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 2019971
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.
** Changed in: linux (Ubuntu)
Status: New => Incomplete
** Changed in: linux (Ubuntu Jammy)
Status: New => Incomplete
** Changed in: linux (Ubuntu Lunar)
Status: New => Incomplete
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/2019971
Title:
Add EPYC-Genoa model
Status in linux package in Ubuntu:
Confirmed
Status in qemu package in Ubuntu:
Triaged
Status in linux source package in Jammy:
Confirmed
Status in qemu source package in Jammy:
Triaged
Status in linux source package in Kinetic:
Won't Fix
Status in qemu source package in Kinetic:
Won't Fix
Status in linux source package in Lunar:
Confirmed
Status in qemu source package in Lunar:
Triaged
Status in linux source package in Mantic:
Confirmed
Status in qemu source package in Mantic:
Triaged
Bug description:
[Impact]
* To avoid bugs with newer Hardware and to allow users/admins to control
the KVM guests correctly we usually try to backport major CPU-
detect/control features back to at least the last LTS (currently jammy)
In SRU Terms this is under the second entry in
https://wiki.ubuntu.com/StableReleaseUpdates#Other_safe_cases
* In this particular case it is about Support for EPYC Genoa chips
https://en.wikipedia.org/wiki/Epyc#Fourth_generation_Epyc_(Genoa)
[Test Plan]
* First of all we'll (and have in advance) run general regression
tests
* Second you'd want to run this with host-model and host-passthrough on
Rome / Milan chips to ensure no case is now falling in to a totally
dysfunctional state
* Qemu shall show to be aware of the new types
# qemu-system-x86_64 -cpu ? | grep EPYC-Genoa
x86 EPYC-Genoa (alias configured by machine type)
x86 EPYC-Genoa-v1 AMD EPYC-Genoa Processor
* Finally migrations between old->new should be checked to work fine.
[Where problems could occur]
* This kind of "add the new type" usually only s a problem in backward-
migratebility which isn't supported anyway. Never the less the areas to
look out for is behavior on various AMD EPYC chips. To ensure that old
chips won't change in a breaking way (they might detect new features
now, but not more) and that new Milan chips are now all detected
properly.
[Other Info]
* This is not the first time new AMD chips need to add their definitions,
for example bug 1921880 was similar
----
QEMU added a separate model for EPYC-Genoa in
https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg02087.html
On the qemu side most bits are already present as far back as jammy. The only
things missing are the vnmi and auto-ibrs flag.
The lfence-always-serializing, amd-psfd, no-nested-data-bp, null-sel-clr-base
are part of the Milan-v2 patch set
https://github.com/qemu/qemu/commit/62a798d4bc2c3e767d94670776c77a7df274d7c5.patch
https://github.com/qemu/qemu/commit/166b1741884dd4fd7090b753cd7333868457a29b.patch
Kernel auto-ibrs et al:
https://lkml.kernel.org/lkml/[email protected]/
kvm: Add support for CPUID_80000021_EAX
*
https://github.com/torvalds/linux/commit/8415a74852d7c24795007ee9862d25feb519007c.patch
kvm: Add the NO_NESTED_DATA_BP feature
*
https://github.com/torvalds/linux/commit/a9dc9ec5a1fafc3d2fe7a7b594eefaeaccf89a6b.patch
kvm: Move X86_FEATURE_LFENCE_RDTSC to its native leaf
*
https://github.com/torvalds/linux/commit/84168ae786f8a15a7eb0f79d34f20b8d261ce2f5.patch
kvm: Add the Null Selector Clears Base feature
*
https://github.com/torvalds/linux/commit/5b909d4ae59aedc711b7a432da021be0e82c95a0.patch
kvm: Add the SMM_CTL MSR not present feature
https://github.com/torvalds/linux/commit/faabfcb194a8d0686396e3fff6a5b42911f65191.patch
x86/cpu: Support AMD Automatic IBRS
https://github.com/torvalds/linux/commit/e7862eda309ecfccc36bb5558d937ed3ace07f3f.patch
KVM: Add common feature flag for AMD's PSFD
https://github.com/torvalds/linux/commit/3d8f61bf8bcd69bcd397276d53aa18f7ca8347f9.patch
Add support for virtual NMIs
https://github.com/torvalds/linux/commit/4a5fd419952e49ef870e9259d815718062871cc1.patch
Please consider adding/backporting these.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2019971/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : [email protected]
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
