[v2,4/5] x86/cpu: Add CPU type to struct cpuinfo_topology

Commit Message

Mario Limonciello Oct. 22, 2024, 3:46 a.m. UTC

From: Pawan Gupta <[e-mail]>

Sometimes it is required to take actions based on if a CPU is a performance
or efficiency core. As an example, intel_pstate driver uses the Intel
core-type to determine CPU scaling. Also, some CPU vulnerabilities only
affect a specific CPU type, like RFDS only affects Intel Atom. Hybrid
systems that have variants P+E, P-only(Core) and E-only(Atom), it is not
straightforward to identify which variant is affected by a type specific
vulnerability.

Such processors do have CPUID field that can uniquely identify them. Like,
P+E, P-only and E-only enumerates CPUID.1A.CORE_TYPE identification, while
P+E additionally enumerates CPUID.7.HYBRID. Based on this information, it
is possible for boot CPU to identify if a system has mixed CPU types.

Add a new field hw_cpu_type to struct cpuinfo_topology that stores the
hardware specific CPU type. This saves the overhead of IPIs to get the CPU
type of a different CPU. CPU type is populated early in the boot process,
before vulnerabilities are enumerated.

Signed-off-by: Pawan Gupta <[e-mail]>
Co-developed-by: Mario Limonciello <[e-mail]>
Signed-off-by: Mario Limonciello <[e-mail]>
---
* Take this patch from Pawan's series and fix up for feedback left on it.
* Add in AMD case as well
---
 arch/x86/include/asm/cpu.h            | 19 +++++++++++++++++++
 arch/x86/include/asm/processor.h      | 18 ++++++++++++++++++
 arch/x86/include/asm/topology.h       |  8 ++++++++
 arch/x86/kernel/cpu/amd.c             | 14 ++++++++++++++
 arch/x86/kernel/cpu/debugfs.c         |  1 +
 arch/x86/kernel/cpu/intel.c           | 18 ++++++++++++++++++
 arch/x86/kernel/cpu/topology_amd.c    |  3 +++
 arch/x86/kernel/cpu/topology_common.c | 13 +++++++++++++
 8 files changed, 94 insertions(+)

Comments

Borislav Petkov Oct. 22, 2024, 11:57 a.m. UTC | #1

On Mon, Oct 21, 2024 at 10:46:07PM -0500, Mario Limonciello wrote:
> * Take this patch from Pawan's series and fix up for feedback left on it.
> * Add in AMD case as well

Yah, this one is adding way more boilerplate code than it should. IOW, I'm
thinking of something simpler like this:

---

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 98eced5084ca..44122b077932 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -53,6 +53,7 @@ static inline void bus_lock_init(void) {}
 #ifdef CONFIG_CPU_SUP_INTEL
 u8 get_this_hybrid_cpu_type(void);
 u32 get_this_hybrid_cpu_native_id(void);
+enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c);
 #else
 static inline u8 get_this_hybrid_cpu_type(void)
 {
@@ -63,6 +64,18 @@ static inline u32 get_this_hybrid_cpu_native_id(void)
 {
 	return 0;
 }
+static enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+#endif
+#ifdef CONFIG_CPU_SUP_AMD
+enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c);
+#else
+static inline enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
 #endif
 #ifdef CONFIG_IA32_FEAT_CTL
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4a686f0e5dbf..c0975815980c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -105,6 +105,24 @@ struct cpuinfo_topology {
 	// Cache level topology IDs
 	u32			llc_id;
 	u32			l2c_id;
+
+	// Hardware defined CPU-type
+	union {
+		u32		cpu_type;
+		struct {
+			// CPUID.1A.EAX[23-0]
+			u32	intel_native_model_id	:24;
+			// CPUID.1A.EAX[31-24]
+			u32	intel_type		:8;
+		};
+		struct {
+			// CPUID 0x80000026.EBX
+			u32	amd_num_processors	:16,
+				amd_power_eff_ranking	:8,
+				amd_native_model_id	:4,
+				amd_type		:4;
+		};
+	};
 };
 
 struct cpuinfo_x86 {
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index aef70336d624..c43d4b3324bc 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -114,6 +114,12 @@ enum x86_topology_domains {
 	TOPO_MAX_DOMAIN,
 };
 
