FAILED: patch "[PATCH] cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode" failed to apply to 6.1-stable tree
The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x ac4e04d9e378f5aa826c2406ad7871ae1b6a6fb9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025050515-constrain-banter-97de@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ac4e04d9e378f5aa826c2406ad7871ae1b6a6fb9 Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Date: Tue, 29 Apr 2025 14:07:11 -0700 Subject: [PATCH] cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode
When turbo mode is unavailable on a Skylake-X system, executing the command:
# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
results in an unchecked MSR access error:
WRMSR to 0x199 (attempted to write 0x0000000100001300).
This issue was reproduced on an OEM (Original Equipment Manufacturer) system and is not a common problem across all Skylake-X systems.
This error occurs because the MSR 0x199 Turbo Engage Bit (bit 32) is set when turbo mode is disabled. The issue arises when intel_pstate fails to detect that turbo mode is disabled. Here intel_pstate relies on MSR_IA32_MISC_ENABLE bit 38 to determine the status of turbo mode. However, on this system, bit 38 is not set even when turbo mode is disabled.
According to the Intel Software Developer's Manual (SDM), the BIOS sets this bit during platform initialization to enable or disable opportunistic processor performance operations. Logically, this bit should be set in such cases. However, the SDM also specifies that "OS and applications must use CPUID leaf 06H to detect processors with opportunistic processor performance operations enabled."
Therefore, in addition to checking MSR_IA32_MISC_ENABLE bit 38, verify that CPUID.06H:EAX[1] is 0 to accurately determine if turbo mode is disabled.
Fixes: 4521e1a0ce17 ("cpufreq: intel_pstate: Reflect current no_turbo state correctly") Signed-off-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Cc: All applicable stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f41ed0b9e610..ba9bf06f1c77 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -598,6 +598,9 @@ static bool turbo_is_disabled(void) { u64 misc_en;
+ if (!cpu_feature_enabled(X86_FEATURE_IDA)) + return true; + rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
return !!(misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
From: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com
[ Upstream commit 37b6ddba967c601479bea418a7ac6ff16b6232b7 ]
Setting global turbo flag based on CPU 0 P-state limits is problematic as it limits max P-state request on every CPU on the system just based on its P-state limits.
There are two cases in which global.turbo_disabled flag is set: - When the MSR_IA32_MISC_ENABLE_TURBO_DISABLE bit is set to 1 in the MSR MSR_IA32_MISC_ENABLE. This bit can be only changed by the system BIOS before power up. - When the max non turbo P-state is same as max turbo P-state for CPU 0.
The second check is not a valid to decide global turbo state based on the CPU 0. CPU 0 max turbo P-state can be same as max non turbo P-state, but for other CPUs this may not be true.
There is no guarantee that max P-state limits are same for every CPU. This is possible that during fusing max P-state for a CPU is constrained. Also with the Intel Speed Select performance profile, CPU 0 may not be present in all profiles. In this case the max non turbo and turbo P-state can be set to the lowest possible P-state by the hardware when switched to such profile. Since max non turbo and turbo P-state is same, global.turbo_disabled flag will be set.
Once global.turbo_disabled is set, any scaling max and min frequency update for any CPU will result in its max P-state constrained to the max non turbo P-state.
Hence remove the check of max non turbo P-state equal to max turbo P-state of CPU 0 to set global turbo disabled flag.
Signed-off-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com [ rjw: Subject edit ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Stable-dep-of: ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/intel_pstate.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index ee676ae1bc488..15d0d498071f1 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -562,13 +562,9 @@ static void intel_pstate_hybrid_hwp_adjust(struct cpudata *cpu) static inline void update_turbo_state(void) { u64 misc_en; - struct cpudata *cpu;
- cpu = all_cpu_data[0]; rdmsrl(MSR_IA32_MISC_ENABLE, misc_en); - global.turbo_disabled = - (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE || - cpu->pstate.max_pstate == cpu->pstate.turbo_pstate); + global.turbo_disabled = misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE; }
static int min_perf_pct_min(void)
From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com
[ Upstream commit 032c5565eb80edb6f2faeb31939540c897987119 ]
Fold intel_pstate_max_within_limits() into its only caller.
