From 9f01129382774d98ec21526f13da26a0630ee3d8 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Mon, 18 Jul 2022 11:56:11 -0700 Subject: intel_idle: Add a new flag to initialize the AMX state The non-initialized AMX state can be the cause of C-state demotion from C6 to C1E. This low-power idle state may improve power savings and thus result in a higher available turbo frequency budget. This behavior is implementation-specific. Initialize the state for the C6 entrance of Sapphire Rapids as needed. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Dave Hansen Signed-off-by: Chang S. Bae Signed-off-by: Borislav Petkov Acked-by: Rafael J. Wysocki Tested-by: Zhang Rui Link: https://lkml.kernel.org/r/20220614164116.5196-1-chang.seok.bae@intel.com --- drivers/idle/intel_idle.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) (limited to 'drivers/idle') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index f5c6802aa6c3..1ec221079367 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -56,6 +56,7 @@ #include #include #include +#include #define INTEL_IDLE_VERSION "0.5.1" @@ -113,6 +114,11 @@ static unsigned int mwait_substates __initdata; */ #define CPUIDLE_FLAG_IBRS BIT(16) +/* + * Initialize large xstate for the C6-state entrance. + */ +#define CPUIDLE_FLAG_INIT_XSTATE BIT(17) + /* * MWAIT takes an 8-bit "hint" in EAX "suggesting" * the C-state (top nibble) and sub-state (bottom nibble) @@ -185,6 +191,13 @@ static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev, return ret; } +static __cpuidle int intel_idle_xstate(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + fpu_idle_fpregs(); + return __intel_idle(dev, drv, index); +} + /** * intel_idle_s2idle - Ask the processor to enter the given idle state. * @dev: cpuidle device of the target CPU. @@ -200,8 +213,12 @@ static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev, static __cpuidle int intel_idle_s2idle(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { - unsigned long eax = flg2MWAIT(drv->states[index].flags); unsigned long ecx = 1; /* break on interrupt flag */ + struct cpuidle_state *state = &drv->states[index]; + unsigned long eax = flg2MWAIT(state->flags); + + if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) + fpu_idle_fpregs(); mwait_idle_with_hints(eax, ecx); @@ -936,7 +953,8 @@ static struct cpuidle_state spr_cstates[] __initdata = { { .name = "C6", .desc = "MWAIT 0x20", - .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED, + .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED | + CPUIDLE_FLAG_INIT_XSTATE, .exit_latency = 290, .target_residency = 800, .enter = &intel_idle, @@ -1851,6 +1869,9 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) drv->states[drv->state_count].enter = intel_idle_ibrs; } + if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_INIT_XSTATE) + drv->states[drv->state_count].enter = intel_idle_xstate; + if ((disabled_states_mask & BIT(drv->state_count)) || ((icpu->use_acpi || force_use_acpi) && intel_idle_off_by_default(mwait_hint) && -- cgit v1.2.3