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Date: Fri, 26 Apr 2024 06:39:53 +0000
From: "Yuan, Perry" <Perry.Yuan@....com>
To: "Limonciello, Mario" <Mario.Limonciello@....com>, "Huang, Ray"
<Ray.Huang@....com>, "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>,
"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>
CC: "Huang, Shimmer" <Shimmer.Huang@....com>, "oleksandr@...alenko.name"
<oleksandr@...alenko.name>, "Du, Xiaojian" <Xiaojian.Du@....com>, "Meng, Li
(Jassmine)" <Li.Meng@....com>, "linux-pm@...r.kernel.org"
<linux-pm@...r.kernel.org>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>, "Deucher, Alexander"
<Alexander.Deucher@....com>, "viresh.kumar@...aro.org"
<viresh.kumar@...aro.org>, "Petkov, Borislav" <Borislav.Petkov@....com>
Subject: RE: [PATCH v7 3/6] cpufreq: amd-pstate: implement cpb_boost sysfs
entry for boost control
[AMD Official Use Only - General]
Hi Mario
> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@....com>
> Sent: Friday, April 26, 2024 5:17 AM
> To: Yuan, Perry <Perry.Yuan@....com>; rafael.j.wysocki@...el.com;
> viresh.kumar@...aro.org; Shenoy, Gautham Ranjal
> <gautham.shenoy@....com>; Petkov, Borislav <Borislav.Petkov@....com>;
> Huang, Ray <Ray.Huang@....com>; Deucher, Alexander
> <Alexander.Deucher@....com>
> Cc: Huang, Shimmer <Shimmer.Huang@....com>; oleksandr@...alenko.name;
> Du, Xiaojian <Xiaojian.Du@....com>; Meng, Li (Jassmine)
> <Li.Meng@....com>; linux-pm@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH v7 3/6] cpufreq: amd-pstate: implement cpb_boost sysfs
> entry for boost control
>
> On 4/23/2024 03:40, Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@....com>
> >
> > With this new sysfs entry `cpb_boost`created, user can change CPU
> > boost state dynamically under `active`, `guided` and `passive` modes.
> > And the highest perf and frequency will also be updated as the boost
> > state changing.
> >
> > 0): check current boost state
> > cat /sys/devices/system/cpu/amd_pstate/cpb_boost
> >
> > 1): disable CPU boost
> > sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
> >
> > 2): enable CPU boost
> > sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
> >
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=217618
> > Signed-off-by: Perry Yuan <Perry.Yuan@....com>
> > ---
> > drivers/cpufreq/amd-pstate.c | 99
> ++++++++++++++++++++++++++++++++++++
> > 1 file changed, 99 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 3d86cd7c9073..49eeb38fcf20 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -1291,6 +1291,103 @@ static ssize_t prefcore_show(struct device *dev,
> > return sysfs_emit(buf, "%s\n",
> str_enabled_disabled(amd_pstate_prefcore));
> > }
> >
> > +static int amd_cpu_boost_update(struct amd_cpudata *cpudata, u32 on)
> > +{
> > + struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
> > + struct cppc_perf_ctrls perf_ctrls;
> > + u32 highest_perf, nominal_perf, nominal_freq, max_freq;
> > + int ret;
> > +
> > + if (!policy)
> > + return -ENODATA;
> > +
> > + highest_perf = READ_ONCE(cpudata->highest_perf);
> > + nominal_perf = READ_ONCE(cpudata->nominal_perf);
> > + nominal_freq = READ_ONCE(cpudata->nominal_freq);
> > + max_freq = READ_ONCE(cpudata->max_freq);
> > +
> > + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> > + u64 value = READ_ONCE(cpudata->cppc_req_cached);
> > +
> > + value &= ~GENMASK_ULL(7, 0);
> > + value |= on ? highest_perf : nominal_perf;
> > + WRITE_ONCE(cpudata->cppc_req_cached, value);
> > +
> > + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> > +
> > + } else {
> > + perf_ctrls.max_perf = on ? highest_perf : nominal_perf;
> > + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls, 1);
> > + if (ret) {
> > + pr_debug("failed to set energy perf value (%d)\n", ret);
> > + return ret;
> > + }
> > + }
> > +
> > + if (on)
> > + policy->cpuinfo.max_freq = max_freq;
> > + else
> > + policy->cpuinfo.max_freq = nominal_freq;
> > +
> > + policy->max = policy->cpuinfo.max_freq;
> > +
> > + if (cppc_state == AMD_PSTATE_PASSIVE) {
> > + ret = freq_qos_update_request(&cpudata->req[1],
> > + policy->cpuinfo.max_freq);
> > + }
> > +
> > + cpufreq_cpu_release(policy);
> > +
> > + return ret;
> > +}
> > +
> > +static ssize_t cpb_boost_show(struct device *dev,
> > + struct device_attribute *attr, char *buf) {
> > + return sysfs_emit(buf, "%u\n", amd_pstate_global_params.cpb_boost);
> > +}
> > +
> > +static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
> > + const char *buf, size_t count) {
> > + bool new_state;
> > + ssize_t ret;
> > + int cpu;
> > +
> > + mutex_lock(&amd_pstate_driver_lock);
>
> This mutex lock should be after the check for cpb_supported and kstrtobool
> check. Right now you have two cases that the lock doesn't get released.
Yes, the issue has been resolved by v8.
I have made one new version addressing the feedback from you and Ray
https://lore.kernel.org/lkml/cover.1714112854.git.perry.yuan@amd.com/
Please help to take a look.
Thank you.
Perry.
>
> > + if (!amd_pstate_global_params.cpb_supported) {
> > + pr_err("Boost mode is not supported by this processor or
> SBIOS\n");
> > + return -EINVAL;
> > + }
> > +
> > + ret = kstrtobool(buf, &new_state);
> > + if (ret)
> > + return -EINVAL;
> > +
> > + amd_pstate_global_params.cpb_boost = !!new_state;
> > +
> > + for_each_present_cpu(cpu) {
> > +
> > + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> > + struct amd_cpudata *cpudata = policy->driver_data;
> > +
> > + if (!cpudata) {
> > + pr_err("cpudata is NULL\n");
> > + ret = -ENODATA;
> > + cpufreq_cpu_put(policy);
> > + goto err_exit;
> > + }
> > +
> > + amd_cpu_boost_update(cpudata,
> amd_pstate_global_params.cpb_boost);
> > + refresh_frequency_limits(policy);
> > + cpufreq_cpu_put(policy);
> > + }
> > +
> > +err_exit:
> > + mutex_unlock(&amd_pstate_driver_lock);
> > + return ret < 0 ? ret : count;
> > +}
> > +
> > cpufreq_freq_attr_ro(amd_pstate_max_freq);
> > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > @@ -1301,6 +1398,7 @@
> cpufreq_freq_attr_rw(energy_performance_preference);
> > cpufreq_freq_attr_ro(energy_performance_available_preferences);
> > static DEVICE_ATTR_RW(status);
> > static DEVICE_ATTR_RO(prefcore);
> > +static DEVICE_ATTR_RW(cpb_boost);
> >
> > static struct freq_attr *amd_pstate_attr[] = {
> > &amd_pstate_max_freq,
> > @@ -1325,6 +1423,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> > static struct attribute *pstate_global_attributes[] = {
> > &dev_attr_status.attr,
> > &dev_attr_prefcore.attr,
> > + &dev_attr_cpb_boost.attr,
> > NULL
> > };
> >
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