+enum x86_topology_cpu_type {
+	TOPO_CPU_TYPE_PERFORMANCE,
+	TOPO_CPU_TYPE_EFFICIENCY,
+	TOPO_CPU_TYPE_UNKNOWN,
+};
+
 struct x86_topology_system {
 	unsigned int	dom_shifts[TOPO_MAX_DOMAIN];
 	unsigned int	dom_size[TOPO_MAX_DOMAIN];
@@ -149,6 +155,8 @@ extern unsigned int __max_threads_per_core;
 extern unsigned int __num_threads_per_package;
 extern unsigned int __num_cores_per_package;
 
+const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c);
+
 static inline unsigned int topology_max_packages(void)
 {
 	return __max_logical_packages;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fab5caec0b72..7d8d62fdc112 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1205,3 +1205,12 @@ void amd_check_microcode(void)
 	if (cpu_feature_enabled(X86_FEATURE_ZEN2))
 		on_each_cpu(zenbleed_check_cpu, NULL, 1);
 }
+
+enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.amd_type) {
+	case 0:	return TOPO_CPU_TYPE_PERFORMANCE;
+	case 1:	return TOPO_CPU_TYPE_EFFICIENCY;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/debugfs.c b/arch/x86/kernel/cpu/debugfs.c
index 3baf3e435834..10719aba6276 100644
--- a/arch/x86/kernel/cpu/debugfs.c
+++ b/arch/x86/kernel/cpu/debugfs.c
@@ -22,6 +22,7 @@ static int cpu_debug_show(struct seq_file *m, void *p)
 	seq_printf(m, "die_id:              %u\n", c->topo.die_id);
 	seq_printf(m, "cu_id:               %u\n", c->topo.cu_id);
 	seq_printf(m, "core_id:             %u\n", c->topo.core_id);
+	seq_printf(m, "cpu_type:            %s\n", get_topology_cpu_type_name(c));
 	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);
 	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);
 	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index d1de300af173..7b1011d0b369 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -907,3 +907,12 @@ u32 get_this_hybrid_cpu_native_id(void)
 	return cpuid_eax(0x0000001a) &
 	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
 }
+
+enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.intel_type) {
+	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
+	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index 7d476fa697ca..03b3c9c3a45e 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -182,6 +182,9 @@ static void parse_topology_amd(struct topo_scan *tscan)
 	if (cpu_feature_enabled(X86_FEATURE_TOPOEXT))
 		has_topoext = cpu_parse_topology_ext(tscan);
 
+	if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES))
+		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
+
 	if (!has_topoext && !parse_8000_0008(tscan))
 		return;
 
diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index 9a6069e7133c..38220b64c6b3 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -27,6 +27,23 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
 	}
 }
 
+const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
+{
+	enum x86_topology_cpu_type type;
+
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		type = get_intel_cpu_type(c);
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		type = get_amd_cpu_type(c);
+
+	if (type == TOPO_CPU_TYPE_PERFORMANCE)
+		return "performance";
+	else if (type == TOPO_CPU_TYPE_EFFICIENCY)
+		return "efficiency";
+	else
+		return "unknown";
+}
+
 static unsigned int __maybe_unused parse_num_cores_legacy(struct cpuinfo_x86 *c)
 {
 	struct {
@@ -87,6 +104,7 @@ static void parse_topology(struct topo_scan *tscan, bool early)
 		.cu_id			= 0xff,
 		.llc_id			= BAD_APICID,
 		.l2c_id			= BAD_APICID,
+		.cpu_type		= TOPO_CPU_TYPE_UNKNOWN,
 	};
 	struct cpuinfo_x86 *c = tscan->c;
 	struct {
@@ -132,6 +150,8 @@ static void parse_topology(struct topo_scan *tscan, bool early)
 	case X86_VENDOR_INTEL:
 		if (!IS_ENABLED(CONFIG_CPU_SUP_INTEL) || !cpu_parse_topology_ext(tscan))
 			parse_legacy(tscan);
+		if (c->cpuid_level >= 0x1a)
+			c->topo.cpu_type = cpuid_eax(0x1a);
 		break;
 	case X86_VENDOR_HYGON:
 		if (IS_ENABLED(CONFIG_CPU_SUP_HYGON))

