Regression: KVM no longer supports Intel CPUs without Virtual NMI
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
High
|
Unassigned | ||
Artful |
Fix Released
|
High
|
Unassigned | ||
Bionic |
Fix Released
|
High
|
Unassigned |
Bug Description
== SRU Justification ==
The following mainline commit introduced a regression in v4.12-rc1:
2c82878b0cb3 ("KVM: VMX: require virtual NMI support")
This regression caused the kvm-intel module fail to load with the following error:
"modprobe: ERROR: could not insert 'kvm_intel': Input/output error"
This error would happen because suppor for CPUs without virtual NMI was removed
by commit 2c82878b0cb3.
Mainline commit 8a1b43922d0d fixes this regression and was added to mainline in v4.15-rc1.
== Fix ==
commit 8a1b43922d0d127
Author: Paolo Bonzini <email address hidden>
Date: Mon Nov 6 13:31:12 2017 +0100
kvm: vmx: Reinstate support for CPUs without virtual NMI
== Regression Potential ==
Low. This patch fixes a current regression. It was cc'd to upstream stable
so had additional upstream review.
## Original Bug Description ##
Since upgrading from zesty to artful, I'm not longer able to use KVM on my server:
# modprobe kvm-intel
modprobe: ERROR: could not insert 'kvm_intel': Input/output error
Searching tells me this is caused by requiring Virtual NMI support[1]
Running the script provided on the mailing list[1] to check virtualization features confirms my CPU (Xeon E5345) doesn't support Virtual NMIs:
# python features.py | grep NMI
NMI exiting yes
Virtual NMIs no
NMI-window exiting no
Virtual NMI support was required in v4.12[1] and later reverted in v4.14.3[2] as some models (including Xeons) don't support it, even if others with the same core do.
[1] https:/
[2] https:/
[3] https:/
[4] https:/
Changed in linux (Ubuntu): | |
status: | Confirmed → Triaged |
Changed in linux (Ubuntu Artful): | |
status: | New → Triaged |
importance: | Undecided → High |
Changed in linux (Ubuntu Bionic): | |
status: | Triaged → In Progress |
Changed in linux (Ubuntu Artful): | |
status: | Triaged → In Progress |
assignee: | nobody → Joseph Salisbury (jsalisbury) |
Changed in linux (Ubuntu Bionic): | |
assignee: | nobody → Joseph Salisbury (jsalisbury) |
no longer affects: | linux-hwe (Ubuntu Bionic) |
no longer affects: | linux-hwe (Ubuntu Artful) |
no longer affects: | linux-hwe (Ubuntu) |
Changed in linux (Ubuntu Bionic): | |
status: | In Progress → Fix Committed |
Changed in linux (Ubuntu Artful): | |
status: | In Progress → Fix Committed |
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1741655
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.