| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <aDaB63tDvbdcV0cg@HQ-GR2X1W2P57>
Date: Tue, 27 May 2025 20:24:27 -0700
From: Manu Bretelle <chantr4@...il.com>
To: "Gautham R. Shenoy" <gautham.shenoy@....com>
Cc: Mario Limonciello <mario.limonciello@....com>,
Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
"Rafael J . Wysocki" <rafael@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, Adam Clark <Adam.Clark@....com>
Subject: Re: [PATCH] acpi-cpufreq: Fix max-frequency computation
On Mon, Jan 13, 2025 at 10:11:07AM +0530, Gautham R. Shenoy wrote:
> commit 3c55e94c0ade ("cpufreq: ACPI: Extend frequency tables to cover
> boost frequencies") introduces an assumption in
> acpi_cpufreq_cpu_init() that the first entry in the P-state table is
> the nominal frequency. This assumption is incorrect. The frequency
> corresponding to the P0 P-State need not be the same as the nominal
> frequency advertised via CPPC.
>
> Since the driver is using the CPPC.highest_perf and CPPC.nominal_perf
> to compute the boost-ratio, it makes sense to use CPPC.nominal_freq to
> compute the max-frequency. CPPC.nominal_freq is advertised on
> platforms supporting CPPC revisions 3 or higher.
>
> Hence, fallback to using the first entry in the P-State table only on
> platforms that do not advertise CPPC.nominal_freq.
>
Gautham, this got recently pulled in 5.15.179 [0] but it seems to have broken
what max CPU get reported.
I hit the issue on Ubuntu 22.04 with kernel 5.15.0-140-generic. My read from [1]
is that that kernel is pretty much 5.15.79.
I rebuilt it with this patch removed and max CPU now show as before.
Here some output that may help, which is what is mostly down to what is reported
by /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq . Posting the whole
lscpu hoping that contain more useful data. Happy to provide more if needed.
Ubuntu 22.04 with 5.15.0-140-generic (affected, note CPU max MHz: 2000.0000):
$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Address sizes: 48 bits physical, 48 bits virtual
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Vendor ID: AuthenticAMD
Model name: AMD EPYC 7713P 64-Core Processor
CPU family: 25
Model: 1
Thread(s) per core: 2
Core(s) per socket: 64
Socket(s): 1
Stepping: 1
Frequency boost: enabled
CPU max MHz: 2000.0000
CPU min MHz: 1500.0000
BogoMIPS: 3992.30
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monit
or ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy a
bm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb
cat_l3 cdp_l3 invpcid_single hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm
rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm
_local clzero irperf xsaveerptr rdpru wbnoinvd amd_ppin arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyas
id decodeassists pausefilter pfthreshold v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow
_recov succor smca fsrm
Virtualization features:
Virtualization: AMD-V
Caches (sum of all):
L1d: 2 MiB (64 instances)
L1i: 2 MiB (64 instances)
L2: 32 MiB (64 instances)
L3: 256 MiB (8 instances)
NUMA:
NUMA node(s): 1
NUMA node0 CPU(s): 0-127
Vulnerabilities:
Gather data sampling: Not affected
Itlb multihit: Not affected
L1tf: Not affected
Mds: Not affected
Meltdown: Not affected
Mmio stale data: Not affected
Reg file data sampling: Not affected
Retbleed: Not affected
Spec rstack overflow: Mitigation; safe RET
Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Spectre v2: Mitigation; Retpolines; IBPB conditional; IBRS_FW; STIBP always-on; RSB filling; PBRSB-eIBRS Not affected; BHI Not affe
cted
Srbds: Not affected
Tsx async abort: Not affected
With 5.15.0-999-generic (5.15.0-140-generic without this patch), max CPU is back
to 3720.7029, which is also what I get with 5.15.0-139-generic.
