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Subject[PATCH v4] x86, sched: Fix the AMD CPPC maximum perf on some specific generations
Date
Some AMD Ryzen generations has different calculation method on maximum
perf. 255 is not for all asics, some specific generations should use 166
as the maximum perf. Otherwise, it will report incorrect frequency value
like below:

~ → lscpu | grep MHz
CPU MHz: 3400.000
CPU max MHz: 7228.3198
CPU min MHz: 2200.0000

Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems")
Fixes: 3c55e94c0ade ("cpufreq: ACPI: Extend frequency tables to cover boost frequencies")

Reported-by: Jason Bagavatsingham <jason.bagavatsingham@gmail.com>
Tested-by: Jason Bagavatsingham <jason.bagavatsingham@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211791
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Nathan Fontenot <nathan.fontenot@amd.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
---

Changes from V1 -> V2:
- Enhance the commit message.
- Move amd_get_highest_perf() into amd.c.
- Refine the implementation of switch-case.
- Cc stable mail list.

Changes from V2 -> V3:
- Move the update into cppc_get_perf_caps() to correct the highest perf value in
the API.

Changes from V3 -> V4:
- Rollback to V2 implementation because acpi_cppc.c will be used by ARM as well.
It's not good to add x86-specific calling there.
- Simplify the implementation of the functions.

---
arch/x86/include/asm/processor.h | 2 ++
arch/x86/kernel/cpu/amd.c | 16 ++++++++++++++++
arch/x86/kernel/smpboot.c | 2 +-
drivers/cpufreq/acpi-cpufreq.c | 6 +++++-
4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index f1b9ed5efaa9..908bcaea1361 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -804,8 +804,10 @@ DECLARE_PER_CPU(u64, msr_misc_features_shadow);

#ifdef CONFIG_CPU_SUP_AMD
extern u32 amd_get_nodes_per_socket(void);
+extern u32 amd_get_highest_perf(void);
#else
static inline u32 amd_get_nodes_per_socket(void) { return 0; }
+static inline u32 amd_get_highest_perf(void) { return 0; }
#endif

static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 347a956f71ca..bc3496669def 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1170,3 +1170,19 @@ void set_dr_addr_mask(unsigned long mask, int dr)
break;
}
}
+
+u32 amd_get_highest_perf(void)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+
+ if (c->x86 == 0x17 && ((c->x86_model >= 0x30 && c->x86_model < 0x40) ||
+ (c->x86_model >= 0x70 && c->x86_model < 0x80)))
+ return 166;
+
+ if (c->x86 == 0x19 && ((c->x86_model >= 0x20 && c->x86_model < 0x30) ||
+ (c->x86_model >= 0x40 && c->x86_model < 0x70)))
+ return 166;
+
+ return 225;
+}
+EXPORT_SYMBOL_GPL(amd_get_highest_perf);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 02813a7f3a7c..7bec57d04a87 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -2046,7 +2046,7 @@ static bool amd_set_max_freq_ratio(void)
return false;
}

- highest_perf = perf_caps.highest_perf;
+ highest_perf = amd_get_highest_perf();
nominal_perf = perf_caps.nominal_perf;

if (!highest_perf || !nominal_perf) {
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index d1bbc16fba4b..7e7450453714 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -646,7 +646,11 @@ static u64 get_max_boost_ratio(unsigned int cpu)
return 0;
}

- highest_perf = perf_caps.highest_perf;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+ highest_perf = amd_get_highest_perf();
+ else
+ highest_perf = perf_caps.highest_perf;
+
nominal_perf = perf_caps.nominal_perf;

if (!highest_perf || !nominal_perf) {
--
2.25.1
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