arch/x86/kernel/cpu/intel.c | 3 ++- arch/x86/kernel/smpboot.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-)
From: Len Brown <len.brown@intel.com>
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.
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@vger.kernel.org # 6.10
Signed-off-by: Len Brown <len.brown@intel.com>
---
This is a backport of the upstream patch to Linux-6.10 and earlier
---
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 3ef4e0137d21..e6f4c16c0267 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -583,7 +583,8 @@ static void init_intel(struct cpuinfo_x86 *c)
set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_MWAIT) &&
- ((c->x86_model == INTEL_FAM6_ATOM_GOLDMONT)))
+ ((c->x86_model == INTEL_FAM6_ATOM_GOLDMONT) ||
+ (c->x86_model == INTEL_FAM6_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 0c35207320cb..ca9358acc626 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1376,6 +1376,9 @@ 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 MWAIT unreliable, send IPI */
+ if (boot_cpu_has_bug(X86_BUG_MONITOR))
+ __apic_send_IPI(cpu, RESCHEDULE_VECTOR);
udelay(5);
}
--
2.43.0
On Fri, Nov 08 2024 at 08:49, Len Brown wrote: > From: Len Brown <len.brown@intel.com> > > 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. > 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@vger.kernel.org # 6.10 > Signed-off-by: Len Brown <len.brown@intel.com> > --- > This is a backport of the upstream patch to Linux-6.10 and earlier You either fail to understand or intentionally ignore the process for stable backports, which is in place since more than a decade. Documentation/process/* has plenty of information how that works and you're around long enough to know that already. I don't care about you wasting your time, but I very much care about you wasting my time to deal with pointless emails. I get plenty enough of them every day. Thanks, tglx
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