$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Address sizes: 48 bits physical, 48 bits virtual
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Vendor ID: AuthenticAMD
Model name: AMD EPYC 7713P 64-Core Processor
CPU family: 25
Model: 1
Thread(s) per core: 2
Core(s) per socket: 64
Socket(s): 1
Stepping: 1
Frequency boost: enabled
CPU max MHz: 3720.7029
CPU min MHz: 1500.0000
BogoMIPS: 3992.55
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monit
or ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy a
bm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb
cat_l3 cdp_l3 invpcid_single hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm
rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm
_local clzero irperf xsaveerptr rdpru wbnoinvd amd_ppin arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyas
id decodeassists pausefilter pfthreshold v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow
_recov succor smca fsrm
Virtualization features:
Virtualization: AMD-V
Caches (sum of all):
L1d: 2 MiB (64 instances)
L1i: 2 MiB (64 instances)
L2: 32 MiB (64 instances)
L3: 256 MiB (8 instances)
NUMA:
NUMA node(s): 1
NUMA node0 CPU(s): 0-127
Vulnerabilities:
Gather data sampling: Not affected
Itlb multihit: Not affected
L1tf: Not affected
Mds: Not affected
Meltdown: Not affected
Mmio stale data: Not affected
Reg file data sampling: Not affected
Retbleed: Not affected
Spec rstack overflow: Mitigation; safe RET
Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Spectre v2: Mitigation; Retpolines; IBPB conditional; IBRS_FW; STIBP always-on; RSB filling; PBRSB-eIBRS Not affected; BHI Not affe
cted
Srbds: Not affected
Tsx async abort: Not affected
Thought to post here instead of [0] to get your thought on this. Am I missing
something simple to get the right value? Or should this be pulled out of 5.15
LTS?
Thanks
[0]: https://lore.kernel.org/all/2025031356-rerun-remold-30b9@gregkh/
[1]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2106026
> Fixes: 3c55e94c0ade ("cpufreq: ACPI: Extend frequency tables to cover boost frequencies")
> Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
> Signed-off-by: Gautham R. Shenoy <gautham.shenoy@....com>
> ---
> drivers/cpufreq/acpi-cpufreq.c | 36 +++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index c9ebacf5c88e..744fcdeab173 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -623,7 +623,14 @@ static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c)
> #endif
>
> #ifdef CONFIG_ACPI_CPPC_LIB
> -static u64 get_max_boost_ratio(unsigned int cpu)
> +/*
> + * get_max_boost_ratio: Computes the max_boost_ratio as the ratio
> + * between the highest_perf and the nominal_perf.
> + *
> + * Returns the max_boost_ratio for @cpu. Returns the CPPC nominal
> + * frequency via @nominal_freq if it is non-NULL pointer.
> + */
> +static u64 get_max_boost_ratio(unsigned int cpu, u64 *nominal_freq)
> {
> struct cppc_perf_caps perf_caps;
> u64 highest_perf, nominal_perf;
> @@ -652,6 +659,9 @@ static u64 get_max_boost_ratio(unsigned int cpu)
>
> nominal_perf = perf_caps.nominal_perf;
>
> + if (nominal_freq)
> + *nominal_freq = perf_caps.nominal_freq;
> +
> if (!highest_perf || !nominal_perf) {
> pr_debug("CPU%d: highest or nominal performance missing\n", cpu);
> return 0;
> @@ -664,8 +674,12 @@ static u64 get_max_boost_ratio(unsigned int cpu)
>
> return div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
> }
> +
> #else
> -static inline u64 get_max_boost_ratio(unsigned int cpu) { return 0; }
> +static inline u64 get_max_boost_ratio(unsigned int cpu, u64 *nominal_freq)
> +{
> + return 0;
> +}
> #endif
>
> static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
> @@ -677,7 +691,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
> struct cpuinfo_x86 *c = &cpu_data(cpu);
> unsigned int valid_states = 0;
> unsigned int result = 0;
> - u64 max_boost_ratio;
> + u64 max_boost_ratio, nominal_freq = 0;
> unsigned int i;
> #ifdef CONFIG_SMP
> static int blacklisted;
> @@ -827,16 +841,20 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
> }
> freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
>
> - max_boost_ratio = get_max_boost_ratio(cpu);
> + max_boost_ratio = get_max_boost_ratio(cpu, &nominal_freq);
> if (max_boost_ratio) {
> - unsigned int freq = freq_table[0].frequency;
> + unsigned int freq = nominal_freq;
>
> /*
> - * Because the loop above sorts the freq_table entries in the
> - * descending order, freq is the maximum frequency in the table.
> - * Assume that it corresponds to the CPPC nominal frequency and
> - * use it to set cpuinfo.max_freq.
> + * The loop above sorts the freq_table entries in the
> + * descending order. If ACPI CPPC has not advertised
> + * the nominal frequency (this is possible in CPPC
> + * revisions prior to 3), then use the first entry in
> + * the pstate table as a proxy for nominal frequency.
> */
> + if (!freq)
> + freq = freq_table[0].frequency;
> +
> policy->cpuinfo.max_freq = freq * max_boost_ratio >> SCHED_CAPACITY_SHIFT;
> } else {
> /*
> --
> 2.34.1
>
Powered by blists - more mailing lists