Borislav Petkov Oct. 22, 2024, 12:03 p.m. UTC | #2

On Tue, Oct 22, 2024 at 01:57:20PM +0200, Borislav Petkov wrote:
> diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
> index 9a6069e7133c..38220b64c6b3 100644
> --- a/arch/x86/kernel/cpu/topology_common.c
> +++ b/arch/x86/kernel/cpu/topology_common.c
> @@ -27,6 +27,23 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
>  	}
>  }
>  
> +const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
> +{
> +	enum x86_topology_cpu_type type;
> +
> +	if (c->x86_vendor == X86_VENDOR_INTEL)
> +		type = get_intel_cpu_type(c);
> +	if (c->x86_vendor == X86_VENDOR_AMD)
> +		type = get_amd_cpu_type(c);
> +
> +	if (type == TOPO_CPU_TYPE_PERFORMANCE)
> +		return "performance";
> +	else if (type == TOPO_CPU_TYPE_EFFICIENCY)
> +		return "efficiency";
> +	else
> +		return "unknown";
> +}

I guess you still need topology_cpu_type() in your next patch but that's easy
- you simply call it in get_topology_cpu_type_name().

The point being debugfs will dump the name of the core type and not some magic
number which no one knows.

Thx.

Mario Limonciello Oct. 22, 2024, 3:41 p.m. UTC | #3

On 10/22/2024 07:03, Borislav Petkov wrote:
> On Tue, Oct 22, 2024 at 01:57:20PM +0200, Borislav Petkov wrote:
>> diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
>> index 9a6069e7133c..38220b64c6b3 100644
>> --- a/arch/x86/kernel/cpu/topology_common.c
>> +++ b/arch/x86/kernel/cpu/topology_common.c
>> @@ -27,6 +27,23 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
>>   	}
>>   }
>>   
>> +const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
>> +{
>> +	enum x86_topology_cpu_type type;
>> +
>> +	if (c->x86_vendor == X86_VENDOR_INTEL)
>> +		type = get_intel_cpu_type(c);
>> +	if (c->x86_vendor == X86_VENDOR_AMD)
>> +		type = get_amd_cpu_type(c);
>> +
>> +	if (type == TOPO_CPU_TYPE_PERFORMANCE)
>> +		return "performance";
>> +	else if (type == TOPO_CPU_TYPE_EFFICIENCY)
>> +		return "efficiency";
>> +	else
>> +		return "unknown";
>> +}
> 
> I guess you still need topology_cpu_type() in your next patch but that's easy
> - you simply call it in get_topology_cpu_type_name().
> 
> The point being debugfs will dump the name of the core type and not some magic
> number which no one knows.

Yeah; makes sense.  I'll pull your suggestions in.

Dave Hansen Oct. 22, 2024, 4:03 p.m. UTC | #4

On 10/22/24 04:57, Borislav Petkov wrote:
> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	switch (c->topo.intel_type) {
> +	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
> +	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
> +	}
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}

This makes me feel a _bit_ uneasy.  0x20 here really does mean "Atom
microarchitecture" and 0x40 means "Core microarchitecture".

We want to encourage folks to use this new ABI when they want to find
the fastest core to run on.  But we don't want them to use it to bind to
a CPU and then deploy Atom-specific optimizations.

We *also* don't want the in-kernel code to do be doing things like:

	if (get_intel_cpu_type() == TOPO_CPU_TYPE_EFFICIENCY)
		setup_force_cpu_bug(FOO);

That would fall over if Intel ever mixed fast and slow core types with
the same microarchitecture, which is what AMD is doing today.

