SRU request submitted to the Ubuntu kernel team mailing list for impish and
focal:
https://lists.ubuntu.com/archives/kernel-team/2022-March/thread.html#128449
Changing status to 'In Progress' for impish and focal.
** Changed in: linux (Ubuntu)
Status: In Progress => Fix Released
** Changed in: linux (Ubuntu Focal)
Status: New => In Progress
** Changed in: linux (Ubuntu Impish)
Status: New => In Progress
** Changed in: ubuntu-z-systems
Status: New => In Progress
** Description changed:
- Decription:
- KVM: SIGP RESTART is reporting a CPU state 'stopped' after SIGP RESTART
was issued, while it should report a 'busy' condition until the CPU is really
started.
+ SRU Justification:
+ ==================
- The patches to fix this have already been picked for jammy/master-next:
+ [Impact]
+
+ * The SIGP processing on KVM/s390x is incorrect and not fully conformant to
+ the 'Principles of Operations', the IBM Z architecture definition
+ and documentation.
+
+ * KVM: SIGP RESTART is reporting a CPU state 'stopped' after SIGP RESTART
+ was issued, while it should report a 'busy' condition until the CPU is
+ really started.
+
+ * The fix for this consists of three patches:
+ 812de04661c4 "KVM: s390: Clarify SIGP orders versus STOP/RESTART"
+ 435d17955519 "KVM: s390: Add a routine for setting userspace CPU state"
+ 4563bcad46bf "KVM: s390: Simplify SIGP Set Arch handling"
+ whereas 812de04661c4 already landed via upstream stable,
+ hence only two are left and need to be cherry-picked:
+
+ [Fix]
+
+ * 67cf68b6a5ccac8bc7dfef0a220b59af4c83fd2c 67cf68b6a5cc "KVM: s390: Add
+ a routine for setting userspace CPU state"
+
+ * 8eeba194a32e0f50329354a696baaa2e3d9accc5 8eeba194a32e "KVM: s390:
+ Simplify SIGP Set Arch handling"
+
+ [Test Case]
+
+ * Install an LPAR on IBM Z (z13+) or LinuxONE (Emperor / Rockhopper)
+ with Ubuntu Server 20.04 using kernel standard kernel 5.4.
+
+ * Setup this LPAR as QEMU/KVM host and a focal VM as guest.
+
+ * The test itself is the following unit test:
+ https://lore.kernel.org/r/20220303210425.1693486-1-far...@linux.ibm.com/
+
+ * The test and verification will be done by the IBM Z team.
+
+ [Where problems could occur]
+
+ <this is pretty high level and generic, anything more specific to add?>
+
+ * A broken patch could harm KVM ioctl on s390x or the (virtual) CPU
+ state control in general.
+
+ * The SIGP handing (on s390x) can become broken, which could lead to
+ incorrect (virtual) CPU states.
+
+ * In worst case KVM can become broken on s390x entirely.
+
+ * The modified code is all s390x specific QEMU/KVM code,
+ no common code is touched.
+
+ [Other]
+
+ * The two remaining patches are upstream since 5.16,
+ the first one already landed in 5.4 via upstream stable bug LP#1959701
+ and in 5.13 via upstream stable bug LP#1960861.
+
+ * The patches already landed in jammy (master-next) based on LP#1959735,
+ hence only SRU to impish and focal is needed.
+
+ * This patches got discussed here:
+ https://lore.kernel.org/all/20211008203112.1979843-2-far...@linux.ibm.com/
+
+ * This not only fixes the SIGP processing, but is also important in terms of
+ long term maintainability.
+
+ __________
+
+ Description:
+ KVM: SIGP RESTART is reporting a CPU state 'stopped' after SIGP RESTART
was issued, while it should report a 'busy' condition until the CPU is really
started.
+
+ The patches to fix this have already been picked for jammy/master-next:
812de04661c4 "KVM: s390: Clarify SIGP orders versus STOP/RESTART"
435d17955519 "KVM: s390: Add a routine for setting userspace CPU state"
4563bcad46bf "KVM: s390: Simplify SIGP Set Arch handling"
- For Ubuntu 20.04 the focal/master-next already contains:
+ For Ubuntu 20.04 the focal/master-next already contains:
d74b0d2d38d3 KVM: s390: Clarify SIGP orders versus STOP/RESTART
- so we additionally need the following two upstream commits in focal
+ so we additionally need the following two upstream commits in focal
67cf68b6a5cc KVM: s390: Add a routine for setting userspace CPU state
8eeba194a32e KVM: s390: Simplify SIGP Set Arch handling
** Changed in: linux (Ubuntu Focal)
Assignee: (unassigned) => Canonical Kernel Team (canonical-kernel-team)
** Changed in: linux (Ubuntu Impish)
Assignee: (unassigned) => Canonical Kernel Team (canonical-kernel-team)
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https://bugs.launchpad.net/bugs/1962578
Title:
[UBUNTU 20.04] Fix SIGP processing on KVM/s390
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