5.15-stable review patch. If anyone has any objections, please let me know.
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From: Gautam Menghani gautam@linux.ibm.com
commit 44e5d21e6d3fd2a1fed7f0327cf72e99397e2eaf upstream.
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 Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://patch.msgid.link/20241108094839.33084-1-gautam@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/kernel/setup_64.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -952,6 +952,7 @@ static int __init disable_hardlockup_det hardlockup_detector_disable(); #else if (firmware_has_feature(FW_FEATURE_LPAR)) { + check_kvm_guest(); if (is_kvm_guest()) hardlockup_detector_disable(); }