Having:

	TOPO_CPU_TYPE_EFFICIENCY, and
	TOPO_CPU_TYPE_PERFORMANCE

is totally fine in generic code.  But we also need to preserve the:

	TOPO_HW_CPU_TYPE_INTEL_ATOM
	TOPO_HW_CPU_TYPE_INTEL_CORE

values also for use in vendor-specific code.

In the ABI, I think we should probably make this an explicit
power/performance interface rather than "cpu_type".  As much as I like
the human readable "performance" and "efficiency", I'm worried it won't
be flexible enough for future maniacal hardware designers.  To be 100%
clear, all the hardware designs that I know of would fit in a two-bucket
("performance" and "efficiency") scheme.  But we've got to decide
whether to commit to that forever.

Mario Limonciello Oct. 22, 2024, 4:13 p.m. UTC | #5

On 10/22/2024 11:03, Dave Hansen wrote:
> On 10/22/24 04:57, Borislav Petkov wrote:
>> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
>> +{
>> +	switch (c->topo.intel_type) {
>> +	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
>> +	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
>> +	}
>> +	return TOPO_CPU_TYPE_UNKNOWN;
>> +}
> 
> This makes me feel a _bit_ uneasy.  0x20 here really does mean "Atom
> microarchitecture" and 0x40 means "Core microarchitecture".
> 
> We want to encourage folks to use this new ABI when they want to find
> the fastest core to run on.  But we don't want them to use it to bind to
> a CPU and then deploy Atom-specific optimizations.
> 
> We *also* don't want the in-kernel code to do be doing things like:
> 
> 	if (get_intel_cpu_type() == TOPO_CPU_TYPE_EFFICIENCY)
> 		setup_force_cpu_bug(FOO);
> 
> That would fall over if Intel ever mixed fast and slow core types with
> the same microarchitecture, which is what AMD is doing today.
> 
> Having:
> 
> 	TOPO_CPU_TYPE_EFFICIENCY, and
> 	TOPO_CPU_TYPE_PERFORMANCE
> 
> is totally fine in generic code.  But we also need to preserve the:
> 
> 	TOPO_HW_CPU_TYPE_INTEL_ATOM
> 	TOPO_HW_CPU_TYPE_INTEL_CORE
> 
> values also for use in vendor-specific code.

What you're suggesting is to keep an enum in the intel.c code and any 
code that needs to match atom vs core can directly use

c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM

Right?

> 
> In the ABI, I think we should probably make this an explicit
> power/performance interface rather than "cpu_type".  As much as I like
> the human readable "performance" and "efficiency", I'm worried it won't
> be flexible enough for future maniacal hardware designers.  To be 100%
> clear, all the hardware designs that I know of would fit in a two-bucket
> ("performance" and "efficiency") scheme.  But we've got to decide
> whether to commit to that forever.

As it stands today none of this is exported anywhere but debugfs; so I 
wouldn't say we have ABI concerns (yet).  Could we wait until the one 
that breaks the mold shows up?

Dave Hansen Oct. 22, 2024, 5:09 p.m. UTC | #6

On 10/22/24 09:13, Mario Limonciello wrote:
> On 10/22/2024 11:03, Dave Hansen wrote:
...
>> Having:
>>
>>     TOPO_CPU_TYPE_EFFICIENCY, and
>>     TOPO_CPU_TYPE_PERFORMANCE
>>
>> is totally fine in generic code.  But we also need to preserve the:
>>
>>     TOPO_HW_CPU_TYPE_INTEL_ATOM
>>     TOPO_HW_CPU_TYPE_INTEL_CORE
>>
>> values also for use in vendor-specific code.
> 
> What you're suggesting is to keep an enum in the intel.c code and any
> code that needs to match atom vs core can directly use
> 
> c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM
> 
> Right?

Yep, exactly.

> As it stands today none of this is exported anywhere but debugfs; so
> I wouldn't say we have ABI concerns (yet).  Could we wait until the
> one that breaks the mold shows up?

Oh, debugfs is fine.  I was, for some reason, assuming that the strings
were getting spit out in sysfs proper somewhere, not debugfs.  Sorry for
the noise.

