From: Len Brown <len.brown@xxxxxxxxx> Under some conditions, MONITOR wakeups on Lunar Lake processors can be lost, resulting in significant user-visible delays. Add LunarLake to X86_BUG_MONITOR so that wake_up_idle_cpu() always sends an IPI, avoiding this potential delay. Also update the X86_BUG_MONITOR workaround to handle the new smp_kick_mwait_play_dead() path. Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219364 Cc: stable@xxxxxxxxxxxxxxx # 6.11 Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- arch/x86/kernel/cpu/intel.c | 3 ++- arch/x86/kernel/smpboot.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index e7656cbef68d..aa63f5f780a0 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -586,7 +586,8 @@ static void init_intel(struct cpuinfo_x86 *c) c->x86_vfm == INTEL_WESTMERE_EX)) set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR); - if (boot_cpu_has(X86_FEATURE_MWAIT) && c->x86_vfm == INTEL_ATOM_GOLDMONT) + if (boot_cpu_has(X86_FEATURE_MWAIT) && + (c->x86_vfm == INTEL_ATOM_GOLDMONT || c->x86_vfm == INTEL_LUNARLAKE_M)) set_cpu_bug(c, X86_BUG_MONITOR); #ifdef CONFIG_X86_64 diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 766f092dab80..910cb2d72c13 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1377,6 +1377,9 @@ void smp_kick_mwait_play_dead(void) for (i = 0; READ_ONCE(md->status) != newstate && i < 1000; i++) { /* Bring it out of mwait */ WRITE_ONCE(md->control, newstate); + /* If MONITOR unreliable, send IPI */ + if (boot_cpu_has_bug(X86_BUG_MONITOR)) + __apic_send_IPI(cpu, RESCHEDULE_VECTOR); udelay(5); } -- 2.43.0
