu-block-extra
    - tolerate ipxe size change on migrations to >=18.04 (LP: 1713490)
      - d/p/ubuntu/pre-bionic-256k-ipxe-efi-roms.patch: old machine types
        reference 256k path
      - d/control-in: depend on ipxe-qemu-256k-compat-efi-roms to be able to
        handle incoming migrations from former releases.
    - d/qemu-system-x86.README.Debian: add info about updated nesting changes
    - d/control*, d/rules: disable xen by default, but provide universe
      package qemu-system-x86-xen as alternative
      [includes compat links changes of 5.0-5ubuntu4]
    - d/p/ubuntu/enable-svm-by-default.patch: update to match v6.0
    - d/p/ubuntu/define-ubuntu-machine-types.patch: add ubuntu machine types
      for v6.0
    - d/p/ubuntu/lp-1929926-*: avoid segfaults by uretprobes (LP 1929926)
    - Ease the use of module retention on upgrades (LP 1913421)
      - debian/qemu-block-extra.postinst: enable mount unit on install/upgrade
  * Dropped Changes [in 1:6.0+dfsg-2exp]:
    - d/control-in: Disable capstone disassembler library support (universe)
    - Disable fuse export (universe dependency)
    - Ease the use of module retention on upgrades (LP 1913421)
      - d/run-qemu.mount, d/rules: provide run-qemu.mount in qemu-block-extra
      - d/rules: only save modules if /run/qemu isn't noexec
      - d/rules: clear all (current and former) modules on purge
    - d/control: qemu 6.0 broke libvirt <7.2 add a breaks to avoid partial
      upgrade issues (LP 1932264)
    - Enable SDL as secondary UI backend (LP 1256185)
      - d/control: add build dependency libsdl2-dev
      - d/control: enable sdl graphics on build
      - d/qemu-system-gui.install: add ui-sdl.so
      - d/control: add run...

Read more...

Changed in qemu (Ubuntu):
status: Fix Committed → Fix Released
Christian Ehrhardt  (paelzer)
Changed in qemu (Ubuntu Hirsute):
assignee: nobody → Christian Ehrhardt  (paelzer)
Christian Ehrhardt  (paelzer)
description: updated
description: updated
Revision history for this message
Robie Basak (racb) wrote : Please test proposed package

Hello Christian, or anyone else affected,

Accepted qemu into hirsute-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/qemu/1:5.2+dfsg-9ubuntu3.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-hirsute to verification-done-hirsute. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-hirsute. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in qemu (Ubuntu Hirsute):
status: Triaged → Fix Committed
tags: added: verification-needed verification-needed-hirsute
Revision history for this message
Ubuntu SRU Bot (ubuntu-sru-bot) wrote : Autopkgtest regression report (qemu/1:5.2+dfsg-9ubuntu3.2)

All autopkgtests for the newly accepted qemu (1:5.2+dfsg-9ubuntu3.2) for hirsute have finished running.
The following regressions have been reported in tests triggered by the package:

ubuntu-image/1.11+21.04ubuntu2 (amd64)
casper/1.461 (amd64)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/hirsute/update_excuses.html#qemu

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

FYI the test issues were just flaky tests and are resolved by now.

Revision history for this message
Christian Ehrhardt  (paelzer) wrote :
Download full text (4.1 KiB)

Pre update
root@h:~# qemu-system-x86_64-microvm -M ? | grep -e 'default' -e 'microvm'
microvm microvm (i386)
pc-i440fx-hirsute Ubuntu 21.04 PC (i440FX + PIIX, 1996) (default)

Upgrade
apt install qemu-system-x86
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  qemu-block-extra qemu-system-common qemu-system-data qemu-system-gui qemu-utils
Suggested packages:
  samba vde2 debootstrap
The following packages will be upgraded:
  qemu-block-extra qemu-system-common qemu-system-data qemu-system-gui qemu-system-x86 qemu-utils
6 upgraded, 0 newly installed, 0 to remove and 18 not upgraded.
Need to get 12.6 MB of archives.
After this operation, 1024 B disk space will be freed.
Do you want to continue? [Y/n] Y
Get:1 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-utils amd64 1:5.2+dfsg-9ubuntu3.2 [1262 kB]
Get:2 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-system-common amd64 1:5.2+dfsg-9ubuntu3.2 [1697 kB]
Get:3 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-system-gui amd64 1:5.2+dfsg-9ubuntu3.2 [38.3 kB]
Get:4 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-system-data all 1:5.2+dfsg-9ubuntu3.2 [1109 kB]
Get:5 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-block-extra amd64 1:5.2+dfsg-9ubuntu3.2 [50.3 kB]
Get:6 http://archive.ubuntu.com/ubuntu hirsute-proposed/main amd64 qemu-system-x86 amd64 1:5.2+dfsg-9ubuntu3.2 [8478 kB]
Fetched 12.6 MB in 2s (7536 kB/s)
(Reading database ... 48802 files and directories currently installed.)
Preparing to unpack .../0-qemu-utils_1%3a5.2+dfsg-9ubuntu3.2_amd64.deb ...
Unpacking qemu-utils (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Preparing to unpack .../1-qemu-system-common_1%3a5.2+dfsg-9ubuntu3.2_amd64.deb ...
Unpacking qemu-system-common (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Preparing to unpack .../2-qemu-system-gui_1%3a5.2+dfsg-9ubuntu3.2_amd64.deb ...
Unpacking qemu-system-gui:amd64 (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Preparing to unpack .../3-qemu-system-data_1%3a5.2+dfsg-9ubuntu3.2_all.deb ...
Unpacking qemu-system-data (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Preparing to unpack .../4-qemu-block-extra_1%3a5.2+dfsg-9ubuntu3.2_amd64.deb ...
Unpacking qemu-block-extra (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Preparing to unpack .../5-qemu-system-x86_1%3a5.2+dfsg-9ubuntu3.2_amd64.deb ...
Unpacking qemu-system-x86 (1:5.2+dfsg-9ubuntu3.2) over (1:5.2+dfsg-9ubuntu3.1) ...
Setting up qemu-system-data (1:5.2+dfsg-9ubuntu3.2) ...
Setting up qemu-system-x86 (1:5.2+dfsg-9ubuntu3.2) ...
Setting up qemu-block-extra (1:5.2+dfsg-9ubuntu3.2) ...
Setting up qemu-system-common (1:5.2+dfsg-9ubuntu3.2) ...
Setting up qemu-system-gui:amd64 (1:5.2+dfsg-9ubuntu3.2) ...
Setting up qemu-utils (1:5.2+dfsg-9ubuntu3.2) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for man-db (2.9.4-2) ...
Scanning processes... ...

Read more...

tags: added: verification-done verification-done-hirsute
removed: verification-needed verification-needed-hirsute
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package qemu - 1:5.2+dfsg-9ubuntu3.2

---------------
qemu (1:5.2+dfsg-9ubuntu3.2) hirsute; urgency=medium

  * d/rules fix microvm default machine type for a new build system
    (LP: #1936894) - Thanks to Michael Tokarev for the fix.
  * enhance loading of old modules post upgrade (LP: #1913421)
    - d/rules: clear all (current and former) modules on purge
    - d/rules: test for exec and prepare /var/run/qemu if needed

 -- Christian Ehrhardt <email address hidden> Thu, 19 Aug 2021 11:25:17 +0200

Changed in qemu (Ubuntu Hirsute):
status: Fix Committed → Fix Released
Revision history for this message
Brian Murray (brian-murray) wrote : Update Released

The verification of the Stable Release Update for qemu has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

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