Pawan Gupta Oct. 23, 2024, 3:58 a.m. UTC | #7

On Tue, Oct 22, 2024 at 11:13:00AM -0500, Mario Limonciello wrote:
> > This makes me feel a _bit_ uneasy.  0x20 here really does mean "Atom
> > microarchitecture" and 0x40 means "Core microarchitecture".
> > 
> > We want to encourage folks to use this new ABI when they want to find
> > the fastest core to run on.  But we don't want them to use it to bind to
> > a CPU and then deploy Atom-specific optimizations.
> > 
> > We *also* don't want the in-kernel code to do be doing things like:
> > 
> > 	if (get_intel_cpu_type() == TOPO_CPU_TYPE_EFFICIENCY)
> > 		setup_force_cpu_bug(FOO);
> > 
> > That would fall over if Intel ever mixed fast and slow core types with
> > the same microarchitecture, which is what AMD is doing today.
> > 
> > Having:
> > 
> > 	TOPO_CPU_TYPE_EFFICIENCY, and
> > 	TOPO_CPU_TYPE_PERFORMANCE
> > 
> > is totally fine in generic code.  But we also need to preserve the:
> > 
> > 	TOPO_HW_CPU_TYPE_INTEL_ATOM
> > 	TOPO_HW_CPU_TYPE_INTEL_CORE
> > 
> > values also for use in vendor-specific code.
> 
> What you're suggesting is to keep an enum in the intel.c code and any code
> that needs to match atom vs core can directly use
> 
> c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM

To be able to match ATOM and CORE in the affected processor table, the
enums need to be defined in a way that they can be used in the common code.
Specially for !CONFIG_CPU_SUP_INTEL case.

