| Message ID | 20241108094839.33084-1-gautam@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 44e5d21e6d3fd2a1fed7f0327cf72e99397e2eaf |
| Headers | show |
| Series | [v2] arch/powerpc/pseries: Fix KVM guest detection for disabling hardlockup detector | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
| snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 5 jobs. |
| snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 21 jobs. |
On Fri, 08 Nov 2024 15:18:37 +0530, Gautam Menghani wrote: > As per the kernel documentation[1], hardlockup detector should be > disabled in KVM guests as it may give false positives. On PPC, hardlockup > detector is enabled inside KVM guests because disable_hardlockup_detector() > is marked as early_initcall and it relies on kvm_guest static key > (is_kvm_guest()) which is initialized later during boot by > check_kvm_guest(), which is a core_initcall. check_kvm_guest() is also > called in pSeries_smp_probe(), which is called before initcalls, but it is > skipped if KVM guest does not have doorbell support or if the guest is > launched with SMT=1. > > [...] Applied to powerpc/next. [1/1] arch/powerpc/pseries: Fix KVM guest detection for disabling hardlockup detector https://git.kernel.org/powerpc/c/44e5d21e6d3fd2a1fed7f0327cf72e99397e2eaf cheers
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 22f83fbbc762..1edc7cd68c10 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -920,6 +920,7 @@ static int __init disable_hardlockup_detector(void) hardlockup_detector_disable(); #else if (firmware_has_feature(FW_FEATURE_LPAR)) { + check_kvm_guest(); if (is_kvm_guest()) hardlockup_detector_disable(); }
As per the kernel documentation[1], hardlockup detector should be disabled in KVM guests as it may give false positives. On PPC, hardlockup detector is enabled inside KVM guests because disable_hardlockup_detector() is marked as early_initcall and it relies on kvm_guest static key (is_kvm_guest()) which is initialized later during boot by check_kvm_guest(), which is a core_initcall. check_kvm_guest() is also called in pSeries_smp_probe(), which is called before initcalls, but it is skipped if KVM guest does not have doorbell support or if the guest is launched with SMT=1. Call check_kvm_guest() in disable_hardlockup_detector() so that is_kvm_guest() check goes through fine and hardlockup detector can be disabled inside the KVM guest. [1]: Documentation/admin-guide/sysctl/kernel.rst Fixes: 633c8e9800f3 ("powerpc/pseries: Enable hardlockup watchdog for PowerVM partitions") Cc: stable@vger.kernel.org # v5.14+ Signed-off-by: Gautam Menghani <gautam@linux.ibm.com> --- v1 -> v2: 1. Call check_kvm_guest() call in disable_hardlockup_detector() instead of relying on pSeries_smp_probe() 2. Add the fixes and stable tags 3. Some changes in patch description arch/powerpc/kernel/setup_64.c | 1 + 1 file changed, 1 insertion(+)