No functional impact.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Stable-dep-of: ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/intel_pstate.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 15d0d498071f1..39af2970a4297 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1984,14 +1984,6 @@ static void intel_pstate_set_min_pstate(struct cpudata *cpu) intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate); }
-static void intel_pstate_max_within_limits(struct cpudata *cpu) -{ - int pstate = max(cpu->pstate.min_pstate, cpu->max_perf_ratio); - - update_turbo_state(); - intel_pstate_set_pstate(cpu, pstate); -} - static void intel_pstate_get_cpu_pstates(struct cpudata *cpu) { int perf_ctl_max_phys = pstate_funcs.get_max_physical(cpu->cpu); @@ -2573,12 +2565,15 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) intel_pstate_update_perf_limits(cpu, policy->min, policy->max);
if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) { + int pstate = max(cpu->pstate.min_pstate, cpu->max_perf_ratio); + /* * NOHZ_FULL CPUs need this as the governor callback may not * be invoked on them. */ intel_pstate_clear_update_util_hook(policy->cpu); - intel_pstate_max_within_limits(cpu); + update_turbo_state(); + intel_pstate_set_pstate(cpu, pstate); } else { intel_pstate_set_update_util_hook(policy->cpu); }
From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com
[ Upstream commit 0940f1a8011fd69be5082015068e0dc31c800c20 ]
The global.turbo_disabled is updated quite often, especially in the passive mode in which case it is updated every time the scheduler calls into the driver. However, this is generally not necessary and it adds MSR read overhead to scheduler code paths (and that particular MSR is slow to read).
For this reason, make the driver read MSR_IA32_MISC_ENABLE_TURBO_DISABLE just once at the cpufreq driver registration time and remove all of the in-flight updates of global.turbo_disabled.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Stable-dep-of: ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/intel_pstate.c | 51 ++++++---------------------------- 1 file changed, 8 insertions(+), 43 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 39af2970a4297..1918cceca6cea 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -172,7 +172,6 @@ struct vid_data { * based on the MSR_IA32_MISC_ENABLE value and whether or * not the maximum reported turbo P-state is different from * the maximum reported non-turbo one. - * @turbo_disabled_mf: The @turbo_disabled value reflected by cpuinfo.max_freq. * @min_perf_pct: Minimum capacity limit in percent of the maximum turbo * P-state capacity. * @max_perf_pct: Maximum capacity limit in percent of the maximum turbo @@ -181,7 +180,6 @@ struct vid_data { struct global_params { bool no_turbo; bool turbo_disabled; - bool turbo_disabled_mf; int max_perf_pct; int min_perf_pct; }; @@ -559,12 +557,13 @@ static void intel_pstate_hybrid_hwp_adjust(struct cpudata *cpu) cpu->pstate.min_pstate = intel_pstate_freq_to_hwp(cpu, freq); }
-static inline void update_turbo_state(void) +static bool turbo_is_disabled(void) { u64 misc_en;
rdmsrl(MSR_IA32_MISC_ENABLE, misc_en); - global.turbo_disabled = misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE; + + return !!(misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE); }
static int min_perf_pct_min(void) @@ -1119,40 +1118,16 @@ static void intel_pstate_update_policies(void) static void __intel_pstate_update_max_freq(struct cpudata *cpudata, struct cpufreq_policy *policy) { - policy->cpuinfo.max_freq = global.turbo_disabled_mf ? + policy->cpuinfo.max_freq = global.turbo_disabled ? cpudata->pstate.max_freq : cpudata->pstate.turbo_freq; refresh_frequency_limits(policy); }
-static void intel_pstate_update_max_freq(unsigned int cpu) -{ - struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu); - - if (!policy) - return; - - __intel_pstate_update_max_freq(all_cpu_data[cpu], policy); - - cpufreq_cpu_release(policy); -} - static void intel_pstate_update_limits(unsigned int cpu) { mutex_lock(&intel_pstate_driver_lock);
- update_turbo_state(); - /* - * If turbo has been turned on or off globally, policy limits for - * all CPUs need to be updated to reflect that. - */ - if (global.turbo_disabled_mf != global.turbo_disabled) { - global.turbo_disabled_mf = global.turbo_disabled; - arch_set_max_freq_ratio(global.turbo_disabled); - for_each_possible_cpu(cpu) - intel_pstate_update_max_freq(cpu); - } else { - cpufreq_update_policy(cpu); - } + cpufreq_update_policy(cpu);
mutex_unlock(&intel_pstate_driver_lock); } @@ -1252,7 +1227,6 @@ static ssize_t show_no_turbo(struct kobject *kobj, return -EAGAIN; }