Pawan Gupta Oct. 23, 2024, 4:40 a.m. UTC | #8

On Tue, Oct 22, 2024 at 01:57:20PM +0200, Borislav Petkov wrote:
> On Mon, Oct 21, 2024 at 10:46:07PM -0500, Mario Limonciello wrote:
> > * Take this patch from Pawan's series and fix up for feedback left on it.
> > * Add in AMD case as well
> 
> Yah, this one is adding way more boilerplate code than it should. IOW, I'm
> thinking of something simpler like this:
> 
> ---
> 
> diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
> index 98eced5084ca..44122b077932 100644
> --- a/arch/x86/include/asm/cpu.h
> +++ b/arch/x86/include/asm/cpu.h
> @@ -53,6 +53,7 @@ static inline void bus_lock_init(void) {}
>  #ifdef CONFIG_CPU_SUP_INTEL
>  u8 get_this_hybrid_cpu_type(void);
>  u32 get_this_hybrid_cpu_native_id(void);
> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c);
>  #else
>  static inline u8 get_this_hybrid_cpu_type(void)
>  {
> @@ -63,6 +64,18 @@ static inline u32 get_this_hybrid_cpu_native_id(void)
>  {
>  	return 0;
>  }
> +static enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}
> +#endif
> +#ifdef CONFIG_CPU_SUP_AMD
> +enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c);
> +#else
> +static inline enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}
>  #endif
>  #ifdef CONFIG_IA32_FEAT_CTL
>  void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 4a686f0e5dbf..c0975815980c 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -105,6 +105,24 @@ struct cpuinfo_topology {
>  	// Cache level topology IDs
>  	u32			llc_id;
>  	u32			l2c_id;
> +
> +	// Hardware defined CPU-type
> +	union {
> +		u32		cpu_type;
> +		struct {
> +			// CPUID.1A.EAX[23-0]
> +			u32	intel_native_model_id	:24;
> +			// CPUID.1A.EAX[31-24]
> +			u32	intel_type		:8;
> +		};
> +		struct {
> +			// CPUID 0x80000026.EBX
> +			u32	amd_num_processors	:16,
> +				amd_power_eff_ranking	:8,
> +				amd_native_model_id	:4,
> +				amd_type		:4;
> +		};
> +	};
>  };
>  
>  struct cpuinfo_x86 {
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index aef70336d624..c43d4b3324bc 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -114,6 +114,12 @@ enum x86_topology_domains {
>  	TOPO_MAX_DOMAIN,
>  };
>  
> +enum x86_topology_cpu_type {
> +	TOPO_CPU_TYPE_PERFORMANCE,
> +	TOPO_CPU_TYPE_EFFICIENCY,
> +	TOPO_CPU_TYPE_UNKNOWN,
> +};
> +
>  struct x86_topology_system {
>  	unsigned int	dom_shifts[TOPO_MAX_DOMAIN];
>  	unsigned int	dom_size[TOPO_MAX_DOMAIN];
> @@ -149,6 +155,8 @@ extern unsigned int __max_threads_per_core;
>  extern unsigned int __num_threads_per_package;
>  extern unsigned int __num_cores_per_package;
>  
> +const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c);
> +
>  static inline unsigned int topology_max_packages(void)
>  {
>  	return __max_logical_packages;
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index fab5caec0b72..7d8d62fdc112 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -1205,3 +1205,12 @@ void amd_check_microcode(void)
>  	if (cpu_feature_enabled(X86_FEATURE_ZEN2))
>  		on_each_cpu(zenbleed_check_cpu, NULL, 1);
>  }
> +
> +enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	switch (c->topo.amd_type) {
> +	case 0:	return TOPO_CPU_TYPE_PERFORMANCE;
> +	case 1:	return TOPO_CPU_TYPE_EFFICIENCY;
> +	}
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}
> diff --git a/arch/x86/kernel/cpu/debugfs.c b/arch/x86/kernel/cpu/debugfs.c
> index 3baf3e435834..10719aba6276 100644
> --- a/arch/x86/kernel/cpu/debugfs.c
> +++ b/arch/x86/kernel/cpu/debugfs.c
> @@ -22,6 +22,7 @@ static int cpu_debug_show(struct seq_file *m, void *p)
>  	seq_printf(m, "die_id:              %u\n", c->topo.die_id);
>  	seq_printf(m, "cu_id:               %u\n", c->topo.cu_id);
>  	seq_printf(m, "core_id:             %u\n", c->topo.core_id);
> +	seq_printf(m, "cpu_type:            %s\n", get_topology_cpu_type_name(c));
>  	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);
>  	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);
>  	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index d1de300af173..7b1011d0b369 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -907,3 +907,12 @@ u32 get_this_hybrid_cpu_native_id(void)
>  	return cpuid_eax(0x0000001a) &
>  	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
>  }
> +
> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	switch (c->topo.intel_type) {
> +	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
> +	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
> +	}
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}

The name of the function is a bit misleading, as it suggests that it
returns the Intel specific CPU type(ATOM/CORE), but it actually returns
the performance/efficiency generic types.

I would suggest to name the function based on what it returns, like:

get_generic_cpu_type(struct cpuinfo_x86 *c)
{
     enum x86_topology_cpu_type type;

	if (c->x86_vendor == X86_VENDOR_INTEL) {
	     switch (c->topo.intel_type) {
		     case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
		     case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
	}
	if (c->x86_vendor == X86_VENDOR_AMD) {
	     switch (c->topo.amd_type) {
		     case 0: return TOPO_CPU_TYPE_PERFORMANCE;
		     case 1: return TOPO_CPU_TYPE_EFFICIENCY;
	}

	return TOPO_CPU_TYPE_UNKNOWN;
}

get_intel_cpu_type(struct cpuinfo_x86 *c)
{
	return c->topo.intel_type;
}

get_amd_cpu_type(struct cpuinfo_x86 *c)
{
	return c->topo.amd_type;
}

Borislav Petkov Oct. 23, 2024, 3:59 p.m. UTC | #9

On Tue, Oct 22, 2024 at 09:40:15PM -0700, Pawan Gupta wrote:
> get_generic_cpu_type(struct cpuinfo_x86 *c)
> {
>      enum x86_topology_cpu_type type;
> 
> 	if (c->x86_vendor == X86_VENDOR_INTEL) {
> 	     switch (c->topo.intel_type) {
> 		     case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
> 		     case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
> 	}
> 	if (c->x86_vendor == X86_VENDOR_AMD) {
> 	     switch (c->topo.amd_type) {
> 		     case 0: return TOPO_CPU_TYPE_PERFORMANCE;
> 		     case 1: return TOPO_CPU_TYPE_EFFICIENCY;
> 	}
> 
> 	return TOPO_CPU_TYPE_UNKNOWN;
> }

Ok...

