6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gautam Menghani <gautam@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx # v5.14+
Signed-off-by: Gautam Menghani <gautam@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20241108094839.33084-1-gautam@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -920,6 +920,7 @@ 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();
}