- update_turbo_state(); if (global.turbo_disabled) ret = sprintf(buf, "%u\n", global.turbo_disabled); else @@ -1282,7 +1256,6 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b,
mutex_lock(&intel_pstate_limits_lock);
- update_turbo_state(); if (global.turbo_disabled) { pr_notice_once("Turbo disabled by BIOS or unavailable on processor\n"); mutex_unlock(&intel_pstate_limits_lock); @@ -2253,8 +2226,6 @@ static void intel_pstate_adjust_pstate(struct cpudata *cpu) struct sample *sample; int target_pstate;
- update_turbo_state(); - target_pstate = get_target_pstate(cpu); target_pstate = intel_pstate_prepare_request(cpu, target_pstate); trace_cpu_frequency(target_pstate * cpu->pstate.scaling, cpu->cpu); @@ -2572,7 +2543,6 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) * be invoked on them. */ intel_pstate_clear_update_util_hook(policy->cpu); - update_turbo_state(); intel_pstate_set_pstate(cpu, pstate); } else { intel_pstate_set_update_util_hook(policy->cpu); @@ -2616,7 +2586,6 @@ static void intel_pstate_verify_cpu_policy(struct cpudata *cpu, { int max_freq;
- update_turbo_state(); if (hwp_active) { intel_pstate_get_hwp_cap(cpu); max_freq = global.no_turbo || global.turbo_disabled ? @@ -2713,8 +2682,6 @@ static int __intel_pstate_cpu_init(struct cpufreq_policy *policy)
/* cpuinfo and default policy values */ policy->cpuinfo.min_freq = cpu->pstate.min_freq; - update_turbo_state(); - global.turbo_disabled_mf = global.turbo_disabled; policy->cpuinfo.max_freq = global.turbo_disabled ? cpu->pstate.max_freq : cpu->pstate.turbo_freq;
@@ -2880,8 +2847,6 @@ static int intel_cpufreq_target(struct cpufreq_policy *policy, struct cpufreq_freqs freqs; int target_pstate;
- update_turbo_state(); - freqs.old = policy->cur; freqs.new = target_freq;
@@ -2903,8 +2868,6 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy, struct cpudata *cpu = all_cpu_data[policy->cpu]; int target_pstate;
- update_turbo_state(); - target_pstate = intel_pstate_freq_to_hwp(cpu, target_freq);
target_pstate = intel_cpufreq_update_pstate(policy, target_pstate, true); @@ -2922,7 +2885,6 @@ static void intel_cpufreq_adjust_perf(unsigned int cpunum, int old_pstate = cpu->pstate.current_pstate; int cap_pstate, min_pstate, max_pstate, target_pstate;
- update_turbo_state(); cap_pstate = global.turbo_disabled ? HWP_GUARANTEED_PERF(hwp_cap) : HWP_HIGHEST_PERF(hwp_cap);
@@ -3112,6 +3074,9 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver)
memset(&global, 0, sizeof(global)); global.max_perf_pct = 100; + global.turbo_disabled = turbo_is_disabled(); + + arch_set_max_freq_ratio(global.turbo_disabled);
intel_pstate_driver = driver; ret = cpufreq_register_driver(intel_pstate_driver);
From: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com
[ Upstream commit ac4e04d9e378f5aa826c2406ad7871ae1b6a6fb9 ]
When turbo mode is unavailable on a Skylake-X system, executing the command:
# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
results in an unchecked MSR access error:
WRMSR to 0x199 (attempted to write 0x0000000100001300).
This issue was reproduced on an OEM (Original Equipment Manufacturer) system and is not a common problem across all Skylake-X systems.
This error occurs because the MSR 0x199 Turbo Engage Bit (bit 32) is set when turbo mode is disabled. The issue arises when intel_pstate fails to detect that turbo mode is disabled. Here intel_pstate relies on MSR_IA32_MISC_ENABLE bit 38 to determine the status of turbo mode. However, on this system, bit 38 is not set even when turbo mode is disabled.
According to the Intel Software Developer's Manual (SDM), the BIOS sets this bit during platform initialization to enable or disable opportunistic processor performance operations. Logically, this bit should be set in such cases. However, the SDM also specifies that "OS and applications must use CPUID leaf 06H to detect processors with opportunistic processor performance operations enabled."
Therefore, in addition to checking MSR_IA32_MISC_ENABLE bit 38, verify that CPUID.06H:EAX[1] is 0 to accurately determine if turbo mode is disabled.
Fixes: 4521e1a0ce17 ("cpufreq: intel_pstate: Reflect current no_turbo state correctly") Signed-off-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Cc: All applicable stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/intel_pstate.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 1918cceca6cea..7d28bf7548cfa 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -561,6 +561,9 @@ static bool turbo_is_disabled(void) { u64 misc_en;
+ if (!cpu_feature_enabled(X86_FEATURE_IDA)) + return true; + rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
return !!(misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
linux-stable-mirror@lists.linaro.org
-
gregkh＠linuxfoundation.org -
Sasha Levin