> get_intel_cpu_type(struct cpuinfo_x86 *c)
> {
> 	return c->topo.intel_type;
> }
> 
> get_amd_cpu_type(struct cpuinfo_x86 *c)
> {
> 	return c->topo.amd_type;

... except those silly wrappers can go. There's a reason cpuinfo_x86 has
well-defined members which can be used directly.

Patch

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 98eced5084ca7..28bb177241131 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -53,6 +53,8 @@  static inline void bus_lock_init(void) {}
 #ifdef CONFIG_CPU_SUP_INTEL
 u8 get_this_hybrid_cpu_type(void);
 u32 get_this_hybrid_cpu_native_id(void);
+u32 intel_native_model_id(struct cpuinfo_x86 *c);
+enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c);
 #else
 static inline u8 get_this_hybrid_cpu_type(void)
 {
@@ -63,6 +65,23 @@  static inline u32 get_this_hybrid_cpu_native_id(void)
 {
 	return 0;
 }
+
+static u32 intel_native_model_id(struct cpuinfo_x86 *c)
+{
+	return 0;
+}
+static enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+#endif
+#ifdef CONFIG_CPU_SUP_AMD
+enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c);
+#else
+static inline enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
 #endif
 #ifdef CONFIG_IA32_FEAT_CTL
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4a686f0e5dbf6..872e5a429d00d 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -105,6 +105,24 @@  struct cpuinfo_topology {
 	// Cache level topology IDs
 	u32			llc_id;
 	u32			l2c_id;
+
+	// Hardware defined CPU-type
+	union {
+		u32		cpu_type;
+		struct {
+			// CPUID.1A.EAX[23-0]
+			u32	intel_native_model_id:24;
+			// CPUID.1A.EAX[31-24]
+			u32	intel_type:8;
+		};
+		struct {
+			// CPUID 0x80000026.EBX
+			u32  amd_num_processors             :16,
+			     amd_power_efficiency_ranking   :8,
+			     amd_native_model_id            :4,
+			     amd_type                       :4;
+		};
+	};
 };
 
 struct cpuinfo_x86 {
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index aef70336d6247..5b344ff81219d 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -114,6 +114,12 @@  enum x86_topology_domains {
 	TOPO_MAX_DOMAIN,
 };
 
+enum x86_topology_cpu_type {
+	TOPO_CPU_TYPE_PERFORMANCE,
+	TOPO_CPU_TYPE_EFFICIENCY,
+	TOPO_CPU_TYPE_UNKNOWN,
+};
+
 struct x86_topology_system {
 	unsigned int	dom_shifts[TOPO_MAX_DOMAIN];
 	unsigned int	dom_size[TOPO_MAX_DOMAIN];
@@ -149,6 +155,8 @@  extern unsigned int __max_threads_per_core;
 extern unsigned int __num_threads_per_package;
 extern unsigned int __num_cores_per_package;
 
+enum x86_topology_cpu_type topology_cpu_type(struct cpuinfo_x86 *c);
+
 static inline unsigned int topology_max_packages(void)
 {
 	return __max_logical_packages;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fab5caec0b72e..779073e5a6468 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -29,6 +29,9 @@ 
 
 #include "cpu.h"
 
+#define TOPO_HW_CPU_TYPE_AMD_PERFORMANCE 0
+#define TOPO_HW_CPU_TYPE_AMD_EFFICIENCY  1
+
 static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
 {
 	u32 gprs[8] = { 0 };
@@ -1205,3 +1208,14 @@  void amd_check_microcode(void)
 	if (cpu_feature_enabled(X86_FEATURE_ZEN2))
 		on_each_cpu(zenbleed_check_cpu, NULL, 1);
 }
+
+enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.amd_type) {
+	case TOPO_HW_CPU_TYPE_AMD_PERFORMANCE:
+		return TOPO_CPU_TYPE_PERFORMANCE;
+	case TOPO_HW_CPU_TYPE_AMD_EFFICIENCY:
+		return TOPO_CPU_TYPE_EFFICIENCY;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/debugfs.c b/arch/x86/kernel/cpu/debugfs.c
index 3baf3e4358347..c3361e496df99 100644
--- a/arch/x86/kernel/cpu/debugfs.c
+++ b/arch/x86/kernel/cpu/debugfs.c
@@ -22,6 +22,7 @@  static int cpu_debug_show(struct seq_file *m, void *p)
 	seq_printf(m, "die_id:              %u\n", c->topo.die_id);
 	seq_printf(m, "cu_id:               %u\n", c->topo.cu_id);
 	seq_printf(m, "core_id:             %u\n", c->topo.core_id);
+	seq_printf(m, "cpu_type:            %u\n", topology_cpu_type(c));
 	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);
 	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);
 	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index d1de300af1737..8887b5ed1fbca 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -878,6 +878,8 @@  static const struct cpu_dev intel_cpu_dev = {
 cpu_dev_register(intel_cpu_dev);
 
 #define X86_HYBRID_CPU_TYPE_ID_SHIFT	24
+#define TOPO_HW_CPU_TYPE_INTEL_ATOM	0x20
+#define TOPO_HW_CPU_TYPE_INTEL_CORE	0x40
 
 /**
  * get_this_hybrid_cpu_type() - Get the type of this hybrid CPU
@@ -907,3 +909,19 @@  u32 get_this_hybrid_cpu_native_id(void)
 	return cpuid_eax(0x0000001a) &
 	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
 }
+
+u32 intel_native_model_id(struct cpuinfo_x86 *c)
+{
+	return c->topo.intel_native_model_id;
+}
+
+enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.intel_type) {
+	case TOPO_HW_CPU_TYPE_INTEL_ATOM:
+		return TOPO_CPU_TYPE_EFFICIENCY;
+	case TOPO_HW_CPU_TYPE_INTEL_CORE:
+		return TOPO_CPU_TYPE_PERFORMANCE;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index 7d476fa697ca5..03b3c9c3a45e2 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -182,6 +182,9 @@  static void parse_topology_amd(struct topo_scan *tscan)
 	if (cpu_feature_enabled(X86_FEATURE_TOPOEXT))
 		has_topoext = cpu_parse_topology_ext(tscan);
 
+	if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES))
+		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
+
 	if (!has_topoext && !parse_8000_0008(tscan))
 		return;
 
diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index 9a6069e7133c9..04b012dffa473 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -27,6 +27,16 @@  void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
 	}
 }
 
+enum x86_topology_cpu_type topology_cpu_type(struct cpuinfo_x86 *c)
+{
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		return intel_cpu_type(c);
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		return amd_cpu_type(c);
+
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+
 static unsigned int __maybe_unused parse_num_cores_legacy(struct cpuinfo_x86 *c)
 {
 	struct {
@@ -87,6 +97,7 @@  static void parse_topology(struct topo_scan *tscan, bool early)
 		.cu_id			= 0xff,
 		.llc_id			= BAD_APICID,
 		.l2c_id			= BAD_APICID,
+		.cpu_type		= TOPO_CPU_TYPE_UNKNOWN,
 	};
 	struct cpuinfo_x86 *c = tscan->c;
 	struct {
@@ -132,6 +143,8 @@  static void parse_topology(struct topo_scan *tscan, bool early)
 	case X86_VENDOR_INTEL:
 		if (!IS_ENABLED(CONFIG_CPU_SUP_INTEL) || !cpu_parse_topology_ext(tscan))
 			parse_legacy(tscan);
+		if (c->cpuid_level >= 0x1a)
+			c->topo.cpu_type = cpuid_eax(0x1a);
 		break;
 	case X86_VENDOR_HYGON:
 		if (IS_ENABLED(CONFIG_CPU_SUP_HYGON))